Biological features of Chanda nama (Ambassidae) in the Old Brahmaputra River, Bangladesh

Biological features including sex ratio, length-frequency distributions (LFDs), size at sexual maturity, spawning season, length-weight relationships (LWRs) and condition factor of Chanda nama were studied in the Old Brahmaputra River, Bangladesh. There was no significant difference in sex ratio. LFDs indicated no significant differences in size between the sexes. Size at sexual maturity was estimated at ~3.0 cm standard length. Monthly variations in gonadosomatic index indicate that the main spawning season is from July to August. The LWRs showed isometric growth in males and positive allometric growth in females. Fulton’s condition factor varied in both sexes and was attributed to variations in GSI with maturity. The findings of this study will be helpful to formulate conservation and management strategies of C. nama population in the Old Brahmaputra River and surrounding ecosystems

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

Age and growth of hilsa shad, Tenualosa ilisha (Hamilton, 1822) of the river Tentulia in Bangladesh

This study was carried out on age and growth of hilsa shad, Tenualosa ilisha in river Tentulia in Bhola district using monthly samples from January to December 2009 by checking annual rings or growth checks on hard parts. Age and growth of T. ilisha got progressed by direct fit of length frequency data both to standard and to modified von Bertalanffy growth models with ELEFAN I procedure where the predicted maximum total length were (TL∞) 41.88 cm for male and 52.40 cm for female. Powell-Wetherall procedure gave an initial asymptotic total length (TL∞) for both male and female 40.42 cm, 50.61 cm respectively. The values of Z/K were 3.362 for male and 2.626 for female. The growth co-efficient (K) was obtained as 1.40 year-1 for male and 1.00 year-1 for female. The von Bertalanffy growth equations in terms of body weight (BW) for both male and female were BWt=799.26[1-exp{-1.40(t+0.002)}]3 and BWt=1717.82[1-exp{-0.99(t+0.013)}]3 respectively. The length-weight relationship for both sexes were BW=0.0101 TL 3.02 for male and BW=0.0086 TL 3.08 for female. The value of coefficient of determination (R2) was estimated for both male and female species were 0.969 and 0.968

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

UGROŽENE VRSTE RIBA U SVIJETU: Mastacembelus armatus (Lacepede, 1800) (Synbranchiformes: Mastacembelidae)

Spiny eel Mastacembelus armatus is one of the economically important species both as food and for aquarium trades in Asian countries but the natural population is decreasing due to over-exploitation and for various ecological imbalances including the changes in its natural habitats. This paper suggests steps for the sustainable conservation of the remnant isolated population of M. armatus in the natural water-bodies of Asian countries.Mastacembelus armatus jedna je od gospodarsko važnijih vrsta, kao hrana i kao akvarijska vrsta u azijskim zemljama. Prirodni prirast se smanjuje zbog eksploatacije i različitih ekoloških neuravnoteženosti, uključujući promjene prirodnog staništa. Predlažu se koraci za održivo očuvanje ostatka izolirane populacije M. armatus u prirodnim vodenim staništima u azijskim zemljama

UGROŽENE VRSTE RIBA U SVIJETU: Heteropneustes fossilis (Bloch, 1794) (Siluriformes: Heteropneustidae)

The threatened stinging catfish Heteropneustes fossilis is a nutritionally valuable food in Asian countries but its natural populations have declined due to over-exploitation, habitat loss and pollution, thus deserving high conservation importance for the remaining isolated, wild populations of H. fossilis in Asian countries. The results would be useful for the protection of the presence of endemic species and sustainable fisheries in the lake.Ugroženi bodljasti som, Heteropneustes fossilis, je nutritivno vrijedna namirnica u azijskim zemljama, ali njegove prirodne populacije opadaju zbog pretjeranog iskorištavanja, gubitka staništa i zagađenja zbog kojih zaslužuje visoku važnost za zaštitu preostalih izoliranih, divljih populacija H. fossilis u azijskim zemljama

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