Fishery and feeding ecology of delagoa threadfin bream, nemipterus bipunctatus (valenciennes, 1830) along the coastal waters of Dar es Salaam

Nemipterus bipunctatus, delagoa threadfin bream is commercially important at local markets in Tanzania as many people along the coast prefer it as a source of protein. Fishers earn much money from this species as it is sold at relatively higher prices. Regardless of its importance, very little is known about this species. In view of the above knowledge gap, this study aimed to assess the fishery and feeding ecology of N. bipunctatus along the coastal waters of Dar- es Salaam. The study was conducted at three landing sites along the coast of Dar es Salaam (Mbweni, Ununio and Kunduchi). Sampling was done for three months (January-March, 2012). Individuals of N.bipunctatus were purchased from artisanal fishers at the three sites. Results show, at smaller sizes (9.5- 11.5cm) to (13.6-15.5cm) this species relies on meiofauna, molluscs and annelids as its main food. In larger sizes (15.6-17.5cm) to (>21cm) fish was the secondary food item in all sites. The % IRI of fish in this size category was higher and increased with increase in fish sizes; ranging from 35.16% (15.6-17.5 cm) to 77.93% (>21 cm). There was significant relationship between the main food category and fish size with the exception of miscellaneous food in all sites (one Way ANOVA, P< 0.001). CPUE was highest at Mbweni (4.84kg) followed by Ununio (4.03kg) and finally, Kunduchi (3.19 kg) (one way ANOVA, P<0.001). This species is mainly caught by hand line using fish or squid as a bait. Its minimum size at maturity was found to be 13.7cm for female and 13.4cm for males. Although more than 50% of individuals caught in all sites were mature, a study on reproductive biology of this species should be done. Such study will depict specific period for spawning and recruitment of the fish hence contribute to the management strategies of this species including closing fishing activities in their grounds.