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摘要
The sea cucumber Isostichopus fuscus (Ludwig, 1875) has been exploited, legally, and illegally, on the Baja California peninsula since 1988. The fishery was closed in 1994 due to overfishing symptoms but reopened in 2007 under management strategies and harvesting permits. Nocturnal samplings surveyed abundance, size and weight of 1. fuscus. Density, proportion of individuals above the minimum size for fishing (MSF), weight length relationship parameters, relative condition index (Kn), parameters of the von Bertalanffy growth equation (VBGE), individual and average age from the VBGE, natural mortality rate (M) and survival percentage cohort were estimated from the data set for the population in 2005 2007, and compared with the same population in 2013 at the Biosphere Reserve Bahia de los Angeles. Semi-structured interviews were also conducted to obtain the stakeholders' perspectives and opinions about the fishery. There were no significant differences in the weight length relationship (W = 7.17.L-129), relative condition index (Kn = 1.08), and parameters of the von Bertalanffy growth equation (L-infinity = 35.74 cm, K = 0.26 y(-1)), between the study periods. The population in the 2005-2007 period was mainly constituted by individuals <20 cm in length (90%), probably due to intensive poaching. Only 10% of the population was in the reproductive age (4-5 y; 21 cm), and juveniles were observed (4%). The mean length and proportion of individuals >= 20 cm in length increased in the 2013 samplings (17.8 +/- 3.8 cm and 35%), although observed mean length is shorter than minimum size for fishing and size at first maturity. On the other hand, density decreased in 2013 (0.15 +/- 0.01 ind m(-2)), compared to the 2005-2007 period (0.27 +/- 0.04 ind m(-2)). Interviewees agreed that poaching was the main problem for the fishery, as well as the difficulty for fishers to obtain their own harvesting permits, because they were dependent on the permits holders to operate. Our results corroborated that the growth rate and mortality rate of the 1. fuscus population in its northernmost geographical distribution were similar to those from southern locations. However, the observed values of the density and mean length were well below those previously registered in Bahia de los Angeles or in other localities, and may compromise reproductive success, because low recruitment was observed. Some actions are proposed for the sustainable management of this resource.
- 出版日期2016-3
