Estimation of mortality

Jayasankar, J (2015) Estimation of mortality. In: Training Manual Fish Stock Assessment and Management. ICAR- Central Marine Fisheries Research Institute, Kochi, pp. 91-100. ISBN 978-93-82263-07-4

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Abstract

Fish as a natural resource follows most of the established behavior expected of ay similar animal. The birth and ensuing recruitment, growth, reproduction and death, technically referred to as mortality are well defined phases of any animal’s life time and fishes are no exceptions to this. As is evident from its logic, fish populations increase in their abundance, popularly termed as biomass, by birth of animals or by growth apart from occasional immigrations. The loss of animals is mostly through death (mortality) which could occur due to ageing, natural mortality, or due to fishing, fishing mortality apart from the predation inflicted by larger animals in the sea. Hence mortality phenomenon happens to be the single most important cause of change in abundance of fish in any defined population or technically referred to as stock. By its sheer importance as the leveling force in face of animals with varying degrees of reproduction, mortality assumes an important position in the study of dynamics or fluctuations in the biomass of a given resource. Like its growth counterparts mortality too has well laid conceptualization coupled with clearly defined procedures of measurement or technically termed as estimation. Thus the phenomenon of rate of loss of animals in a particular population is a parameter to be estimated with the sampled animals. The measurements taken from the sampled individuals help an assessor to find out the composition of fish available at various ages and such information collected over a period of time will enable the observer to find out the rates at which fish of a particular age die due to natural and unnatural causes.

Item Type:	Book Section
Subjects:	Marine Environment > Fish Mortality Marine Fisheries > Estimation
Divisions:	CMFRI-Kochi > Marine Capture > Fishery Resources Assessment, Economics and Extension Division Subject Area > CMFRI > CMFRI-Kochi > Marine Capture > Fishery Resources Assessment, Economics and Extension Division CMFRI-Kochi > Marine Capture > Fishery Resources Assessment, Economics and Extension Division Subject Area > CMFRI-Kochi > Marine Capture > Fishery Resources Assessment, Economics and Extension Division
Depositing User:	Arun Surendran
Date Deposited:	05 Aug 2024 09:57
Last Modified:	05 Aug 2024 09:57
URI:	http://eprints.cmfri.org.in/id/eprint/18683

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