Population Biology of the Indian River Shad, Gudusia chapra (Clupeidae) in the Old Brahmaputra River, North-Eastern Bangladesh

Population biology including population structure, reproduction, length-weight relationship and condition factor of a commercially important clupeid freshwater fish, Gudusia chapra was studied in the Old Brahmaputra River, Bangladesh during January-December 2009. In the present study, a total of 2032 specimens (1091 male; 941 female) were collected. The overall sex ratio showed significant difference from the expected value 1:1 (male: female = 1:0.86, χ2 = 11.07, p<0.001). Length-frequency distribution showed a size predominance of females over males, where mean female size consistently exceeded that of males throughout the year. Female size at first sexual maturity was estimated as 8.3 cm in standard length (SL). Monthly gonadosomatic index (GSI) was higher during March-September with a peak in April, indicating this was the main spawning season. The allometric coefficient b of the length-weight relationship (LWR) indicated negative allometric growth in males and females, but the analysis of covariance (ANCOVA) showed significant differences in slope and intercept between the sexes (p<0.001). Fulton’s condition factor by months and SLs varied in both sexes and was attributed to variations in GSI with maturity

UGROŽENE VRSTE RIBA U SVIJETU: Botia dario (Hamilton, 1822) (Cypriniformes: Cobitidae)

Bengal loach Botia dario is a valuable food fish in South Asian countries including Bangladesh, Bhutan, India and Nepal. However, the wild population is declining due to heavy harvest, habitat loss and its ecological changes. This paper suggests actions for the conservation of the lasting isolated populations of B. dario in Asian countries.Benegalski vijun, Botia dario, u južnim azijskim zemljama, uključujući Bangladeš, Butan, Indiju i Nepal, ima visoku važnost u prehrani. Međutim, divlje populacije su u opadanju zbog teškog iskorištavanja, gubitka staništa i ekoloških promjena. U ovom članku se predlažu akcije za očuvanje posljednjih izoliranih populacija B. dario u azijskim zemljama

UGROŽENE VRSTE RIBA U SVIJETU: Eutropiichthys vacha (Hamilton, 1822) (Siluriformes: Schilbeidae)

River catfish Eutropiichthys vacha is one of the foods high in nutritional value in Asian countries. However, natural populations have seriously declined or are on the verge of extinction due to over-exploitation and various ecological changes in its natural habitats, leading to an alarming situation which deserves high conservation attention. This paper suggests conservation measures that should be taken into account towards the preservation of the remnant isolated population of E. vacha in Asian countries.Riječni som, Eutropiichthys vacha, služi kao komercijalno visoka, nutritivno vrijedna hrana u azijskim zemljama. Međutim, prirodne populacije ozbiljno su opale ili su na rubu izumiranja zbog prekomjernog iskorištavanja i raznih ekoloških promjena u svojim prirodnim staništima, što dovodi do alarmantne situacije te je potreban visok stupanj zaštite. U radu se predlažu mjere zaštite koje treba uzeti u obzir kako bi se očuvao ostatak izolirane populacije E. vacha u azijskim zemljama

Temporal variations of sex ratio and growth pattern of critically endangered catfish Clupisoma garua from the Ganges river of north-western Bangladesh

647-653This research work states the temporal variations of sex ratio (SR), length-frequency distributions (LFDs), growth type based on length-weight relations (LWRs) and length-length relations (LLRs) of Clupisoma garua from the Ganges river of north-western Bangladesh. A total of 1200 specimens (male=630, female=570) were sampled using traditional fishing gears during May 2014 to April 2015. Then, total length (TL), standard length (SL) and fork length (FL) were taken to about 0.1 cm, and body weight (W) was taken to 0.1 g accuracy. The overall SR (male: female=1.0:0.90) did not vary statistically from the expected ratio of 1:1 (df =1, χ2 = 3.00, p>0.05). However, monthly variations of SR indicate males were higher in each month except June-August when females were greater in percentage. The LFDs showed that in males C. garua, ranged from 3.8-25.9 cm TL and females 3.9-26.3 cm TL. The LFDs for both sexes did not pass the normality; and Mann-Whitney U-test showed significant differences between sexes (pbvs. FL and TL vs. SL) of C. garua were highly significant (pr2 values >0.975. Finally, the findings of this study will be helpful for fishery biologists and conservationists to recommend adequate policy for the sustainable fishery of C. garua in the Ganges river and surrounding ecosystem

UGROŽENE VRSTE RIBA U SVIJETU: Labeo calbasu (Hamilton, 1822) (Cypriniformes: Cyprinidae)

Orangefin labeo Labeo calbasu is one of the commercially and nutritionally valuable food fish in Asian countries including Bangladesh, India, Nepal, Pakistan, Thailand and China. Unfortunately, natural populations of this species are decreasing due to over-exploitation and various biological changes to its habitats. This article suggests the steps for the conservation of the remnant isolated population of Indian major carps, L. calbasu, in the waters of Asia.Narančastoperajni labeo, Labeo calbasu, je visoko nutritivna vrijedna hrana u azijskim zemljama, uključujući Bangladeš, Indiju, Nepal, Pakistan, Tajland i Kinu. Nažalost, prirodne populacije ove vrste se smanjuju zbog pretjeranog iskorištavanja i raznih bioloških promjena u njihovim staništima. U ovom članku predlažu se koraci za očuvanje ostatka izolirane populacije indijskih velikih šarana, L. calbau, u vodama Azij

UGROŽENE VRSTE RIBA U SVIJETU: Anabas testudineus (Bloch, 1792) (Perciformes: Anabantidae)

Climbing perch Anabas testudineus is commercially important fish in Asian countries, mostly in Bangladesh, China, India, Malaysia, Pakistan, Sri Lanka and Thailand. Also, it is used as valuable food fish in different countries of the world. Nevertheless, its natural populations are seriously declining due to heavy harvest, habitat destruction and other ecological changes to its habitat. This paper recommends actions for the conservation of the long-lasting isolated populations of A. testudineus in Asian countries.Grgeč penjač, Anabas testudineus, je komercijalno važna vrsta ribe u azijskim zemljama, uglavnom u Bangladešu, Kini, Indiji, Maleziji, Pakistanu, Šri Lanki i Tajlandu. Također, koristi se kao vrijedna hrana u različitim zemljama svijeta. Ipak, prirodne populacije ozbiljno opadanju zbog pretjeranog izlova, uništavanja staništa i drugih ekoloških promjena. U članku se preporučuju akcije za očuvanje dugotrajnih izoliranih populacija A. testudineus u azijskim zemljama

Biometric relationships of the pool barb puntius sophore (Hamilton 1822) (Cyprinidae) from three major rivers of Bangladesh

The present study describes population structure (length-frequency distribution-LFD) and biometric relationships including length-weight relationship (LWR), length-length relationship (LLR), Fulton’s condition factor (K), relative weight (Wr) and form factor (a3.0) of Puntius sophore wild populations from three major rivers of different geographical locations of Bangladesh. A total of 784 specimens were caught by traditional fishing gear from March 2010 to February 2011. For each individual, the total length (TL), fork length (FL) and standard length (SL) were measured by digital slide calipers. Individual body weight (BW) was also taken by a digital balance. The results showed significant differences in TL-frequency distributions among populations (p0.921). Fulton’s condition factor (K) showed significant variations (p<0.001) among the populations, with best performance by the Padma River, followed by the Jamuna and Rupsha River; whereas, relative weight (Wr) was close to 100 for all the populations, indicating the balance habitat with food availability relative to the presence of predators. The estimated values of a3.0 were as 0.0158, 0.0142 and 0.0152 for P. sophore in the Jamuna, Padma and Rupsha River. These results will be useful for fishery biologists and conservationists to suggest adequate regulations for sustainable fishery management and conservation its numerous stocks in the region

Life-history traits of the Threatened Freshwater Fish Cirrhinus reba (Hamilton 1822) (Cypriniformes: Cyprinidae) in the Ganges River, Northwestern Bangladesh

The threatened Reba carp, Cirrhinus reba is a freshwater fish species found in ponds, rivers, canals and tanks of Bangladesh, India, Myanmar, Nepal and Pakistan. The present study describes the first complete and inclusive description of life-history traits including sex ratio, length-frequency distributions (LFD), length-weight relationships (LWR), condition factors (Allometric, KA; Fulton’s, KF; Relative condition, KR; Relative weight, WR), form factor (a3.0) and size at first sexual maturity of C. reba in the Ganges River, NW Bangladesh. Sampling was done using traditional fishing gears including cast net, square lift net and conical trap from April 2011 to March 2012. The total length (TL), fork length (FL) and standard length (SL) were measured to the nearest 0.01 cm using digital slide calipers and total body weight (BW) was measured using an electronic balance with 0.01 g accuracy. The LWR was calculated using the expression: W= a Lb, where W is the BW, L the TL. The size at first sexual maturity of C. reba was estimated using the empirical equation by Binohlan and Froese (2009) for male and female, separately. A total of 250 specimens ranging from 8.00 cm – 23.40 cm TL and 4.30 g – 200 g BW were analyzed in this study. The overall sex ratio did not differ significantly from the expected value of 1:1 (χ2 = 3.38, p 3.00) in male and female and there was significant differences in the intercepts (ancova, p< 0.001) and in the slopes (ancova, p< 0.001) between the sexes. In addition, the Mann-Whitney U-test showed significant differences in the Fulton’s condition factor between male and female (p< 0.001). The one sample t-test showed that the mean WR (actual mean = 99.50) did not differ from 100 for male (p= 0.523) and female (p= 0.197) in this study, indicating the habitat was still in good condition for C. reba. Moreover, the size at sexual maturity of male and female C. reba were estimated as 11.50 cm TL and 13.50 cm TL, respectively. The results of this study would be useful for the sustainable conservation of this threatened carp fishery in Bangladesh and also neighboring countries

Life-history traits of the freshwater garfish xenentodon cancila (Hamilton 1822) (Belonidae) in the Ganges River, Northwestern Bangladesh

The freshwater garfish, Xenentodon cancila (Hamilton 1822), is one of the commercially important, nutritionally valuable food fish in Asian countries, but the natural populations are seriously decreasing due to high fishing pressure and other factors. This study describes the life history traits, including sex ratio (SR), length-frequency distributions (LFDs), length-weight relationships (LWRs), length-length relationships (LLRs), condition factors (Allometric, KA; Fulton’s, KF; relative condition, KR; relative weight, WR) and form factor (a3.0) of X. cancila in the Ganges (Padma) River, northwestern Bangladesh. A total of 175 specimens ranging from 10.50-21.00 cm TL (total length) and 1.44-20.67 g BW (body weight) were investigated in this study. Sampling was done using traditional fishing gears from April 2011 to March 2012. The overall sex ratio showed no significant differences from the expected value of 1:1 (df = 1, χ2 = 0.28, p<0.05), whereas significant difference was found in the LFD (TL) between the sexes (Two tailed, p<0.001). The allometric coefficient b for the LWR indicated positive allometric growth in males, females and combined sexes. The results further indicated that the LLRs were highly correlated. Both KR and KF showed significant variations (Two tailed, p<0.001) between male and female. Also, WR was significantly different from 100 for both sexes (p<0.01), indicating the imbalance habitat with food availability relative to the presence of predators for X. cancila. The calculated values of a3.0 were as 0.0304, 0.0268 and 0.0252 for males, females and combined sexes of X. cancila. This study reports the first complete and comprehensive description of life-history traits for X. cancila from Bangladeshi waters. The data should be useful for the sustainable conservation of this critically endangered fishery in Bangladesh and neighboring countries