Escalation in shrimp production in the Sierra Leone industrial fishery

Applying Turkey's jackknife method on MSY estimates from the surplus production models of Schaefer and Fox showed that the optimum yield for shrimps in industrial fishery in Sierra Leone is estimated at 2,686.8 t with 15,822 fishing days. Annual catch for 1996 was 2,788 t, indicating an escalation in exploitation which, if prolonged, could bring reduced productivity as experienced in the fishery some years ago.

Biological survey: River Teign and tributaries with references to the discharge of ball clay wastes

This is the Biological survey of River Teign and tributaries with references to the discharge of ball clay wastes, document produced by South West Water Authority in 1973. This report focuses on on-site assessment of the benthic macro-invertebrates of the lower River Teign, River Bovey, Ugbrooke Stream and Blatchford Brook was undertaken on 19th and 22nd August 1977 to assess the effects of discharges from ball clay mining premises. Inspection of aquatic fauna in the field is of necessity, less extensive than laboratory identification of sorted samples, so that the resulting data underestimates the water quality. This is more pronounced in the Chandler Score than in the Trent Biotic Index which does not take account of species abundance. Chandler should thus be interpreted by the trends described rather than by absolute values calculated.

Prioritizing county-level well-being: Moving toward assessment of Gulf Coast counties impacted by the Deepwater Horizon Industrial Disaster

To develop a portfolio of indicators and measures that could best measure changes in the social, economic, environmental and health dimensions of well-being in coastal counties we convened a group of experts March 8-9, 2011 in Charleston, SC, U.S.A. The region of interest was of the northern Gulf of Mexico, specifically, those coastal counties most impacted during the explosion and subsequent oil spill from the Macondo Prospect wellhead during the summer of 2010. Over the course of the two-day workshop participants moved through presentations and facilitated sessions to identify and prioritize potential indicators and measures deemed most valuable for capturing changes in well-being related to changes in or disruption of ecosystem services. The experts reached consensus on a list of indicators that are now being operationalized by NOAA researchers. The ultimate goal of this research project is to determine whether a meaningful set of social and economic indicators can be developed to document changes in well-being that occur as a result of changes in ecosystem services. The outcomes and outputs from the workshop that is the subject of this report helped us to identify high-quality indicators useful for measuring well-being.

Induced breeding, embryonic and larval development in Heteropneustes fossilis (Bloch) in the agro-climatic conditions of Maharashtra

Heteropneustes fossilis was induced bred for the first time in the agro-climatic conditions of Maharashtra, India. The embryonic development was completed within 16-18h after fertilisation. Head and tail ends were distinguishable after 3h and 11-12 somites were visible after 6-7h. The eggs started hatching after 14h of incubation. Average hatching time was 16-18h at 26 degrees C. In first day old pro-larva, notochord was deflected upwards, eyes were darkly pigmented and alimentary canal appeared. In fourth day old post-larva intestinal coiling could be seen and yolk was absorbed. Aerial respiration started by 8th day. The 10 day old post-larva was free swimming and fed voraciously attaining a length of 20 mm in 30 days.

A case study on the impact of industrial effluent disposal on the fishery of Amba River estuary, Maharashtra

The impact of waste discharge on fishery resources is a matter of great concern. The accepted norm in all environmental impact assessment studies is to avoid areas of high fishery potential while locating a marine outfall. Contemplating on this aspect a case study was conducted in the Amba River estuary before and after the establishment of a petrochemical complex at Nagothane. The treated wastewater from this complex is released through a subsurface outfall after adopting effective control measures for marine disposal of waste. Experimental trawling was done at five locations covering a distance of 30 km during 1990 to 1991. The catch rate within the estuary varied from 0.6 to 255 kg/h (av 24 kg/h). The trend indicated considerable decrease in fishery potential from the mouth of the estuary (av 64 kg/h) to the upstream location (av 11 kg/h). A total of 49 species of fishes, 16 species of prawns, 7 species of crabs and 1 species of lobster were identified from the collections. Number of species gradually increased from the interior segment at Dharamtar (8) to the outer area near Revas (18). A comparison of the quantitative and qualitative nature of the post outfall and pre outfall data revealed only marginal difference. The study indicates that if necessary precautions are taken to render the waste harmless the marine ecology will hardly be affected.

Recolha de camarões reprodutores vivos da espécie Fenneropenaeus indicus da pesca de arrasto semi-industrial na Baía de Maputo

The collection of wild breeders of the Indian white prawn Fenneropenaeus indicus from two semi-industrial trawlers fishing in Maputo Bay is assessed for the period between August and November 1993. The daily mean catch (12-21 prawns dayˉ¹) increased until October but monthly yields were not significantly different (P>0.05). The monthly mean mortality ranged between 8% and 20% and was similar for males and females. More than 70% of the catch comprised small (grade B1: 20-39 g) and medium size (grade B2: 40-59 g) prawns. While males were exclusively of grade B1 (99%), the females were predominantly of grades B2 and B3 (60-80 g). The collection of larger breeders (grade B4: >80 g) was low and represented only 1% of total catches and a maximum of 3% of females. The net profit of breeders collection increased with size (grade) of prawns, and represented a maximum yield of 114% for grade B3. The added value of live prawns exceeded 450% of the cost to the fisherman, but decreased with size of breeders. It is considered that the semi-industrial trawling fishery operating in Maputo Bay has potential for supplying wild breeders of the Indian white prawn for aquaculture. This activity can also contribute to value adding of part of the catch traditionally destined for human consumption.

Techno-economic analysis of production and marketing of marine by-products in India

Marine by-products coming under the ancillary products group found many applications in pharmaceutical and industrial sectors. Although many of these products are fetching very high price at the export market, adequate statistics regarding their current production, marketing and utilisation is lacking. The present analysis deals with the production potential, level of exploitation, uses, export growth rate and potential for the future of some of these marine by-products. The analysis revealed that an estimated quantity of 205 t. of shells, 10 t. of gastropod operculum, 4,932 t. of shark liver oil and 4,384 t. of shark cartilage could be produced annually in India with the current landings. The production potential of chitin is estimated as 3,560 t. from shrimp shell wastes and 1,354 t. from crab shell wastes. The high unit value of different products clearly indicates the scope for their development by evolving appropriate utilisation and marketing strategies.

Soluble protein isolated from low cost fish and fish wastes

The method of preparation, composition, amino acid content, protein efficiency ratio and areas of possible application of water soluble protein isolates from low cost fish and fish wastes are discussed in detail in this communication.

Growth performance evaluation of genetically improved silver barb (Barbonymus gonionotus Bleeker) in different agro-ecological zones in Bangladesh

On farm trials of silver barb with other carps were carried out in 40 ponds during May to October 2005 in four agro-ecological zones viz., Trishal, Muktagacha, Parbotipur and Paikgacha in Bangladesh. In Trishal and Muktagacha zones, ponds were stocked with silver barb, silver carp and common carp at the stocking density of 11,500 fish/ha, whereas in Parbotipur and Paikgacha zones, ponds were stocked with silver barb, rohu, catla and mrigal at the stocking density of 10,000/ha. Among the ponds, 50% (20 ponds) were stocked with BFRI improved stock of silver barb (Treatment-1) and rest of the 20 ponds stocked with local silver barb stock (Treatment-2). The harvest weight of BFRI improved silver barb were 149±16.01, 168±18.06, 198±14 and 230±9.25g in Trishal, Muktagacha, Paikgacha and Parbotipur, whereas the data obtained at 113±15.52, 136±20.66, 170±17.0 and 205±12.10g for local stock of silver barb, respectively. In all trials, the harvest weight of BFRI improved stock showed significantly higher growth performance (P<0.05) over the local stocks.