Our study is the first detailed examination of species composition using DNA COI barcoding of elasmobranchs from an artisanal fishery of Papua New Guinea. The study is the first in the region to provide biomass estimates based on species confirmation following examination of dried fins. Over 20 species of elasmobranchs were identified from 623 fins from the artisanal fishery in Milne Bay Province of PNG, with Carcharhinus amblyrhynchos and Carcharhinus melanopterus the most abundant species in the catches. Of concern, 21% of fins examined were from IUCN listed threatened species (Vulnerable or Endangered) with 8% of fins from the Endangered scalloped hammerhead (Sphyrna lewini). Following species identifications and use of species-specific length and weight extrapolations, we estimated over 9 t of elasmobranchs contributed to the fin batch. Importantly, the vast majority of the elasmobranchs in this batch were from immature animals. Genetic identification has an important role to play in the ongoing sustainable management of elasmobranchs in artisanal fisheries in PNG and more widely. However in the absence of ongoing genetic testing, recording the species (if known) at the time of catch is more achievable and would provide more robust data for fisheries managers in PNG over the longer term.
Bioeconomic models have been developed and applied to a range of fisheries around the world. However, an even greater number of fisheries are relatively data poor, and development of traditional bioeconomic models is not feasible. For small‐scale fisheries, the cost of data collection and model development may exceed the additional value these models may generate. Fisheries biologists have grappled with similar issues and have developed a range of data‐poor methods for estimating reference points related to fishing mortality based on life history characteristics and other indicators. In other cases, catch and effort data may be sufficient to estimate sustainable biomass levels. However, model‐derived economic target reference points require robust biological models as well as appropriate economic information, both of which are often unavailable. In this paper, we extend the data‐poor work to move from biological to economic target reference points for single‐species fisheries. We show that the relationship between economic (maximum economic yield) and biological (maximum sustainable yield) reference points depends primarily on the cost : revenue ratio, and that, where unavailable, these can be inferred from fisheries characteristics. We show that good estimates of biomass‐ and effort‐based economic target reference points can be achieved with limited data.
Received September 4, 2013; accepted August 10, 2014
RESUMEN: El interés creciente de establecer el máximo rendimiento económico (MRE) como objetivo de manejo, ha suscitado un intenso debate en cuanto a cómo éste debe ser calculado. Las diferentes interpretaciones de cómo deben considerarse los costos económicos de una pesquería, han dado lugar a distintos resultados. Por ejemplo un artículo reciente de Wang y Wang (Fisheries, 37(9)) muestra el análisis retrospectivo de un programa de compra de embarcaciones de una de las más importantes pesquerías de Australia, con el objetivo de dirigir a la pesquería hacia el MRE, y se concluye que se hubieran logrado mayores beneficios económicos de no haberse establecido el programa de compra. No obstante, las suposiciones económicas detrás de esto, son controversiales. En este artículo se ofrece un análisis propio utilizando parámetros económicos corregidos y se sugiere que, de no haber tenido lugar la compra de embarcaciones, los beneficios industriales de 2006 a 2009 hubieran sido del orden de $22-25 millones menos. Estos nuevos hallazgos se contextualizan en los eventos que dieron lugar al programa de compra de barcos, y se concluye que dicho programa produjo en importantes beneficios para la industria.
ABSTRACT: The increasing interest in maximum economic yield (MEY) as a management target has been accompanied by considerable debate as to how MEY should be determined.Different interpretations as to how economic costs are treated may lead to different outcomes. For example, a recent paper by Wang and Wang (2012b) provided a retrospective analysis of a recent buyback program in a major Australian fishery aimed at moving the fishery to MEY and concluded that greater economic benefits would have been achieved had the buyback not taken place. However, the economic assumptions underlying this result are debatable. In this article, we provide our own analysis using corrected economic parameters and suggest that, had the buyback not taken place, industry profits from 2006 to 2009 would have been $22-25 million lower. These new findings are placed in the context of the events that led to the buyback taking place and we conclude that the buyback resulted in substantial benefits to the industry.
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