Gonadosomatic index-based size at first sexual maturity of the catfish Eutropiichthys vacha (Hamilton, 1822) in the Ganges River (NW Bangladesh)

Summary This study describes the size at first sexual maturity, length–weight relationships (LWR) in relation to size at first sexual maturity, and Fulton’s condition factor (KF) of Eutropiichthys vacha in the Ganges River, northwestern Bangladesh. Sampling was done using traditional fishing gear including cast nets, square lift nets and conical traps during January and April, and July to December 2010. For each individual, total length (TL) was measured to the nearest 0.01 cm, and total weight (BW) was determined to the nearest 0.01 g. The gonadosomatic index (GSI) was calculated by the equation, GSI (%) = (Gonad weight in g/BW) × 100. The size at first sexual maturity of males and females was estimated by the relationship between gonadosomatic index and total length. A total of 583 specimens (289 males; 294 females) ranging from 8.30 to 27.00 cm TL and 3.16 to 159.50 g BW were analyzed. Sizes at first sexual maturity for male and female E. vacha were 13.15 and 14.00 cm TL, respectively. The analysis of covariance (ancova) revealed significant differences in slope and intercept between early and late phases for males (F = 4.532, P < 0.001) and females (F = 21.984, P < 0.001). The KF was not significantly correlated with TL for males (rs = 0.052; P = 0.378), but was highly correlated for females (rs = −0.165; P = 0.005). This study establishes a strong base for monitoring changes in length at first sexual maturity attributable to high fishing pressures or other reasons within the Ganges and associated river ecosystems.

[1]  Md. Mosaddequr Rahman,et al.  Length-weight and length-length relationships of five threatened fish species from the Jamuna (Brahmaputra River tributary) River, northern Bangladesh , 2012 .

[2]  M. Hossain,et al.  Life history traits of the Monsoon River prawn Macrobrachium malcolmsonii (Milne-Edwards, 1844) (Palaemonidae) in the Ganges (Padma) River, northwestern Bangladesh , 2011 .

[3]  M. Hossain.  Length-Weight, Length-Length Relationships and Condition Factors of Three Schibid Catfishes from the Padma River, Northwestern Bangladesh , 2010 .

[4]  W. S. Lakra,et al.  Fish diversity, habitat ecology and their conservation and management issues of a tropical River in Ganga basin, India , 2010 .

[5]  M. Y. Hossain,et al.  Gonadosomatic index-based size at first sexual maturity and fecundity indices of the Indian River shad Gudusia chapra (Clupeidae) in the Ganges River (NW Bangladesh) , 2010 .

[6]  W. S. Lakra,et al.  Length–weight relationships of 14 Indian freshwater fish species from the Betwa (Yamuna River tributary) and Gomti (Ganga River tributary) rivers , 2010 .

[7]  D. Quicke,et al.  Do shifting baselines in natural history knowledge threaten the environment? , 2010 .

[8]  Siddhartha Mishra,et al.  Development of tools for assessing conservation categories of siluroid fishes of fresh water and brackish water wetlands of South West Bengal, India , 2009, Environmental Biology of Fishes.

[9]  Mohammad Mustafizur Rahman,et al.  Length–weight and length–length relationships of 10 small fish species from the Ganges, Bangladesh , 2009 .

[10]  M. Hossain,et al.  Morphometric, Meristic Characteristics and Conservation of the Threatened Fish, Puntius sarana (Hamilton, 1822) (Cyprinidae) in the Ganges River, Northwestern Bangladesh , 2009 .

[11]  J. Ohtomi,et al.  Reproductive biology of the southern rough shrimp Trachysalambria curvirostris (Penaeidae) in Kagoshima Bay, southern Japan , 2008 .

[12]  C. Ferraris,et al.  Revision of Catfishes of the Genus Eutropiichthys, with the Description of Two New Species (Siluriformes: Schilbidae) , 2007, Copeia.

[13]  W. A. Baloch,et al.  Studies on length-weight and length-length relationships of a catfish Eutropiichthyes vacha Hamilton (Schilbeidae: Silurifo- , 2007 .

[14]  Rainer Froese,et al.  Cube law, condition factor and weight-length relationships: history, meta-analysis and recommendations , 2006 .

[15]  J. Oscoz,et al.  Length–weight and length–length relationships of some small indigenous fish species from the Mathabhanga River, southwestern Bangladesh , 2006 .

[16]  J. Oscoz,et al.  Condition, length-weight and length-length relationships of the Asian striped catfish Mystus vittatus (Bloch, 1794) (Siluriformes: Bagridae) in the Mathabhanga River, southwestern Bangladesh , 2006 .

[17]  T. Tashiro,et al.  Comparison of spatiotemporal patterns in reproduction of the kuruma prawn Marsupenaeus japonicus between two regions having different geographic conditions in Kyushu, southern Japan , 2003 .

[18]  Mahabub Alam,et al.  Physicochemical Properties and Fatty Acid Distribution Pattern in Lipids of Eutropiichthys vacha Hamilton-buchanan (Fam. Schilbeidae) , 2002 .

[19]  Shamik Das,et al.  Conservation of endangered fish stocks through artificial propagation and larval rearing technique in West Bengal , India , 2002 .

[20]  A. Nishat,et al.  Red book of threatened birds of Bangladesh , 2000 .

[21]  Juan L. Valero,et al.  Length at maturity of the greeneye spurdog shark, Squalus mitsukurii (Elasmobranchii : Squalidae), from the SW Atlantic, with comparisons with other regions , 1999 .

[22]  A. Jhingran,et al.  Inland Fishes of India and Adjacent Countries , 1991 .

[23]  S. Garcia.  Reproduction, stock assessment models and population parameters in exploited penaeid shrimp population , 1985 .

[24]  E. Cren,et al.  THE LENGTH-WEIGHT RELATIONSHIP AND SEASONAL CYCLE IN GONAD WEIGHT AND CONDITION IN THE PERCH , 2022 .