STUDIES ON THE PHYSIOLOGICAL AND BIOCHEMICAL ASPECTS OF OSMOREGULATION IN TWO INTERTIDAL BIVALVE MOLLUSCS

Division of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology

HYPOXIC ADAPTATIONS AND CAROTENOIDS OF TWO INTERTIDAL MOLLUSCS

The present investigation is to find the hypoxic adaptations and role of carotenoids in the anaerobic catabolism of two intertidal bivalves-Sunetta scripta and Perna viridis. Physiological and cytological responses during hypoxic stress have been studied and compared to that of sublethal heavy metal (copper) exposure using two indices : total carotenoid concentration and accumulation of lipofuscin granules. A close similarity has been observed between hypoxic exposed and copper (sublethal) exposed animals regarding the total carotenoid concentration and lipofuscin accumulation. In the case of S.scripta, the total caroteniod increase at 48h of both hypoxic and heavy metal exposure was found to be nearly 40% greater than that of the control (0h). Whereas in P.viridis, the increment in the total carotenoid concentration at 48h of hypoxic exposure and 48h of heavy metal exposure were found to be nearly 87% and 95% higher than that of the control (0h) respectively.Regarding the lipofuscin accumulation, in both S.scripta and P.viridis , the characteristic features of the granule at 48h of hypoxia is very much similar to that observed at 48h of heavy metal exposure. Thus, the present study suggests that the increase in carotenoid concentration and lipofuscin accumulation expressed by bivalves under heavy metal stress can be due to the indirect effect of hypoxia.

Electrophoretic, Biochemical and Morphometric studies on Three Bivalves of Cochin and Nearby Waters

Division of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology

INDIAN AND ANTARCTIC BRYOZOANS - TAXONOMY AND OBSERVATIONS ON TOXICOLOGY

This thesis embodies findings on a taxonomical investigation of a group of lower marine invertebrates belonging to the category coelomata. Bryozoans are well known both in fossil and recent taxonomical history. They comprise of about 5,000 living and 16000 fossil species. Bryozoans are well known for their taxonomic abundance and structural diversity,representing the various ecological niches ranging from the intertidal to the abyssal benthic. At a time when global marine biological diversity has become a concern of not only to the scientists but also to the policy makers,an understanding of species diversity and abundance are cardinal aspects of biological studies. Geological time scales which is known that by Pre-Cambrian, marine invertebrate diversity reach the maximum and this diversity has become more comprehensive as time advanced. Taxonomists a vanishing species of scientists have become more concerned in discerning patterns of species diversity. The basic tool for this is identification fo animals. with this idea in mind a detailed study of taxonomy of bryozoan was undertaken . The major part of this thesis is devoted to describe various species of bryozoans with detailed description and ecotypical variations.The pattern of distribution and abundance which are important aspects of animal groups have also been documented. Possible effects of heavy metal contamination on the tolerance and growth of bryozoans, a few species of which have been eliminated from the chronically polluted areas of Cochin backwaters have also been documented.

Studies on the Survival of Sunetta Scripta in Different Salinities

Division of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology

HEAVY METAL TOXICITY IN BIVALVE- HISTOLOGICAL AND HISTOCHEMICAL ENQUIRY

Division of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology

Investigations on the Effects of Petroleum Hydrocarbons on the Marine Bivalves Perna viridis (Linnaeus) and Sunetta scripta (Linne')

The thesis deals with different aspects connected with the distribution and toxicity of PHC in crude oils in the aquatic environment and marine molluscs. Information has been gathered and presented on the present status of research in the field based on a thorough review of recent literature. It is seen from the literature that the resident time of PHC becomes lesser and lesser when crude oil is discharged in large quantities into the coastal waters where excess oxygenation light penetration, temperature availability and strong tidal currents persist. This results in the reduction of the onslaught of oil pollution. This probably shows that taxic insult of crude oil in tropical shores will be relatively lesser than that occurring in temperate and boreal waters. However, there is no record of major episodal oil pollution comparable in quantum and extent to that of Torrey Canyon or Amoco Cadiz which prevents a more reliable analysis on the issue. Considerable controversy exists on the method of estimation of PHC in seawater. However, Ultra-violet fluorescence spectroscopy has been widely recommended as an analytical tool for the determination of total hydrocarbons. Similarly representation of values as chrysene equivalents has been recognised as the most reliable method of Quantum representation.

INVESTIGATIONS ON THE STRESS EFFECTS OF PETROLEUM HYDROCARBONS ON METAPENAEUS DOBSON (MIERS)

The present investigation has addressed the effects of PHC contaminated culture medium on the morphology, physiology and behaviour of shrimps. The shrimp Metapenaeus dobsoni is an important member of the crustacean animal community abounding the oil contaminated benthic regions of Cochin backwater system. Since it is known that true pollutants can disrupt the sustainability of ecosystems by its effect on species, populations and communities,a representative species was used for the study. The results discussed in this work is bound to help in understanding the ecotoxicant resistance that the animal may display under toxic conditions compared to dynamic steady-state systems in nature.

Biochemical and Histopathological Effects of Aflatoxin on Oreochromis mossambicus ( Peters )

Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology

Metabolic Efficiency of Penaeus Indicus H.Milne Edwards Under Different Salinity Stress Conditions

The investigation was aimed at establishing the effect of salinity on the culture performance of Peneus Indicus in pokkali fields and also to find out the growth performance of the shrimp at varying salinities. The experiments were laid out at Rice Research Station, Vyttila of Kerala Agriculture University in three fields of area 1000 m2 each. The results of the experiment clearly establish that shrimps when stocked at higher salinity (20-25 ppt) for 45 days has given higher growth, survival and production than those stocked at lower salinity (10-15 ppt) in all the above parameters even when the culture experiment was maintained for longer periods in lower salinity. In the prolonged culture experiments conducted for 120 days in 10-25 ppt salinity, the results were poorer than the short period culture in higher salinity and the production values similar to lower saline culture. This clearly establishes the importance of salinity as an ecological factor which will have profound influence in shrimp farming operations.

STUDIES ON SOME ASPECTS OF REPRODUCTION OF FEMALE ANABAS TESTUDINEUS ( BLOCH )

Department of Marine Biology, Microbiology and Biochemistry

Effects of the Piscicides, Mahua Oil Cake and Croton Seed on the Prawn Culture System

Department of Marine Biology, Microbiology and Biochemistry

Toxicant Induced Antioxidant Activity in Oreochromis Mossambicus (Peters)

Dept.of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology

Nutritional responses in Indian white shrimp Fenneropenaeus indicus to varying protein: energy combinations in compounded artificial feeds

Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology

Biochemical Effects of Anionic, Cationic and Non Ionic Surfactants on a Tropical Teleost Oreochromis Mossambicus(Peters) and a Marine Cyanobacterium Synechocystis Salina Wislouch

The present work is a base line attempt to investigate and assess the toxicities of three surfactants viz. anionic sodium dodecyl sulfate (SDS), non ionic Triton X-1OO (TX-IOO) and cationic cetyl trimethyl ammonium bromide (CTAB). These compounds represent simple members of the often neglected group of aquatic pollutants i.e. the anionic alkyl sulfates, non ionics and the cationics. These compounds are widely used In plastic industry, pesticide/herbicide formulations, detergents, oil spill dispersants, molluscicides etc. The test organisms selected for the present study are the cyanobacterium Synechocystis salina Wislouch representing a primary producer in the marine environment and a fresh water adapted euryhaline teleost Oreochromis mossambicus (peters) at the consumer level of the ecological pyramid. The fish species, though not indigenous to our country, is now found ubiquitously in fresh water systems and estuaries. Also it is highly resistant to pollutants and has been suggested as an indicator of pollution in tropical region .