Loggerhead sea turtle abundance at a foraging hotspot in the eastern Pacific Ocean: implications for at-sea conservation
Loggerhead sea turtle abundance at a foraging hotspot in the eastern Pacific Ocean: implications for at-sea conservation
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东太平洋觅食热点地区红海龟的丰度：对海上保护的影响
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
S. H. Peckham
中科院分区：
文献类型：
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作者：
J. Seminoff;Tomoharu Eguchi;James V. Carretta;Camryn D. Allen;D. Prosperi;R. Rangel;J. W. Gilpatrick;K. Forney;S. H. Peckham
墨西哥下加利福尼亚半岛（BCP）的太平洋海岸是一个老龄红海龟的热点，这种海龟来自日本的筑巢海滩。BCP地区也因每年有数千只海龟的人为海龟死亡而闻名。为了将这种死亡率的保护意义纳入生物学背景，我们进行了航空调查，以确定沿着BCP太平洋海岸的Ul- loa湾的红海龟的分布和丰度。从2005年到2007年，我们每年都在调查。3700公里的样条线，包括离岸140公里的区域。在这些调查中，我们在水面上发现了755只红海龟（总共785只红海龟，每组最多7只）。我们采用标准的线样方法来估计海龟丰富的调查数据收集在良好的良好的观测条件，其中包括447个红海龟目击在~6400公里的调查工作。我们根据现场潜水数据得出了红海龟在水面上的时间比例，以及测量人员可以看到的时间比例。43226只北美红海龟的年平均丰度（CV = 0.51，95%CI范围= 15017 ~ 100444）代表了基于稳健分析方法的北太平洋红海龟觅食丰度的首次估计。我们的密度估计证实了BCP作为北太平洋红海龟主要觅食区的重要性。在BCP附近的红海龟的年度死亡率估计的背景下，这些结果表明，该地区的红海龟种群的高达11%，每年可能会由于人为和/或自然的威胁而死亡。我们计算出，如果目前的死亡率继续下去，在任何一年中居住在BCP地区的红海龟中有50%将在15年内死亡。这说明迫切需要尽量减少当地红海龟的人为和自然死亡率。
The Pacific Coast of the Baja California Peninsula (BCP), Mexico, is a hotspot for for- aging loggerhead turtles Caretta caretta originating from nesting beaches in Japan. The BCP re- gion is also known for anthropogenic sea turtle mortality that numbers thousands of turtles annu- ally. To put the conservation implications of this mortality into biological context, we conducted aerial surveys to determine the distribution and abundance of loggerhead turtles in the Gulf of Ul- loa, along the BCP Pacific Coast. Each year from 2005 to 2007, we surveyed ca. 3700 km of transect lines, including areas up to 140 km offshore. During these surveys, we detected loggerhead turtles at the water's surface on 755 occasions (total of 785 loggerheads in groups of up to 7 turtles). We applied standard line-transect methods to estimate sea turtle abundance for survey data collected during good to excellent sighting conditions, which included 447 loggerhead sightings during ~6400 km of survey effort. We derived the proportion of time that loggerheads were at the surface and visible to surveyors based on in situ dive data. The mean annual abundance of 43 226 logger- head turtles (CV = 0.51, 95% CI range = 15 017 to 100 444) represents the first abundance estimate for foraging North Pacific loggerheads based on robust analytical approaches. Our density estimate confirms the importance of the BCP as a major foraging area for loggerhead turtles in the North Pacific. In the context of annual mortality estimates of loggerheads near BCP, these results suggest that up to 11% of the region's loggerhead population may perish each year due to anthro- pogenic and/or natural threats. We calculate that up to 50% of the loggerhead turtles residing in the BCP region in any given year will die within 15 yr if current mortality rates continue. This un- derscores the urgent need to minimize anthropogenic and natural mortality of local loggerheads.