Coastal management to protect the fisheries resources of Gujarat coast - a case study

Gujarat, a unique maritime state has the longest coastline of 1 ,663 km length and characterized by presence of two gulfs namely the Gulf of Kachchh and the Gulf of Khambhat. The four major rivers of Gujarat (Sabarmati, Mahi, Narmada and Tapti) discharged 70387 Mm3IYear to the Gulf of Khambhat as of 1975. Since then several dams have been constructed on these rivers and their tributaries reducing the volumes of the outflow. It can, safely be assumed that the outflow of nutrient-laden silt from these rivers has, also reduced proportionately/ significantly changing the hydrological cycles

Fish Community Structure and Trophic Status - A Measure of Ecological Degradation: A Case Study From Powai Lake Mumbai

Powai lake, a monomictic shallow lake, presenting some characteristics typical of a progressive trophic state specifically the permanent turbid water, the recurrent occurrence of cyanobacterial blooms which occasionally leads to large fish kills and the reduction in biodiversity. The study was carried out to understand the ecological degradation of Powai lake by using the abiotic and biotic factors. Twenty-four fish species were recorded and the fish yield was found to be 98 kg ha yr where -1 -1 here the actual potential lies about 363 kg ha-1 yr-1. The diet composition of 10 of the most abundant fishes in the lake revealed that, there were about 13 major food items from the gut contents, includes phytoplankton green algae, phytoplankton blue-green algae, diatoms, cladocerans, copepods, benthic algae, benthic weeds, macrophytes, detritus, fish eggs and larvae, shrimps, fish scales and insects parts. The Food Richness index (N) varied from 12 (Heteropneustes fossilis) to 29 (Oreochromis mossambicus), Diet Breadth (D) from 0.12 (Heteropneustes fossilis) to 0.77 (Oreochromis mossambicus) and the Gut repletion index (GRI) as 100% for all the species. Most of the fish species in the lake were either planktivores or detritivores with high feeding avidity and trophic adaptability, hence are capable of altering diet according to availability. The estimated trophic level indicates that almost all the fishes in the lake depend on primary producers or consumers as their diet. The dominance of omnivores and planktivores and the submissive occurrence of carnivores in the lake indicates the rampant ecological degradation of the lake

Length-weight relationship and condition factor of Dawkinsia filamentosa (Valenciennes, 1844) in different aquatic habitats

The growth rate of a species in any aquatic environment is an indicator of the water quality of the system. In the current study, the Length-weight relationship (LWR) and the condition factor of Dawkinsia filamentosa from various aquatic ecosystems especially lotic, lentic and brackish lentic systems were compared. It was observed that growth rate of the fish was more in brackish lentic systems. The study showed that already reported growth rate (b) of the species in brackish lentic systems is around 3.273 indicating proximity towards the isometric growth pattern as compared to the growth rate in reservoirs (2.3184) and that in lentic systems (3.116) obtained from present study. Similar studies supplemented with environmental variables can be used to study the health status of the ecosystem. The best system suitable for the adaptive growth of the species can be ascertained only after a holistic approach involving environmental variables

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Not AvailableThe growth rate of a species in any aquatic environment is an indicator of the water quality of the system. In the current study, the Length-weight relationship (LWR) and the condition factor of Dawkinsia filamentosa from various aquatic ecosystems especially lotic, lentic and brackish lentic systems were compared. It was observed that growth rate of the fish was more in brackish lentic systems. The study showed that already reported growth rate (b) of the species in brackish lentic systems is around 3.273 indicating proximity towards the isometric growth pattern as compared to the growth rate in reservoirs (2.3184) and that in lentic systems (3.116) obtained from present study. Similar studies supplemented with environmental variables can be used to study the health status of the ecosystem. The best system suitable for the adaptive growth of the species can be ascertained only after a holistic approach involving environmental variables.Not Availabl