Indian Council of Agricultural Research
CENTRAL MARINE FISHERIES RESEARCH INSTITUTE
  •  

HomeLATEST RESEARCH FINDINGS

GIS based mapping of spatio-temporal distribution pattern of ribbonfish Trichiurus lepturus along Saurashtra coast, India.

GIS based mapping of spatio-temporal distribution pattern of ribbonfish Trichiurus lepturus (Linnaeus, 1758) along Saurashtra coast, India - CMFRI Repository

Identification of spatio-temporal distribution of fish species represents fundamental information for stock assessment which in turn is essential for formulation of fishery management plans as well as for GIS based decision making. This study investigated the spatio-temporal distribution and abundance of different life stages of ribbonfish, Trichiurus lepturus (Linnaeus, 1758) off Saurashtra coast. Geographical coordinates of fishing and allied information on the time of fishing, depth of the fishing area as well as catch details were collected using a structured schedule, from selected trawlers operated from Veraval. Information was mapped using a GIS software to get the spatio-temporal distribution of the species. It was observed that juveniles were more abundant along the south Saurashtra coast whereas subadults and adults showed a discontinuous distribution with abundance in the waters off south Saurashtra as well as north Saurashtra coasts.

Read more...

 

Fishery, diet composition and reproductive biology of the dolphinfish Coryphaena hippurus off Karnataka, south-west coast of India

Fishery, diet composition and reproductive biology of the dolphinfish Coryphaena hippurus (Linnaeus, 1758) off Karnataka, south-west coast of India - CMFRI Repository

Fishery, diet composition and reproductive biology of the dolphinfish Coryphaena hippurus (Linnaeus, 1758) landed along Karnataka Coast during 2013-15 were studied. The estimated average landing of the species in India during the study period was 7975 t of which Karnataka contributed 2.73% (218 t). The fish is mainly exploited by gillnet and also by troll lines operated from trawlers. A few stray specimens were also landed by purse seines. The fork length (FL) was in the range of 32-128 cm and fishes in the length range (FL) of 55-90 cm dominated the catch, contributing 79.8% of the total landings. The most dominant prey item, in terms of occurrence (70.57%) and weight (83.18%) were finfishes followed by cephalopods (19.62% by occurrence and 13.66% by weight) and crustaceans (7.01% occurrence and 1.32% by weight). The index of relative importance (IRI ) values were 85.3, 13.39 and 0.68% respectively for fish, cephalopods and crustaceans respectively. Sex ratio (1:2.05) indicated dominance of females in the fishery. Presence of mature and spent specimens throughout the year suggests that the species spawns all through the year. Peak spawning period was from June to September. This coincided with gradual increase in gonadosomatic index (GSI) values ahead of May which reached a peak during August-September.

Read more..

 

Diet and feeding habits of Saurida tumbil (Bloch, 1795) from northern Kerala, south-west coast of India

Diet and feeding habits of Saurida tumbil (Bloch, 1795) from northern Kerala, south-west coast of India - CMFRI Repository

Composition of the diet of greater lizardfish Saurida tumbil (Bloch, 1795), caught from northern Kerala, south-west coast of India was studied and described. The stomachs of 1981 specimens were collected between January, 2012 and June, 2014. Analysis of stomach contents based on index of relative importance (IRI) revealed that this species is exclusively piscivorous. Contrary to other benthic predators of the study area, it mainly feeds on pelagic and demersal fishes (IRI = 63.2), molluscs (IRI = 17.86), crustaceans (IRI = 18.33) and other miscellaneous items (IRI = 2.54). The diet of S. tumbil were found to be related to the seasonal availability of resources, occurrence of juveniles of certain species and on the migration of fishes from nearby places to the study area. Significant changes in prey items were observed between predator length groups, but a positive, significant relationship was recorded between prey size and predator size (p<0.05). Statistical analysis indicated a uniform representation of different diets in the stomach. Maximum similarity in diet between different food items was found in April and November.

Read more..

 

Use of commercial probiotics for the improvement of water quality and rotifer density in outdoor mass culture tanks

Use of commercial probiotics for the improvement of water quality and rotifer density in outdoor mass culture tanks - CMFRI Repository

An experimental study was carried out to evaluate the efficacy of three commercially available probiotics P1, P2 and P3 consisting of mainly Bacillus spp. and nitrifying bacteria against Vibrio loads in mass culture tanks of the rotifer Brachionus plicatilis. Triplicate tanks were maintained for each of the probiotic treatment as well as for control group. All the tanks were inoculated with 50 rotifers ml-1 and were fed with Nannochloropsis oculata at a density of 1 x 107 cells ml-1. Every alternate day, all the experimental tanks were treated with probiotics at a concentration of 1 x 104 cfu ml-1 and the experiment was carried out for one week. The study showed a significant increase in rotifer density (p<0.05) in all the tanks treated with the probiotics and a maximum density of 400 nos. ml-1 was observed in the tanks treated with P3. After 5th and 6th day of culture, total elimination of Vibrios was also recorded in the tanks treated with P3 and P2 respectively. The study revealed that P3, with a combination of Bacillus, Thiobacillus, Acetobacter and Paracoccus supplemented with enzymes, was found to be most effective in the enhancement of rotifer density and also in the elimination of Vibrios in rotifer mass culture tanks.

Read more...

 

Identification and characterisation of microsatellite markers in narrow barred Spanish mackerel Scomberomorous commerson

Identification and characterisation of microsatellite markers in narrow barred Spanish mackerel Scomberomorous commerson (Lacepede, 1800) - CMFRI Repository

Narrow barred Spanish mackerel, Scomberomorus commerson (Lacepede 1800) is one of the commercially important fish in Indian waters. For sustainable management of the species, it is necessary to understand the genetic stock structure of the species. Accurate delineation of genetic stock structure can be achieved using nuclear microsatellite markers. A study was carried out to identify and validate polymorphic microsatellite markers in S. commerson using information available from closely related fish species. The study could identify 10 polymorphic microsatellite loci which can be effectively utilised for identifying genetic stock structure of the species. Validation of the identified loci was also done by testing the loci in natural populations of the species. The findings of the present study will be useful in devising stock-specific management measures for conservation and sustainable utilisation of this commercially important fish species in Indian waters.

Read more...

 

Impact of Trawling in Indian Waters - A Review

Impact of Trawling in Indian Waters - A Review - CMFRI Repository

Trawling which is the highest contributor to the marine fishery in India has undergone sea change as a fishing technique and fishing pattern. During recent years, the reduction of catch per unit effort from existing fishing grounds led to various modifications in trawl net design and trawling operations, which has resulted in increase in fish production. Impacts of trawling in Indian waters have been monitored by various agencies during last 25 years. Although there are a good number of articles in peer reviewed journals, a huge quantity of useful information still lies in the form of reports and grey literature which is not easily available to the researchers. This paper attempts to compile information available from various research papers, reports and presentations in seminars and symposia, to serve as an updated guide for trawl impact studies. The information are categorized as (i) impact on the ecosystem, (ii) impact on fishery and (iii) impact on biodiversity. The paper also analysis recent trends in trawling like pelagic and high speed trawling in Indian waters, taking up an example from the trawl fishing off Karnataka, south west coast of India. It was seen that after the introduction of high speed pelagic trawling, some of the areas which were unsuitable for trawling, have also been brought under exploitation. The utility of log book data in resource conservation studies and the need for incorporating spatial studies in trawling impact assessment in the context of ecosystem stability and fishery sustainability are also discussed.

Read more...