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

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.

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    Abstract

    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.

    Item Type: Thesis (Doctoral)
    Uncontrolled Keywords: Fisheries; Biology; Oil sardine; Sardinella longiceps; Indian mackerel; Rastrelliger kanagurta; Kochi; Chennai
    Subjects: Fish and Fisheries > Fish biology
    Pelagic Fisheries > Mackerel fishery
    Pelagic Fisheries > Oil sardine
    Pelagic Fisheries
    Theses
    Divisions: CMFRI-Kochi > Fishery Environment
    Subject Area > CMFRI > CMFRI-Kochi > Fishery Environment
    CMFRI-Kochi > Fishery Environment
    Subject Area > CMFRI-Kochi > Fishery Environment
    Depositing User: Arun Surendran
    Date Deposited: 05 Jun 2018 05:33
    Last Modified: 05 Jun 2018 05:33
    URI: http://eprints.cmfri.org.in/id/eprint/12836

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