Modelling of Geochemical Processes in Mangrove Ecosystem

The mangrove ecosystem is one of the earth’s most endangered ecosystems. In this study, geochemical features of three mangrove ecosystems, Mangalavanam, Vypeen and Nettoor were compared. Water, sediment and core samples were collected from these stations for a period of one year. Nutrients, organic compounds orgnic carbon and hydrographical parameters of the samples were estimated. The present study revealed higher concentration of carbon in the surface sediments. The major temporary or ultimate sink for various pollutants in estuaries is the sedimentary reservoir, including intertidal areas. In the present study, higher values for dissolved nutrients, POC and carbohydrates were observed during low tide.

Molecular Genetic Characterization of Endemic Yellow Catfish, Horab rus brachysoma (Gunther)

The present study Molecular genetic characterization of endemic yellow catfish ,generated an important information on the genetic variation and stock structure of the endangered yellow catfish(Horabagrus brachysoma) endemic to the western Ghats. Three genetically discrete stocks of the species have been identified for the first time using allozymes, RAPD(Random Amplified Polymorphic DNA) and microsatelite markers and it is a significant step towards realizing the goal of management of fishery and conservation of the yellow catfish populations in the rivers of the Western Ghats region. In conclusion genetic markers were found to be powerful tools to analyze the population genetic structure of the yellow catfish. Geographic isolation by land distance,inbreading as a result of over-exploitation etc are some reasons for the genetic differenciation between the pairs and deficiency of hetrozygosity revealed by the two co dominant markers, allozyme, and microsatelites.the study emphasizes the need for stock-wise, propagation assisted-rehabilitation of the natural populations yellow catfish

Systematics, Germplasm evaluation and pattern of distribution and abundance of freshwater fishes of Kerala (lndia)

The overall focus of the thesis involves the systematics,germplasm evaluation and pattern of distribution and abundance of freshwater fishes of kerala (india).Biodiversity is the measure of variety of Life.With the signing on the convention on biodiversity, the countries become privileged with absolute rights and responsibility to conserve and utilize their diverse resources for the betterment of mankind in a sustainable way. South-east Asia along with Africa and South America were considered to be the most biodiversity rich areas in the world .The tremendous potential associated with the sustainable utilization of fish germplasm resources of various river systems of Kerala for food, aquaculture and ornamental purposes have to be fully tapped for economic upliftment of fisherman community and also for equitable sharing of benefits among the mankind without compromising the conservation of the rare and unique fish germplasm resources for the future generations.The study was carried during April 2000 to December 2004. 25 major river systems of Kerala were surveyed for fish fauna for delineating the pattern of distribution and abundance of fishes both seasonally and geographically.The results of germplasm inventory and evaluation of fish species were presented both for the state and also river wise. The results of evaluation of fish species for their commercial utilization revealed that, of the 145, 76 are ornamental, 47 food and 22 cultivable. 21 species are strictly endemic to Kerala rivers. The revalidation on biodiversity status of the fishes assessed based on IUCN is so alarming that a high percentage of fishes (59spp.) belong to threatened category which is inclusive of 8 critically ndangered (CR), 36 endangered and 15 species under vulnerable (VU) category.The river wise fish germplasm inventory surveys were conducted in 25 major river systems of Kerala.The results of the present study is indicative of existence of several new fish species in the streams and rivulets located in remote areas of the forests and therefore, new exclusive surveys are required to surface fish species new to science, new distributional records etc, for the river systems.The results of fish germplasm evaluation revealed that there exist many potential endemic ornamental and cultivable fishes in Kerala. It is found imperative to utilize these species sustainably for improving the aquaculture production and aquarium trade of the country which would definitely fetch more income and generate employment.