For large-scale seed production of sea cucumbers through a hatchery system, it is imperative to know the effects of environmental parameters on larval rearing. Auricularia larvae (48 h post-fertilization) were obtained from induced spawning of Holothuria spinifera and used in experiments to ascertain the effects of temperature, salinity and pH on the growth and survivorship of the larvae. The larvae were reared for 12 days at temperatures of 20, 25, 28 and 32 8C; salinities of 15, 20, 25, 30, 35 and 40 ppt; and pH of 6.5, 7.0, 7.5, 7.8, 8.0, 8.5 and 9.0. The highest survivorship and growth rate and fastest development of auricularia indicated that water temperature of 28-32 8C, salinity of 35 ppt and pH of 7.8 were the most suitable conditions for rearing larvae of H. spinifera. D

The results of the study on the suitable algal feed for the mass rearing of holothurian larvae through hatchery system are presented. Auricularia larvae. after 48 h of fertilization, obtained from induced spawning of Holoth~iria spinifera, were fed with different algae Isochrysis galbana, Nanodlloropsis snlinn, Pavlava lutheri. Tetmselmis chllii and Chaetoceros cnlcitrans as well as I. galbana+C. calcitrans to ascertain the effect of single and combined microalgal diet. The rate of feeding was 2 x lo4 cells larvae-'.day-l for a period of 9-12 days. The growth rate of 59 pm day -' with 90% and 43 pmday with 100% occurrence of late auricularia in the larvae fed with C. calcitrans alone and I. galbnna+C, calcitrans, respectively, indicated that C.calcitrans itself or in combination with I. gnlbana is the effective feed for the larvae of H. spinijera.

The annual reproductive cycle of the commercial sea cucumber Holothuria spinifera was studied in Tuticorin, Tamil Nadu, India, from September 2000 to October 2001, by macroscopic and microscopic examination of gonad tubule, gonad index and histology of gametogenic stages, to determine the spawning pattern. The gonad consists of long tubules with uniform development. It does not confirm the progressive tubule recruitment model described for other holothurians. The maximum percentage of mature animals, gonad and fecundity indices, tubule length and diameter, with the observations on gonad histology, ascertained that H. spinifera had the peak gametogenic activity

The present study was conducted to develop the hatchery technology for seed production of the widely exploited commercial sea cucumber Holothuria spinifera Theel 1886, to facilitate an e¡ective stock enhancement programme. Broodstock collected by skin divers were used for spawning trials. The embryonic and larval stages were similar to other aspidochirotes. The larval survival rate was 43.5% on day 9, which decreased to 18.3% nearing metamorphosis on day 13, the growth rate was 48 mm day À1 and the settlement rate was 3.5%. Algamacs used to induce settlement also served as the food source for the early settled juveniles, followed by Sargassum spp. extract (o40 mm) for the ¢rst month. Sargassum spp. powder along with ¢ne sand (1:1) was given to juveniles 420 mm. Addition of Spirulina spp. along with Sargassum spp. powder and ¢ne sand (0.5:1:2) enhanced the growth rate of the juveniles. In the hatchery, the juveniles attained an average size of 1, 30 and 48 on 20, 80 and 120 days respectively.

Beach litter are man-made objects discarded directly or indirectly. This study brings out synoptic picture of status and composition of beach were found in Kerala (17), Maharashtra (12), Tamil Nadu (2), Andhra Pradesh (4), Odisha (7) and West Bengal (3). Whereas extremely littered beaches (>100 g/m 2 ) were found in Karnataka (13), Goa, Gujarat, and Andaman Island. With reference to the coastal population and per capita share of beach debris, Goa registered highest values (40.97 kg/head) and the Odisha coast registered the lowest values (0.005 kg/head).

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A study was conducted to find out the possible cause of sudden changes in the colour of the Karapad lagoon water and associated variation in the hydrography. The discolouration of lagoon water was noticed after the excavation work to deepen the lagoon area by the Municipal authorities to enable free boating. Microscopic examination of the lagoon water revealed the blooming of micro alga Chlorella marina. The blooming lasted for a month and has not caused any adverse effect. During the bloom days, the algal cell density attained a peak of 3.1x 105 cells l -1 on 5 th day. Very high chlorophyll concentration was noticed in the lagoon water during the bloom days than the post bloom days. The studies revealed that the nutrient enrichment due to the re-suspension of sediments from the excavation activities might have triggered the algal outburst in the Karapad lagoon. Along with high nutrients, the surface water temperature and salinity might also have supported the algal proliferation.

A study was conduced to assess the depth wise variation and influence of lunar cycle and hydrological parameters on the distribution of zooplankton constituents in Tuticorin inshore waters between April 2011 and March 2012. Fortnightly sampling of zooplankton and hydrological parameters at four different depths like 5 m, 10 m, 15 m and 20 m was carried out on every full moon and new moon day to assess the variation. The zooplankton constituents were found in dominance in the order of copepod> decapod>Lucifer>fish eggs>cladocerans> Alima larvae>chaetognatha at all the depths. The swarming of zooplankton constituents were noticed more towards 15 m depth especially during new moon period. The full moon and new moon variation in the density was statistically significant for bivalve larvae and Lucifer (p<0.05) and the depth wise variation was significant only for decapods (p<0.05). The studies indicated that northeast monsoon which starts during late September in Tuticorin influences the environmental conditions as well as the distribution patterns of the zooplankton constituents in the Tuticorin inshore waters.