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Fisheries and Biology of Oil sardine, Sardinella longiceps (Valenciennes) and Indian mackerel, Rastrelliger kanagurta (Cuvier) from Kochi and Chennai coasts

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Relation http://eprints.cmfri.org.in/12836/
 
Title Fisheries and Biology of Oil sardine, Sardinella longiceps (Valenciennes) and Indian mackerel, Rastrelliger kanagurta (Cuvier) from Kochi and Chennai coasts
 
Creator Remya, R
 
Subject Fish biology
Mackerel fishery
Oil sardine
Pelagic Fisheries
Theses
 
Description The oil sardine Sardinella longiceps and the Indian mackerel
Rastrelliger kanagurta are tropical coastal and small pelagic fish, forming massive
fisheries in India. They are governed by the vagaries of ocean climatic conditions.
Until the mid 1980s, the oil sardine formed fishery almost exclusively along
southwest coast, and did not form fishery along southeast coast. However oil
sardine emerged as a major fishery in the last 30 years, and the average annual
catch along Tamil Nadu coast alone recorded more than 1 lakh tonnes in the last
five years. The Indian mackerel also formed a major fishery along southwest
coast and a minor fishery along southeast coast. Similar to the oil sardine, the
mackerel also is contributing a major fishery in the last 30 years along the southeast
coast. It is not clear whether stocks of Sardinella longiceps and Rastrelliger
kanagurta in the two regions are the same, and how similar or dissimilar is their
spawning and diet. To understand this, samples of the two species were collected
from Kochi (representing the southwest coast) and Chennai (representing the
southeast coast). The study has attempted a comparison between the fishery as
well as biological parameters namely morphometrics, maturity patterns, diet
composition of the two species along the Kochi and Chennai coasts during 2010-
2012. The study revealed that there has been considerable increase in the landings
of both the species along Kochi and Chennai coasts especially from the mechanised
sector when compared to previous years. The analysis of morphometric characters
showed that Sardinella longiceps and Rastrelliger kanagurta occurring along Kochi
and Chennai coasts belong to a single stock. S. longiceps of both the coasts
spawns once in a year lasting from June to September. The peak spawning period
of R. kanagurta along Kochi was during June-August and along Chennai, during
April-June. The length at first maturity
of mackerel showed much variation during
the period and was lower than that reported during the period prior to the 90s.
The absolute fecundity was within the range of 4,072-63,475 and 10,116-1, 84,350
eggs in the case of S. longiceps and R. kanagurta respectively along both the
coasts. The diet of S. longiceps consisted of phytoplankton as the major share in
both the coasts, and the major phytoplankton species in the diet were almost
the same. The diet of R. kanagurta was much diverse with phytoplankton and
zooplankton, and in this species too, the major species in the diet were almost
the same in the two locations. From the results obtained in the present study, no
significant differences could be observed in the spawning and diet composition
within each of the two species between the two locations. The results further
show that the two species have adapted to the conditions and have established
their populations along the southeast coast of India.
 
Date 2016
 
Type Thesis
NonPeerReviewed
 
Format text
 
Language en
 
Identifier http://eprints.cmfri.org.in/12836/1/Remya%20R_Thesis.pdf
Remya, R (2016) Fisheries and Biology of Oil sardine, Sardinella longiceps (Valenciennes) and Indian mackerel, Rastrelliger kanagurta (Cuvier) from Kochi and Chennai coasts. Doctoral thesis, Central Marine Fisheries Research Institute.