Abstract:Labeo bata is one of the important minor carps in Bangladesh with great demand as good table fish. The study was conducted to observe the breeding performance at different management practices in Mafatema, Rupali, Modhumoti and Anan fish hatchery and disinfection treatments of water, eggs and fry in Jessore, Bangladesh during 10 March 2014 to 15 May 2015. An improvement in broodstock nutrition and feeding has been shown to greatly improve seed production. Protein and lipid percentage of broodstock diet have been identified as major dietary factors. Protein level was 24.77%, 23.47%, 18.08%, 17.78% and lipid level was 11.07%, 9.50%, 7.74%, 8.14% in Mafatema, Rupali, Modhumoti and Anan fish hatchery respectively. Three concentrations of four chemical-formalin (10, 20, 30 mg/L), malachite green (1, 3, 5 mg/L), NaCl (1, 2, 3 g/L) and methylene blue ( 1, 3, 5 mg/L) treatment regimes and a control were compared for efficacy in treating L. bata eggs to prevent fungus and bacterial infection and improve hatch and survival rate of fry. Highest correlation value between absolute fecundity and body weight (r=.938, p<.05) and total length (r=.891, p<.05) and gonadosomatic index (26.2%) were found in Mafatema fish hatchery among four experimental hatcheries at 24.77% protein and 11.07% lipid level. Better fertilization rate (84.2±5.17%) and hatching rate (82.0±4.30%) were found in Mafatema and Rupali fish hatchery respectively that has significant difference (P<0.05) from that of Modhumoti and Anan fish hatchery at higher protein and lipid level. Lowest deformity rate (6.05+2.65) was observed in Mafatema fish hatchery that was significantly different (P<0.05) from that of Modhumoti fish hatchery. In case of disinfection treatment, methylene blue at 1mg/L bath treatment daily for 4 days showed significantly higher hatching rate (92.33±3.51%) and survival rate (94.33±4.73%).

Common carp (Cyprinus carpio) is one of the commercially important and commonly cultured fish. In the hatchery intensive incubation leads to microbial overgrowth in C. carpio eggs that hamper egg development, hatchability and larval survivability. The aim of this study is to find out causes of mass mortality in C. carpio eggs during peak-breeding season between March to May 2015 at Mafatema fish hatchery, Chanchra, Jessore sadar upazilla. In the present study three disinfectants with three different concentrations in each such as methylene blue 1, 3 and 5mg/L., malachite green 1, 3 and 5mg/L., sodium chloride 1, 2 and 3g/L were used to observe the hatching rate of fertilized eggs and survival rate of larvae. Bacterial load of culture water was examined during the induced breeding of C. carpio with mycological examination of egg samples with different disinfectants. The total bacterial count fluctuated from 3.4 x 10 8 CFU/ml to 32.7 x 10 8 CFU/ml during the period of fertilization to 4days of hatching. The fertilized eggs infected by Saprolegnia spp. were appeared as tuft hairy like balls with a white cottony envelop. Among all the treatment 1mg/L methylene blue, 3mg/L malachite green and 1g/L sodium chloride showed significantly better (P<0.05) hatching rate 95·33±2·08, 88.00±2.64 and 92.33±4.04% respectively. The same concentration of methylene blue, malachite green and sodium chloride showed significantly better (P<0.05) better survival rate 95·00±4.35, 75.00±3.00 and 87.00±6.24% respectively. Finally among all the treatment 1mg/L of methylene blue showed significantly better (P<0.05) hatching and survival rate 95·33±2·08% and 95·00±4.35 % respectively. So 1mg/L of methylene blue is the best disinfectant for C. carpio fertilized egg treatment.

Fisheries biodiversity is important especially for the rural poor who often rely on fishing to earn their livelihoods. This study was carried out to examine the fish species diversity and livelihood status of fishermen around the Titas River falls under the villages of Radhanagar and Uzanchar at Bancharampur upazila of Brahmanbaria district. Data were collected from randomly selected 80 fishermen and analyzed using descriptive statistical tools, viz. frequency and percentage. A total of 55 fisheries species under 10 orders and 20 families were recorded from the Titas River. Cypriniformes was the most dominant order comprising 19 species followed by Siluriformes (12 species), Perciformes (8 species), Synbranchiformes (4 species), Channidiformes (3 species), Beloniformes (1 species), Osteoglossiformes (2 species), Clupeiformes (2 species) and Tetraodontiformes (2 species). Results also revealed that 60.0% of fishermen were belonged to the age group 31–50 years and 75.0% of them had no individual water body of their own. All of the fishermen were male, of whom 83.7% were married living in kutcha house (55.0%) and 52.5% of their families were nuclear type consisting of husband wife and their children. The illiteracy rate among fishermen was 26.0%, while 41.3% of them could sign only. Many fishermen (68.8%) were able to sell their catch at local market and 60.0% had an annual income ranging BDT 71,000–100,000 (= USD 844.887–1189.92). Overall, fish biodiversity in the Titas River is declining as compared to abundance observed from previous findings. Moreover, the fishermen of that place are leading a poor life having lower income than that of the government minimum wage, a basic pay of BDT 8,250 per month. J. bio-sci. 27: 59-67, 2019

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Sea cucumbers belonging to the phylum Echinodermata are important marine invertebrates, generally occur in the sandy substrates and rocky shores near the bottom of sea. This review work has been attempted to make an interlink between biological and socio-economical perspectives of sea cucumber because of the high demand in the present world. The outer body part of sea cucumber (bêche-de-mer) has been recognized for producing secondary metabolites including vitamins and triterpenoid glycoside saponins that have profound ecological and bio-medicinal significance. Sea cucumbers are also used to remove arthritis pain, exert wound healing, and nowadays, are utilized in human health therapeutics and Asian folk medicine. Due to higher pharmaceutical, cosmeceutical and nutraceutical values, sea cucumber has become one of the most essential products, and fetched higher market prices and therefore, provide a significant earning source and employment opportunity to the coastal communities in many countries. The sea cucumber and its product have been considered to be the excellent bioresource in the invertebrate fishery, whose harvestings, transporting, handlings, processing and maintenance are easy, convenient and cost-effective. Historically, bêche-de-mer were harvested from the multi-species capture fishery and stored for long times for selling to the businessmen and traders directly on the site. As like other lucrative and expensive food items viz., fish-maws, shark-fins and abalones, sea cucumbers are taken into the account as the high-valued products in the world seafood markets. Nevertheless, bêche-de-mer product supply in the South-East Asian countries has been decreasing day by day because of unstrained harvesting and overexploitation. On the other hand, the marketing structure in these countries is typically ineffective and the trading networks are multifaceted. Due to the lack of proper information, fishermen are not usually getting proper values and actual prices from the sea cucumber products, whereas other distributors and value-chain members have made complex systems, which have led to high cost of the products. The sea cucumber products will still have higher possibility of trading throughout the world markets, that might eventually contribute to the global economy in a very worthwhile, significant and sustainable manner.