Small-scale gill-net fisheries cause massive green turtle Chelonia mydas mortality in Baja California Sur, Mexico
Small-scale gill-net fisheries cause massive green turtle Chelonia mydas mortality in Baja California Sur, Mexico
复制标题
墨西哥南下加利福尼亚州小规模刺网渔业导致绿海龟大量死亡
作者：
A. Mancini;V. Koch;J. Seminoff;B. Madon
摘要墨西哥南下加利福尼亚沿海沃茨是东太平洋绿色海龟Chelonia mydas最重要的觅食地。然而，它们也是个体船队的重要渔场，可能导致副渔获物死亡率很高。我们研究的影响，一个小规模刺网渔业在圣伊格纳西奥泻湖，墨西哥西北部，一个重要的绿色海龟觅食地。我们进行了死亡率普查，并采访了当地渔民估计总误捕死亡率在泻湖。我们还使用标记的漂流者和尸体，以估计搁浅的海龟作为兼捕的概率。在2006 - 2009年期间，我们发现了262只死亡的海龟; 96%的死亡发生在5月至8月，对应于大比目鱼（Paralichthys californicus）和吉它鱼（Rhinobatus sp.）的捕鱼季节。根据漂流者估计的搁浅概率为0.062（95%置信区间，CI，0.035 - 0.094），2006 - 2008年期间最低死亡率为3，516只海龟（95% CI 2，364 - 6，057）或每年1，172只动物。这可能低估了真实的死亡率，因为漂流者搁浅的概率高于尸体，而且大多数渔网都设置在尸体很少搁浅的较低泻湖。对当地渔民的采访得出了类似的估计，每年有1，087只（95% CI 901 - 1，286）海龟死亡。这项研究是个体船队对海龟造成的影响的象征，因为捕捞区和海龟饲养区重叠。2009年，搁浅数量下降了97%以上，这是因为执法当局提高了警惕，改变了捕捞做法，这突出表明了执法对保护受威胁物种的重要性。
Abstract The coastal waters of Baja California Sur, Mexico, include some of the most important foraging grounds of the East Pacific green turtle Chelonia mydas. However, they are also important fishing grounds for artisanal fleets, leading potentially to high levels of bycatch mortality. We studied the impact of a small-scale gill-net fishery at San Ignacio lagoon, north-west Mexico, an important green turtle feeding ground. We conducted mortality censuses and interviewed local fishers to estimate total bycatch mortality at the lagoon. We also used marked drifters and carcasses to estimate stranding probabilities of turtles taken as bycatch. During 2006–2009 we found 262 dead turtles; 96% of the mortality occurred in May–August corresponding to the fishing season for halibut Paralichthys californicus and guitar-fish (Rhinobatus sp.). Stranding probability estimated from drifters was 0.062 (95% confidence interval, CI, 0.035–0.094), yielding a minimum mortality of 3,516 turtles during 2006–2008 (95% CI 2,364–6,057) or 1,172 animals per year. This is probably an underestimate of real mortality as the drifters have higher stranding probabilities than carcasses and most of the nets were set in the lower lagoon where carcasses rarely strand. Interviews with local fishers yielded a similar estimate of 1,087 (95% CI 901–1,286) dead turtles per year. This study is emblematic of the impact of artisanal fleets on marine turtles caused by overlap of fishing and turtle feeding areas. In 2009 strandings declined by > 97%, resulting from a change in fishing practices because of increased vigilance by enforcement authorities, underscoring the importance of law enforcement to protect threatened species.