M. A. Hanif

FISH DIVERSITY IN THE SOUTHERN COASTAL WATERS OF BANGLADESH: PRESENT STATUS, THREATS AND CONSERVATION PERSPECTIVES

Despite the enormous anthropogenic and environmental hazards affecting wild fisheries resources, southern coastal waters are still considered one of the aquatic biodiversity hotspots in Bangladesh. Therefore, the present study was conducted to make a complete account of fishes and to assess their condition and conservation status in the rivers spread across four southern coastal districts of Bangladesh. During the study period from January to December 2014, a total of 98 species of fish were recorded belonging to 81 genera, 48 families and 13 orders. Perciforms were recorded as the most diverse fish group in terms of both number and individuals of species observed. Of the 98 species, 26.53% were listed as Locally Threatened in Bangladesh, including 11.22% species listed as Vulnerable, 10.20% as Endangered and 5.10% as Critically Endangered. Four population indices viz, Shannon–Wiener index (H), Simpson’s dominance index (D), Simpson’s index of diversity (1-D) and Margalef’s index (d) were applied to demonstrate the species diversity, richness and evenness of fish in sampling areas and their overall values were 3.54-3.70, 0.04-0.05, 0.95-0.96 and 7.48-8.67, respectively. To sustain the prospect of fisheries biodiversity in the southern coastal areas of Bangladesh, management and conservation strategies like restocking economically important fish species, establishing and maintaining fish sanctuaries, banning indiscriminate fishing and destructive fishing gears, identification and protection of the breeding and nursery grounds should be taken into consideration with utmost priority.

Stock Identification of Critically Endangered Olive Barb, Puntius sarana(Hamilton, 1822) with Emphasis on Management Implications

The study was carried out to investigate the stock identification of the olive barb, Puntius sarana (Hamilton, 1822) through morphometric characters. A total of 110 sample ranging from 10.00-16.80 cm in total length (LT) and 13.94-63.46 g in body weight (BW) were examined to assess the morphometric variation of Puntius sarana from four mighty rivers; the Padma, Meghna, Jamuna and the Halda in Bangladesh. The univariate result showed significantly variation (p<0.05) in seven morphometric characters out of 23 characters among the populations. The discriminant analysis revealed a morphological segregation among the studied populations based on the characters of length of anal base (YZ) and pre-dorsal length (LM). Discriminant function analysis (DFA) showed 55.0% of the individuals were correctly classified into the four regions on the basis of morphological characters. The first principal component (PC I) analysis elucidated 51.56% of total variation whereas PC II and PC III were 10.72% and 8.28%, respectively. The dendrogram was drawn by using morphometric data showed that the Meghna and Halda population make one cluster and the Jamuna and the Padma population form another cluster and the distance between the Padma and Meghna river population were the highest. The canonical graph also revealed all population of the Meghna and Halda were highly overlapped compare to others. The results of the present study would help monitoring the species status in Bangladesh as a bid to take appropriate management measures for its wide geographical distribution.

Morphometric Parameters and Allometric Growth in Paradise Threadfin Polynemus paradiseus (Linnaeus, 1758) from a Coastal River of Bangladesh

Morphological parameters comprising length-weight relationships (LWRs), sex ratio, condition factor (KF) and allometric growth of paradise threadfin, Polynemus paradiseus from the southern coast of Bangladesh were estimated. A total of 221 specimens were collected with the help of local fishermen ranging size 8.30-13.70 cm standard length (SL) and 11.64-50.67 g body weight (BW) during the period of January to October, 2104. The overall sex ratio of the samples did not reveal significant variation from the expected value of 1:1 (male: female=1:0.99, χ2=0.004, P < 0.05). Length-frequency distribution revealed a size predominance of males over females, where mean variation of males consistently exceeded that of females throughout the year. The allometric coefficient b of LWR significantly deviated from 3 indicating allometric growth in males and females. The analysis of covariance (ANCOVA) showed significant differences in slope and intercept between the sexes (P < 0.001). KF by month in both sexes indicating the fishes were thriving very well in the coast of Bangladesh. This study reports the first findings regarding the LWRs, sex ratio and KF of Polynemus paradiseus in the coastal waters of Bangladesh

The Current Status of Small Indigenous Fish Species (SIS) of River Gorai, aDistributary of the River Ganges, Bangladesh

Small indigenous fish species (SIS) play a vital role in providing animal protein sources for human. The Gorai river, a Ganges tributary is a habitat of considerable number of SIS. A total of 11040 individual from 40 species were collected belonging 7 orders and 19 families using 5 fishing nets and 1 fish trap of which 2 species were critically endangered, 7 endangered, 7 species vulnerable, 18 species not threatened, 2 data deficient and 4 species were not in evaluated category. Dominant orders were Cypriniformes and Perciformes each contained 12 species, dominant family was Cyprinidae (11 species) and most dominant species was Chela cachius (2253 individuals). Diversity indices ranges from Simpson’s dominance index (0.06-0.09), Simpson’s index (0.91-0.94), Shannon Weiner index (3.08-3.24), Evenness (0.56-0.66), Menhinick’s index (0.61-0.67), Margalef’s index (4.48-4.77), Equitability (0.84-0.89) and Fisher alpha (5.86-6.31), respectively. Highest numbers (38) of SIS were caught by set bag net. Maximum total length 4.6 cm of Corica soborna was the new record. Considering the nutritional importance and reducing number of SIS inhabiting in the river Gorai, the present study aimed at documentation of SIS, their threatened status and conservation of SIS through laws and regulations.