The present study describes the annual condition as well the length-weight (LWR) and length-length relationships (LLR) of the Asian striped catfish, Mystus vittatus (Bloch, 1794) (Siluriformes: Bagridae), an important fishery in the Mathabhanga River (SW Bangladesh). A total of 2438 specimens (3.60-9.60 cm standard length) used in this study was caught with traditional fishing gear from January to December 2004. Overall, the allometric coefficient b of the LWR was close to the isometric value (b ¼ 3.058), although it suggested negative allometric growth for males (b ¼ 2.959) whilst positive allometric growth for females (b ¼ 3.134). The results further indicated that the LLRs were highly correlated (r 2 > 0.989, P < 0.001). The monthly gonadosomatic index showed that the reproductive period of M. vittatus began in April, and ended in August when the highest values of the Fulton's condition factor (K) indicated their recovery. These results will be useful for fishery managers to impose adequate regulations for sustainable fishery management not only in the Mathabhanga River of Bangladesh but also in neighbouring countries.

The small indigenous species, namely Ailiichthys punctata (Day, 1871), Botia lohachata (Chaudhuri, 1912), Chanda nama (Hamilton, 1822), Laubuca laubuca (Hamilton, 1822) and Mystus cavasius (Hamilton, 1822), comprise an important component of riverine fisheries of Bangladesh. This study describes the length-weight relationships (LWRs) and lengthlength relationships (LLRs) of five threatened fishes from the Jamuna River, a distributary of the Brahmaputra River in northern Bangladesh. A total of 919 specimens from five species in five families used for this study were caught by traditional fishing gear, March 2010 through February 2011. The allometric coefficient (b) of the LWRs indicated negative allometric growth in A. punctata, B. lohachata, and C. nama (b < 3.00), but positive allometric growth in L. laubuca and M. cavasius (b > 3.00). Furthermore, the LLRs were highly correlated (r 2 > 0.978; P < 0.001). This study presents the first reference on LWRs and LLRs for these threatened species in Bangladesh. The results would be useful for sustainable management and conservation of the limited stocks in the Brahmaputra River ecosystem.

The present study describes the length-weight (LWR) and length-length (LLR) relationships for eight important small indigenous fish species (SIS) from the Mathabhanga River, southwestern Bangladesh, namely Amblypharyngodon mola

SummaryThis study describes the length-weight (LWR) and lengthlength (LLR) relationships for ten small indigenous fish species from the lower part of the Ganges, Bangladesh, namely Ailia coila, Amblypharyngodon mola, Aspidoparia morar, Clupisoma atherinoides, Eutropiichthyes vacha, Glossogobius giuris, Gudusia chapra, Lepidocephalus guntea, Mystus vittatus, and Puntius ticto. A total of 2142 specimens, representing 10 species of 5 families used for this study were caught by traditional fishing gear from March 2006 to February 2007. Standard length (SL), total length (TL) and fork length (FL) for each specimen were measured by digital slide calipers and each body weight (BW) was taken by a digital balance. The allometric coefficient b of the LWR was close to the isometric value (b = 3.001) in G. giuris, although it suggested negative allometric growth in A. coila, A. morar, C. atherinoides, E. vacha, and P. ticto, whilst positive allometric growth in rest of the species. The results further indicated that the LLRs were highly correlated (r 2 > 0.890; P < 0.01). To the best our knowledge, this study presented the first reference on LWR and LLR for most of the species in Bangladesh.

The present study describes the length-weight relationships (LWRs) for nine fish species from the Tetulia River, southern Bangladesh, namely Anabas testudineus, Coilia dussumieri, Otolithoides biauritus, Otolithoides pama, Pethia conchonius, Polynemus paradiseus, Puntius lateristriga, Setipinna taty and Sillaginopsis panijus. A total of 1380 specimens were caught using traditional fishing gear from March 2012 to February 2013. Individual total length (TL) and body weight (BW) were measured by digital slide calipers and digital balance, respectively. The LWR was calculated as W= a L b , where the W is the BW in g and L the TL in cm, a and b are regression parameters. This study presents the very first references on LWRs for seven of the species. The results are valuable for the application of sustainable management and conservation of these fishes in the Tetulia River and surrounding ecosystems.