The fisheries resources at sub-zones irrigation works of Omon - Xano and Quan Lo - Phung Hiep in the Ca Mau peninsula

Abstract

A study on the fisheries resources at sub-zones irrigation works of O Mon - Xa No and Quan Lo - Phung Hiep in the Ca Mau Peninsula was conducted from January to December 2016. The data on fish species compositions were collected from the field in six times a year in combination with using the prepared questionnaire for interviews of 240 fishing households inside and outside the irrigation system (IS) area in two freshwater and brackish water ecosystems. The results showed that the composition of fish species in the study area was diverse. The size of major fish species recorded in the study area was relatively small. The production of fish and shrimp in 2016 decreased by 50 - 60% as compared to 2012 and the production inside the IS area was lower than that outside the IS area in both ecosystems. Some indigenous fish species, such as Channalucius, Notopterus notopterus, Clarias macrocephalus, Clarias batrachus, Morulius chrysophekadion and Toxotes chatareus were rarely found in freshwater ecosystems. Similarly, the indigenous fish species of Arius maculatus and Otolithoides biauritus were rarely found in brackish water. Pterygoplichthys disjunctivus has established populations in many natural water bodies in this study area resulting in a threat to competition, diversity and abundance of indigenous fish species. There were many reasons for the significant decline of fisheries resources; for example, the IS has blocked the migration of aquatic species. Many fishermen used electricity, poisoning, catching broodfish and fry during breeding season and water pollution by waste from aquaculture pond rehabilitation in the study area. Thus, it is necessary to deploy a community-based model of fishery resources management and preservation in the Ca Mau Peninsula.