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Answer added in Fisheries Science29 Is anyone using fish markets, esp. in artisanal fisheries, to measure exploitation rates or biomass in the wild?Assessment of exploitation rates and/or fishing pressure and estimation of biomass (read stock assessment) can be conducted using market data and usin... [more]
Publications (9) View all
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Article: Comparative Study of Carp Pituitary Gland (PG) Extract and Synthetic Hormone Ovaprim Used in the Induced Breeding of Stinging Catfish, Heteropneustes fossilis (Siluriformes: Heteropneustidae)
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ABSTRACT: The present study compared the effectiveness of the Carp pituitary gland extract (PGE) and the synthetic hormone Ovaprim on spawning success of the stinging catfish, Heteropneustes fossilis during induced breeding. The PGE hormone was administered at 6 mg/kg of body weight for females and 2 mg/kg of body weight for males. In contrast, Ovaprim was administered at 0.3 ml/kg body weight and 0.1 ml/kg of body weight for females and males, respectively. The spawning success was higher in the Ovaprim-induced individuals with better performance recorded at all stages of spawning including latency period, ovulation, fertilization, hatching and incubation period compared to the PGE-induced individuals. In the Ovaprim induced individuals, the latency period occurred within 10 hours while in PGinduced individuals, the latency was after 15 hours. Similarly, ovulation rate was 90% for Ovaprim injected fish but lower 78.7% for PGE injected fish. Higher rate of fertilization was observed in the eggs of Ovaprim treated fishes 86.7% compared to 69.2% in PGE induced fish. On the other hand, hatching rate was 76.9% in eggs spawned from Ovaprim induced individuals compared to 72.7% in PGE induced fish and the incubation period was also shorter at 3.5 h for eggs from Ovaprim-induced fish while the PGE induced fish eggs required a 5-h incubation period. Finally, the results showed that Ovaprim treated fish yielded better results compared the PGE treated fish in terms of ovulation, fertilization and hatching rates of H. fossilis.Our Nature 03/2013; 10:89-95. -
Article: Conditions- and Form-Factor of the Five Threatened Fishes from the Jamuna (Brahmaputra River Distributary) River, Northern Bangladesh
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ABSTRACT: 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. But the natural populations are decreasing fast due to high fishing pressure as well as environmental degradation. Therefore, data and information is needed to avert the alarming decline and initiate conservation measures for these important fishes of the Jamuna River. This study describes the condition- (Fulton’s and Relative weight) and form-factor (a3.0) of the 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 during March 2010 through February 2011. For each individual, the total (TL), fork (FL) and standard (SL) length were measured by digital slide calipers while individual body weight (BW) was measured using a digital balance. The Fulton’s condition factor (KF) showed significant variations (p<0.01) among species, with best performance by B. lohachata (1.49±0.20) followed by C. nama (1.41±0.19), M. cavasius (0.79±0.14), L. laubuca (0.78±0.09) and A. punctata (0.71±0.12). The calculated minimum and maximum relative weight (WR) was 53.14 for C. nama and 167.88 for A. punctata, respectively. However, the estimated relative weight (WR) was close to 100 for all populations (p>0.05) indicating a balanced habitat with food availability relative to the presence of predators. The calculated minimum and maximum form factor (a3.0) was 0.0062 for A. punctata and 0.0158 for B. lohachata, respectively. To the best of our knowledge, this study presents the first reference on KF, WR and a3.0 factors 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.Sains Malaysiana. 06/2012; 41(6):671-678. -
Article: Conditions- and From-Factor of the Five Threatened Fishes from the Jamuna (Brahmaputra River Distributary) River, Northern Bangladesah
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ABSTRACT: 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. But the natural populations are decreasing fast due to high fishing pressure as well as environmental degradation. Therefore, data and information is needed to avert the alarming decline and initiate conservation measures for these important fishes of the Jamuna River. This study describes the condition- (Fulton’s and Relative weight) and form-factor (a3.0) of the 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 during March 2010 through February 2011. For each individual, the total (TL), fork (FL) and standard (SL) length were measured by digital slide calipers while individual body weight (BW) was measured using a digital balance. The Fulton’s condition factor (KF) showed significant variations (p<0.01) among species, with best performance by B. lohachata (1.49±0.20) followed by C. nama (1.41±0.19), M. cavasius (0.79±0.14), L. laubuca (0.78±0.09) and A. punctata (0.71±0.12). The calculated minimum and maximum relative weight (WR) was 53.14 for C. nama and 167.88 for A. punctata, respectively. However, the estimated relative weight (WR) was close to 100 for all populations (p>0.05) indicating a balanced habitat with food availability relative to the presence of predators. The calculated minimum and maximum form factor (a3.0) was 0.0062 for A. punctata and 0.0158 for B. lohachata, respectively. To the best of our knowledge, this study presents the first reference on KF, WR and a3.0 factors 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.Sains Malaysiana 06/2012; 41(6):671-678. · 0.27 Impact Factor -
Article: Conditions- and Form-Factor of the Five Threatened Fishes from the Jamuna (Brahmaputra River Distributary) River, Northern Bangladesh.
[show abstract] [hide abstract]
ABSTRACT: 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. But the natural populations are decreasing fast due to high fishing pressure as well as environmental degradation. Therefore, data and information is needed to avert the alarming decline and initiate conservation measures for these important fishes of the Jamuna River. This study describes the condition- (Fulton’s and Relative weight) and form-factor (a3.0) of the 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 during March 2010 through February 2011. For each individual, the total (TL), fork (FL) and standard (SL) length were measured by digital slide calipers while individual body weight (BW) was measured using a digital balance. The Fulton’s condition factor (KF) showed significant variations (p<0.01) among species, with best performance by B. lohachata (1.49±0.20) followed by C. nama (1.41±0.19), M. cavasius (0.79±0.14), L. laubuca (0.78±0.09) and A. punctata (0.71±0.12). The calculated minimum and maximum relative weight (WR) was 53.14 for C. nama and 167.88 for A. punctata, respectively. However, the estimated relative weight (WR) was close to 100 for all populations (p>0.05) indicating a balanced habitat with food availability relative to the presence of predators. The calculated minimum and maximum form factor (a3.0) was 0.0062 for A. punctata and 0.0158 for B. lohachata, respectively. To the best of our knowledge, this study presents the first reference on KF, WR and a3.0 factors 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.Sains Malaysiana 05/2012; 41(6):671-678. · 0.27 Impact Factor -
Article: Determination of effective tow duration for estimation of fish and shellfish abundance in deeper-water bottom trawl surveys
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ABSTRACT: Experimental trawl surveys were conducted to determine effective tow durations for estimating fish and shellfish abundances in deeper-water bottom trawl surveys. A total of 304 hauls were conducted in Kagoshima Bay, southern Japan, for preset tow durations of 10 and 20min, using a simple trawl net fitted with depth loggers. Towing durations were recorded at the ship’s bridge based on the shooting, towing and hauling times of the trawl net, using pre-established warp lengths for different water depths. Effective tow durations were computed by plotting depth logger and echo sounder data against tow time, and compared with preset tow durations. Trawled distances and swept areas were calculated using the Euclidean distance method. Effective tow durations ranged from 9 to 23 and from 19 to 37 for the 10 and 20min preset tow durations, respectively. Preset tow duration estimations for abundance were highly biased: −10 to 130% and −5 to 85% biases relative to the effective tow duration estimations, respectively. Moreover, the biases were more pronounced in the shorter tow durations in deeper-water trawl hauls. The computation of effective tow durations using depth loggers and the ship’s onboard instrumentation presents a simple approach for correcting inadvertent estimations of effective tow duration, swept area and abundance indices. KeywordsAbundance–Deeper-water–Experimental trawl survey–Swept area–Tow duration–TrawlFisheries Science 05/2012; 77(4):487-495. · 0.94 Impact Factor
