NOPR Collection:

Zooplankton of Trichodesmium Phenomenon

Sat, 01 Mar 1980 00:00:00 GMT

Title: Zooplankton of Trichodesmium Phenomenon Authors: Nair, Vijayalakshmi R; Devassy, V P; Qasim, S Z Abstract: Zooplankton abundance has a direct relationship with Trichodesmium phenomenon. The main components of zooplankton during Trichodesmium blooms are cladocerans, copepods, decapod larvae, chaetognaths, fish eggs and larvae and appendicularians. There is a periodicity in the appearance of various groups of organisms and this seems to be repeated with the return of Trichodesmium phenomenon each year. There is no food relationship between zooplankton and Trichodesmium but the relationship is through enrichment caused by the bloom which promotes almost concurrently the growth of diatoms and dinoflagellates on which the herbivores feed. The herbivores are followed by carnivores. Page(s): 1-6

Seasonal variations in Secondary Production of the Mandovi-Zuari Estuarine System of Goa

Sat, 01 Mar 1980 00:00:00 GMT

Title: Seasonal variations in Secondary Production of the Mandovi-Zuari Estuarine System of Goa Authors: Selvakumar, R A; Nair, Vijayalakshmi R; Madhupratap, M Abstract: Mean rates of secondary production in the Mandovi, Zuari and Cumbarjua canal, Goa, India were 16.9, 35.9 and 32.4 mg C/m2/day respectively. The general hydrographic conditions of the Zuari were responsible for the higher secondary production. In general, the saline period was more productive (12.9 mg dry wt/m3/day) compared to the low saline period (11 mg dry wt/m3/day). The average secondary production in the estuarine system was 21.4 mg dry wt/m3/day or 1078 tonnes carbon/yr. The coefficient of energy transfer from primary to secondary level was 6.6%. Theoretical estimate of fish biomass in this estuarine system was 1007 tonnes/yr. Page(s): 7-9

Seasonal Variations in Sterol Content of the Oyster, Crassostrea virginica (Gmelin), from Natural Reefs in the Mississippi Sound

Sat, 01 Mar 1980 00:00:00 GMT

Title: Seasonal Variations in Sterol Content of the Oyster, Crassostrea virginica (Gmelin), from Natural Reefs in the Mississippi Sound Authors: Krishnamoorthy, R V; Lakshmi, G J; Biesiot, Patricia; Venkataramiah, A Abstract: Sterol composition of C. virginica was assayed by gas-liquid chromatography. Total sterol levels were determined by analyzing colorimetrically the sterol digitonides prepared from single whole oysters. The predominant sterols (~,:,)wert: cholesterol (33), campesterol (20), brassicasterol (18) and 22 dehydrocholesterol (12): also found were (ßsitosterol (6) and a C 26 sterol (9). Percentage composition of sterols in oysters was not significantly different in relation to season or sex. Total sterol level varied with season and sex. Lowest levels were seen during winter (February) at which time the sexes could not be distinguished. Male oysters had higher sterol levels than females in the spring (April) and fall (October) while females had higher levels during summer when the spawning season was ending. Total sterol content decreased with an increase in size of the oysters during all seasons; the relationship followed a polynomial function. Comparison with values reported indicated that southern oysters have higher fat but lower cholesterol than their northern counterparts. Page(s): 10-14

Breeding in Balanus amphitrite Amphitrite Darwin Inhabiting Polluted Waters Off Bombay Coast

Sat, 01 Mar 1980 00:00:00 GMT

Title: Breeding in Balanus amphitrite Amphitrite Darwin Inhabiting Polluted Waters Off Bombay Coast Authors: Rege, M S; Joshi, S S; Karande, A A Abstract: B. amphitrite Amphitrite in highly polluted (Mahim Creek), moderately (Haji Ali Bay) and relatively clean (Middle Ground) waters along the Bombay Coast showed identical seasonal rhythm in breeding. The species, irrespective of the habitat, attained sexual maturity on reaching a basal shell diameter of 2-3 mm. However, for a given body weight, the number of eggs produced was lowest in the population inhabiting polluted waters and well grown adult barnacles amongst them showed poor breeding potential. Page(s): 15-18