Vol. 12(2), pp. 36-46, July-December 2020 DOI: 10.5897/IJFA2020.0779 Article Number: CD8F0AC65250 ISSN 2006-9839 Copyright ©2020 International Journal of Fisheries and Author(s) retain the copyright of this article http://www.academicjournals.org/IJFA Aquaculture Full Length Research Paper Socio-economic and cultural values of two species of crabs (Cardisoma armatum Herklots and Callinectes amnicola Rochebrune) in Southern Benin, Africa: Management of post-harvest losses and exoskeletons Toussaint Mikpon1,2, Durand Dah-Nouvlessounon2, Nadège Adoukè Agbodjato2, Halfane Lehmane2, Olaréwadjou Amogou2, Christine N’Tcha2, Wassiyath Mousse2, Haziz Sina2, Hyacinthe Ahissou3, Adolphe Adjanohoun1 and Lamine Baba-Moussa2* 1South Agricultural Research Center, National Institute for Agricultural Research of Benin Attogon, 01 BP 884 Cotonou, Bénin. 2Laboratory of Biology and Molecular Typing in Microbiology, Faculty of Sciences and Techniques, University of Abomey-Calavi, 05 BP 1604 Cotonou, Benin. 3Biomembrane and Proteins Laboratory, University of Abomey-calavi, 04 BP 0320, ISBA, Champ de foire, Cotonou Bénin. Received 29 May, 2020; Accepted 10 September, 2020 Crabs play an important economic and bio-ecological role in most aquatic ecosystems and occupy an important place in the variety of trophic niches. Callinectes amnicola Rochebrune and Cardisoma armatum Herklots are two edible species widely exploited in Benin. The present work aims to i) evaluate the socio-economic and cultural importance of those two crab species, ii) analyze the dynamics of the value chain, and iii) monitor the flow of their resources. Surveys were carried out during February 2018 to September 2019 among target groups in Ouémé, Atlantic and Littoral administrative Departments of Benin through structured and semi-structured interview methods as well as free interview. Results indicate that fishermen/catchers (12.76%), wholesalers/collectors (25.53%) and retailers (61.70%) are the actors involved in the crab value chain. Between 40 and 50% of fishery products are exported to markets in Togo and Ghana. Not all of the exoskeletons resulting from post-capture losses and those resulting from treatments for consumption, in particular C. amnicola (74.46%) and C. armatum (76.59%) are used, which poses an environmental management problem. The gains made in the sector vary from 8.000±2.828 Financial Community African Franc (FCAF) (C. amnicola) to 20.000±21.213 FCAF (C. armatum). The study found that crabs (C. armatum and C. amnicola) have remarkable socio-economic importance in Southern Benin, Africa. Key words: Crab, economic analysis, monitoring, Benin. INTRODUCTION In Africa, lagoon and mangrove complexes play important ecological, economic and socio-cultural roles in *Corresponding author. E-mail: [email protected]. Tel: +22997123468. Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Mikpon et al 37 the existence of coastal communities by providing a In several countries, the use of crabs is essentially the variety of plant products, fish and crustaceans (Sowman, consumption of their flesh, on the other hand the 2006). Among a crustaceans group, crabs take an exoskeletons are often regarded as waste and do not important place. Thirty-two crab species are reported in make much use. The management and impact of this lagoons or different habitats ranging from the marine waste on the environment is no less. The crustacean environment to the firm ground from Côte d’Ivoire to shells provide a high proportion of lime carbonate and a Nigeria. These species are divided into twenty-three nitrogenous material, chitin, analogous to the keratin of genera and thirteen families (Dessouassi et al., 2018). the hairs and nails of terrestrial animals, little or no According to available literature, the highest species digestible, only disintegrating with extreme slowness soil richness of lagoon crabs is observed in Nigeria (twenty- where it will be buried (Gustave, 1929). The three species) and the lowest is observed in Togo (two biodegradation of the shell of crustaceans is very slow species). Regional surveys conducted during colonial (Kandra et al., 2012). There is an urgent need to treat times and around the period of the independence and use crustacean waste, which contains several movement in West Africa have not included all the bioactive compounds such as chitin, pigments, amino lagoons in such countries as Benin or Côte d’Ivoire acids and fatty acids (Kandra et al., 2012). (Dessouassi et al., 2018). Nowadays, in lagoon systems Literature review on the exploitation and production of of South Benin, the exploitation of fishery resources Callinectes sp. and Cardisoma sp. in West Africa constitutes an essential economic activity that contributes (d’Almeida and Fiogbé, 2008) indicates an insufficient to the livelihoods of neighboring populations (Goussanou body of knowledge about these two species despite their et al., 2017a). The lagoon systems of southern Benin socio-economic relevance. The authors have suggested contain a wide variety of crustaceans, including that knowledge be improved relative to the estimation Cardisoma armatum Herklots and Callinectes amnicola and exploitation of stocks as well as to the biological Rochebrune (Goussanou et al., 2017a; Dessouassi et al., understanding necessary for a successful breeding of 2018). These two abundant aquatic species are Callinectes amnicola Rochebrune and Cardisoma extensively caught for own consumption and trade at the armatum Herklots. Indeed, in Southern Benin, information Lake Nokoué (Tohozin, 2012) and Porto-Novo lagoon on the different uses and the socio-cultural importance of (Goussanou et al., 2017b). C. armatum and C. amnicola is not well understood. The Crab fishing in Benin aquatic environments was same applies for the use and management of the considered as an accessory fishery compared to the fish exoskeletons of the two crab species in southern Benin that made up almost all the landings. Following the fishes for better environmental management. This study aims to decrease reflected by the decrease in captures, assess the socio-economic and cultural importance of fishermen turned to crab fishing of which exploitation these two crab species, and to analyze the dynamics of intensifies from day to day in Benin aquatic environments their value chain, as well as monitor the flow of their (Goussanou et al., 2017b). Crabs are an important resources. Achieving the objectives of this work will source of protein and several species are caught and provide new knowledge about the resources of the study traded by local populations (Olalekan et al., 2015). The area. It is expected also to improve practices and knowledge based on lagoon crabs is variable in Gulf of management of aquatic resources, mainly crabs, and Guinea countries, namely from Côte d’Ivoire to Nigeria. incomes of stakeholders in the value chain of these Some works were conducted on C. armatum and C. species. amnicola species in West Africa and provided information on diversity (Dessouassi et al., 2018), ecological (Shahdadi and Schubart, 2017), biology (George and MATERIALS AND METHODS Abowei, 2009), reproduction (Jivoff et al., 2007), Identification of the study area morphological description, structural characteristics, and the growth of the two main species of crab (Goussanou The study area was identified after a documentary study that made et al., 2017b). Information in relation with the socio- it possible to target the large crab production areas in Southern Benin. A prospective study was carried out during February 2018 to cultural importance of these species is not available. September 2019 in these areas through meetings with community In general, artisanal fishermen harvest a wide variety of leaders and actors involved in the crab value chain. This made it fish, crustaceans and molluscs and use them for various possible to select areas to be taken into account for the surveys domestic purposes. Therefore, wetland organisms such and target groups to be surveyed. Additional criteria that were taken as plankton, crabs and fish are linked to the human food into account included accessibility of the area and the openness of chain. It is evident that most of the coastal areas of West the natives to participate in the study. At the end of the prospective study, 10 municipalities and 2 districts (Figure 1) belonging to three Africa depend on mangroves for their survival, Departments (Atlantic, Littoral and Ouémé) were selected for subsistence and income. However, several aquatic surveying. resources such as crabs are today harvested in an unsustainable and uncontrolled manner, both on a Study area commercial scale and by artisanal fishermen (Akegbejo- Samsons and Omoniyi, 2009). The study area belongs to the Guinean Zone between 6°25’-730’N 38 Int. J. Fish. Aquac. Figure 1. Location of the survey areas in Southern Benin, Africa. and 2°33’-2°58’E (Figure 1) where the rainfall is bimodal (April to Description and common use of C. armatum and C. amnicola June and September to November) with a mean annual rainfall of 1200 mm (Assogbadjo et al., 2005). The Atlantic Department is C. amnicola is the swimming species with lateral and sub-lateral located on a sandy coastal strip, 2 to 5 km wide and cut by lagoons spines and the last pair of legs transformed into a "paddle". C. and marshes that stretch along the coast. The lagoon complex of armatum is the walking species that has 5 pairs of legs with hair, this department is increasingly salty in this case Lake Ahémé and the first pair of which is transformed into pincers. This species can Lake Nokoué. Lake Toho, on the other hand, contain fresh water be found both in water (fresh and above all brackish) and on land which is mainly used for the irrigation of a 400 ha palm grove (swampy regions) by digging the soil to make burrows where it (INSAE, 2013). Average monthly temperatures range from 27 to takes refuge. Figure 2 shows the morphology of the two species 31°C.