Biology and feeding behavior of Orbinia johnsoni

Orbinia johnsoni were studied from a small sandy beach near Mussel Pt., Pacific Grove, California, where they are most abundant at low tide levels in fine sand. They were found to have a mean length of 190 mm. The orbiniids were found with their guts the fullest during incoming to high tides. It is plausible that this is when they are feeding. It takes about 3 to 3.5 hours for food to travel through the length fo the gut. The orbiniids eat 93 percent sand and seven percent organic detritus. Special note should be taken that some food selectivity appears to be involved and that high percentages of organic matter in the feces are found in worms collected during low, outgoing tides. Evidence suggests that the worms are bottom feeders, not coming to the surface to feed.

Report on the biology of Pacific hagfish, Eptatretus stouti and the development of its fishery in California

Hagfish, often referred to as "slime eels", are familiar to most fishermen as pests that frequently devour fish caught by trap, hook, and gillnet. In the Republic of Korea (ROK or South Korea), however, hagfish are sought after as valuable fish not only for their edible flesh, but also for their skin, which is processed into leather used to make expensive purses, shoes, and other articles. In fact, because of a shortage of hagfish in the waters near the ROK, the leather industry there has started to import hagfish, first from Japan in the mid 1980's, then from the United States starting in 1988. This report describes the nascent fishery for Eptatretus stouti (Pacific hagfish) in California, and includes aspects of its life history. The hagfish industry in the ROK is also briefly described.

Biology and morphometry study of Drepane punctata (Cuv and Val) at juvenile stage of Bombay coast

The metric and meristic characters of Drepane punctata from Versova Fish Landing Centre of Bombay have been studied. The meristic characters showed considerable variations. The number of dorsal fin rays were relatively stable characters. Statistical interpretation of metric data indicated that there is a direct relationship between the preanal, predorsal in relation to total length and eye-diameter in relation to head length.

Some aspects of the biology of Trypauchen vagina Bloch and Schneider of Bombay coast

Morphometrics of 14 metric and 6 meristic characters of Trypauchen vagina of Bombay coast is presented. Number of spines and rays of dorsal, anal and pectoral fins differ with earlier studies. Sexual dimorphism in the length of caudal and anal fins was observed. Length weight relationship of males and females have been worked out to be W = 0.00000 687L super(2.8440) and W = 0.00000 2747L super(3.0274) respectively. The fish is a prolific breeder and peak breeding activity occurs in December. The growth rate was found to be 15.20 mm/month.

Recent advances in our knowledge of the biology and conservation of mahseers

Mahseers (Tor khudree), at one time considered to be of single species, are now represented by 6 valid species distributed all over India. Studies on their food habits, ecology of spawning grounds, eggs, larval development and especially methods of artificial propagation have advanced in recent years. Transport of eggs of Tor khudree by air in moist cotton has been possible for easy distribution. Breeding of T. khudree not only by hypophysation, but even without it in small ponds by manipulation of flow of water, exercise and feed has also been possible. Fry and fingerlings of T. khudree are being distributed to many of the states in the country to help conserve the species.

Reproductive biology of Parapenaeopsis stylifera

Controversy exists regarding the incidence and reproductive habits of Parapenaeopsis stylifera along the coast of Kerala, India. Results are reported of a detailed study on the different aspects of the reproductive biology based on the trawl catches landed at Neendakara Coast for a period of one year. This species breeds throughout the year with peak breeding activity in May and November. The monsoon catches consist of juveniles. Life span of the species is 2.5 years and total length at first maturity is 75 mm. Measures for the effective management of the species in the area are discussed.

Some aspects of reproductive biology of two sciaenids, Otolithes cuvieri Trewavas and Johnius elongatus Mohan: maturation, spawning, sex ratio and fecundity

The gonads of Otolithes cuvieri and Johnius elongatus are described in seven maturity stages. O. Cuvieri spawns once a year from April to September as evidence by ova diameter frequency distribution and GSI values. 50% maturity is attained at 210mm TL in males and 200mm TL in females. Fecundity ranged from 2387 to 104379 with a mean value of 33502. Log-Log relationship between fecundity and total lenght, body weight and ovary weight were determined. An overall sex ratio of 1.54:1.00 was unequal in favour of males. Johnius elongatus spawns twice a year from January-February to Aprile-May and from August to October as evidence by ova diameter frequency distribution and GSI values. 50% maturity is attained at 140-143mm TL in both sexes. Fecundity ranged from 4238 to 167669 with a mean value of 42818. Log-Log relationship between fecundity and total lenght, body weign and ovary weight were determined. An overall sex ratio of 1.00:1.20 was unequal in favour of females.

Biology of Balanus amphitrite communis (Darwin) in the Cochin harbour waters

Seasonal viariations in the incidence on fresh surfaces, breeding season, rate of growth and mortality of Balanus amphitrite communis was studied for a period of twelve months in the Cochin harbour waters, situated 76̊ 14'E and 90̊ 57'N, and subjected to annual seasonal changes in salinity.