Audrey Toussaint
email: momecak@hotmail.fr

Témoignage d'une aide-soignante aux urgences de nuit

Keywords: alcool, nettoyage, violence, urgence Illus Toussaint.jpg

Travailler la nuit aux urgences permet de prendre en charge une population différente du jour, des personnes alcoolisées, plus fragiles. Des stratégies sont mises en place afin de prévenir la violence. Témoignage d'une aide-soignante qui a choisi ce mode d'exercice.

Les urgences, c'est un des rares lieux d'accueil 24/24 h, tout comme les sapeurs-pompiers ou les services de police. Cette situation en fait une unité de soins où le travail diffère d'un service de médecine ou de chirurgie. Le travail de nuit semble différent au travail de jour. Le travail de l'aide-soignante de nuit aux urgences est formalisé sur une fiche de poste. À notre arrivée, il y a tout d'abord les transmissions orales avec l'équipe descendante 1 . S'ensuit la vérification du matériel présent au déchocage, en collaboration avec l'infirmière (vérification des scopes, des pousse-seringues électriques, du matériel d'aspiration trachéale, des prises d'air et d'oxygène). Il va de soi que le rôle de l'aide-soignante en structure d'urgences s'affirme également à travers les toilettes de personnes infirmes ou en état d'incurie, les changes, la prévention des escarres, l'aide à la marche, à la mobilisation, l'aide à l'alimentation entérale, la participation à la surveillance, la prise de paramètres… La douleur est évaluée, en collaboration avec l'infirmière, d'après l'échelle la plus adaptée à l'état de santé du patient (échelle verbale simple, échelle visuelle analogique…). Son évaluation est renouvelée plusieurs fois au cours de la prise en charge. La nuit, c'est aussi la période qui a été choisie pour réaliser le ménage des locaux (hors sol), le rangement et la participation à la commande du matériel avec l'infirmière. Aux urgences, comme dans beaucoup d'autres unités, l'encadrement est moins présent la nuit, ce qui confère plus de responsabilités et d'autonomie aux équipes de soins (par exemple, appel du service brancardage lorsqu'il y a un manque de brancards aux urgences la nuit). En effet, la nuit, un cadre de santé est présent sur le site pour l'ensemble des services. T1 Prévention de la violence D'une façon générale, la population accueillie la nuit est sensiblement différente du jour. Nous sommes davantage confrontés aux personnes en état d'exogénose 2 , parfois en garde à vue et transportées par les forces de l'ordre (ivresse publique manifeste), à des blessés physiques en raison de rixes, à la misère sociale, notamment en période hivernale ou lorsque le Samu social est débordé. Ces situations peuvent entraîner une rapide montée de la violence qu'il faut contenir au plus vite. Le travail en équipe est primordial et la présence du service de sécurité incendie est rassurant. Ces derniers, ainsi que les brancardiers, peuvent être joints pour aider à gérer une situation violente et à la sécurité du personnel. Si nécessaire, les forces de l'ordre peuvent être contactées à l'aide d'un bouton poussoir spécifique aux demandes de renfort. Ces derniers interviennent alors en quelques minutes. Ce qui compte avant tout, c'est le dialogue. Bon nombre de situations conflictuelles sont désamorcées grâce à la communication. Ainsi, parfois de simples mots, des attentions, permettent de prévenir ou d'anticiper la violence. Cela se traduit en donnant régulièrement des informations aux familles, en n'hésitant pas à aller vers eux plutôt que d'attendre qu'ils viennent chercher l'information, ce qui contribue à diminuer leur anxiété. Pour le patient, soulager sa douleur et être à son écoute est incontournable. Une partie de l'équipe soignante des urgences a d'ailleurs bénéficié de la formation Omega 3 , ce qui nous aide à anticiper au mieux et à définir la conduite à tenir lors de situations de violence.

T1 Conclusion

Travailler la nuit, c'est aussi une lutte permanente contre le sommeil, un temps de travail à contre-courant de la population active en générale, un sommeil de moins bonne qualité, d'où une moins bonne récupération et de la fatigue. Mais le travail de nuit permet de découvrir une autre façon de travailler. Néanmoins, cet exercice, contraire au rythme physiologique, a des répercussions sur notre vie de tous les jours. Pour autant, travailler aux urgences est un réel plaisir pour moi car il n'y a pas de monotonie, ce sont tous les jours des pathologies et des patients nouveaux. De plus, le travail en 12 heures est intense mais permet d'atteindre rapidement le nombre d'heures hebdomadaires légales. Ceci me permet d'être plus présente pour ma vie de famille. Déclaration de liens d'intérêts : L'auteur déclare ne pas avoir de liens d'intérêts.

Notes

1 Équipe descendante : équipe qui quitte son poste. 2 État d'exogénose : état d'ébriété.

3 Omega : méthode canadienne de prévention et de gestion des situations violentes et agressives.

Dochead dossier Sous-dochead Le travail de nuit


Marion Blanchard

Cindy Chaillou

Catherine Allain

Stéphanie Castellani

Solène Jovelin

Nathalie Jousset

Sophie Mareni

Repérer les violences conjugales à l'hôpital

En effet, le dénigrement, les insultes, le contrôle permanent, l'isolement, la jalousie pathologique, le harcèlement, les actes d'intimidation, les humiliations, les menaces, le chantage au suicide sont autant d'éléments caractéristiques d'une maltraitance très subtile dont l'enjeu pour l'agresseur est d'établir un climat de tension, de mal-être, de peur, afin d'établir sa domination sur sa partenaire. La relation n'est pas égalitaire, la victime est sous emprise.

Violences psychologiques et physiques sont intimement liées : si certains auteurs de violences conjugales ne portent jamais de coups, la violence psychologique est systématiquement présente. Aussi, plus insidieuse, c'est elle qui perdure après un jugement ou après une séparation. Aussi, les violences conjugales se manifestent la plupart du temps de manière cyclique. Les victimes décrivent des phases "de lune de miel", une période d'accalmie plus ou moins courte, où leur bourreau justifie son comportement ou ses propos. Saisissant ce moment de pause, elles acceptent même de s'excuser et se remettent en question (« je n'ai pas un caractère facile vous savez ») et elles listent des circonstances atténuantes chez leur agresseur (« il n'a pas eu une enfance facile », « quand il n'a pas bu, ça se passe bien », « je dois l'aider à se soigner »).

TEG1 « C'est un peu de leur faute, pourquoi restent-elles avec leur conjoint violent

Enfin, le sentiment de culpabilité déjà très intense est exacerbé dans les situations de couples parentaux. Prendre la décision de quitter le domicile conjugal, les rendrait alors responsable de la séparation et donc d'une situation déstabilisante pour leurs enfants.

T1 Détecter

Plusieurs indices peuvent être relevés au cours des échanges avec les victimes de violences, auquel le professionnel sera attentif [1] :

• des éléments comportementaux tels que :

-une timidité importante lors d'un échange, peu de prise de parole, -si le conjoint est présent, la victime est effacée et demande son approbation, -une difficulté pour trouver ses mots, des pertes de mémoire, -une dépréciation systématique, une dévalorisation de sa personne, elle se dit incapable ou incompétente, -elle paraît détachée émotionnellement, -elle décrit des problèmes de santé récurrents ou/et plaintes somatiques régulières, -une importante pudeur, -elle sursaute devant des gestes brusques ou une porte qui claque par exemple (hypervigilance), -une vie émotionnelle donc marquée par un sentiment de honte, une culpabilité écrasante, une méfiance importante de la victime pour qui tout est insécurisant, une ambivalence (d'une part elle reconnaît souffrir de la violence imposée par son partenaire mais dit avoir des sentiments pour celui-ci), une perte de repère, une anxiété, une irritabilité, un émoussement des émotions, la banalisation de la situation, -des engagements non tenus (absentéisme au travail ou rendez-vous déplacés ou annulés) ;

• une situation personnelle caractérisée par :

-un isolement social et familial, -peu de loisir et d'activité personnelle, -une mauvaise santé, des problèmes psychosomatiques, -des blessures physiques, -une discordance entre ce qui est observé et les explications fournies par la personne, -une dépendance économique (les victimes parfois ne possèdent pas leurs propres moyens de paiement ni leurs papiers d'identité), -des conduites addictives et des tentatives de suicide.

Ces éléments sont des indices qui peuvent mettre le soignant en éveil lors de la prise en charge des patients, mais ce n'est pas parce qu'un de ces signes est présent qu'il s'agit forcément d'une situation de violence conjugale.

T1 Conclusion

Le professionnel de santé débarrassé des préjugés et connaissant les signes d'alerte est fondé à amorcer le dialogue sur les violences conjugales. La reconnaissance intime de la souffrance endurée est une première étape avant de pouvoir s'extraire d'une relation écrasante. Il s'agit d'un long parcours, semé d'embûches pour les victimes. Aussi, les acteurs du soin ont une place déterminante pour les aider dans ce cheminement. L'enjeu sera alors d'offrir une écoute pour favoriser la mise en mots de ce qui est ressenti, puis de leur proposer un accompagnement.

Les dispositifs sur le CHU d'Angers

Hormis son rôle sur réquisition judiciaire et lors des consultations ambulatoires, l'Unité médicojudicaire (UMJ) du CHU d'Angers (49) s'attache à former les différentes catégories socio professionnelles pouvant être amenées à prendre en charge les victimes de violences conjugales. Ses actions passent notamment par l'élaboration récente d'une formation agréée DPC (développement professionnel continu) où l'UMJ intervient sur les volets "Psychotraumatisme" et "Violences conjugales". Le service a élaboré une plaquette d'aide à la prise en charge des victimes de violences conjugales pour les professionnels de santé 1 . L'équipe pluridisciplinaire s'attache également à former régulièrement les étudiants (médecins, infirmières, aides-soignantes, carrière sociales…) et organise des actions ponctuelles en lien avec le réseau associatif du Maine-et-Loire (expositions, colloques, soirées d'informations…).

  des universités, praticien hospitalier, chef de service Sophie Mareni* Cadre de santé CHU d'Angers, Unité médico-judiciaire, 4, rue Larrey, 49100 Angers, France Tout professionnel de santé doit être à même de repérer les victimes de violences conjugales. Pour ce faire, il faut en premier lieu s'abstraire des préjugés vis-à-vis de ces personnes. Certains indices dans leurs discours et comportements peuvent mettre le soignant en éveil. ©2018 Mots clés -comportement ; isolement ; repérage ; vécu psychotraumatique ; violences Physiques, sexuelles, mais également psychologiques, les violences conjugales peuvent prendre différentes formes, qui s'entremêlent pour donner lieu à des situations complexes. Si chaque vécu est unique, on retrouve chez les victimes, l'existence d'un ensemble de manifestations comportementales et psychologiques communes qui témoignent d'un vécu psychotraumatique chronique. T1 Se défaire des préjugés pour mieux repérer TEG1 « Les violences conjugales touchent des catégories sociales défavorisées » : faux. Personne n'est à l'abri de ce type de violences. Elles existent dans toutes les catégories sociales, économiques et culturelles quel que soit le niveau éducatif ou le contexte religieux. Moins fréquemment, les hommes peuvent vivre des violences conjugales, elles seront davantage psychologiques. TEG1 « Il n'y a pas de coup physique, ce n'est pas vraiment de la violence conjugale » : faux. La loi du 9 juillet 2010 sur les violences faites spécifiquement aux femmes reconnaît avec l'article 222-33-2-1 l'existence des violences psychologiques et les punit de trois ans d'emprisonnement et de 45 000 euros d'amende. Ces violences correspondant à une série d'attitudes et de propos visant à déstabiliser et blesser l'autre dans sa façon d'être, sont extrêmement destructrices.

  ? » : faux. D'abord, ces violences s'installent progressivement au cours de la relation, la jalousie pathologique par exemple pourra être prise comme une preuve d'amour. Au fur et à mesure des reproches, des contrôles de leurs faits et gestes, les victimes ont tendance à perdre confiance en elle et à perdre tout esprit critique. L'isolement dans lequel elles sont plongées peu à peu renforce cette impossibilité à reconnaître ce vécu comme violent et anormal.L'emprise ainsi installée conditionne tous les actes et pensées de la victime qui perd toute capacité à penser, à être et à agir par elle-même. Tout se passe comme si elle intégrait les propos dénigrants de son conjoint à son égard, elle doute de son ressenti et de sa capacité à avoir de bonnes perceptions. Cette situation d'emprise explique les difficultés à réagir et à fuir une situation hostile.

  L'équipe travaille également à l'élaboration d'outils d'aide au dépistage. 1 Service de Médecine légale -CHU Angers. Violences conjugales : Aide à la prise en charge médicale à destination des médecins. 2013. http://stop-violencesfemmes.gouv.fr/IMG/pdf/Plaquette_CHU_Angers_1.pdf Déclaration de liens d'intérêts Les auteurs déclarent ne pas avoir de liens d'intérêts.


Sabaly Bocar

Massal Balde

Justin Fall

Fambaye Ngom Kantoussan

Malick Sow

Patrice Diouf

Brehmer

Bocar Sabaly Baldé

Massal Fall

Justin Kantoussan

Fambaye Ngom Sow

Malick Diouf

Patrice Brehmer

Fish-length based indicators for improved management of the sardinella fisheries in Senegal

Keywords: Data poor fisheries, Fisheries management, Shared stocks, Small scale fisheries, Small pelagic fish, West Africa

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

INTRODUCTION

For small-scale, data-poor fisheries where age data collection is often limited by lack of technical expertise and funds, length-frequency data is often the only form of information available for researchers and managers [START_REF] Baldé | Population dynamics and stock assessment of Ethmalosa fimbriata in Senegal call for fishing regulation measures[END_REF]. Length-frequency data, when available, can be used by researchers to inform management. Length is also an important index of the biomass (length-weight relationship), the biology (number of eggs produced according to the size of the body) and the trophic position of many fish species (e.g., [START_REF] Hixon | BOFFFFs: on the importance of conserving oldgrowth age structure in fishery populations[END_REF]. The length of the organisms is thus a determining parameter in the ecological processes of the species. Due to the rapid availability of length data for many stocks, a number of length-based methods have been developed and applied to estimate biological parameters and to understand the dynamics of fish populations [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF](Froese et al., , 2016;;[START_REF] Mildenberger | TropFishR: an R package for fisheries analysis with length-frequency data[END_REF]. Thus, it is possible to conduct simple size-based assessments of many stocks considered too poor in data to be evaluated [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF]. Several size-based techniques have been developed to estimate fish growth and mortality rates (e.g., [START_REF] Mcquinn | Estimation de la mortalité naturelle[END_REF][START_REF] Pauly | Some simple methods for the assessment of tropical fish stocks[END_REF]. Other length-based techniques using the population size structure to estimate stock status and assist managers have been implemented recently (e.g., [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF][START_REF] Hordyk | A novel length-based empirical estimation method of spawning potential ratio (SPR), and tests of its performance, for smallscale, data-poor fisheries[END_REF][START_REF] Thorson | Catch curve stock-reduction analysis: an alternative solution to the catch equations[END_REF].

For example, the length-based empirical estimation method of spawning potential ratio (LB-SPR) model implemented by [START_REF] Hordyk | A novel length-based empirical estimation method of spawning potential ratio (SPR), and tests of its performance, for smallscale, data-poor fisheries[END_REF], estimates the length selectivity and the F/M ratio, which are then used to calculate the Stock Reproductive Potential Ratio (SPR). The SPR is defined as the proportion of unexploited breeding potential, regardless of the level of fishing pressure retained [START_REF] Walters | Fisheries ecology and management[END_REF]. This equilibrium-based method, which assumes constant recruitment, cannot accommodate multimodal length composition, a situation known as the "Lee's phenomenon" [START_REF] Lee | An investigation into the methods of growth determination in fishes by means of scales[END_REF]. As a result, any estimate of F/M ratio, selectivity, and SPR may be unrealistic. To cope with this handicap, [START_REF] Hordyk | A simple length-structured model based on life history ratios and incorporating size-dependent selectivity: application to spawning potential ratios for data-poor stocks[END_REF] developed a new length structured model using the Growth-Type-Group approach (GTG). Indeed, this new model has the particularity, compared to LB-SPR, of using the life-time ratio M/K, as well as estimates of the size at first maturity (L50), the asymptotic length (L∞) and the length composition, to estimate the potential spawning ratio with size-dependent selectivity models [START_REF] Hordyk | A simple length-structured model based on life history ratios and incorporating size-dependent selectivity: application to spawning potential ratios for data-poor stocks[END_REF]. However, in the case where the selectivity is not agedependent, the results of the model may be strongly biased. Another model, Length-based Integrated Mixed Effects (LIME), is used to study age-structured population dynamics [START_REF] Rudd | Accounting for variable recruitment and fishing mortality in lengthbased stock assessments for data-limited fisheries[END_REF], while taking into account variable fishing mortality and recruitment over time, which makes it different from the two models mentioned above (LB-SPR and GTG). For the LIME model, the input parameters are data on the length composition of catches for a given year as well as information on the assumed life cycle, including the length-age relationship, an assumed natural mortality rate, and a length at 50% of maturity [START_REF] Rudd | Accounting for variable recruitment and fishing mortality in lengthbased stock assessments for data-limited fisheries[END_REF]. However this model works well only for fish with a short life span. The higher the age of the fish, the greater the uncertainty becomes. Indeed, the increasing length makes cohorts unclear with age, making it difficult to track recruitment events without a much longer time series of length data [START_REF] Rudd | Accounting for variable recruitment and fishing mortality in lengthbased stock assessments for data-limited fisheries[END_REF]. And like LB-SPR and GTG, LIME requires setting biological parameters and good knowledge of species biology to their true value for estimating unbiased reference points.

Thereby, a new model based solely on length frequencies called Length-based Bayesian biomass (LBB) seems to be an interesting option for estimating tropical and subtropical stocks poor in data [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF]. However, [START_REF] Hordyk | Comment on "A new approach for estimating stock status from length frequency data[END_REF] found that LBB model has some major problems such as the values of the M / K relationship that can change depending on the species exploited. As a result, a misinterpretation of values of this relationship can bias the results. [START_REF] Froese | On the pile-up effect and priors for Linf and M/K: response to a comment by Hordyk et al. on "A new approach for estimating stock status from length frequency data[END_REF] indicates that these parameters can be taken into account by LBB model users and modified according to the available information. According to [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF], this model is a length-based Bayesian estimator that further reduces data requirements for preliminary stock assessments. The LBB model assumes that most tropical and subtropical species reach maximum size at maximum age. This implies that somatic growth and natural mortality of adults are aligned so that they can be expressed in a constant ratio [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF]. In tropical areas such as West Africa where species growth is rapid (e.g., [START_REF] Ba | Resilience of Key Biological Parameters of the Senegalese Flat Sardinella to Overfishing and Climate Change[END_REF]Baldé et al., 2019) and mortality is growth dependent (Z/K) [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF], the LBB model appears to be more appropriate. This model was largely developed by [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF] and may be useful to provide management options for stocks with limited catch data. The LBB allows a simple analysis of size frequency data to obtain the length at first capture that would maximize catch and biomass for the given fishing effort, and provides an estimation of a proxy for the relative biomass capable of producing maximum sustainable yields. The model only requires length frequency data, length at first maturity (L50) and life cycle parameters as inputs. LBB model estimates percentage of mature individuals, relative natural mortality (M) and relative fishing mortality (F) as means over the age range represented in the length-frequency sample [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF].

This study demonstrates the applicability of the LBB model, for the first time in West Africa, on small-scale data-poor fisheries, and illustrates the results of the assessment. In this work we assess the stock status of two commercially important species, which account for 75% of total landings of small pelagic species in 2015 from Senegalese waters [START_REF] Thiao | Statistiques de la pêche maritime sénégalaise en 2015 : Pêche artisanale, Pêche thonière et Pêche chalutière[END_REF]. The approach applied is based on two sets of stock status indicators that are well suited to data-poor fisheries. Indeed, they require only data of length frequency representative of the Sardinella maderensis and Sardinella aurita fisheries over 11 years, collected in Senegalese waters, and other external life cycle parameters generally available in the literature. It is hoped that these results could help in assessing many stocks currently considered too data poor to be evaluated, especially in developing countries.

MATERIAL AND METHODS

Study area

The Senegalese coast is divided between the Northern and the Southern part (Petite Côte and Casamance). The Northern part (Figure 1) extends from Saint-Louis (16 ° 04 N) north to the tip of the Almadies (14 ° 36 N). It is characterized by the presence of strong swells, a succession of dunes and coastlines. This area is home to cold, salty waters as early as October and covering the entire continental shelf by January [START_REF] Faye | A model study of the seasonality of sea surface temperature and circulation in the Atlantic North-eastern Tropical Upwelling System[END_REF]. There is the presence of a large canyon in Kayar (15 ° 00 N). The Northern part concentrates very important fishing centers such as Saint-Louis and Kayar in relation with the present ecological conditions and a strong presence of the traditional fishing communities.

The Petite Côte (14 ° 36 N at 13 ° 36 N, Figure 1) has a great geomorphological and biodiversity richness: cords and sand arrows, cliffs, bays, lagoons and mangrove estuaries (Saloum estuary, lagoon-estuarine system of Somone [START_REF] Baldé | Population dynamics and stock assessment of Ethmalosa fimbriata in Senegal call for fishing regulation measures[END_REF]. This area is home of a seasonal upwelling cell that affects ambient temperature fluctuations in the area. Due to the topography of the continental shelf, the trade winds in the north induce a strong upwelling in winter (November to December) [START_REF] Ndoye | Dynamics of a "low-enrichment high-retention" upwelling center over the southern Senegal shelf[END_REF][START_REF] Ndoye | SST patterns and dynamics of the southern Senegal-Gambia upwelling center[END_REF]. Combined with sunlight, rich groundwater nutrients promote phytoplankton production [START_REF] Auger | What drives the spatial variability of primary productivity and matter fluxes in the North-West African upwelling system? A modelling approach and box analysis[END_REF]. This is at the base of the food chain in all oceanic upwelling ecosystems and serves as a food source for the upper trophic levels where small pelagic fish are distributed.

The Casamance (13 ° 04 N and 12 ° 20 N, Figure 1) is located between the borders of The Gambia and Guinea Bissau. The continental shelf reaches its maximum width, at nearly 54 miles and the rocky bottoms are located offshore, mainly on the edge of the plateau. Its estuary is in fact an estuary which runs for 250 km inside the continent [START_REF] Sakho | Évolution et fonctionnement hydro-sédimentaire de la lagune de la Somone, Petite Côte, Sénégal[END_REF]. It receives inputs of fresh water only during the rainy season which lasts only 5 months, from June to October. The climate is mainly characterized by the alternation of a hot wet season from around July to October and a cold dry season from around November to June. During the dry season, the many small streams that form the Casamance River are often dry. Declining rainfall in the Casamance River Basin and increased temperature have resulted in a runoff deficit and saline intrusion [START_REF] Thiam | Space-time-frequency analysis of rainfall, runoff and temperature in the Casamance River basin, southern Senegal, West Africa[END_REF].

Study species

In Senegal, two species of coastal pelagic fish appear to dominate the epipelagic fish biomass sequentially: S. maderensis and S. aurita [START_REF] Diankha | Contrasted optimal environmental windows for both sardinella species in Senegalese waters[END_REF][START_REF] Thiaw | Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa: the case of both Senegalese sardinella[END_REF]. S .maderensis is a species with tropical affinity tolerating temperature ranges from 20 to 23 ° C [START_REF] Marchal | Nanisme et sédentarité chez certaines espèces de[END_REF] and it is found from the southern Mediterranean to Angola [START_REF] Whitehead | An annotated and illustrated catalogue of the Herrings, Sardines, Pilchards, Sprats, Shads, Anchovies and Wolf-Herrings. Part 2, Engraulidae[END_REF]. According to [START_REF] Ben-Tuvia | Synopsis on the systematics and biology of Sardinella maderensis (Lowe)[END_REF], depending on the region, it can withstand temperatures ranging from 15 ° C to 25 ° C (in Algeria) and salinities ranging from 20 ‰ at the level of estuary of large rivers (Niger, Congo, Nile) to 40 ‰ in the eastern Mediterranean. It spawns throughout the year in Senegal. The first breeding season runs from April to October. A second breeding season, with continuous reproduction (more intense than during the first period), occurs from January to the end of February [START_REF] Ba | Resilience of Key Biological Parameters of the Senegalese Flat Sardinella to Overfishing and Climate Change[END_REF]. In Senegal, catches of S. maderensis increased significantly during the period from 1981 to 2003, reaching a peak of more than 100,000 tons per year, but subsequently declined to below 60,000 tons per year in 2010 (Figure 2). The species S. aurita, lives in the tropical and subtropical regions of the eastern Atlantic and is found in large concentrations along the West coast of Africa in three main areas [START_REF] Roy | Stratégies spatio-temporelles de la reproduction des clupéidés des zones d'upwelling d'Afrique de l'Ouest[END_REF]: between southern Morocco (Western Sahara) and Guinea (26 ° -10 ° N), between Côte d'Ivoire and Ghana (7 ° -5 ° N) and and further south between Gabon and southern Angola (0 ° -18 ° S) (Froese and Pauly, 2016). S. aurita is also present in the western Atlantic Ocean, from Cape Cod (United States) to Argentina, including the West Indies and the Gulf of Mexico [START_REF] Felder | Gulf of Mexico origin, waters, and biota: Biodiversity, College Station[END_REF]. It also lives in the Mediterranean Sea [START_REF] Boltachev | Faunistic revision of alien fish species in the Black Sea[END_REF]. In all regions, the species preferentially inhabits continental shelves where it prefers saline waters (between 34 ‰ and 36 ‰), and warm sea temperatures (between 17° C and 30 °C; [START_REF] Boëly | Biologie de deux espèces de sardinelles Sardinella aurita Valenciennes, 1847 et Sardinella maderensis Lowe, 1841 des côtes sénégalaises[END_REF]. The first reproductive period occurred from February to May off Senegal. A second reproductive period, with continuous spawning (more intense than during the first period), occurred from October to the end of December (Baldé et al., 2019).

Catches of S. aurita in Senegal showed an increase between 1966-1998 and 2005-2011 and a slight decrease between 1999-2004 (on average 100 086 tons of catches; Figure 2).

Biological data

Data on the growth of S. maderensis and S. aurita were obtained from fish landed from January 2004 to December 2014 in the seven main artisanal fishing ports along the Senegalese coast (Table 1; maderensis and S. aurita, respectively (see supplementary material). Total length (TL in cm) of fish was measured to the nearest cm, to calculate size-frequency distributions and to estimate growth parameters.

Environmental data

We used local environmental indices as the Coastal Upwelling Index (CUI) and coastal sea surface temperature (SST) for the period from 2004 to 2014 to analyse the effect of the environmental conditions on inter-annual variability of sardinella mean length in Senegalese waters. The methodology used to calculate CUI (m 3 s -1 m -1 ) and SST (°C) has been widely described by [START_REF] Baldé | Dynamique des petits poissons pélagiques (Sardinella aurita et Ethmalosa fimbriata) au Sénégal dans un contexte de changement climatique : diagnostic et synthèse bioécologiques[END_REF]. The SST data (averaged on a monthly basis) were obtained from advanced, very-highresolution radiometer (AVHRR) satellite images (5 km resolution) where upwelling-induced SST anomalies are generally maximal [START_REF] Thiaw | Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa: the case of both Senegalese sardinella[END_REF]. The CUI was deduced from wind speed data obtained from the U.S. NOAA Environmental Research Division website (ERD, Upwelling and Environmental Index Products, http://www.pfeg.noaa.gov; Upwelling and Environmental Index Products, last visited: 20/11/2017).

Simulation model

The simulation carried out in this work involves the empirical estimation of the stock status (Z/K, E) as well as catch control indicators (Lc, Lopt and Lc_opt; Table 2) in order to adjust the fishing effort to sustainable stock exploitation.

The von [START_REF] Von Bertalanffy | A quantitative theory of organic growth (inquiries on growth laws. II)[END_REF] growth parameters [coefficient of growth rate (K), asymptotic length (L∞), time "t" when the fish length is zero (t0)] of S. maderensis et S. aurita were estimated from monthly length-frequency data (2004-2014) using the 'TropFishR' (Tropical Fisheries Analysis with R) package [START_REF] Mildenberger | TropFishR: an R package for fisheries analysis with length-frequency data[END_REF]. Length-based Bayesian biomass (LBB) model of [START_REF] Froese | A new approach for estimating stock status from length frequency data[END_REF] included in 'TropFishR' package was also used in this study. Allometric parameters (a and b), length-at-maturity (L50) data and life cycle parameters for LBB model were obtained from [START_REF] Ba | Resilience of Key Biological Parameters of the Senegalese Flat Sardinella to Overfishing and Climate Change[END_REF].

Calculations were computed using in R software and MS-Excel, and alternatively used the following basic equations. The meanings of the variables used in the formulas have been added in Table 3.

All fork length (FL in cm) measurements were converted to total length (TL) according to the relationship [START_REF] Sylla | Senegalese Sardinella aurita from 1995 to 2011: review of size spectra, sex ratio, gonadal somatic and condition indexes from small scale main national landing sites[END_REF]):

= 1.08264 + 0.08066 Eq. 1 Where = -1.08264 /0.08066 Eq. 2

The weight growth equation is obtained by combining the linear growth equation and the length-

weight relationship: = 1 - Eq. 3
Where Wt is the body weight at age t, W∞ is the asymptotic body weight, K is the coefficient of growth rate, t0 is the time "t" when the fish length is zero and W∞=a*L∞ b with a and b are the parameters of the length-weight relationship. The parameters of the length-weight ratio used are derived from [START_REF] Ba | Resilience of Key Biological Parameters of the Senegalese Flat Sardinella to Overfishing and Climate Change[END_REF].

The corresponding age at maximum growth (tmax) rate is:

= ! " + # Eq. 4
The body weight, Wopt , where unexploited cohort biomass reaches a maximum is given by [START_REF] Holt | The evaluation of fisheries resources by the dynamic analysis of stocks, and notes on the time factors involved[END_REF] as:

$% = & ' ( ) * Eq. 5
The length, Lopt , corresponding to Wopt is given by [START_REF] Beverton | Patterns of reproductive strategy parameters in some marine teleost fishes[END_REF] as:

$% = " "' ( +
Eq. 6

The age at the peak of unexploited cohort biomass topt is given by:

$% = !, ) -( ( .
+ # Eq. 7

Starting fishing at Lc_opt results in a mean length of Lopt for the catch and the exploits part of the population (Froese et al., 2016):

/_$% = 1'"2 3 ⁄ 5'2 3 ⁄ "'3 ⁄
Eq. 8

The age tc_opt corresponding to Lc_opt is obtained by:

6_$% = !, 7 )+-( ( 7-+ .
+ # Eq. 9

Total mortality (Z) can be measured by:

8 = + 9
Eq. 10

The exploitation rate (E) was estimated using the formula:

: = 2 ;
Eq. 11

From the basic equations presented above, an index of yield per recruit expressed as a function of the length at first capture Lc is given by [START_REF] Beverton | Manual of methods for fish stock assessment: Part 2-tables of yield functions[END_REF] as:

<′ > ⁄ = 2 3 ⁄ 5'2 3 ⁄ 1 -/ ⁄ 3 ⁄ &1 - " 5 ? @ ? A ⁄ 5' B ( + B-C ( ⁄ ⁄ + " 5 ? @ ? A ⁄ 5' D ( + B-C ( ⁄ ⁄ - 5 ? @ ? A ⁄ ) 5' ) ( + B-C ( ⁄ ⁄ *
Eq. 12 Yield per recruit (Y/R) curves were calculated using the Beverton-Holt yield per recruit model [START_REF] Beverton | On the dynamics of exploited fish populations, Fishery Investigations[END_REF] :

< > ⁄ = E 3 F G H ∑ J K L MK+ N F MN 2'3'O " OP# Eq. 13
With tr is the mean age (years) at recruitment to the fishing area, tc is the mean age at first capture, Un is the summation parameter (U0=l, U1=-3, U2=3, U3=-1) and F is the fishing mortality coefficient.

Lastly biomass-per recruit (B/R) curves was calculated using the following equation derived by [START_REF] Beverton | On the dynamics of exploited fish populations, Fishery Investigations[END_REF]:

Q > ⁄ = E 3 F G H ∑ J K L MK+ N F MN ;'O " OP#
Eq. 14

We have calculated Y/R and B/R for a range of F-values, which produced a Y/R and B/R curve as a function of F [START_REF] Eskandari | Yield and Biomass-per-recruit Analysis of Tiger Tooth Croaker (Otolithes ruber) in the Northwest of the Persian Gulf[END_REF][START_REF] Pitcher | Beverton and Holt equations: spreadsheet functions and uncertainty[END_REF]. The yield isopleths diagram of S. maderensis and S. aurita was used to assess the impact on yield created by changes of exploitation rate E and the ratio of length at first capture to asymptotic length (Lc / L∞) in relation to changes in mesh size [START_REF] Ama-Abasi | The dynamics of the exploited population of Ethmalosa fimbriata (Bowdich, 1825, Clupeidae) in the Cross River Estuary and adjacent Gulf of Guinea[END_REF][START_REF] Pauly | Some practical extensions to Beverton and Holt's relative yield-perrecruit model[END_REF].

Statistical analysis

Statistical analyses were performed using the "stats", "Hmisc" R packages [START_REF] Harrell | with contributions from Charles Dupont and many others: Hmisc: Harrell Miscellaneous[END_REF][START_REF] Mcdonald | Handbook of biological statistics[END_REF] in RStudio 1.1.463 [START_REF] Team | RStudio: integrated development for R[END_REF], with a significance level of α < 0.05. Annual mean length of both sardinella were analysed using a one-way analysis of variance (ANOVA), followed by a post-hoc Kruskal-Wallis test [START_REF] Sokal | [END_REF]. The Pearson test was used to study the correlation between the annual mean length of each sardinella with the mean annual of each environmental parameter, SST and CUI [START_REF] Zar | Biostatistical Analysis: Pearson New International Edition[END_REF].

RESULTS

Annual variability of mean length of both sardinella related to environmental parameters

The mean annual length of both species of sardinella remained fairly stable over the 11-years of the study period (Anova; F-value = 39.04, df = 1, p-value < 0.05 for S. maderensis and F-value = 5.873, df = 1, p-value < 0.05 for S. aurita) (Figure 3). The annual variation of the mean length during the study period showed two peaks of mean length for S. maderensis, one in 2007 (TL mean: 27 cm) and the other in 2014 (TL mean: 29 cm) whereas for S. aurita peaks are observed in 2008 (TL mean: 31cm) and 2010 (TL mean: 31 cm) (Figure 3). The mean annual length in 2014 was significantly higher than the other years of the study period (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) for S. maderensis (Kruskal-Wallis test, X² = 30178, df = 10, p value <0.001). While for S. aurita, the mean annual length in 2008 was higher than the other years of the study period (Kruskal-Wallis test, X² = 33275, df = 10, p value <0.001). Over the period 2004-2014, the SST and CUI varied inter-annually. Mean SST increased in 2005, 2008 and 2010, but decreased in 2009 (Figure 3). CUI showed a quick and considerable increase in 2004 and 2009 (Figure 3). No correlation was found between the annual mean length of each species and environmental parameters (Table 2).

Fishing mortality and exploitation rate for both sardinella

The mortality estimated (on samples 2004-2014) was Z = 2.3 and 2.4 with F = 1.8 and 1.7 and M = 0.5 and 0.7 for S. maderensis and S. aurita, respectively (Table 3). The F/M ratio was higher for S. aurita (3.6) than for S. maderensis (2.4). Using a LBB model, Z/K was estimated to be 2.2 and 2.3 for S. maderensis and S. aurita, respectively (Figure 4). For S. maderensis and S. aurita, the current rates of exploitation (E) in Senegal waters were 0.8 and 0.7, respectively. The yield contour predicts the response of the yield-per-recruit to changes in Lc and rate of exploitation E; Lc / L∞ = 0.7 and 0.8 for S. maderensis and S aurita, respectively.

Length-based indicators of fishing sustainability for both sardinella

The von Bertalanffy equations fit well with the observed data (R² ≥ 0.90 in all cases except in 2004 and R² = 0.70 for S. maderensis and S. aurita, respectively). Asymptotic length (L∞) for the entire period was 37.5 cm (TL) for both sardinella while Lc was 24.5 and 27.5 cm (TL) for S. maderensis and S. aurita, respectively (Figure 4). Our growth studies, indicate that growth of S. aurita and S. maderensis (K = 1.01 and 1.02, respectively) in Senegal is fast. The likelihood ratio test indicated that there was no difference between the K and L∞ values of both sardinella species, which implies that they follow the same pattern of growth. When L50 were 20.3 cm for both sardinella species, 95 and 92% mature individuals are observed for the entire study period for S. maderensis and S. aurita, respectively.

The biomasses of unexploited cohorts of S. maderensis and S. aurita were highest (Lopt) at 26 and 29 cm (TL) at an age of 1.9 and 1.3 years (topt), respectively (Table 3). Optimal lengths at first capture (Lc_opt) were 25 and 28 cm (TL) for S. maderensis and S. aurita respectively (Table 3). The index of yield per recruit (Y'/R) was estimated to be 0.2 for both sardinella (Table 3).

Changes of Y/R and B/R for S. maderensis and S. aurita according to various values of F and tc are given in Figure 5. For S. maderensis, when M = 0.5, Y/R (564 kg; Figure 5a) and B/R (2,862 kg; Figure 5b) reach its maximum when tc = 2.5 year -1 . While S. aurita, Y/R reached its maximum value (426 kg) after two to three years (tc) when M was 0.7 (Figure 5a) and B/R decreased rapidly as F increased.

Maximum B/R occurred at tc < 2.5 years -1 (1,387 kg; Figure 5b) for S. aurita.

DISCUSSION

The data for this work have significant disadvantages to consider. Senegalese sardinella cannot be isolated from sardinella caught in neighboring countries and any exploitation outside Senegal's maritime borders has a significant impact on production in Senegalese waters. Interpretation of the growth of both sardinella will depend on the season in which the samples are obtained and seasonal differences in growth have been reported [START_REF] Thiaw | Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa: the case of both Senegalese sardinella[END_REF]. In migratory species such as sardinella, the input data in growth studies can often be biased, i.e., some elements may be missing because the whole cohort may not be present in the area where the samples are taken. As a result, management guidelines and controls must be simple, but also robust protecting against uncertainties, as well as being proportionate to the information available (Pilling et al. 2009).

Growth variability of both sardinella

As fish growth is variable, a same species may have different growth patterns according to its environment (e.g., Baldé et al., 2019). Indeed, during the study period (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014), interannual variability was detected between the length distributions of both sardinella in Senegalese waters. These difference may be partly determined by the temporal difference (during the spawning period) when larvae hatch (Tiedemann and Brehmer, 2017), food availability [START_REF] Thiaw | Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa: the case of both Senegalese sardinella[END_REF] and environmental conditions [START_REF] Diankha | Contrasted optimal environmental windows for both sardinella species in Senegalese waters[END_REF]. Our results showed that the annual mean length of the two species of sardinella followed the CUI pattern (Figure 3). In the study area, primary production is, to a large extent, determined by upwelling processes [START_REF] Auger | What drives the spatial variability of primary productivity and matter fluxes in the North-West African upwelling system? A modelling approach and box analysis[END_REF] during the winter period (dry season), which can have a major effect on juvenile growth. During their migration, adults are subject to variable environmental conditions, which affect their growth and spawning potential (Tiedemann et al., 2017). The coincidence of the annual mean length peaks of the two round sardinellas with the lowest temperatures (Figure 3), could suggest that temperature is also an important factor in the control of sardinella growth in the study area. Another clupeid species the Pacific herring (Clupea harengus pallasi), had optimal juvenile growth with SST between 12 ° and 13 ° C [START_REF] Haist | Growth and maturation of Pacific herring (Clupea harengus pallasi) in the Strait of Georgia[END_REF]. Another cause of variability in sardinella growth rate could be the effect of abundance of cohort size [START_REF] Thiaw | Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa: the case of both Senegalese sardinella[END_REF] and recruitment. [START_REF] Diankha | Contrasted optimal environmental windows for both sardinella species in Senegalese waters[END_REF] showed that the key environmental variables influencing the recruitment success are different for both studied species: the Coastal Upwelling Index and the SST for S. aurita and S. maderensis, respectively. Thus, we assume that the environmental variability can also have a significant impact on both sardinella species growth variability.

Diagnosis of sardinella fisheries

The level of exploitation could be due to the increasing demand for sardinella for human consumption (e.g., fresh, processed by hand and more recently in fishmeal), the increasing fishing effort of the Mauritanian-Senegalese artisanal fleets and the European Union [START_REF] Baldé | Dynamique des petits poissons pélagiques (Sardinella aurita et Ethmalosa fimbriata) au Sénégal dans un contexte de changement climatique : diagnostic et synthèse bioécologiques[END_REF][START_REF] Stilwell | Sustainable development and the governance of fisheries frequented by heterogeneous user groups: a political economy perspective on the case of European Union participation in the Senegalese marine fishery[END_REF]. For example, in Mauritania, the increase in fishing effort is linked to the expansion of the fish flour industry in Nouadhibou and Nouakchott [START_REF] Fao | Report of the FAO working group on the assessment of small pelagic fish off Northwest Africa Casablanca, Morocco, 20-25[END_REF]. Indeed, landings of S. aurita to flour mills increased from 30% in 2012 to 45% in 2013 and to 62% in 2014 [START_REF] Fao | Report of the FAO working group on the assessment of small pelagic fish off Northwest Africa Casablanca, Morocco, 20-25[END_REF]. The number of flour companies in operation has increased from 18 factories in 2012 to 22 in 2013 [START_REF] Fao | Report of the FAO working group on the assessment of small pelagic fish off Northwest Africa Casablanca, Morocco, 20-25[END_REF]. The same scenario is noted in Senegal where production in Saint-Louis and along the Petite Côte (Mbour and Joal) is still stimulated by the existence of the sub-regional market and the establishment of fishmeal production plants [START_REF] Fao | Report of the FAO working group on the assessment of small pelagic fish off Northwest Africa Casablanca, Morocco, 20-25[END_REF]. It is also worth reporting that catches off the Sahara bank have increased. Indeed, with climate change, there is an increased presence of S. aurita towards Cape Blanc in Morocco [START_REF] Sarré | Approche acoustique de la dynamique et la distribution spatiale des ressources halieutiques de petits pélagiques dans l'upwelling sénégalo-mauritanien[END_REF]. Thus, more sardinella were caught in Morocco between 2005 and 2014 [START_REF] Sarré | Approche acoustique de la dynamique et la distribution spatiale des ressources halieutiques de petits pélagiques dans l'upwelling sénégalo-mauritanien[END_REF]. This can explain the significant decrease in S. aurita abundance in Senegal during this period [START_REF] Thiaw | Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa: the case of both Senegalese sardinella[END_REF], accented by a lack of sub-regional collaboration in their fisheries management [START_REF] Nguyen | Competition or cooperation in transboundary fish stocks management: Insight from a dynamical model[END_REF]. Indeed, the decline in industrial catches has been partially offset by an increase in landings by the fishing fleets of coastal states with a predominantly artisanal role (see [START_REF] Thiaw | Effect of environmental conditions on the seasonal and inter-annual variability of small pelagic fish abundance off North-West Africa: the case of both Senegalese sardinella[END_REF]. This is also reflected in the decrease in fishing effort between 2004 and 2014 in Senegalese waters (Figure 6) on both species.

The F/M ratio is high for S. maderensis (F/M = 3.6) and S. aurita (F/M = 2.4). This comes from the change of fishing techniques and the motorization of the Senegalese canoes in recent years. In fact, the Senegalese canoe fleets are by far the most important in the West African region (including Nigeria and Ghana). In 2005, the number of fishing units was estimated to 13, 900 while the last census in 2015 reported 18,284 fishing units, including more than 90% motorized canoes [START_REF] Sow | Appui à la mise en place des plans de gestion des petits pélagiques au Sénégal (Rapport No. 1)[END_REF]. The dynamism of the artisanal fisheries resides in its capacity to adapt permanently to the changes of the context of the activity. This adaptive capacity depends on the qualitative and quantitative of the resource availability, economic context with reference to the possibilities of flow of the products and the levels of market remuneration [START_REF] Binet | Migration of Senegalese fishers: a case for regional approach to management[END_REF]. The strong reactivity of the Senegalese artisanal fishermen is linked, among others, to their good knowledge of the behavior of the resources but also their great organizational capacities to deal with changing institutional environment and appropriation of new techniques to exploit new resources [START_REF] Binet | Migration of Senegalese fishers: a case for regional approach to management[END_REF]. Given the level of exploitation of these species and the development and modernization of small-scale fisheries, indicators based on lengthfrequencies should help sustainable management at a critical time for these fisheries.

Indicators for sustainable management

One of the objectives of fisheries management is to minimize the impact of fishing on the size and age structure of exploited populations (Froese et al., 2016). Indeed, fishing with no size limit further reduces biomass, especially if higher values of M and hence of F are applied to pre-recruits [START_REF] Froese | Size still matters. A response to Svedäng (2013): Size matters: Ne quid nimis[END_REF]. In Senegal, according to the 2015 Fishing code, the mesh size allowed for sardinella fisheries is restricted between 40 and 60 mm that represents a fish size TL ≥ 18.0 cm. Nevertheless, the average sizes of individuals caught in both sardinella species are smaller than the L50 of 20.3 cm (TL) [START_REF] Ba | Resilience of Key Biological Parameters of the Senegalese Flat Sardinella to Overfishing and Climate Change[END_REF]. In the long-term, this fact could prevent the sustainability of sardinella stocks because it does not allow them to renew properly. Indeed, sardinella species show patterns of spatial and temporal distribution by size group [START_REF] Ba | Resilience of Key Biological Parameters of the Senegalese Flat Sardinella to Overfishing and Climate Change[END_REF]Baldé et al., 2019). Indicators based on length-frequencies can be used to establish management measures for fisheries [START_REF] Froese | Keep it simple: three indicators to deal with overfishing[END_REF]Froese et al., 2016). The Lc found in our study is higher than the Lc indicated by the Senegalese fishing code (TL ≥ 18.0 cm) and also the L50 (20.3 cm) for both sardinella species found by [START_REF] Ba | Resilience of Key Biological Parameters of the Senegalese Flat Sardinella to Overfishing and Climate Change[END_REF].

Fishing at Lc (24.5 and 27.5 cm for S. maderensis and S. aurita, respectively) would allow all fish to reproduce at least once before being caught. This will result in rebuilding and maintaining reproductive stocks in good health. However, such a tactic is only possible if the recruitment is successful each year. According to [START_REF] Diankha | Contrasted optimal environmental windows for both sardinella species in Senegalese waters[END_REF], the recruitment of S. maderensis and S.

aurita in Senegal is subject to variation depending on the sea surface temperature and the coastal upwelling index, respectively. As a result, the environment will have to be taken into account in this sustainable fishery hypothesis. The second indicator Lopt (26 and 29 cm for S. maderensis and S.

aurita, respectively) is the length where maximum yield can be obtained. This focus on large specimens is based on the growing evidence that older fish play several important roles in the longterm survival of a population (e.g., egg production; Baldé et al., 2019). This size (Lopt) is greater than

Lc found in our study, therefore greater than Lc indicated by the Senegalese fishing code and the L50 of both sardinella. However, the realities of Senegalese fisheries must be taken into account. In fact, to cope with the scarcity of resources, Senegalese fishermen are increasingly using more selective techniques such as monofilament fishing lines and purse seines [START_REF] Chauveau | Les pêches piroguières en Afrique de l'Ouest: dynamiques institutionnelles-pouvoirs, mobilités, marchés[END_REF][START_REF] Thiao | Focusing on monofilament nets while overlooking the priorities of artisanal fisheries governance in Senegal[END_REF]. Indeed, fisheries managers have not been able to effectively implement the law on the Lc indicated by the Senegal's fisheries code. Most of the sardinella individuals landed in recent year are small [START_REF] Sow | Appui à la mise en place des plans de gestion des petits pélagiques au Sénégal (Rapport No. 1)[END_REF], while the last indicator Lc_opt (25 and 28 cm for S. maderensis and S. aurita, respectively) would help implement a fishing strategy that does not catch any mega-parent [START_REF] Froese | Keep it simple: three indicators to deal with overfishing[END_REF]. According to Froese et al. (2016), to obtain a maximum yield for a given F, the Lc can be increased to allow a longer non-exploited growth phase, until the exploitable biomass and therefore the catch per unit of effort (CPUE) reach a maximum. Therefore, any catch at Lc_opt, close to Lc and therefore greater than the L50 of both sardinella (TL; 20 cm), could make it possible to better reach sustainability. However, the current governance framework of the sardinella fisheries does not allow for the definition and implementation of appropriate conservation and management measures for these shared stocks (sardinella species) because the existing regional body, like the Sub-Regional Fisheries Commission (SRFC), has only advisory mandates. The SRFC is not, yet, a Regional fisheries management organizations (RFMO). This situation is unfortunate because it does not comply with the provisions of the United Nations Convention on the Law of the Sea, which obliges States to consult each other and to endeavor to reach agreement in order to keep exploited populations within viable biological limits.

CONCLUSION

The

Figure 1 )

 1 Figure 1). Three landing sites (Kayar, Saint-Louis and Yoff) are located in the Northern part. The other landing sites (Hann, Mbour, Joal and Kafountine) are located along the Southern part (Petite Côte and Casamance). Length data were collected at random approximately 5 days per week. This study used only specimens captured with purse seiners in order to have the same selectivity for fishing gear in monthly statistics to allow the comparisons of size distribution. A total of 143,984 and 193,283 fish samples were recorded along the Senegalese coast during the surveys (2004-2014) for S.

Figures captions FIGURE 1 :

 captions1 Figures captions

FIGURE 2 :

 2 FIGURE 2: Landing of sardinella species [Sardinella aurita (grey fill), S. maderensis (black fill) of the artisanal fishery of Senegal (1981 to 2011). Data obtained from the Centre de Recherches Océanographiques de Dakar-Thiaroye (CRODT; Senegal).

FIGURE 3 :

 3 FIGURE 3: Annual mean of both Sardinella lengths [Sardinella maderensis (black solid line, n = 143 562) and Sardinella aurita (black dashed line, n = 193 283)] combined to Coastal Upwelling Index (CUI; grey solid line) and Sea Surface temperature (SST; grey dashed line) over the Senegalese continental shelf (data: 2004 to 2014).

FIGURE 4 :

 4 FIGURE 4: The accumulated length data used to estimate priors Length at first capture (Lc), asymptotic length (Linf), and Z/K for Sardinella maderensis (a) and Sardinella aurita (b). The blue lineshows the exploited part of the population, meaning the population that is susceptible to the fishing gear. Lc: the length-at first capture i.e. the length at which 50% of the individuals are retained by the fishing net. Linf: the maximum length of the fish species according to your data. (Linf is actually the asymptotic length, but here approximated by the maximum observed length).

FIGURE 5 :

 5 FIGURE 5: Isopleth diagrams of yield and biomass-per-recruit for Sardinella maderensis (a) and Sardinella aurita (b) in Senegal (data: 2004-2014).

FIGURE 6 :

 6 FIGURE 6: Number of fishermen trips using the purse seines canoe for Sardinella maderensis (curve with cross) and Sardinella aurita (curve with circle) between 2004 and 2014 in Senegal over the main landing sites.

  FIGURE 1:

  FIGURE 6:

Table 1 :

 1 Length-based Bayesian biomass (LBB) model provided a widely applicable and cost-effective starting point for use in establishing indicators for sustainable management of data-poor fisheries on tropical small pelagics. Its common use at least in West Africa will allow comparative analysis and thus provide better information to fisheries managers. Thus, to rebuild sardinella fisheries in Senegal, fisheries management should include: a revision of Senegal's fishing code, which should set a length at first capture ≥ 18 cm, is recommended by adopting Lc even if Lc_opt should be a better option. Indeed, captured individuals at Lc_opt (25 and 28 cm for S. maderensis and S. aurita, respectively) should be a natural safeguard against any failure of recruitment and to enable individuals to ensure the long-term survival of populations, in a context of data poor fisheries. Size distribution (Total length) of Sardinella maderensis(n= 143,621) and Sardinella aurita 601 (n= 193,357) specimens collected in Senegalese waters from 2004 to February 2014. ML: Midpoint 602 Length (cm) 603

	Sardinella maderensis

TABLE 1 :

 1 Number of individuals captured per port of landing during the study period(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) in Senegalese waters.

	Port	Sardinella maderensis	Sardinella aurita
	Hann	21187	22280
	Joal	14896	11638
	Kafountine	2201	342
	Kayar	30735	70618
	Mbour	10064	7318
	Saint Louis	62452	72863
	Yoff	2449	8224
	Total	143984	193283

ACKNOWLEDGEMENTS

Data analysis was done inside the AWA project funded by IRD and the BMBF (grant 01DG12073E, 01DG12073B), www.awa.ird.fr (SRFC: Sub Regional Fisheries Commission), the Preface project funded by the European Commission's Seventh Framework Program (2007Program ( -2013) ) under Grant Agreement number 603521, https://preface.b.uib.no/ and the DAAD program under Grant Agreement number 57314022. The data for this study were collected through the CRODT (Senegal) fisheries information system from 2004-2014. We are thankful to all CRODT technicians for their professionalism during the data collection on the field all the year around. We also thank the editor Gunnar Lauenstein and three anonymous reviewers for their useful comments on this manuscript.

Author contributions

Conceptualization: BSB JK.

COMPETING INTERESTS 431

The authors have declared that no competing interests exist. 432

Supplementary material


MD Charles Sabbagh

Loréna Masseline

MSc Gérard Grelpois

MD Alexandre Ntouba

M.D Jeanne Dembinski

Jean-Marc Regimbeau
email: regimbeau.jean-marc@chu-amiens.fr

MD, PhD Jean-Marc Regimbeau

Professor J.-M Regimbeau

Management of Uncomplicated Acute Appendicitis as Day Case Surgery: Can Outcomes of a Prospective Study Be Reproduced in Real Life?

INTRODUCTION

Acute appendicitis (AA) is still currently one of the most common digestive emergencies and appendectomy remains the reference treatment for AA [START_REF] Wilms | Appendectomy versus antibiotic treatment for acute appendicitis[END_REF][START_REF] Vons | Amoxicillin plus clavulanic acid versus appendicectomy for treatment of acute uncomplicated appendicitis: an open-label, non-inferiority, randomised controlled trial[END_REF]. Uncomplicated AA (UCAA) is a disease of young people in good general condition treated by appendicectomy, mostly performed by laparoscopy, with a short hospital stay and few postoperative complications. UCAA may therefore be a good indication for day case surgery (DCS). The feasibility of a length of stay (LOS) less 24 hours has been evaluated in several previous studies [START_REF] Sabbagh | The feasibility of short-stay laparoscopic appendectomy for acute appendicitis: a prospective cohort study[END_REF][START_REF] Gilliam | Day case emergency laparoscopic appendectomy[END_REF][START_REF] Cash | A prospective treatment protocol for outpatient laparoscopic appendectomy for acute appendicitis[END_REF][START_REF] Frazee | Outpatient laparoscopic appendectomy should be the standard of care for uncomplicated appendicitis. The journal of trauma and acute care surgery[END_REF] and a review of the literature [START_REF] Cosse | Day case appendectomy in adults: a review[END_REF] and DCS, which corresponds to an LOS less than 12 hours without overnight hospitalization, has also been recently validated [START_REF] Cash | A prospective treatment protocol for outpatient laparoscopic appendectomy for acute appendicitis[END_REF][START_REF] Jain | Outpatient laparoscopic appendectomy[END_REF][START_REF] Dubois | Impact of an outpatient appendectomy protocol on clinical outcomes and cost: a case-control study[END_REF][START_REF] Lefrancois | Management of Acute Appendicitis in Ambulatory Surgery: Is It Possible? How to Select Patients?[END_REF][START_REF] Grelpois | Management of Uncomplicated Acute Appendicitis as Day Case Surgery: Feasibility and a Critical Analysis of Exclusion Criteria and Treatment Failure[END_REF]. The AppendAmbu trial (NCT01839435) was the only study on DCS (together with the study by Lefrancois et al. [START_REF] Lefrancois | Management of Acute Appendicitis in Ambulatory Surgery: Is It Possible? How to Select Patients?[END_REF]) based on a prospective cohort, with intention-to-treat (ITT) analysis. This methodology is the best available to evaluate the feasibility of DCS, but might induce a bias, as the protocol could artificially increase the DCS rate and may not accurately reflect the situation in clinical practice.

The aim of this non-interventional study was to evaluate the real-life feasibility of DCS for UCAA.

PATIENTS AND METHODS

Study design

This study (AppendAmbu II) was a single-center, retrospective, non-interventional study performed over a period following the single-center, prospective, descriptive, nonrandomized, cohort, and intention-to-treat (ITT) study (AppendAmbu study, NCT01839435).

Inclusion and exclusion criteria

The inclusion and exclusion criteria were the same as those of the AppendAmbu study [START_REF] Grelpois | Management of Uncomplicated Acute Appendicitis as Day Case Surgery: Feasibility and a Critical Analysis of Exclusion Criteria and Treatment Failure[END_REF].

• Preoperative inclusion criteria:

-Related to AA: UCAA diagnosed on the basis of clinical, laboratory, and imaging criteria (CT scan or ultrasound).

-Related to DCS: American Society Anesthesiology (ASA) score less than three, patient with sufficient understanding and good compliance with the DCS procedure, availability of another person to spend the night at the patient's home in the event of an emergency, living less than one hour from a hospital and able to be contacted.

• Preoperative exclusion criteria:

-Related to AA: complicated AA (CAA) on the base of clinical features (sepsis), laboratory signs (renal failure) or radiological signs (abscess, localized or generalized peritonitis, fecaliths, pneumoperitoneum on CT scan or ultrasound).

-Related to DCS: patient's refusal of DCS, contraindication to DCS (pain refractory to usual painkillers, another person not available to spend the night at the patient's home in the event of an emergency, living more than one hour from a hospital and unable to be contacted).

-Related to this specific study: diagnosis of UCAA between 12 P.M and 7 A.M, attending the emergency department over the weekend.

• Intraoperative exclusion criteria:

-Related to AA: the presence a CAA (abscess, localized or generalized peritonitis, fecaliths).

-Related to the diagnosis: intraoperative finding of an alternative diagnosis.

-Related to surgery: associated surgical procedure (colectomy, cecectomy or adnexectomy).

Preoperative management

All physicians in the emergency, radiology, anesthesiology and surgery departments were aware of the DCS management of UCAA, as all were involved in the AppendAmbu trial.

The diagnosis of uncomplicated or complicated AA (UCAA or CAA) was established by the digestive surgeon in the emergency department. The diagnosis was based on clinical, laboratory and radiological data. CT scan and ultrasound were performed and examined by a radiologist. The decision to propose DCS and include the patient in the study was taken and validated on admission by the digestive surgeon and the anesthesiologist. After being selected for DCS management of UCAA, patients received detailed information about the protocol, the DCS program, and the on-call surgeon's telephone number. All patients received a single dose of analgesic (Ixprim ® ) and antibiotic (amoxicillin and clavulanic acid 1000 mg or ofloxacin 200 mg + metronidazole 500 mg (when the patient was allergic to penicillin)). Patients took their treatment in the presence of the investigator. Three management plans were defined according to the time of patient's diagnosis (Figure 1). If the patient was admitted between 12 P.M and 7 A.M, DCS was not proposed because the DCS department was not available. If the patient was admitted between 7 A.M and 12 A.M, DCS was proposed; the patient was admitted to the DCS department, and was operated in the morning and discharged in the afternoon. If the patient was admitted between 12 A.M and 12 P.M, the patient was discharged home and asked to return to the DCS department the next morning, to be operated and discharged in the afternoon.

Anaesthesia protocol

No premedication was administered prior to anaesthesia. In the operating room, patients were pretreated with an inspired oxygen fraction of 1 for 5 min. General anaesthesia was induced with propofol (2.5 mg/kg), sufentanil (0.5 µg/kg) and rocuronium (0.6 mg/kg) to facilitate tracheal intubation. An intravenous dose of 2g of cefazolin was administered at induction. Anaesthesia was maintained with 4-6% desflurane and 0.1-0.25 µg kg -1 min -1 remifentanil.

Mechanical ventilation was adjusted to maintain arterial oxygen saturation above 95% and CO2 between 30 and 35 mmHg with an inhaled oxygen concentration of 50%. Neuromuscular blockade was reversed in every case with neostigmine bromide 40µg/kg and atropine 1 mg or sugammadex 2-4 mg/kg when the train-of-four ratio was greater than 2. Postoperative analgesia was ensured by a combination of nefopam 20mg, tramadol 100 mg and acetaminophen 1 g. Patients received an IV injection of dexamethasone 8 mg and droperidol 0.625 mg on induction of anaesthesia and ondansetron 4 mg postoperatively to prevent postoperative nausea and vomiting. A TAPP block and incision infiltration were not systematically performed. When a nasogastric tube was placed during surgery, it was always removed in the operating room at the end of surgery. Urinary tube and abdominal drain were never used. The patient was asked to urinate before the intervention.

Operative management

Regardless of the type of appendicitis (UCAA or CAA), patients were ask to urinate before anesthesia to avoid the need for a bladder catheter. Appendectomies were performed laparoscopically using the three-port technique (one at the umbilicus, one in the left inferior quadrant and one in the suprapubic position). All of abdominal cavity was explored to determine whether or not AA was complicated. Whenever possible, a pus sample was taken intraoperatively for bacteriological examination and further antibiotic therapy in the presence of postoperative infectious complications. Appendicectomy was performed with coagulation of the meso-appendix and section of the appendix at its root using an Endoloop®. The surgical specimen was removed in a bag and abdominal drains and nasogastric tubes were not used [START_REF] Mutter | Drainage in digestive surgery. French Society of Digestive Surgery[END_REF].

-For patients with UCAA, in accordance with the French Society of Anesthesia and Resuscitation Medicine's guidelines [START_REF] Montravers | Guidelines for management of intra-abdominal infections. Anaesthesia, critical care & pain medicine[END_REF], patients were given a single intravenous (IV) injection of amoxicillin plus clavulanic acid (2 g) or ofloxacin 200 mg + metronidazole 500 mg (when the patient was allergic to penicillin) on induction of general anesthesia and did not receive any antibiotics thereafter.

Postoperative management

After surgery, all patients who had been admitted between 7 A.M and 12 A.M or between 12 A.M and 12 P.M were systematically transferred to the DCS department. Patients admitted between 12 P.M and 7 A.M were hospitalized in the conventional ward. Admission to the DCS department was organized preoperatively in the emergency department. Two DCS beds are devoted to emergencies (mainly for digestive surgery and orthopedic surgery). When the patient was admitted on the day of surgery, the surgeon called the DCS department to book a bed for the patient and, when the patient was admitted in the evening or in the night, the surgeon sent an email to book a bed for the next morning.

During the postoperative period, on arrival in the DCS department, a clear liquid diet was commenced immediately after surgery, and a soft diet was introduced two hours later. Patients were discharged home with oral analgesia when they tolerated a liquid diet. When the patient was unable to be discharged, he or she was admitted to the department of digestive surgery.

When the patient was able to be discharged, he or she was given a detailed information sheet providing instructions, including contact numbers for urgent advice in an emergency. The telephone numbers connected to the DCS specialist nurse during normal working hours (8 A.M -6 P.M) and to the on-call surgical team outside of these times. Patients were advised to contact the team by telephone or in person if they experienced any of the following symptoms: nausea, vomiting, abdominal distension or fever. Each patient was contacted by telephone by a nurse 24 hours after discharge from the DCS department. The follow-up assessment was performed in the outpatient clinic on postoperative days 7 and 30.

Endpoints

Primary endpoint

The primary endpoint was the DCS success rate (LOS less than 12 hours) in the intention-totreat (ITT) population (all patients with UCAA) and in the per protocol (PP) population (population with UCAA and no preoperative or intraoperative exclusion criteria). The DCS success rate in this study (AppendAmbu II) was compared to the DCS success rate in the AppendAmbu study.

Secondary endpoints

The secondary endpoints were:

-to determine the DCS quality criteria (i.e. the rate of unplanned consultations, unplanned hospitalizations, unplanned reoperations) and to compare these rates to those of the AppendAmbu study, -to evaluate and compare the morbidity and mortality of DCS for UCAA to the morbidity and mortality of conventional hospitalization for UCAA using Clavien classification ( 14) and the comprehensive complication index (CCI) [START_REF] Slankamenac | The comprehensive complication index: a novel continuous scale to measure surgical morbidity[END_REF]. For evaluation of this endpoint, patients of the present study (AppendAmbu II) and patients of the AppendAmbu study managed by DCS were pooled and compared to patients managed by conventional surgery during the same period (mainly due to organizational contraindications to DCS).

-to externally validate the St Antoine score [START_REF] Lefrancois | Management of Acute Appendicitis in Ambulatory Surgery: Is It Possible? How to Select Patients?[END_REF] The overall population comprised 386 patients. The St Antoine score was not available for 59 of these patients and was therefore analysed for 327 patients.

Definitions

Diagnosis of UCAA

The diagnosis of UCAA was established in the absence of any signs of CAA. Preoperatively, UCAA was defined on the basis of clinical examination (pain not refractory to usual painkillers, no sepsis) and laboratory parameters (no signs of renal failure). The definitive diagnosis of UCAA was based on CT scan or ultrasound and required clear visualization of the appendix (appendix diameter >6 mm), and absence of any of the following criteria of CAA (abscess, localized or generalized peritonitis, fecaliths, pneumoperitoneum) (2). The intraoperative diagnosis of UCAA was defined by the absence of abscess, localized or generalized peritonitis or fecaliths. Clear liquid in the right iliac fossa or pelvis was not considered to be a sign of complicated acute appendicitis.

Day case surgery quality criteria

The quality criteria used in this study were the International Association for Ambulatory Surgery quality indicators for DCS outcomes (www.iaas-med.com; unplanned overnight admission, unplanned consultation, unplanned hospitalization and unplanned reoperation) in patients in whom DCS management was successful. The unplanned overnight admission rate corresponds to the proportion of patients who were not discharged in the evening after the surgical procedure and who were hospitalized for at least one night. The unplanned consultation rate represents the proportion of patient attending a consultation for a postoperative complication during the first month of follow-up. The unplanned hospitalization rate corresponds to the proportion of patients who were readmitted after appendectomy.

Finally, the unplanned reoperation rate is defined as the proportion of patients who were operated after their post-DCS discharge.

Predictive factors of success of ambulatory surgery (St Antoine's score) [START_REF] Lefrancois | Management of Acute Appendicitis in Ambulatory Surgery: Is It Possible? How to Select Patients?[END_REF] This score was constructed in the overall population of patients with AA to determine the day 1 successful discharge rate according to 5 criteria exclusively related to AA (and not to research or organizational criteria or DCS): BMI < 28, preoperative CRP level < 30 mg/dL, preoperative leukocyte count < 15,000/mm 3 ; diameter of the appendix < 10 mm, no radiological signs of perforation (i.e. no abscess and no local peritonitis on CT scan). The absence of any of these criteria corresponds to a 0% day one discharge rate, while the presence of all five criteria corresponds to a 92% day one discharge rate.

Ethical approval

This retrospective study (AppendAmbu II) was declared to the Commission National de l'Information et des Libertés (CNIL) (Study DRCI T181). The AppendAmbu study was approved by the "Agence Nationale de Sécurité du Médicament et des produits de santé" (ANSM), the "Comité de Protection des Personnes -Nord Ouest II" (CPP) ethics committee and the CNIL. The study was registered on www.clinicaltrials.gov with the number NCT01839435.

Statistical analysis

The characteristics of the study population are described in terms of mean ± standard deviation and median (minimum -maximum) for quantitative variables and frequency and 95% confidence interval for qualitative variables. For analysis of the primary endpoint, the DCS success rate is reported with a 95% confidence interval. For analysis of the secondary endpoints, the unplanned consultation, unplanned readmission and unplanned reoperation rates are reported as percentages. The morbidity (assessed by Clavien-Dindo classification) is expressed as a percentage for each rank. Statistical analysis was performed with SAS® version 9.2 software (SAS Institute, Cary, NC). A p value ≤ 0.05 was considered to be statistically significant.

RESULTS

Population

From January 2016 to September 2017, 296 patients were operated for AA, comprising 176 men (59%) with a mean age of 38 years ± 18. All procedures were performed by laparoscopy without conversion. Among these 296 patients, 201 (68%) had UCAA (ITT population) (Table 1). Among the patients with UCAA, 107 patients (53%) presented preoperative exclusion criteria and 94 (47%) met the preoperative inclusion criteria of this study.

Thirty-seven (18%) of these 94 patients presented intraoperative exclusion criteria (Figure 2).

The remaining 57 patients (28%) presented no preoperative or intraoperative exclusion criteria (PP population). The PP population represents 19.2% (57 patients out of 296) of the entire population of patients operated for AA. Thirty-one (54%) of these 57 patients were admitted between 12 AM and 12 PM and were discharged home before the operation.

Primary endpoint

The proportion of patients with successful DCS management (AppendAmbu II study) was 27% (54/201) in the ITT population and 95% (54/57) in the PP population. In the AppendAmbu study, the success rate was 32% in the ITT population and 92% in the PP population. The success rate was not significantly different between AppendAmbu II and AppendAmbu in the ITT population (p=0.2) or the PP population (p=0.2). The success rate of patients discharged home before the operation (n=31) was 100%.

Secondary endpoints

Day case surgery quality criteria

Eight (15%) of the 54 patients with successful DCS management attended an unplanned consultation for vomiting (n=1), right lower quadrant pain (with no laboratory or CT abnormalities) (n=5), deep abscess treated by antibiotics (n=1) and treated by radiological drainage (n=1). Two patients (4%) with abscess who attended an unplanned consultation subsequently had an unplanned hospitalization. No patients required an unplanned reoperation. The unplanned consultation (p=0.8), unplanned hospitalization (p=0.9) and unplanned reoperation (p=0.9) rates were not significantly different between the AppendAmbu and AppendAmbu II studies.

Morbidity

The postoperative morbidity according to the Dindo-Clavien classification of patients managed by DCS (AppendAmbu and AppendAmbu II populations) (n=140) was not significantly different from that of patients managed by conventional hospitalization (n=256) during the same study period (p=0.7). According to the CCI classification, postoperative morbidity was lower after DCS than after conventional surgery (5.77 vs 9.48, p=0.0009) (Table 2).

Validation of factors predictive of success of day case surgery (St Antoine score)

The DCS rate for the 327 patients, according to the St Antoine score, was 0% (0 out of 7) for patients with a St Antoine score of 0, 6% (2 out 31) for patients with a St Antoine score of 1, 9% (7 out of 78) for patients with a St Antoine score of 2, 37% (29 out of 79) for patients with a St Antoine score of 3, 68% (52 out of 77) for patients with a St Antoine score of 4 and 80% for patients with a St Antoine score of 5 (28 out of 35) (p<0.0001).

DISCUSSION

The AppendAmbu study confirmed the feasibility of DCS for UCAA with a 31.5% success rate in the ITT population and a 90.5% success rate in the per protocol population, but these results could be related to the context of the protocol. This study (AppendAmbu II) confirms the real-life feasibility of DCS for UCAA with a 27% success rate in the ITT population and a 95% success rate in the PP population and confirms the high success rate in selected patients.

Appendectomy for UCAA is a good indication for DCS, but remains challenging as emergency digestive surgery procedures are usually not managed by DCS. Discharging a patient prior to surgery may be a source of anxiety for the surgeon and for the patient. The AppendAmbu study was designed to build a rigorous protocol for the DCS management of emergencies by reducing the anxiety in relation to DCS.

These outcomes are probably due to the use of a dedicated DCS circuit in the DCS department, with 12 hours opening and thus patients must be discharged at the end of the opening of the DCS department as any of the other patients managed in DCS. It is an important point, as the development of DCS must be supported by optimizing validated elective indications and by proposing new elective indications, such as fundoplication and sleeve gastrectomy [START_REF] Gronnier | Day-case versus inpatient laparoscopic fundoplication: outcomes, quality of life and cost-analysis[END_REF][START_REF] Rebibo | Laparoscopic sleeve gastrectomy as day-case surgery (without overnight hospitalization)[END_REF] as well as emergency procedures [START_REF] Sabbagh | The feasibility of short-stay laparoscopic appendectomy for acute appendicitis: a prospective cohort study[END_REF][START_REF] Cash | A prospective treatment protocol for outpatient laparoscopic appendectomy for acute appendicitis[END_REF][START_REF] Dubois | Impact of an outpatient appendectomy protocol on clinical outcomes and cost: a case-control study[END_REF][START_REF] Lefrancois | Management of Acute Appendicitis in Ambulatory Surgery: Is It Possible? How to Select Patients?[END_REF][START_REF] Fuks | Can we consider day-case laparoscopic cholecystectomy for acute calculous cholecystitis? Identification of potentially eligible patients[END_REF][START_REF] Sabbagh | Ambulatory management of gastrointestinal emergencies: what are the current literature data?[END_REF][START_REF] Franck | Feasibility study for ambulatory surgery in emergency[END_REF]. DCS teams are trained in the management of DCS, which should improve the success rate. The DCS rate remained stable but did not increase compared to the AppendAmbu study.

The main issue remains how to increase the DCS rate as the safety of DCS for UCAA make it a challenging strategy for antibiotic therapy as antibiotic therapy requires hospitalization for 5 days and is associated with up to 29% of failure (2).

One of the limitations of this study is that, for safety reasons, the inclusion criteria were limited and only 57 of the 296 (19.2%) patients operated for appendicitis during the study period were eligible for DCS. Thus, the PP population represents only 19.2% of the entire population. In real life, in order to increase the number of patients managed by DCS, this procedure must be clearly explained to the patients before the operation in order to avoid refusal (n=19 in this study). Despite the team's extensive experience, the DCS refusal rate remains high, which also highlights the need to include the patient in the decision-making process, which cannot be performed without the patient's consent and understanding based on adequate information about the safety of DCS. CAA, which represents about one-third of all patients operated for appendicitis (32.4% in a nationwide cohort in the UK) may also be suitable for DCS. It could be particularly useful in patients with localized peritonitis (pus in no more than 2 quadrants) as recently published by our team in a dedicated video survey study [START_REF] Mariage | Surgeon's definition of complicated appendicitis: a prospective video survey study under submission[END_REF]), for whom a strategy without postoperative antibiotic therapy is currently being studied (ABAP trial, NCT03688295). However the definition of uncomplicated appendicitis remains not unclear. In our study, it was defined as the absence of abscess, localized or generalized peritonitis, fecaliths or penumoperitoneum. It should be noted that the definition ranged from 0% for a score of 0 to 80% for a score of 5. DCS is therefore proposed to patients with a St Antoine score of 4 or 5. Among these data, CRP level is not usually ordered in the workup of appendicitis, however some data suggest than CRP is valid in distinguishing complicated and uncomplicated appendicitis. In 1999, Grönroos et al. evaluated CRP in a cohort of 300 patients and found that CRP value was superior to leucocyte count in reflecting complicated appendicitis. In their study, the mean value of CRP in complicated appendicitis was 99 mg/l and 31 mg/l in uncomplicated appendicitis [START_REF] Gronroos | Leucocyte count and C-reactive protein in the diagnosis of acute appendicitis[END_REF]. Moreover in a publication by our group, we found that age<23 years and CRP<18 mg/l were associated with a predictive positive value of 100% for a length of stay of less than 24 hours (3).

CONCLUSION

It is legitimate to question the purpose of DCS appendectomy. DCS constitutes a progress in surgery as a result of enhanced recovery programs. DCS avoids unnecessary prolonged hospitalization and allows the patient to safely stay at home, as there is no excess risk of complications.

  for the selection of patients for DCS based on evaluation of the pooled AppendAmbu and AppendAmbu II populations. Patients with preoperative UCAA (n=100 in AppendAmbu and n=95 in AppendAmbu II), patients with intraoperative CAA (n=12 in AppendAmbu and n=30 in AppendAmbu II), patients with an associated procedure (n=2 in AppendAmbu and 7 in AppendAmbu II) and the per protocol population (n=83 in AppendAmbu and 57 in AppendAmbu II) were included in this analysis.

Table 1 .

 1 Characteristics of the AppendAmbu and AppendAmbu II PopulationsFigure 1. Study population and patient flow according to the time of diagnosis. AA, acute appendicitis; CAA, complicated acute appendicitis; DCS, day case surgery Figure 2. Study flowchart. AA, acute appendicitis; DCS, day case surgery; PP, per protocol; ITT, intention-to-treat

	Variable	AppendAmbu study	AppendAmbu II	p Value
			study (n=296)
		(n=340)
	Male sex, n (%)	181 (53)	176 (59)	0.1
	Age, y, mean ± SD	35±18	38±18	0.04
	BMI, kg/m 2 , mean ± SD	24±6	25±8	0.6
	Time of consultation, n (%)			0.2
	Midnight to 7 AM	72 (21)	74 (25)
	7 AM to mid-day	32 (9)	34 (12)
	Mid-day to midnight	236 (70)	187 (63)
	Complicated acute appendicitis, n (%)	100 (29)	95 (32)	0.4

of localized peritonitis is controversial in terms of the macroscopic aspect of the liquid (from serosity to pus) and the number of quadrants contaminated by pus. It is therefore easier to first define uncomplicated appendicitis (i.e. catarrhal appendicitis without any liquid in the abdomen) and then define complicated appendicitis as any appendicitis that is not uncomplicated. It should also be noted that in a recent report on a randomized, controlled trial in children, St Peter et al. defined complicated appendicitis as appendicitis with a hole in the appendix or with fecaliths; this excluded abscesses and local peritonitis from the definition because the latter conditions were associated with a lower rate of post-operative complications than the former conditions (14% vs. 18%, respectively) [START_REF] Peter | An evidence-based definition for perforated appendicitis derived from a prospective randomized trial[END_REF]. Nevertheless, St Peter et al.'s study is the only one to have specified the nature of complicated appendicitis; all other studies have referred to "complicated appendicitis" without giving any details.

However, the risk of postoperative complications is not itself a contraindication to DCS as complications can happened after patient's discharge even in traditional hospitalisation and most of patients with CAA have a preserved general condition and might thus be good candidates for DCS.

Patients suitable for DCS appendectomy must be carefully selected during the preoperative period by using a DCS success predictive score. To increase the number of patients undergoing DCS, it would also be necessary to reassure the patient by suggesting postoperative follow-up at home with "smart devices" or home nurse follow-up. It is also important to propose DCS to patients admitted over the weekend or between midnight and 7 am by allowing around-the-clock discharge [START_REF] Franck | Feasibility study for ambulatory surgery in emergency[END_REF].

In the present study, we also externally validated the St Antoine score [START_REF] Lefrancois | Management of Acute Appendicitis in Ambulatory Surgery: Is It Possible? How to Select Patients?[END_REF], which is very useful to ensure objective patient selection. This score included a BMI < 28 Kg/m 2 , preoperative CRP level < 30 mg/dL, preoperative leukocyte count < 15,000/mm 3 ; diameter of the appendix < 10 mm, no radiological signs of perforation. In this study, the success rate

Precis

The aim of this study was to evaluate the real-life feasibility of day case surgery for uncomplicated appendicitis. The proportion of patients with success was 95%. The unplanned consultation rate was 15%, the unplanned hospitalization rate was 4%, and the unplanned reoperation rate was 0%. Day case surgery constitutes progress in surgery.