Shrimp industry in and around Mandapam

Mandapam is an important place in view of living marine resources, particularly the. shrimp. The. Term 'Shrimp' includes prawns and lobsters, Shrimp industry has its full compliment of infrastructure facilities from building trawlers, to processing at Mandapam

Shrimp hatchery

Successful spawning of Penaeus japonicus under controlled conditions and their subsequent rearing upto the juvenile stage by Hudinaga (1942) and his team paved way for the large scale hatchery production of shrimp seed for aquaculture

On the occurrence of mature specimens of Metapenaeus burkenroadi Kubo in the Pulicat lake

Mature females and males of Metapenaeus burkenroadi with fully developed ovaries and petasmae were collected from the Pulicat lake in January 1972. The possibility of their breeding inside the lake and the feasibility of utilizing this species for culturing in the Pulicati lake are indicated. Some morphological features of the specimens which are at variance with previous descriptions of the species are pointed out

Exploitation of juveniles of green tiger prawn. Penaeus (penaeus) semisulcatus, along Palk Bay and its impact on the prawn fishery of the region

The green tiger prawn Penaeus (Penaeus) semisulcatus, contributes to over 50% of the total prawn catch landed along the Palk Bay coast. They are caught by the indigenously developed trawl-like bottom nets and trawl nets operated by non-mechanised and mechanised fishing vessels within the 12 metre depth zone With the increasing demand for prawns by the export trade, intense fishing for juvenile prawns which inhabit the sea grass ecosystem near the shore It t-iking place all along the coast. The results of the survey carried out on this exploitation pattern are reported in the pape

Culture experiments on the edible oyster Crassostera madrasensis in the Bheemunipatnam backwater

Studies on the possibilities of culture of edible oyster Crassostrea madrasensis in the Bheemunipatnam backwater were conducted during 1977-79. Spat collection experiments using different types, of spat collectors showed that empty oyster shells and close meshed plastic baskets were most efficient. Setting of spat on the spat collectors kept near the bottom was more than on those kept suspended off bottom. Spat fall was observed throughout the year with peaks in March and October. The oyster attained a size of about 8 cm during the first year. Low salinity during monsoon months appeared to retard growt

Studies on some aspects of biology and transplantation of the clam Meretrix casta (Chemnitz) in the Bheemunipatnam backwaters

Studies on the growth of Meretrix casta (Chemintz) showed that the clams in the natural bed grew at the rate of 3.6-3.9 mm per month while the speciemens kept in the cages showed growth rates of 0.9 mm and 0.77 mm per month respectively for on bottom and off bottom culture. The equation for length weight relation was found .The spawning period of M. casta was found to be between April-May. Dispersal of clam seed in virgin areas did not yield fruitful results as there was heavy mortality due to floods

Sea ranching of prawn

Sea ranching of praw

Technological advancements in shrimp seed production with reference to demand and supply

Shrimp aquaculture has been developed as an industry to cater to the ever increasing export market. Controlled production of the desired species of shrimp seed is vital for the sustained development of shrimp aquaculture industry. The major technologies for shrimp seed production are the Japanese system and the Galveston system. Over the years these systems have undergone a series of modifications to suit the location, species and local requirements. In Kerala two major systems for shrimp seed production are in vogue, one developed by the Central Marine Fisheries Research Institute and the other by the Kerala Fisheries Department. Semidosed hatchery technology is adopted mainly in these systems so as to take advantage of the prevailing climatic conditions of this area, thereby reducing the production cost. As this technology relies mainly on the prevailing climatic conditions, shrimp seed production can be undertaken for a part of the year only. During monsoon months the hatchery ran conveniently switch over to the production of 'Scampi' seed, which has great demand when the production of shrimp seed is not profitable due to unfavorable climatic conditions such as low salinity and temperature, thereby assuring year round operation of the hatchery and increasing the profitability of the unit. The present paper also deals with working details and economics of two types of hatcheries to cater to the needs of two levels of entrepreneurs. A backyard hatchery with a production capacity of 3 million seeds (25 million shrimp seed and 0.5 million seed of 'scampi') established with an initial investment of Rs. 3.7 lakhs on infrastructure and an annual operating cost of Rs.125 lakhs can yield a net profit of Rs. 0.83 lakhs per year at an average production cost of Rs. 126/1000 seeds. A medium scale hatchery with a production capacity of 15.8 million seeds (15.1 million shrimp seeds and 0.7 million 'scampi' seeds) established at an initial investment of Rs. 4438 lakhs and operating cost of Rs. 4.81 lakhs can yield a net profit of Rs. 6.08 lakhs per year at an average production cost of Rs. 113/lM)O seeds

Hatchery Production of Shrimp Seeds

T he pioneering efforts of Hudinaga in the successful spawning of Penaeus japonicus under controlled conditions and their subsequent rearing upto the juvenile stage have paved way for the large scale hatchery production of seed of penaeid prawns for aquaculture. There are two basic hatchery techniques for mass rearing of larvae of penaeid prawns - Japanese techniques and Galveston technique. These techniques have been appropriately modified to suit different geographical and climatic conditions and different species of prawns used for aquaculture. Thus m any gradations between these two techniques have been noticed in different parts of the world. Som etim es combinations o f these two techniques have also been used

Some aspects of biology and exploitation of the green tiger prawn, Penaeus (Penaeus) semisulcatus de Haan from Mandapam (Palk Bay) and Pamban (Gulf of Mannar), southeast coast of India

The results of the exploitation of Penaeus (Penaeus) semisiiicaliis by the Mandapam-based small mechanized vessels and shrimp trawl nets operating at 7 11 m depth in the Palk Bay, and Pamban-based shrimp trawl nets operating in the Gulf of Mannar at 7-45 m depth, are presented. The catch per unit of effort in both the regions declined from 1986-87 to 1988 89. The spawning took place throughout the year with two peaks, one during July-September and the other during February-March. The overall growth rate, estimated from the modal progression in the monthly length frequency distribution, was 13.75 mm per month for females (60-285 mm) and 12.3 mm per month for male (71 225 mm) in the Palk Bay. In the Gulf of Mannar it was 13.0 mm per month for female (86- 225 mm) and 10.0 mm per month for males (91 180 mm). The differential growth between the sexes occurred as the prawns grew to 40-50 mm size. Males/females attained a size of 115/125 mm at the end of 6 months, 170/195 mm at 12 months, 215/250 mm at 24 months and 230/270 mm at the end of 36 months in the Palk Bay. The corresponding male/female sizes in the Gul I" of Mannar were 120/135 mm, 170/200 mm. 200/250 mm and 205/265 mm. The commercial fishery in both the regions was contributed by the 0-year group prawns. The total mortality rates in the population exploited in these regions were relatively high, particularly for the male population. The stock in the fishing grounds considered at present is being subjected to over-exploitation