Asian Journal of Fisheries and Aquatic Research

Daha river, a threatened water body of polluted nature in the Gopalganj district of Bihar was studied for its degradation and possible restoration. The study reveals high rate of sedimentation and agricultural activities, changes in water quality and biotic community. Agricultural activities have led to high input of nitrogen (N) and phosphate (P) fertilizers along with pesticides being used by the farmers. The positives response of restoration practices was observed with partial improvement in fish-productivity due to hindrance factors acting upon severe fish species.The mean concentration of phosphate, nitrate and ammonia corresponds about 0.60-1.40 mg/l, 1.30-2.50 mg/l and 23-43 mg/l in polluted river, while after restoration declines to 0.20-0.48 mg/l, 0.60-1.10 mg/l and 14-27 mg/l, respectively indicating more suitable towards fish productivity. The observations on other water parameters also showed similar trend during partial restoration of Daha river. The cause of algal bloom and other macrophytic population is inorganic ammonia, however, organic pollution is also in polluted state observed as more quantity of ammonia than nitrate especially at site II and Site III during the study period. The concentration of nitrate is much higher than the critical value in polluted river which causes algal diversity and macrophytic vegetation. Therefore, partial restoration of the river helped to enhance fish productivity concluded from this study.

This study aims to analyze the added value of the catfish skin cracker product in CV. Raja                Patin, Sugiharjo Village, North Sumatra Province. The method used in this research is a case study method and quantitative descriptive analysis as data analysis used. The sampling              technique was carried out using a purposive sampling method. The added value of the fish skin cracker product is IDR 31,700 / kg with an added value ratio of 67.44%. Fish products that are processed into fish crackers are worth 0.47 times the price of fresh fish. This indicates that processing activities provide a sizeable contribution to economic value added and product added value.

Sea cucumbers (Holothuria sp) are a leading export commodity for Indonesian fishermen. The increase in the selling price and demand for sea cucumbers in 2018 made fishermen in Cirebon Regency modify the fishing gear to maximize the catch of sea cucumbers which is called the sea cucumber dredge gear. The purpose of this research is to identify the specifications of the gear, catch, selectivity and productivity of the sea cucumber dredge gear operated in Cirebon Regency, West Java. The research was carried out in July 2019 - September 2020 in Gebang Mekar District. Fishing gear measurements were carried out along the fishing village of Gebang Mekar Village. The method used is a case study method with quantitative descriptive analysis to determine the specifications of the fishing gear and catches taken by interviewing fishermen. The results showed that sea cucumber dredge gear was included in the dredge gear category. The components consist of a mouth, a hook, a frame, a net, and a rope of varying sizes. The materials used are iron and stainless steel, weighing up to 50 kg. The main catch of sea cucumber in Cirebon Regency consists of Phylloporus sp or ondol - ondol and bycatch in the form of several demersal fish, with a total of 7 species. This fishing gear is classified as not selective because of its construction which has a net with a small mesh size (2-5 inches) so that this fishing gear captures many species of different sizes and the results of the calculation of the proportion show that bycatch has a percentage of 74,75%.

Nilem fish (Osteochilus hasselti) are native Indonesian fish that live in freshwaters, such as rivers and swamps. This research aims to obtain the composition of proximate cakwe with the addition of nilem fish protein concentrate. Proximate parameters observed were water content, protein content, fat content, and ash content using the Association of Official Analytical Chemists (AOAC) method. This research was conducted from March 2019 to January 2020 at the Laboratory of Fishery Product Processing, Faculty of Fisheries and Marine Sciences, Padjadjaran University and Laboratory of Chemistry Research, PPBS, Padjadjaran University. The method used is an experimental method with the treatment of 5% nilem fish protein concentrate. The proximate test results showed that cakwe with the addition of nilem fish protein concentrate contained 27.72% water content, 10.42% protein content, 5.36% fat content, and 4.38% ash content.

The purpose of this research was to determine the appropriate combination of commercial feed and maggot to produce optimum growth, feed efficiency and food conversion ratio for catfish. This research used experimental method with Completely Randomized Design (CRD) consisting of four treatments and four replications. The study was conducted in the Ciparanje Land Fisheries Area, Faculty of Fisheries and Marine Sciences, Padjadjaran University. The research was carried out between January - July 2019. The treatments are combination of commercial feed and maggots consisting of A (control, 100% commercial feed), B (75% commercial feed + 25% maggot), C (50% commercial feed + 50% maggot) and D (25% commercial feed + 75% maggot). The parameters observed were survival rate, daily growth rate, length ratio, feed efficiency, food conversion ratio and water quality. The combination of commercial feed and maggots affected the daily growth rate, length ratio, feed efficiency and food conversion ratio of catfish. The survival rate of each treatment was 88.75, 92.50%. Treatment C showed the value of highest daily growth rate, length ratio, feed efficiency namely 1.86%, 1.40%, 65.09% respectively and the lowest feed conversion ratio 1.54%.