Equilibrium yield-curve analysis through an analytic age-structured production model: A sensitivity study for the Chilean jack mackerel fishery

Cubillos, Luis A.; Hernández, Aldo Fidel Izaguirre; Sepúlveda, Aquiles; Arcos, Dagoberto

doi:10.1016/s0165-7836(01)00273-9

Cited by 3 publications

(1 citation statement)

References 24 publications

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“…For option (i) this included ages 2-8, while options (ii) and (iii) included ages larger than the corresponding MLS (Table 3). Two reference points were used to assess the status of pike population in the study region (Pauly, 1984;Cubillos et al, 2002): F 0.1 , the fishing mortality rate at which the marginal increase in YPR is 10% of that at F = 0, and F MSY , the fishing mortality rate that gives the maximum sustainable yield (MSY).…”

Section: Mortality and Yield-per-recruitmentioning

confidence: 99%

Demographic variables and stock status of pike,Esox lucius, in the commercial fishery in the Anzali Wetland (SW Caspian Sea) near the southern limits of its distribution range

Moslemi-Aqdam

Namin

Sattari

et al. 2017

Aquat. Living Resour.

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The demographic variables of pike (Esox lucius) were studied at the southern edge of the species' distribution in the Anzali Wetland, south-western Caspian Sea. The main aim was to provide data for the assessment of the stock and to explore possible fisheries management measures such as setting minimum landing size based on length-at-maturity. Pike collected from commercial landings ranged from 15.4 to 75.4 cm in fork length (FL), from 52.9 to 3462.5 g in weight and were between 0 and 8 years old. Von Bertalanffy growth function parameters were L ∞ = 90.6 cm FL, k = 0.12 yr À1 and t 0 = À1.74 yr À1 . Male pike matured at 1-2 years with L 50 of 28.6 cm FL, whereas females matured at 2-3 years with a L 50 of 33.9 cm FL. Instantaneous total mortality (Z) was estimated as 0.93 yr À1 , while fishing mortality (F) was estimated to be 0.66 yr À1 . Yield-per-recruit analysis indicated that pike in the Anzali Wetland seems to be growthoverfished under the current fishing regime with no management measures, and substantial increases in yield could be achieved by increasing the length at first harvest. The results indicated that management actions such as enforced legislation are required to obtain a better stock status and higher yield. Management could be more effective if the number of fishers and their catch could be controlled, e.g., through the allocation of fishing licenses.

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Section: Mortality and Yield-per-recruitmentioning

confidence: 99%

Demographic variables and stock status of pike,Esox lucius, in the commercial fishery in the Anzali Wetland (SW Caspian Sea) near the southern limits of its distribution range

Moslemi-Aqdam

Namin

Sattari

et al. 2017

Aquat. Living Resour.

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Using an age-structured model to simulate the recovery of the Australian pilchard (Sardinops sagax) population following epidemic mass mortality

Murray

Gaughan

2003

Fisheries Research

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Evaluación talla estructurada de los stocks de Ensis macha y Tagelus dombeii en el Golfo de Arauco, Chile

Hernández¹,

Cubillos²,

Quiñones³

2011

Rev. biol. mar. oceanogr.

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Abstract.-A stock assessment of Ensis macha and Tagelus dombeii for the fishery within the Gulf of Arauco, Chile was conducted from 1996 to 2007. The stock assessment model consisted of: (i) a general model of species-specific population dynamics, ii) models for the observations of annual catches, size composition and catch per unit effort; iii) log-likelihood functions for each segment of information and penalties, and iv) a numerical estimation process. The estimation process allows the simultaneous determination of population parameters such as von Bertalanffy growth parameters, rate of natural mortality at age, fishing mortality rates, selectivity, and recruitment. The results for E. macha show clear signs of overfishing between 1996 and 2007, with a critical condition existing in regards to spawning stock and recruitment; the size and age structure in the landings indicates fishing activities are selecting fish that are smaller than the size at first maturity. In the case of T. dombeii, some signs of over exploitation are also detected but with spawning stock and recruitments healthier than that observed in the case of E. macha. Nevertheless, the size and age structure of the landings shows high dependence on the annual recruitment for the success of the fishery. The parental stocks of both species show clear declining trends, which is strongly affecting recruitments to the fishery. Our results demonstrate that it is critical to decrease the amount of fishing and improve the selectivity of the fishery. If changes towards this direction are not carried out, the sustainability of these fisheries is under threat.Key words: Stock assessment, razorfish, razor clams, Humboldt Current System, artisanal fisheriesResumen.-Se evaluaron los stocks de Ensis macha y Tagelus dombeii, para la pesquería desarrollada en el Golfo de Arauco, Chile, entre 1996 y 2007. Se utilizó un modelo de evaluación de stock, que consiste en: i) un modelo general de dinámica poblacional especie-específica, ii) modelos para las observaciones de capturas anuales, composición por tamaños y captura por unidad de esfuerzo; iii) funciones de log-verosimilitud para cada segmento de información y penalizaciones y; iv) un proceso de estimación numérica. El proceso de estimación permite la determinación simultánea de los parámetros poblacionales, tales como los parámetros de crecimiento de von Bertalanffy, la tasa de mortalidad natural a la edad, tasas de mortalidad por pesca, selectividad, y reclutamientos. Para E. macha se indican síntomas claros de sobreexplotación entre los años 1996 y 2007, con una condición de stock desovante y reclutamientos crítica y una estructura de tamaños y edades en los desembarques que dan cuenta de selectividades inferiores a la talla de primera madurez. Para el caso de T. dombeii, también se detectan algunos síntomas de sobreexplotación, con una condición de stock desovante y reclutamientos más saludable que la observada en el caso de E. macha, pero con una estructura de tamaños y edades en los desembarques que eviden...

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Equilibrium yield-curve analysis through an analytic age-structured production model: A sensitivity study for the Chilean jack mackerel fishery

Cited by 3 publications

References 24 publications

Demographic variables and stock status of pike,Esox lucius, in the commercial fishery in the Anzali Wetland (SW Caspian Sea) near the southern limits of its distribution range

Demographic variables and stock status of pike,Esox lucius, in the commercial fishery in the Anzali Wetland (SW Caspian Sea) near the southern limits of its distribution range

Using an age-structured model to simulate the recovery of the Australian pilchard (Sardinops sagax) population following epidemic mass mortality

Evaluación talla estructurada de los stocks de Ensis macha y Tagelus dombeii en el Golfo de Arauco, Chile

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