Fish Diversity in the Ghaghot: An Important Meandering River in the Northern Part of Bangladesh

Abstract

One of the important meandering but less studied rivers in Bangladesh, the Ghaghot has its unique features and once was very rich in fish diversity. Different anthropogenic and natural activities like overfishing, siltation, pollution threaten the biodiversity of the river in recent years, and therefore, the study dealt with the present status of fish diversity in the aforementioned river. Semi-structured questionnaire interviews and FGD (Focus Group Discussion) with local fishermen and retailers were conducted to get a scenario of the abundance of fish species. Specimens were collected from local fishers and retailers who collect fish from the river for sale. The study identified 86 fish species from 9 orders and 28 families. Fish species belong to the order cypriniformes and the family cyprinidae was found most abundant. The biodiversity index of the Ghaghot river showed middle stretch is much richer with fish diversity for both seasons than other stretches of the river. The value of Shannon-Weiner index, evenness and Margalef index ranged from 2.86-3.63, 0.49-0.55 and 4.99-9.41, for post-monsoon and 1.89-2.59, 0.35-0.53 and 2.66-4.03, for pre-monsoon, respectively. The qualitative survey result showed the quantity of total catch has declined 29±11.76% in the last decade. Regular sand extractions, use of pesticides in nearby cropland, restrict migration path and unregulated brood fish and juvenile catch were identified as the major threats of the Ghaghot river.