TUNA FISHERIES CATCH LANDED IN ABIDJAN (CÔTE D IVOIRE) AND SOLD ON LOCAL FISH MARKET FOR THE PERIOD (PRELIMINARY DATA) - PDF

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SCRS/214/63 Collect. Vol. Sci. Pap. ICCAT, 71(1): (215) TUNA FISHERIES CATCH LANDED IN ABIDJAN (CÔTE D IVOIRE) AND SOLD ON LOCAL FISH MARKET FOR THE PERIOD (PRELIMINARY DATA) Chavance

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SCRS/214/63 Collect. Vol. Sci. Pap. ICCAT, 71(1): (215) TUNA FISHERIES CATCH LANDED IN ABIDJAN (CÔTE D IVOIRE) AND SOLD ON LOCAL FISH MARKET FOR THE PERIOD (PRELIMINARY DATA) Chavance 1 P., Dewals 1 P., Amande 2 M. J., Delgado de Molina 3 A., Damiano 1 A., Tamegnon 2 A. SUMMARY This note presents data collected (quantities by type of vessels and flags, species composition, size structure) since 1982 on catches landed by tuna fisheries in Abidjan and sold on local market. RÉSUMÉ Cette note présente les données recueillies (quantités par type de navires et pavillons, composition par espèce, structure des tailles) depuis 1982 concernant les prises débarquées par les pêcheries de thonidés à Abidjan et vendues sur le marché local. RESUMEN Este documento facilita los datos recopilados (cantidades por tipo de buque y pabellón, composición por especies y estructura de tallas) desde 1982 para las capturas desembarcadas por las pesquerías de túnidos en Abiyán y comercializadas en el mercado local. KEYWORDS Local market, Data collection, By-catch, Tuna fisheries, Purse seining 1 Institut de Recherche pour le Développement (IRD), UMR 212 Ecosystèmes Marins Exploités, Sète, France patrice.dewals.ird.fr). 2 Centre de Recherches Océanologiques (CRO), Abiddjan, Côte d Ivoire 3 Instituto Espanol de Oceanografia (IEO), C. O. de Canarias, Santa Cruz de Tenerife, Spain 183 Introduction This document presents preliminary data on fish landed by tuna fisheries and sold to the local market in Abidjan from 1982 to 213. This fish are major tunas that are rejected by canneries, undersize and little tunas (skipjack, bullet tuna, yellowfin, bigeye, little tunny) and also appreciated species caught as by-catch like marlin, sailfish, wahoo, dolphinfish, barracuda, triggerfish and shark. Generally called Faux Poisson in French, because it was initially considered as the fish basket given to the fishermen at the end of the trip, this category of fish is now representing a significant component of the landing due to growing bycatch associated with DFAD fishing developpement and sharp local demand in Abidjan city. Origin of data As indicated in Chavance et al. (21), monitoring the fish landed and sold through the local market, is by nature a very difficult task. Since the beginning, it has been considered unrealistic neither to collect formal data (formularies, invoices ) neither to estimate directly weights. It then has been preferred to evaluate the number of transports units associated with weight coefficient. For specimens (billfishes, sharks), numbering of heads are used in order to avoid double counting associated with a mean weight by types of specimen. Weight coefficients by transport units were fixed empirically periodically by observers and try to reflect changes occurring in transport practices. Since May 29, a weighbridge has been installed at the fishing port exit and generates exact weights of transport unit each one being inventoried and its specific net weight defined. All industrial vessels, in principle, are systematically monitored for their landings destined to local market whatever their nationality and their type (fishing or carrier vessels). These data were collected through a collaboration between France (IRD), Spain (IEO) and Côte d Ivoire (CRO). Computation Total estimates of landings are obtained by summing up the product of the numbering of transport units (vehicle, bags, pieces ) by their reference weights. When direct weights are available, they are also used. The precise origin of the product (vessels, type of boats, nationality, fleet and date of landings) is therefore known. Species composition before 25 has been estimated using species composition given by N Goran (2) (Table 1 and Figures 1 to 6). Since 25 species composition of the landings destined to local market is done by dedicated port samplers that estimate visually the percentage of species for each vehicle. This species composition is applied for fish landed in bulk when available. Length measurements have been set in place in a regular manner since 27. They occur on board vessel (all type and all nationality) for samples around 2 individuals each and concerns uniquely tuna fish species (major and minor). Percentage of species composition of these samples may therefore also be used to estimate composition among tunas. Structure of data set folder ABJ_LM_ xls LANDINGS: Annee (year) Mois (month) ICCAT_FLAG (Vessel flag) L_TYP_B (Type of vessel) FAO_Species_Code_2 (FAO species code) Quantite (Quantities in tons) LENGTH Annee (year) Mois (month) ICCAT_FLAG (Vessel Flag) L_TYP_B (Type of vessel) FAO_Species_Code_2 (FAO species code) V_LONG (Lower Fork Length size classe in cm) Nbre (Number measured) Poids_echant_kilo (Weigth in kg in samples) 184 References Chavance Pierre, Alicia Delgado de Molina, Monin Justin Amandè, Floch Laurent, Dewals Patrice, Tamegnon Athanase Faux poisson landed in Abidjan for the period Preliminary data. ICCAT Tropical tuna species group intersessional meeting on the Ghanaian statistics analysis (Phase II), Madrid, May 3 - June 3, 211. Chavance Pierre, Jean Baptiste Amon Kothias, Patrice Dewals, Renaud Pianet, Monin-Justin Amandè, Alicia Delgado de Molina and Aude Djoh. Statistics on tuna surface fishery s bycatch landed in Abidjan, Côte d Ivoire, for the period. Collect. Vol. Sci. Pap. ICCAT, 66(5): N Goran Nestor. 2. Estimation des quantités de faux poisson débarquées au port d abidjan. Annexe (Document multigraphié). Table 1. Species composition of fish product landed by tuna fisheries in Abidjan as estimated by N Goran (2). FAO_Species_Code_2 prop SKJ.131 BET.21 YFT.62 TUX.65 BIL.24 TRI.13 SHX.4 PEL.95 Total 1. Local Market Landings by species in Abidjan 3 Quantities (t) Species BET BIL PEL SHX SKJ TRI TUX WAH YFT FRI LTA TUN Figure 1. Total fish landed by species groups by tuna fisheries in Abidjan (Côte d Ivoire) destined to local market. Catch composition before 25 is estimated from Ngoran (2) and, after 25, by permanent monitoring. 185 Local Market Landings in Abidjan by vessels 2 15 Quantities (t) Carrier Pole and Line Purse seiner Species BET BIL PEL SHX SKJ TRI TUX WAH YFT FRI LTA TUN Figure 2. Total fish caught by species group and main vessel types landed by tuna fisheries in Abidjan (Côte d Ivoire) destined to local market. Catch composition before 25 is estimated from Ngoran (2) and, after 25, by permanent monitoring. Local Market Landings in Abidjan by main flags 3 25 Quantities (t) ICCAT_FLAG_2 ANT CPV ESP FRA GHA GIN KHM OTH PAN Figure 3. Total fish caught by main fishing countries identified by flag landed by tuna fisheries in Abidjan (Côte d Ivoire) and destined to local market. 186 Size structure and species composition in Abidjan 3 25 Nbr individuals L_ESP_S Auxis thazard Euthynnus alletteratus Katsuwonus pelamis Thunnus alalunga Thunnus albacares Thunnus obesus LF cm Figure 4. Total size structure and species composition of fish landed in Abidjan (Côte d Ivoire) and destined to local market. 187 Size and species composition by type of vessels 2 15 Nbr individuals Carrier Pole and Line Purse seiner L_ESP_S Auxis thazard Euthynnus alletteratus Katsuwonus pelamis Thunnus alalunga Thunnus albacares Thunnus obesus LF cm Figure 5. Size structure and species composition of fish landed by type of type of vessels in Abidjan (Côte d Ivoire) and destined to local market. Number of individuals sampled by species in Abidj 5 4 Nbr sampled 3 2 L_ESP_S Auxis thazard Euthynnus alletteratus Katsuwonus pelamis Thunnus alalunga Thunnus albacares Thunnus obesus Figure 6. Number of individuals measured by year and species in Abidjan (Côte d Ivoire) and destined to local market. 188
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