Different methods for standardization of fishing efforts

Varghese, Eldho and Jayasankar, J and Sathianandan, T V and Kuriakose, Somy and Mini, K G and Gills, Reshma and Muktha, M and Sreepriya, V and Gopalakrishnan, A (2023) Different methods for standardization of fishing efforts. Marine Fisheries Information Service, Technical and Extension Series (257). pp. 7-17. ISSN 0254-380X

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Abstract

Surplus production models are widely employed to evaluate the condition of fish stocks, encompassing the entire stock, overall fishing effort, and the total yield derived from the stock. These models operate under the assumption that variations in population biomass result from hikes due to growth and reproduction, as well as drops due to natural and fishing mortality. Utilizing Catch-Per-Unit-Effort (CPUE) as input, these models rely on the presumption that CPUE is directly proportional to the biomass of fish stock in the sea. An inherent challenge in fitting such a production model lies in determining CPUE, whether in terms of units operated or in hours of operation/actual fishing hours (AFH) or in any measure of fishing efforts. Given the heterogeneous nature of fishing fleets in tropical regions, they are often categorized into boat-gear categories, where fishing units within each category share similar characteristics and performance. When assessing the collective impact of the fishing operations of the entire fleet on the exploitation of fish stock, nominal addition of the efforts of different boat-gear categories may lack meaningfulness without prior effort adjustment to enhance comparability. In tropical regions, due to the varying capacities of gears and the potential presence of multiple species in each gear, the effort expended to catch a resource cannot be simply considered as the sum of the duration/units of operation of all gears. This paper aims to underscore various effort standardization methodologies found in the literature for different situations, offering insights into the challenges faced in tropical fisheries and proposing a way forward.

Item Type:	Article
Uncontrolled Keywords:	Surplus production models; stock assessment; sample-based surveys; standardization of fishing effort; abundance; GAM; GLM; GLMM; delta methods
Subjects:	Fishery Technology > Fishing Marine Fisheries > Stock Assessment Marine Fisheries > Fisheries Survey Marine Fisheries > System analysis
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:	27 Mar 2024 08:46
Last Modified:	27 Mar 2024 08:46
URI:	http://eprints.cmfri.org.in/id/eprint/18230

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