Insectes ravageurs des poissons fumés au cours du stockage et dégâts occasionnés dans la boucle Nord de la Réserve de Biosphère du Dja (Est-Cameroun)

Abstract

Dans de nombreux pays en voie de développement, 80% des captures de poissons sont fumés ou séchés afin de limiter les dégâts. Les insectes constituent un problème récurrent du poisson fumé stocké causant des grandes pertes économiques. Le but de l’étude réalisée dans quatre campements (Djeela, Nemeyong I, Malene I, Ndengué) de la boucle nord de la Réserve de Biosphère du Dja (RBD), était de déterminer la diversité des insectes ravageurs des poissons fumés stockés et leurs dégâts. Dans chaque campement, 25 outils de stockage des poissons fumés ont été inspectés, puis caractérisés et les espèces de poissons fumés identifiées. Lors de cette prospection, des collections de 8 espèces de poissons fumés ont été ramenées et mises en observation au laboratoire. Les insectes émergés des collections ont été dénombrés et identifiés et les dégâts évalués. Il ressort de cette étude que 31 espèces ichtyologiques appartenant à 12 familles sont fumées. Les Cichlidae (35,4%), les Clariidae (20,1%) et les Cyprinidae (10,3%) sont les familles les plus représentées. Oreochromis niloticus, Clarias gariepinus, Clariallabes manyangae sont les espèces les plus fumées. Les claies sont les outils de stockage les plus utilisés (46,66%). Excepté C. gariepinus infesté à 80%, les autres collections sont toutes infestées. Dermestes maculatus, Necrobia rufipes (Coléoptères) et Calliphora sp (Diptères) sont les insectes ravageurs des poissons fumés stockés. D. maculatus est le Coléoptère le plus préjudiciable aux stocks de poissons fumés avec 786 individus (99,49%) et 173,8 g de farine de forage. Les Insectes sont les principaux ravageurs des poissons fumés dans la RBD. C. gariepinus, C. manyangae et M. moorii sont les poissons fumés les plus attaquées. Les claies sont les outils de stockage les plus répandues.Mots clés : poissons fumés, structure de stockage, insectes ravageurs, dégâts, Réserve de Biosphère du Dja.
 English Title: Insect pests of smoked fishes during storage and damages done in the north loop of the Dja Biosphere Reserve (East-Cameroon)
 In many developing countries, 80% of fish catches are smoked or dried to limit losses. Insects are a recurring problem of stored smoked fishes causing great economic losses. The purpose of the study carried out in four camps (Djeela, Nemeyong I, Malene I, Ndengué) of the north loop of the Dja Biosphere Reserve (DBR), was to determine the diversity of insect pests of stored smoked fishes and their damages. In each camp, 25 smoked fish storage tools were inspected, then characterized, and the smoked fish species identified. During this survey, collections of 8 species of smoked fishes were brought back and put under observation in the laboratory. The insects emerged from the collections were enumerated and identified and the damage assessed. This study shows that 31 fish species belonging to 12 families are smoked. Cichlids (35.4%), Clariidae (20.1%) and Cyprinidae (10.3%) are the most common families. Oreochromis niloticus, Clarias gariepinus, Clariallabes manyangae are the most smoked species. Racks are the most used storage tools (46.66%). With the exception of C. gariepinus infested at 80%, the other collections are all infested. Dermestes maculatus, Necrobia rufipes (Coleopterans) andCalliphora sp (Dipterans) are the insect pests of the stored smocked fishes. D. maculatus is the more prejudicial Coleopteran to the storage of smoked fishes with 786 individuals (99.49%) and 173.8 g of drilling flour. Insects are the main pests of smocked fishes in the DBR. C. gariepinus, C. manyangae and M. moorii are the most attacked species. Racks are the most common storage tools.Keywords: Smoked fish, storage structure, insect pests, damages, Dja Biosphere Reserve.

Evaluation of factors of loss on stocks of smoked fish in three subdivisions of the Cameroon maritime coastal zone in Littoral region

“…Indeed, for the beetles which usually attack the treated fish, the population is multiplied by a maximum of 25 or 30 after four weeks [32] ; that is, under optimal conditions, a fertile female can give birth to 15,625 / 27,000 beetles in 12 weeks and these pests can also cause crumbling of treated fish [33] . Loss of quality may also be due to the presence of insect bodies and remains [12] . In fact, insects tunnel in fish and feed on their flesh, fish tend to fragment easily and the friability of fish associated with spoilage odors make fish less attractive and therefore less appetizing [28] .…”

“…The characterization of storage tools has been done to processors, traders, and consumers according to the method used by Tamgno et al [12] . The inspection of the tools for storage of smoked fish was carried out considering several elements: the nature of the tool, the size, the duration of storage (short term, medium term, long term), scope (occasional, local, regional) and dimensioning (length, width, weight).…”

“…The identification was made according to the method adopted by Tamgno et al [12] . The insects that would emerge from the different collections were removed, counted, preserved, identified using a Novex brand magnifying glass.…”

“…Smoking fish can be considered as a permanent and well-paid job [9] , because 75 to 80% of landings are transformed by smoking and contributes 16.8 billion to the Cameroonian economy [10] . The smoked fishes continue to be attacked during the processing and storage by many biotic factors, mainly the insects and may ~ 38 ~ be a source of poisoning for populations [11,12,13] . Indeed, as fisheries management systems improve and resource-related wealth begins to be produced on a sustainable basis, it may be possible to reduce estimated losses [14] .…”

“…Reasonable use of already scarce development resources, as well as the planning and implementation of effective loss reduction strategies, in addition, the scarce information on post-processing losses is unreliable. There are hardly any recent data on the control of insect pests of smoked or dried fish stocks in Cameroon and in the Central Africa sub-region [12] . Reducing these losses by strengthening the performance of players in the sector would require generating objective data that makes it possible to identify truly feasible and effective solutions.…”