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Cleaning process of window pane oyster in the intertidalarea during low tide

Fig. 2. Close view of window pane oyster

Geo-coordinated and Geo-referenced Map showing fishingvillage where Window Pane oyster collection activity isbeing carried out

shell collector travels 5 km up and down usingspecially made thermocol raft and collect shellsdaily by hand picking. Locally these sea shells areknown as “Kachga” (Fig. 2). The collected shellsare sold to the merchants at a rate of ` 6/kg. Eachwomen collect on an average about 12-15 kg shellsfrom the shore. During lowest spring tide, they areable to collect up to 25 kg. On an average, a womanmakes ` 60-75 per day from the shells she collects.The survey conducted under NAIP project“strategies to enhance adaptive capacity to climatechange in vulnerable regions” reveals that, afterDighi port construction, the nearby area of Kudgaonvillage has witnessed abundance of windowpaneoyster. At present, the collection of windowpaneoyster has become an alternative source for incomeof the fisherwomen in this region.

Multifarious utilization of shrimp waste at Visakhapatnam

Madhumita Das, Shubhadeep Ghosh, Biswajit Dash, Maheswarudu G.,Hanumanth Rao M. V. and Venkatheswarlu O.C.H.Visakhapatnam RC of CMFRI,Visakhapatnam

Shrimp with 16% of the total value ofinternationally traded fishery products (Food andAgriculture Organization, 2009) constitute the majormarine resource traded in terms of value. Frozenfish and frozen shrimp are the important marineexport items. About 85 species of shrimp are known

to exist in Indian waters of which 55 species arereported either as commercially important or havingconsiderable demand in the local as well asinternational markets.

The recovery of biochemical compounds fromseafood waste materials, which could be used in

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Fig. 3. Headless shrimps for transport and trade

Fig. 4. Drying of shrimp wastes at Visakhapatnam FishingHarbour

different ways, is a promising area of research fordevelopment of methods for utilization of seafoodby-products. The solid shrimp waste viz., head andshell accounts approximately 40-50% of wholeshrimp weight. These wastes contain protein (35-40%), chitin (10-15%), minerals (10–15%) andcaroteinoids (Sachindra and Bhaskara, 2008). InIndia, Central Institute of Fisheries Technology(ICAR), has initiated research on chitin and chitosan.They found that dry prawn waste contained 23%and dry squilla contain 15% chitin (Madhavan andNair, 1974). They also reported that chitinous solidwaste fraction of the average annual landing ofshellfish ranges from 60,000 to 80,000 tonnes. Theprice of chitosan, a cationic polysaccharide is $ 7.5for 10 g.

The annual landings of both penaeid and non-penaeid prawns at Visakhapatnam ranged from 7797t to 10636 t during 2008 - 2012 period with an annualaverage landing of 9717 t (Fig.1). Random samplesof both high and low value shrimps were collectedto estimate the amount of wastes generated. Thehead generally constitutes 38 to 40% in both the

minimize the pollution problem and at the sametime maximize the profits of the processor. Shrimpheads and the smaller legs of crabs can be collected

Fig. 1. Visakhapatnam Fishing Harbour

Fig. 2. Mean monthly variation in prawn catch and wastegenerated during 2008-2012 at Visakhapatnam

types and the shell constitutes 11to 14%. In low valueprawns the weight of the shell is 2 to 4%. Theseshrimp wastes constitute about 53% of the totalwaste. During the period 2008-2012 the total shrimpwastes generated ranged from 4132 t to 5637 t withan average 5150 t annually (Fig. 1).

Shrimp waste is usually dried on the beaches thatresults not only in environmental pollution but alsoreduces the recoverable components (Fig. 2). Abetter economic use of the shrimp head would

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from the landing centres and fish markets, cleanedand supplied to small restaurants, hotels and addedto the common Indian recipes. Shellfish head wastecan be used in production of soups, stocks andsauces for retail sale. Utilization of fermented fish/shellfish sauces in ancient times was common inRome and is now extremely popular in many Asiancountries where they form a staple part of the diet.Autoclave treatment of shellfish waste can be donewhere steam is applied under pressure for a specificperiod of time. This produces a clean sterilematerial with flesh, shell and an organic liquid. Thesterile shell can be separated from the liquid, sortedand treated for use in a wide range of secondaryproducts. With further treatment the liquid can beused to produce fertilizer, or it can be anaerobicallydigested to produce methane for use as biofuel.

The fleshy wastes from shellfish are suitablematerial for baits. Fishermen at Lawsons Bay andother landing centres at Visakhapatnam have to buythe bait at ` 200/- per kg which adds to the totalfishing cost. Fishing of yellowfin tuna Thunnusalbacares and other tunas using hooks and line bythe traditional fishermen at different landingcentres of Visakhapatnam is a regular activity usingshrimps as bait. Rohit (2010) reported that thecrustaceans were the most abundant prey items foryellowfin tuna. ‘Single species’ baits and ‘Mixedspecies’ baits with low value shrimps can be testedby the fishermen to reduce the cost of baits. Shrimpwastes can also be used for preparation of compostalong with equal amount of cowdung with 10% ureaand applied as manure in brackishwater shrimpculture ponds.

The shrimp waste also contains usefulcomponents such as protein, lipid and astaxanthinpigment, thus making the commercial shrimp wastean attractive material for extraction of the above-mentioned components (Meyers, 1986). Astaxanthinis a natural nutritional component, an antioxidantand can be used as a food supplement. In India cod

liver oil and other fish oil are given as foodsupplement for providing omega-3 fatty acids whichhave beneficial effects on cardiovascular health,inflammation, mental health, andneurodegenerative diseases. Recent studies havereported that adding the antioxidant astaxanthinto fish oil reduces its susceptibility to oxidation andmakes its immunomodulatory properties morepotent. Crustacean exoskeletons contain 15–20%chitin by dry weight. The production of chitin andchitosan from crustacean canning has provedenvironmentally attractive and economicallyfeasible, especially when it includes the recoveryof carotenoids. Shrimp waste is one of the mostimportant natural sources of carotenoids and thehead and body carapace can be used for carotenoidextraction with various organic solvents and solventmixtures under various extraction conditions(Shahidi et al., 1998). The recovered carotenoidscan be effectively used instead of syntheticcarotenoids in aquaculture feed formulations, andthe residue available after extraction may be usedfor the preparation of chitin/chitosan. Conventionalprocessing methods are time consuming andexpensive and therefore innovations in theprocessing methods will reduce time and cost.Chitosan, produced from shrimp and crab shell, haswide range of applications from cosmetic topharmaceutical industries. Protein and pigmentsfound in shrimp waste are excellent animal feedsupplements.

Proteases are the most important group ofindustrial enzymes used in the world and find severalapplications. Proteolysis is one of the gentlemethods for recovering proteins from shrimpwastes. Rich protein hydrolysates generated withlow fat content can be useful for food and feedpurpose. The insoluble fractions generated can befurther separated and reutilized. The utilization ofthe shrimp wastes in a proper manner will help tomake the industry environment friendly and moreefficient.