Optimal fishing mortality assignment for southern hake Merluccius australis in Chile

ABSTRACT Since 1979, southern hake (Merluccius australis) has been exploited in Chile from the Bio Bio to the Magallanes regions, between the parallels 41°28.6'S and 57°S. There is evidence of a constant fishing effort and a sustained reduction of the fish population, consistent with a progress...

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Autores principales:	López,Felipe, Jimenez,Jorge, Canales,Cristian
Lenguaje:	English
Publicado:	Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar 2020
Materias:	Merluccius australis, southern hake non-linear programming, optimal assignment total allowable catch quota quota distribution MSY
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2020000400613
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spelling	oai:scielo:S0718-560X20200004006132020-09-23Optimal fishing mortality assignment for southern hake Merluccius australis in ChileLópez,FelipeJimenez,JorgeCanales,Cristian Merluccius australis, southern hake non-linear programming, optimal assignment total allowable catch quota quota distribution MSY ABSTRACT Since 1979, southern hake (Merluccius australis) has been exploited in Chile from the Bio Bio to the Magallanes regions, between the parallels 41°28.6'S and 57°S. There is evidence of a constant fishing effort and a sustained reduction of the fish population, consistent with a progressive decrease in total annual catches. Management strategies based on the maximum sustainable yield (MSY) and quota assignment/ distribution criteria have not been able to sustain acceptable biomass levels. A non-linear optimization model with two objective functions was proposed to determine an optimal total catch quota for more sustainable exploitation of this fishery. The first function maximizes the total catch over time in response to an optimal assignment of fishing mortality rates per fleet; the second function maximizes the total economic benefit associated with the total catch. The dynamics of the fish population were represented with the equations of a predictive age-structured model. Decision variables were fishing mortality rates and annual catch quotas per fleet, subject to constraints that guarantee a minimum level of biomass escape over a long-term period. The input parameters were obtained from the last stock evaluation report carried out by the Instituto de Fomento Pesquero (IFOP) of Chile. The historical background data of the fishery and the regulatory framework were relevant aspects of the methodology. Five scenarios were evaluated with the two objective functions, including a base scenario, which considered the referential mortality rate as input data as the average mortality rate per fleet from 2007 to 2012. Total economic benefits fluctuate between 102 and USD 442 million for total catches in the range of 108 to 421 thousand tons, which were obtained from maximizing the economic and biological objective functions. Economic benefit/catch ratios were reduced for scenarios with higher constraints on catch limits, and they were more efficient from a biological point of view. Situations with lighter constraints showed in general higher economic benefits and better performance ratios than those with stronger restrictions. The use of optimization models may provide a useful tool to evaluate the effect of regulations for adequate conservation and economical utilization of a limited resource.info:eu-repo/semantics/openAccessPontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del MarLatin american journal of aquatic research v.48 n.4 20202020-09-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2020000400613en10.3856/vol48-issue4-fulltext-2283
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Merluccius australis, southern hake non-linear programming, optimal assignment total allowable catch quota quota distribution MSY
spellingShingle	Merluccius australis, southern hake non-linear programming, optimal assignment total allowable catch quota quota distribution MSY López,Felipe Jimenez,Jorge Canales,Cristian Optimal fishing mortality assignment for southern hake Merluccius australis in Chile
description	ABSTRACT Since 1979, southern hake (Merluccius australis) has been exploited in Chile from the Bio Bio to the Magallanes regions, between the parallels 41°28.6'S and 57°S. There is evidence of a constant fishing effort and a sustained reduction of the fish population, consistent with a progressive decrease in total annual catches. Management strategies based on the maximum sustainable yield (MSY) and quota assignment/ distribution criteria have not been able to sustain acceptable biomass levels. A non-linear optimization model with two objective functions was proposed to determine an optimal total catch quota for more sustainable exploitation of this fishery. The first function maximizes the total catch over time in response to an optimal assignment of fishing mortality rates per fleet; the second function maximizes the total economic benefit associated with the total catch. The dynamics of the fish population were represented with the equations of a predictive age-structured model. Decision variables were fishing mortality rates and annual catch quotas per fleet, subject to constraints that guarantee a minimum level of biomass escape over a long-term period. The input parameters were obtained from the last stock evaluation report carried out by the Instituto de Fomento Pesquero (IFOP) of Chile. The historical background data of the fishery and the regulatory framework were relevant aspects of the methodology. Five scenarios were evaluated with the two objective functions, including a base scenario, which considered the referential mortality rate as input data as the average mortality rate per fleet from 2007 to 2012. Total economic benefits fluctuate between 102 and USD 442 million for total catches in the range of 108 to 421 thousand tons, which were obtained from maximizing the economic and biological objective functions. Economic benefit/catch ratios were reduced for scenarios with higher constraints on catch limits, and they were more efficient from a biological point of view. Situations with lighter constraints showed in general higher economic benefits and better performance ratios than those with stronger restrictions. The use of optimization models may provide a useful tool to evaluate the effect of regulations for adequate conservation and economical utilization of a limited resource.
author	López,Felipe Jimenez,Jorge Canales,Cristian
author_facet	López,Felipe Jimenez,Jorge Canales,Cristian
author_sort	López,Felipe
title	Optimal fishing mortality assignment for southern hake Merluccius australis in Chile
title_short	Optimal fishing mortality assignment for southern hake Merluccius australis in Chile
title_full	Optimal fishing mortality assignment for southern hake Merluccius australis in Chile
title_fullStr	Optimal fishing mortality assignment for southern hake Merluccius australis in Chile
title_full_unstemmed	Optimal fishing mortality assignment for southern hake Merluccius australis in Chile
title_sort	optimal fishing mortality assignment for southern hake merluccius australis in chile
publisher	Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar
publishDate	2020
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2020000400613
work_keys_str_mv	AT lopezfelipe optimalfishingmortalityassignmentforsouthernhakemerlucciusaustralisinchile AT jimenezjorge optimalfishingmortalityassignmentforsouthernhakemerlucciusaustralisinchile AT canalescristian optimalfishingmortalityassignmentforsouthernhakemerlucciusaustralisinchile
_version_	1714205240343920640

Optimal fishing mortality assignment for southern hake Merluccius australis in Chile

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