Journal of Fisheries

Growth dependent changes in protein efficiency and amino acid composition in cultured meagre Argyrosomus regius

2021-02-22T21:15:56+00:00

The goal of this research was to determine the growth dependent changes in protein efficiency and amino acid composition of the cultured meagre Argyrosomus regius (Asso, 1801). The research was carried in net cages in a private company (Gokce Off-shore Sist.) in the Aegean Sea. Meagre of an initial weight of 8.22 ± 0.13 g reached to 373.96 ± 15.65 g in 420 days of production period. Average protein efficiency rate, protein store rate and protein consumption values of cultured meagre were 1.05 ± 0.11%, 11.49 ± 2.98% and 56.67 ± 14.52 g respectively. The total amino acid values varied between 14.97 ± 0.14 and 18.87 ± 0.10 g 100g^–1, the statistical difference among the study periods was significant (p < 0.05). Most of the total essential (EAA), non-essential (NEAA), and branched‐chain amino acid values of cultured meagre were decreasing with increasing fish size but EAA/NEAA ratios were increasing. The findings of this study showed that the composition of amino acids and the consistency of meagre culture were adequate and appropriate for human consumption and nutrition.

Length–weight relationship and condition factor of ten cyprinid fish species from the Caspian Sea, Urmia Lake and Persian Gulf basins of Iran

2021-02-12T20:45:22+00:00

In this study, the length-weight relationships (LWRs) and condition factor (K) were estimated for 1334 specimens belonging to ten species including Acanthobrama marmid, A. microlepis, A. urmianus, Romanogobio persus, Leuciscus aspius, Luciobarbus capito, L. mursa, L. caspius, Alburnus atropatenae and Petroleuciscus ulanus from the Caspian Sea, Urmia Lake and Persian Gulf basins of Iran. The total length and weight of the individuals varied from 3.4 to 84.5 cm and 0.4 to 6600 g respectively. The values of the slope parameter (b) and condition factor ranged from 2.99 – 3.38 and 0.79 – 1.25 respectively. LWRs with high correlation coefficients were calculated for all species (R² > 0.95). Based on the results, the allometric growth pattern of the studied species were positive except for L. aspius, L. capito, L. mursa and P. ulanus. This study provides useful data regarding the LWRs and condition factor of ten endemic fish species in Iranian inland waters that can be used in fisheries management, stock assessment and future studies.

Effects of feeding frequency on the growth and production performance of indigenous catfish Clarias batrachus (Linnaeus, 1758) in ponds of Northern Bangladesh

2021-02-10T03:32:27+00:00

Effects of feeding frequency on the growth performance and production of Clarias batrachus was evaluated for a period of 180 days. Feeding frequency were once (T₁), twice (T₂) and thrice (T₃) per day. Stocking density was 16750 fingerlings ha^–1. The fish were initially fed 28% protein containing formulated feed at the rate of 8% of body weight which subsequently reduced to 5% at the end. The water quality parameters were monitored fortnightly and found similar across treatments and remained within the suitable ranges for aquaculture. The mean weight gain was 41.14±0.15, 44.49±0.78 and 56.10±0.86 g and specific growth rate (SGR) of 1.29±0.002, 1.33±0.01 and 1.44±0.01% per day in T₁, T₂ and T₃ respectively. The highest survival rate was in T₂ (96.23±0.76%) whereas the lowest was in T₁ (95.32±0.76%). The lowest FCR (=best; 1.65±0.12) was found in T₃ and the highest FCR (=worst; 2.14±0.15) was recorded in T₁. The highest production was observed in T₃ (3559.27±85.95 kg ha^–1), which was significantly higher than that of other treatments. This study concludes that feeding three times per day is effective for C. batrachus.

Water pollution effects of river Saraswati and Kunti on livelihood: a case study of fishermen communities in Tribeni and Kuntighat, Hooghly, West Bengal

2021-02-02T20:27:31+00:00

A prolific study was conducted to find out the impact of pollution on the socio-economic status of the fishermen community of Tribeni, Kuntighat - Hooghly, West Bengal, who depend on the rivers Saraswati, Kunti and Ganga for their livelihood. Analysis of important water quality parameters clearly reflects the pollution status of the rivers Saraswati and Kunti. Investigation was carried out by a previously tested questionnaire and personal interaction with 100 fishermen based on which the probable reasons of decline in fish diversity were drawn, which consequently adversely affected the economic conditions of fishermen. The investigation revealed a positive correlation between discharge of industrial effluents, in turn depleting the availability of fish food organisms and fish diversity and warning socioeconomic conditions of fishermen. Results clearly indicate proper steps should be taken by the policy makers towards restoration of water quality and thereby helping the vulnerable fishermen.

Effect of carp species combination on production and economics of stinging catfish, Heteropneustes fossilis based polyculture in homestead ponds under drought prone area of Bangladesh

2020-12-25T03:38:10+00:00

Aquaculture of homestead ponds under drought prone areas is climatically challenged by increased temperature and decreased water level. These ponds are potentials for farming of a short cycle aquaculture species like Heteropneustes fossilis with carps but lack of appropriate species combination is the major constraint for promotion of this technique. To address this problem, an experiment was carried out during July to December, 2019 to evaluate the production and economics of H. fossilis based polyculture under different carp species combinations in homestead ponds in Tanore of Rajshahi district, Bangladesh. Three different combination of carps were tested under three treatments as T₁: Labeo rohita dominant carps (L. rohita 50%, Gibelion catla 25% and Hypophthalmichthys molitrix 25%); T₂: G. catla dominant carps (L. rohita 25%, G. catla 50% and H. molitrix 25%); and T₃: H. molitrix dominant carps (L. rohita 25%, G. catla 25% and H. molitrix 50%), each with three replications. Stocking densities were 123500 ha^–1 for of H. fossilis was and 988 ha^–1 for carps. Water quality was monitored monthly and found within acceptable range. T₃ was found significantly (p < 0.05) better than other groups in terms of yield and cost benefit ratio.