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首页> 外文期刊>Marine biology >Population ecology of the green/black turtle (Chelonia mydas) in Bahia Magdalena, Mexico
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Population ecology of the green/black turtle (Chelonia mydas) in Bahia Magdalena, Mexico

机译：墨西哥巴伊亚州马格达莱纳的绿海龟/黑海龟（Chelonia mydas）的种群生态学

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The mangrove channels of Bahia Magdalena, Mexico, are important developmental areas for juvenile green, or black turtles (Chelonia mydas), but incidental bycatch and illegal hunting threaten population persistence. We studied size distribution, condition index (CI), growth rates, and mortality of black turtles in Estero Banderitas, the largest mangrove channel in Bahia Magdalena, to supply information for the development of effective conservation strategies. A total of 213 black turtles (including 88 recaptures) were caught in entanglement nets between July 2000 and July 2003. Average yearly catch per unit of effort (CPUE, 1 unit: 100 m of net fishing for 12 h) dropped during the study from 2.19 to 0.76. About 97% of all turtles were considered juveniles, average size was 54.6 ± 9.5 cm. Turtles were significantly smaller at the head of Estero Banderitas than in the central part of the Estero and in the open bay, indicating size-based habitat segregation. Average growth rate was 1.62 cm/year and declined with increasing size. Growth was seasonal and three times higher in summer (0.28 cm/month) than in winter (0.09 cm/month), body CI was also significantly higher during the summer months. A seasonalized von Bertalanffy growth function (VBGF) was used to model growth for the size range studied (43-73 cm SCL), with the parameters: L_∞ = 101 cm SCL; K = 0.04 year~(-1); t_0 = 0; C = 0.4 and t_s = 0.75. Growth data indicate that black turtles may spend up to 20 years in Bahia Magdalena before they reach maturity at about 77 cm SCL. The total mortality estimate (Z) from the length converted catch curve was 0.16, corresponding to a yearly survival probability of 0.85.
机译：墨西哥巴伊亚州马格达莱纳的红树林通道是少年绿海龟或黑海龟（Chelonia mydas）的重要发育区，但偶然的兼捕和非法狩猎威胁着人口的持久性。我们研究了巴伊亚州马格达莱纳最大的红树林通道埃斯特罗·班德里塔斯（Esero Banderitas）的黑海龟的大小分布，状况指数（CI），生长速率和死亡率，为开发有效的保护策略提供信息。在2000年7月至2003年7月之间，总共有213只黑海龟（包括88个被捕者）被纠缠网捕获。研究期间，每单位工作量（CPUE，1个单位：100 m的净捕鱼量，持续12 h）的年平均捕捞量从2.19至0.76。所有乌龟中约有97％被认为是幼鱼，平均大小为54.6±9.5厘米。与埃斯特罗中部和开阔海湾相比，埃斯特罗班德里塔斯山顶的海龟明显要小得多，这表明基于大小的生境隔离。平均增长率为1.62厘米/年，并随着尺寸的增加而下降。生长是季节性的，夏季（0.28厘米/月）是冬季（0.09厘米/月）的三倍，夏季的身体CI也显着提高。使用季节性von Bertalanffy生长函数（VBGF）来模拟所研究尺寸范围（43-73 cm SCL）的生长，参数为：L_∞= 101 cm SCL； K = 0.04年〜（-1）; t_0 = 0; C = 0.4，t_s = 0.75。生长数据表明，黑龟在巴伊亚州马格达莱纳（Sahia Magdalena）可能会长达20年，直到它们在约77厘米SCL处成熟。由长度转换的捕获曲线得出的总死亡率估计数（Z）为0.16，对应的年生存概率为0.85。

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