Effects of bycatch on the population viability of the narrow-ridged finless porpoises in Ariake Sound and Tachibana Bay, Japan
Effects of bycatch on the population viability of the narrow-ridged finless porpoises in Ariake Sound and Tachibana Bay, Japan
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DOI：
10.3354/esr00658
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发表时间：
2015-01-01
影响因子：
3.1
通讯作者：
Shirakihara, Miki
中科院分区：
文献类型：
--
作者：
Hashimoto, Midori;Shirakihara, Kunio;Shirakihara, Miki
窄脊江豚Neophocaena asiaeorientalis是一种受到各种人类活动威胁的沿海鲸类。在日本有明湾和立花湾，副渔获物死亡对海豚种群特别危险。为了评估混捕死亡率对该种群生存能力的影响，我们使用Leslie矩阵模型模拟了未来100年种群规模的变化。模拟试验重复了3种可能的兼捕死亡率的情况。如果副渔获死亡率保持在报告的水平，估计年下降率为0.671%至3.87%，估计种群规模减少了29.6%至86.3%，在3代。即使在最乐观的情况下，在几乎一半的模拟试验中，预测种群规模减少>= 30%。所报告的误捕死亡率将对这一江豚种群的生存能力构成严重威胁;因此，根据《自然保护联盟红色名录》所界定的标准A4，这一种群至少应被列为"脆弱"种群。我们的预测是敏感的年度兼捕死亡率估计。因此，应促进收集当前丰度和兼捕数据，以尽量减少风险评估中的不确定性。
The narrow-ridged finless porpoise Neophocaena asiaeorientalis is a coastal ceta cean that is threatened by various human activities. Bycatch mortality is a particular danger to the porpoise population in Ariake Sound and Tachibana Bay, Japan. To evaluate the impact of bycatch mortality on the viability of this population, we simulated changes in population size over the next 100 yr, using a Leslie matrix model. The simulation trials were repeated for 3 scenarios of possible bycatch mortality rates. If bycatch mortality remains at the reported level, the estimated annual rate of decrease is 0.671 to 3.87%, and the estimated population size reduction over 3 generations is 29.6 to 86.3%. A population size reduction of >= 30% was predicted in almost half the simulation trials, even in the most optimistic scenario. The reported bycatch mortalities would pose a serious threat to the viability of this porpoise population; therefore, the population should be classified at least as `Vulnerable' according to Criterion A4, as defined in the IUCN Red List. Our predictions were sensitive to annual bycatch mortality rate estimates. Hence, the collection of current abundance and bycatch data should be promoted in order to minimize uncertainty in risk assessments.