• Waste minimisation in fishing operations

      Boopendranath, M.R. (2012-07)
      Sources of wastes in fishing operations mainlyinclude bycatch discards; processing wastes wherecatch is processed onboard; plastic wastes due toabandoned, lost and discarded fishing gear; bilgesand other wastes from the vessel operations. Fishingsystems in general have an associated catch of nontargetedorganisms known as bycatch. Non-selectivefishing gear that is not modified or equipped toexclude non-targeted organisms, may take a significantquantity of bycatch of non-targeted finfish,juvenile fish, benthic animals, marine mammals,marine birds and vulnerable or endangered speciesthat are often discarded. Average annual globaldiscards, has been estimated to be 7.3 million t,based on a weighted discard rate of 8%, during1992-2001 period. Trawl fisheries for shrimp anddemersal finfish account for over 50% of the totalestimated global discards. Plastic materials areextensively used in fisheries, owing to their durabilityand other desirable properties, contributing tothe efficiency and catchability of the fishing gear.However, plastics biodegrade at an extremely slowrate compared to other organic materials. Abandoned,lost or otherwise discarded fishing gear(ALDFG) and related marine debris have beenrecognized as a critical problem in the marineenvironment and for living marine resources.Prevention of excess fishing capacity by appropriatemanagement measures could lead to enormoussavings in terms of fuel consumption, emissions andbycatch discards from the excess fishing fleet, capitaland operational investments and labour deploymentin capture fisheries, with significant economic gains.In this paper, wastes originating from fishingoperations are reviewed, along with their environmentalimpacts and possible mitigation measures
    • Water imbibition and thawing losses from frozen prawn meat

      Mathen, C.; Thomas, F. (1987)
      Prawn meat which was never in contact with ice or water prior to freezing was frozen at -30°C and was studied up to six months of storage at -23°C for thawing losses and cooked characteristics of the thawed material. Thawing loss was nil in unwashed samples after three days of storage and it gradually increased to 6.6% after 6 months compared to 6.0 and 18.2% in the washed samples during the same periods. It is inferred that the high thawing losses observed in commercial frozen prawn meat immediately after freezing may be mainly an after effect of the water imbibed during the pre-freezing stages. During frozen storage, the changes in texture observed by sensory methods on the cooked product were more in the washed sample indicating that the imbibed water or constituents washed out of the tissue play an important role in textural changes in prawn meat during frozen storage.
    • Water soluble nitrogenous component from squilla (Orato squilla nepa)

      Lekshmy Nair, A.; Prabhu, P.V. (1982)
      A water soluble hygroscopic powder has been isolated from squilla in good yield, ranging from 3.5 to 5.0% of the fresh raw material, by a simple direct method. The process consists of homogenising squilla with an equal quantity of water, removal of chitinous matter from the slurry by filtration, heating the filtrate at 0.7 kg/sq.cm steam pressure for 15-20 minutes, removal of the precipitated protein by filtration and concentration and final drying in vacuum of the filtered cooled liquor. The pale brown powder so obtained consists mainly of peptones and proteoses and has been found to be comparable to BDH peptone for growth of bacteria, ability to serve as source for tryptophan for indole production and to provide substrate for the production of hydrogen sulphide. Comparative studies have been made on similar water soluble fractions from two species of prawns, namely, Metapenaeus affinis and Parapenaeopsis stylifera.