Abundance and diversity of insects associated with dry fish spoilage in three (3) selected markets in Yenagoa, Bayelsa State

Abstract

The insect vectors associated with spoilage of dried fish in Yenagoa were studied. This was done in order to identify the diversity and abundance of Insects implicated in fish spoilage in order to suggest alternate storage means. Insect infested dry fish samples were procured from Three (3) markets (Swali (A), Kpansia (B) and Tombia (C)) and put into clean transparent plastic containers covered with little nets. They were moistened every day with water sprinkled into the containers for 1 week for insects to emerge. Insect vectors were identified to species level using standard keys. Result of the investigation reveal that a total of eleven Taxa and 156 individuals were found: 12 Calliphorid larvae, 1 crane fly larvae, 46 Musca domestica larvae, 5 Phaenicia sericate, 20 Piophilia casei, 20 Calliphorid pupa, 3 Tephritid larvae, 6 Necrobia fufipe larvae, 10 Dermestes maculatus pupae, 30 Phlorid pupa, 3 scatopsidae larvae. The dominant taxon was Musca domestica larvae followed by Phlorid pupa, and the least abundant was crane fly larvae. From the eleven (11) taxa seen, the abundance of Phlorid pupa was observed in station C (30). Piophilia casei and Musca domestica larvae were the only taxa present in the three sample stations. The Shannon index gotten in station B varied from station A and C. Shannon diversity index for station B was observed to be 1.535 and A and C were observed to be 0.918 and 1.466 respectively. Species evenness was greatest at station A (0.835). The insect vector of the order coleoptera (Beetles) were present only in fish samples from Swali and Tombia markets and absent from fish samples from Kpansia market. This may be due to the storage methods for dry fish in these markets and also due to environmental factors prevalent in these markets. The dominance of Musca domestica is indicative of possible health hazards as the consumption of insect infested dried fish in Yenagoa without washing may result in cholera and diarrhea. The study concluded that insects are the major vector pathogens causing spoilage in dried fish in Yenagoa, as indicated in similar studies in the Niger Delta. Therefore, more effort should be taken in the preservation and storage of dry fish to ensure food safety and security.