Some aspects of biology of Octopus defilippi Verany, 1851 from the northwest coast of India

‘Lilliput longarm octopus’, Octopus defilippi Verany, 1851 has been reported for the first time from Mumbai waters, northwest coast of India. This species was observed in trawl catches off Mumbai during March-June from 2007 onwards and the dorsal mantle length (DML) ranged between 52 and 99 mm. The left arm ratio is 3>2>4>1 and the right arm ratio is 2>4>1>3. Relationship between DML and total body weight (TBW) was TBW = 0.01361 * DML 1.83443. Fish formed the major food item with 93.3% and 70.6% of individuals in the samples in mature condition

Commercially exploited edible bivalves off Mumbai

Bivalves are benthic molluscs occurring in intertidal to subtidal areas. In the food chain they feed low, mainly on plankton and detritus, which are abundantly available in the natural waters circulated by the tides . . Many species of bivalves occur abundantly along the Indian coast of which at least 50 species are commercially important. Edible oysters, clams, cockles, mussels and scallops are the prime groups, which contribute towards the fishery in the marine, estuarine and freshwater habitats

Fishery and biology of the octopus, Cistopus indicus (Orbigny, 1840) from Mumbai waters

Fishery of Cistopus indicus by trawlers at New Ferry Wharf from 2000 to 2009 in Mumbai waters is described. The catch showed an increasing trend up to 2006 and declined thereafter. The catch ranged from 2 t (2002) to 324 t (2006) and the catch rate from 0.002 kg/hr (2002) to 0.181 kg/hr (2006). The relationship between dorsal mantle length (DML) and total body weight (TBW) for males was TBW = 0.001053 * DML2.69321 and for females was TBW = 0.009 * DML2.19221. Fish formed the major food item of both the sexes. Majority of the males in the landings was in mature stage, while the maximum number of females was gravid. The size (DML) at 50% maturity for females was estimated as 82.7 mm. The diameter of mature ova ranged from 2 to 6 mm and fecundity was 13,26

Emergence of squid jigging in India

Cephalopods, locally known as 'Makul', have emerged in recent times as one of the prime foreign exchange earners in India. Trawl nets operating up to 100 m depth account for nearly 85% of the cephalopod landings in Indian marine waters. The introduction of high opening bottom trawl nets resulted in rapid increase in cephalopod productio

Record of inarticulate Brachiopoda, Lingula sp. from mangrove areas in Ratnagiri, Maharashtra and its unusual commercial exploitation

The Brachiopoda or ‘lamp shells’ belong to an ancient phylum of filter feeding marine worms. They live inside a pair of shells much like the bivalve; however, brachiopods differ from bivalves in many ways. Their shells have a definite dorsal and ventral (upper and lower) half, while bivalves, which are molluscs, have left and right halves to their shells. The brachiopods are so different internally that they have been grouped under separate phylum. Lingula is a genus of brachiopods with about eleven species within the family lingulidae

Population eruption of sunset shell Siliqua radiata (Linnaeus, 1758) along Versova beach in Mumbai

Sudden population eruption of Siliqua radiata during monsoon months (June-August 2008) was observed along Versova beach in Mumbai. Relationship between shell length (SL) and total weight (TW) was TW = 0.0001137 * SL 2.67922, shell length (SL) and meat weight (MW) was MW = 0.0000237 * SL 2.91756. S. radiata had isometric growth. The average density was estimated as 14 per square meter and the biomass was 153 g.m-2. The proportion of meat was 60%. Analysis of meat showed high amount of heavy metals namely copper, cadmium and arsenic

Gastropod operculum - An unique trade

After the onset of South-west monsoon along the west coast of India, swarming of blue bottle jelly fish the Portuguese man-of-war (Physalia physalis) is observed at Juhu and Girgaum beaches, Mumbai almost every year. Portuguese man-of-war, though often mistaken as a jellyfish, is a marine Cnidarian of the family Physalidae. Its venomous tentacles can deliver painful sting. In July, 2013 sudden strong winds and high tide had brought in several bluebottle jelly fish (Fig 1). For several people, a walk by the seaside at Juhu and Girgaum beaches during first week of July, 2013 ended in redness of skin, swelling, irritation, itching, blisters and severe body ache. The daily news papers carried news items on the marine venomous creature, Portuguese man-of-war and their venomous sting threat to public

Congregations of squids in inshore waters at Mumbai

Squids are known to form large congregations in inshore waters during spawning season. Spawning congregations of squids at staggered intervals along Kerala-Karnataka coast (September – October) have been reported which generally occur along the southwest coast of India with varying intensities during the post monsoon period. The studies suggest that spawning of squids usually occur when water temperatures increase

Studies on the wedge clam Donax scortum Line Versova beach Mumbai, North-westy coast of India

Donax scortum tum was observed along Versova beach in Mumbai. They ranged in length between 48 to 52 mm. Analysis of meat by AAS showed high amount of heavy metals copper and cadmium in the tissues