Spawning, larval development and spat settlement in the Venus clam Gafrarium tumidum (Roding, 1798) from south-east coast of India

Induced spawning, larval development and spat settlement of the venus clam Gafrarium tumidum (Roding, 1798) were studied. Brood clams (27.5-32.8 mm dorsoventral measurement / 5.3-15.8 g) collected from the natural bed were conditioned (24.0 -26.0 °C; 33.5-34.5 ppt) and subjected to thermal stimulation for spawning. Fertilised eggs were spherical in shape and measured, on an average 62 μm in diameter. Day one veliger larvae of mean size 91 ± 1.69 μm transformed into umbo stage on day 7 at a size of 149 ± 6.02 μm, pediveliger on day 11 at 180 ± 6.0 μm size developed functional foot which settled on day 13 at a size of 200 ± 6.945 μm. The growth of post-set clams was monitored and described upto 68 days and the growth equation was derived. Few surviving post-set clams transformed into juveniles and radial ribs were observed with naked eye when they were 2.3 mm in 75 days. These clams reached 6.4 mm in 165 days. Metamorphosis and larval growth are compared with that of other bivalve species reported earlier. Further, specific refining of methodology for post-set clam rearing would pave way for their mass seed production for aquaculture purpose

Seed production and farming of Indian pearl oyster Pinctada fucata- Winter School on Recent Advances in Breeding and Larviculture of Marine Finfish and Shellfish

Indian pearl oyster belonging to the Genus Pinctada occurs in the two Gulf zones of India ie., Gulf of Kutch in Gujarat and Gulf of Mannar in Tamil Nadu. Commercial fishery existed in GoM till 1961 and then has gone into a dormant period due to many reasons including insignificant natural settlement of spat in the pearl beds (‘paars’) of Gulf of Mannar. To sustain a pearl culture industry, a steady supply of pearl oyster seed and farming it to mother oysters is a pre requisite. Large scale collection of pearl oyster spats either by using spat collectors or from their natural beds was not always found dependable owing to the irregular spat fall. Hence, hatchery production of pearl oyster seed and mother oyster culture has become an essential aspect as far as pearl culture is concerned. The following account details the basic hatchery requirement, broodstock maintenance and spawning and hatchery production of spats of Pinctada fucata and the methods of farming the spats for mother oyster development

Shell Industries of Rameswaram Islands

Seashore has always been a fascinating and recreational place for young and old. In every seashore, people of diverse age groups can be seen moving around and picking things. What is that they are looking for and collectingl Yes, it is nothing but the 'SHELLS'. Shells are the hard calcareous part, literally the 'HOUSE' of the soft bodied Jiving animals called molluses. When the animal dies in course of time, the shells are washed ashore and strewned around in the Beach

Reproductive biology of Venus clam Gafrarium tumidum (Roding, 1798) from Southeast coast of India

The reproductive biology of tumid venus clamGafrarium tumidum (Roding) was studied in detail from the Southeast coast of India. Sample size ranged from 10.3 to 41.3mm. Sexes are separate but not di¡erentiated externally. Annual sex ratio male:female (M:F) deviated signi¢cantly from the 1:1 ratio with females dominating. Based on ova diameter progression of gonad smear and histology, four and two maturity stages of gonads were di¡erentiated in female and male clams, respectively. Peak spawning was observed during November and a minor one in April

Age and growth of the venus clam Gafrarium tumidum (Roding) from south-east coast of India

Age and growth of the Venus clam Gafrarium tumidum was studied in detail employing four conventional methods and an electronic package ELEFAN – 1. The growth rate obtained by all the methods was more or less similar and comparable with one another. The clam reached a length of 24.4, 31.9 and 37.7 mm at the end of 1st, 2nd and 3rd year of its life. Growth rates of male and female clams were similar and observed to be faster in the first year and then tended to slow down with age. The life span of Gafrarium tumidum was estimated to be 3 years

Studies on the marine fauna of the Mahatma Gandhi marine national park, Wandoor, South Andaman Part 1 Corals

A comprehensive survey was carried out during October 1990 to April 1991 to document the marine flora and fauna found in the Mahatma Gandhi Marine National Park, Wandoor, South Andaman

Observations on broodstock maintenance, breeding and early larval development of the common spider conch Lambis lambis (Linnaeus, 1758) in captivity

Spider conches are common in shallow waters of the Indian coast. Of the eleven species reported from Indian waters, six species of the genus Lambis are categorised under Schedule IV of the Indian Wildlife Protection Act, 1972. Studies on the breeding of Lambis spp. are limited Considering its importance, an attempt was made to breed the common spider conch Lambis lambis, under controlled conditions. The brooders ranged from 152-184 mm/80-400 g in size/weight. They were maintained on macroalgal diet under static as well as airlift recirculation system. The conch shells, after 4 months of maintenance, exhibited mating behaviour and laid eggs under captivity during October-December 2010. The morphology and development of the embryo within the egg filaments, hatching, embryonic and early larval development up to 35 days post-hatch (dph) is detailed and compared with the similar observation made at Majuro atoll, Marshall Islands

CMFRI guides Sippikulam Fisherwomen in successful Marine Pearl Culture

During 2009-‘11 with the funding assistance from the Centre for Marine Living Resource and Ecology, (CMLRE), Ministry of Earth Science, Govt. of India, a ‘Technology demonstration and transfer’ project on ‘Marine pearl culture’ was formulated and implemented at Sippikulam Village, Tuticorin by TRC of CMFRI

Association of molluscan fauna with the coral reefs of Gulf of Mannar

Coral reefs are one of the important ecosystems in India. Major coral families of Gulf of mannar such as Acroporidae, Pocilloporidae, Poridae were collected. The above reef building corals harboured 51 numbers of molluscan species during this study. Pteria chinensis, Ostrea sp, Nerita rumphi and Cypraea tigris were noted from the study area. The gastropods are mostly associated with the coral reefs than the bivalves. The present study will reveal the diversity of molluscan fauna harbored in the different habitat of corals

Experimental culture of green mussel, Perna viridis (Linnaeus) in the Andamans

Experiments were conducted for the first time In the Andamans to culture green mussels, Perna viridis in veloo netting bags and coi,r ropes in back water creek and inshore water. While growing of mussels in velon netting bags did not succeed, the rope method gave encouraging results. Mussels of 47-81 mm sizes were collected for this purpose from natural habitat and seeded to the coir ropes