BUNDANCE AND DIVERSITY OF FISH LARVAE AT REZUKHAL ESTUARY OF THE COX'S BAZAR COASTS, BANGLADESH

Abstract

The abundance and diversity of fish larvae in the Cox's Bazar Coasts, Bangladesh was investigated using a bongo net with a mouth diameter of 0.50 m, a length of 1.3 m, and a mesh size of 500 μm at the body. Fish larvae were collected from a research station named the Rezukhal estuary, Cox’s Bazar Coasts from March 2020 to February 2021. A total of 15 families of larvae were identified consist of 2467 individuals from the selected station. The average number of fish larvae was 206/1000 m3/month, and the highest abundance (1197 larvae/1000 m3) was found in September. The lowest abundance (0 larvae/1000 m3) was found in June. Based on the percentage of the catch, five (5) dominant families were identified as Engraulidae (45.76%), Clupeidae (42.97%), Mugilidae (5.76%), Ambassidae (2.67%), and Blenniidae (1.01%). The percentages by families of constant: accessory: accidental families were 13:20:67 among the total identified samples. The highest Shannon-Wiener diversity index (1.481) was calculated in February and the highest evenness (0.940) were observed in June and the highest family richness (1.618) was found in July. 15 larvae families were identified and the frequency of occurrence indicated their spawning seasons. The spawning season of the identified families was classified as Winter, Summer, and Monsoon based on monthly larval abundance. The families' highest number 4 (Mugilidae, Blenniidae, Myctophidae and Carangidae) comes from Winter; Monsoon season. Whereas the Summer, Winter (Hemiramphidae); Summer (Sciaenidae) included the lower number of taxa only 1 taxa were recorded. Study findings will contribute to decision-making on marine fisheries management in Rezukhal estuary, Cox’s Bazar Coasts, Bangladesh to decision-maker.