Parasite distribution and histopathological studies on certain commercially important fishes of cochin area

In order to check the damage caused by the parasites, even though it is difficult in open waters, a proper understanding of the seasonal variation in the distribution of the parasite and other factors like age of the host, sex of the host, which affect distribution of parasite is a must. Although several workers have carried out investigations on the taxonomy of metazoan parasites of marine and brackish water Fishes of India, very little attempt is made to correlate such investigations with the host and the environment. In this thesis such an attempt is made by the researcher. In chapter one the literature related to the prevalence, mean intensity of infection, and histopathological changes caused by the metazoan parasites, in particular by helminths, copepods and isopods, was reviewed. Chapter two contains observations on the distribution pattern of parasites in relation to the season, sex, and size of the host. It was found that the prevalence rate of radiorynchus_indicus infecting the alimentary canal of Tachysurugs mgacuglatus, Ergasilus sp. infecting the gills of T maculatus, and Lernaeeniicus ramosus found on the body surface of Qeimgipteirfugs jagonicus was higher during monsoon season. But agarna malayi found in the opercular chamber and Ehilometra cephalus infecting the gonads of valamugil speiglari showed a higher prevalence rate during the postmonsoon season. This was discussed on the basis of the hydrographical characteristics prevailing in the study area during the three different seasons. It was also observed that the sex of the host did not influence significantly the distribution pattern of the parasites. The reasons for this were also discussed. Invariably, the size of the host was found to influence the parasite distribution pattern. It was observed that the prevalence rate showed an increase with increase in size of the fish. This was discussed on the basis of food habits of the host, along with other aspects An attempt was made in chapter three to study the histopathological effects of‘ the various parasites on their respective sites of attachments on host Fishes. It was found that except Rhadinorhyhchugs indicus, all other parasites produced damages of varying intensity, in the form of hypertrophy, rhyperplasia, haemorrhage, tissue disruption and ulcers. Interestingly, E. indicus, an acantho— cephalid with a powerful proboscis for attachment was found not to cause any serious damage to the intestine of the host Fish. All these aspects are included in the third and final chapter of the thesis.

Studies on the teredinids of cochin harbour

Teredinids (shipworms), a group of wood boring bivalves occurring in the Cochin Harbour region have been taken up for the eco-physiological studies. On the ecological part, the occurrence, abunance and seasonal intensity of the teredinids in relation to hydrographic conditions have been studied. On the physiological part, salinity tolerance and oxygen consumption of the most commonly occurring shipworms, Nausitcra hedlgyi and Teredo furcifera have been investigated. The hydrographic factors studied are temperature, salinity, dissolved oxygen, phosphate, nitrite, silicate and pH. The variation in temperature is found to be comparatively narrow. But seasonal variation in salinity, dissolved oxygen, phosphate, nitrite and silicate has been observed, with the highest values during the monsoon period. In the case of pH, the minimum value has been obtained during the low saline period and the maximum value, during the high saline period. Of the various hydrographic factors studied, salinity has been found to be the most important fluctuating environmental parameter influencing the life of organisms in the habitat.

Studies on the effect of pollution, with special reference to benthos, in Cochin backwaters

Considerable number of factories and related establishments forming an industrial complex are located in the upper reaches of the estuary from Varapuzha about 10km from cochin barmouth to Alwaye while lower down are the retting grounds at Vaduthala and nearby places at about 5km from the barmouth. Muncipal wastes from the city population of over 5 lakhs effluents and solid waste from several fish processing factories and other land washings around Willington island reach the estuary move near its lower reaches close to the barmouth. Cochin estuary is the biggest in the state providing water front for the largest number of industries from the small retting grounds of Vaduthala to the huge fertilizer factories of Udyogamandal and receiving the highest quantity of town sewage and land drainage. The estuary contributes itself as nursery ground for shrimps and related fishery as well. Study of this estuary therefore contributes to a typical environment as regards to pollution problems in the tropics and hence the scope of the present investigation

Aquatic Cyanobacteria Isolated from Cochin: Growth characteristics and bioactive impact on selected microflora

Aquatic ecosystem in the south west coast of India is noted for its diversity of habitats. Very often these environments turn bluegreen when the bloom of bluegreen algae (cyanobacteria) appear consequent to eutrophication. This phenomenon occursin these habitats one after the other or simultaneously. This conspicuousness make one curious enough to know more about these nature’s gift bestowed upon mankind. While persuing the literature on the magnificent flora) it is understood that it may provide food fertilizer, chemicals and bioactive substances. These bioactive substances are likely to be involved in regulating natural populations and are potentially useful as biochemical tools and as herbicidal or biocontrol agents. The role of cyanobacteria in the aquatic food chain and contribution in abatement of heavy metals from the natural environment are well documented. Considering the manifold utilization of the flora and their significance in the food chain, the present investigation has been undertaken

Sterols in mangrove sediments of the cochin estuary

The thesis entitled “Sterols in Mangrove Sediments of the Cochin Estuary” is an attempt to characterize the sterol content of the mangrove sediments, their dietary status with respect to the natural flora and fauna present, their transfonnations in the sediment and assess contributions, if any to the nursery character of the mangrove eco system. Samplings were done from two sites at Mangalavanam and Vypin. Mangalavanam is a patchy mangrove area in the heart of the city of Cochin and serves as a small bird sanctuary. This is an almost closed system with a single narrow canal linking to the estuary. Vypin, the largest single stretch of mangroves in Kerala, is regularly inundated by a semi diurnal rhythm of Cochin bar mouth. Perhaps, this is the only site in Kerala where one can see mangroves right along the accreting seacoast. However a lot of developmental pressure is threatening the very existence of these mangroves. Post monsoon sediment samples from these areas were used for the present study, as it is the period of maximum faunal growth and activity

A Study Of The Strength And Compressibility Characteristics Of Cochin Marine Clays

With the advent of urbanisation and consequent search for more and more habitable land, it was imperative that the large tracts of marine clays, considered inhabitable earlier, had to be reclaimed and developed. These marine clays, wellknown for its high compressibility and poor shear strength, posed numerous problems to the builders and Cochin was no exception. It is only less than a decade since active research work was initiated on marine clays in general and Cochin marine clays in particular. Eventhough some systematic studies are available on compressibility characteristics, attempts to study the shear strength aspects and development of techniques to improve it have been very limited. This work is an investigation on the consolidation and shear strength characteristics of Cochin marine clays including methods to improve the same

Studies on the ecology of zooplankton of cochin backwaters(a tropical estuary)

Ecology is the study of systems at a level in which individuals or whole organisms may be considered elements of interaction, either among themselves, or with a loosely organised environmental matrix. Systems at this level are named ecosystems, and ecology, of course, is the biology of ecosystems" (Hargalef, 1968). This thesis includes principally, a study on the ecology of zooplankton of the Cochin backwaters conducted during the years 1971-72. This monsoonal estuarine system is particularly interesting, since it exhibits a wide range of variations in its environmental conditions which is naturally reflected in the fauna also. Several publications on various aspects of its hydrobiology have come out in the recent past. But studies on the zooplankton of the estuary have mostly been discontinuous either in space or time or restricted to its groups

Studies On The Biology Of The Clam Sunetta Scripta (Linne), From The Subtidal Waters Of Cochin

Enhancement and culture of bivalves presents an opportunity to maximise and even increase production of many growing areas. Clam culture is less intensive both for capital and labour, involves simple farming and management techniques and is considered an efficient means of protein production. Clams are efficient converters of primary production and growth rate is fast with maximum production in 5-6 months. with culture, production is less influenced by poor recruitment. Stable production facilitates market development. Rivalves are being increasingly used in bio-medical research. Culture practices would ensure uninterrupted supplies of experimental material. Paucity of biological data restricts the development of efficient management and culture techniques of bivalves. This study was undertaken with a view to provide information on some aspects of biology of the bivalve S_. scripta which have hitherto been uninvestigated.

Chemical Evaluation of Selected Organics and Trace Metals in the Mangrove Macroflora Of Cochin

Mangroves are considered to play a significant role in global carbon cycling. Themangrove forests would fix CO2 by photosynthesis into mangrove lumber and thus decrease the possibility of a catastrophic series of events - global warming by atmospheric CO2, melting of the polar ice caps, and inundation of the great coastal cities of the world. The leaf litter and roots are the main contributors to mangrove sediments, though algal production and allochthonous detritus can also be trapped (Kristensen et al, 2008) by mangroves due to their high organic matter content and reducing nature are excellent metal retainers. Environmental pollution due to metals is of major concern. This is due to the basic fact that metals are not biodegradable or perishable the way most organic pollutants are. While most organic toxicants can be destroyed by combustion and converted into compounds such as C0, C02, SOX, NOX, metals can't be destroyed. At the most the valance and physical form of metals may change. Concentration of metals present naturally in air, water and soil is very low. Metals released into the environment through anthropogenic activities such as burning of fossils fuels, discharge of industrial effluents, mining, dumping of sewage etc leads to the development of higher than tolerable or toxic levels of metals in the environment leading to metal pollution. Of course, a large number of heavy metals such as Fe, Mn, Cu, Ni, Zn, Co, Cr, Mo, and V are essential to plants and animals and deficiency of these metals may lead to diseases, but at higher levels, it would lead to metal toxicity. Almost all industrial processes and urban activities involve release of at least trace quantities of half a dozen metals in different forms. Heavy metal pollution in the environment can remain dormant for a long time and surface with a vengeance. Once an area gets toxified with metals, it is almost impossible to detoxify it. The symptoms of metal toxicity are often quite similar to the symptoms of other common diseases such as respiratory problems, digestive disorders, skin diseases, hypertension, diabetes, jaundice etc making it all the more difficult to diagnose metal poisoning. For example the Minamata disease caused by mercury pollution in addition to affecting the nervous system can disturb liver function and cause diabetes and hypertension. The damage caused by heavy metals does not end up with the affected person. The harmful effects can be transferred to the person's progenies. Ironically heavy metal pollution is a direct offshoot of our increasing ability to mass produce metals and use them in all spheres of existence. Along with conventional physico- chemical methods, biosystem approachment is also being constantly used for combating metal pollution

Alkaline Proteases From Bacteria Isolated From Cochin Estuary

Microorganisms distributed in the marine and brackish environments play an important role in the decomposition of organic matter and mineralisation in the system (Seshadri and lgnacimuthu, 2002). Estuary is one of the most productive ecosystems, at the same time one among the least explored ecosystems on earth, which has immense potential as a source of potent microorganisms that produce valuable compounds particularly, enzymes such as proteases. In this scenario, it is very appropriate to embark on finding novel alkaline protease producers from the estuarine system. The area where the present investigation was carried out is a part of the extensive estuarine system of South India viz. Cochin Estuary. There is meagre knowledge regarding the microbial composition, particularly the protease producers of Cochin Estuary. Hence, the present study has been undertaken with the objective of finding novel alkaline protease producing bacteria from Cochin Estuary

Ecotoxic Metal Records and its Degree of Geochemical Symphony in the Niche of Cochin Estuarine System- A Theraptic Perspective

The heavy metal contamination in the environment may lead to circumstances like bioaccumulation and inturn biomagnification. Hence cheaper and effective technologies are needed to protect the precious natural resources and biological lives. A suitable technique is the one which meets the technical and environmental criteria for dealing with a particular remediation problem and should be site-specific due to spatial and climatic variations and it may not economically feasible everywhere. The search for newer technologies for the environmental therapy, involving the removal of toxic metals from wastewaters has directed attention to adsorption, based on metal binding capacities of various adsorbent materials. Therefore, the present study aim to identify and evaluate the most current mathematical formulations describing sorption processes. Although vast amount of research has been carried out in the area of metal removal by adsorption process using activated carbon few specific research data are available in different scientific institutions. The present work highlights the seasonal and spatial variations in the distribution of some selected heavy metals among various geochemical phases of Cochin Estuarine system and also looked into an environmental theraptic/remedial approach by adsorption technique using activated charcoal and chitosan, to reduce and thereby controlling metallic pollution. The thesis has been addressed in seven chapters with further subdivisions. The first chapter is introductory, stating the necessity of reducing or preventing water pollution due to the hazardous impact on environment and health of living organisms and drawing it from a careful review of literature relevant to the present study. It provides a constricted description about the study area, geology, and general hydrology and also bears the major objectives and scope of the present study.

Heterotrophic bacterial activity in selected aquaculture systems near cochin

The principal interest of the present investigation was to determine seasonal and vertical variation of chemoorganotrophic utilisation of glucose and sodium—acetate by the natural bacterial population in the aquaculture pond of Narakkal, Cochin using techniques which allow maintenance of the in situ gaseous concentrations during incubation. In addition salinity, dissolved oxygen, temperature, hydrogen—ion—.concentration, primary production, plant pigments and total bacterial concentration were determined seasonally and vertically because of their possible relationship to chemoorganotrophy.

Investlgations On The Chemical Constituents And Trace Metal Interactions In Some Bivalve Moll.USCS Of The Cochin Backwaters

The subsequent chapters of the Thesis deal with the toxic effects of mercury, copper, zinc und~1ead on these bivalve molluecs, their accumulation and distribution among various organs of the animals and also the motel retention winstica by the three species. Static biousauy tests have been conducted in these studies. It was found that the concentrations of the various metals studied in these organism are well below the permitted level given far ease ahellfienes (crab and ehrimgi and that these maliuscs are very good integrators ef trace metals from their environment and may be used as an indicator organism sf metal pallutaute. The present investigutionsemphaeie the need for a clean coastal water and gives a serious warning regarding the possiblc route of heavy metals in ta human body thraugh marine food chain.

Studies on the nemipterid fishes (pisces:Nemipteridae) of cochin coast

Detailed information on the biology of fishes is an essential prerequisite for their proper conservation, management and exploitation. An amplified knowledge on the biology isfundamentally essential to plan sound management policies for rational utilization of Nemipterid fishes along the Indian coast. Any information on the biochemical composition of fishes will be of immense use in assessing their nutritive value. The importance of understanding body composition during growth is essential in production studies. Detailed work on Nemipterid fishes has been done in other parts of the world whereas along the Indian coast_ not much work has been carried out. Hence the present investigation is undertaken on the systematics of Nemipterids available at Cochin and the biology and biochemical aspects of_N. jagonicus and_M. mesogrion

Studies on the ecophysiology of periphytic algae in cochin estuary

The estuaries are highly productive ecosystems and characteristically are more productive than the adjacent river or sea. Estuarine producers which include planktonic algae, periphyton, herpobenthos as well as macrophytes are capable of nearly year round photosynthesis. Productivity of an environment is mainly the contribution of various groups of autotrophic flora. Any quantitative estimation excluding any one of these would be an underestimation. Periphyton plays a very important role in the productivity of estuarine and coastal waters. It has been reported that periphytic algae attain high biomass (Moss, 1968; Hansson, 1988a) and may contribute up to 80% of the primary production (Persson gt gtt, 1977); Considerable amount of work has been done on the productivity in Cochin backwaters by different investigators (Qasim, 1973, 1979; Nair gt gtt, 1975; Gopi— nathan gt gtt, 1984). All of them have estimated the primary production based only on phytoplankton of the estuary. Considering the contribution of other autotrophic components of the estuary such as periphyton (haptobenthos), sediment flora (herpebenthos) and macropytes, the productivity estimated by earlier authors were essentially underestimations. The present work is an attempt inter glig to assess the contribution of periphytic flora towards the total organic production in the estuary