Université de la Nouvelle-Calédonie, ISEA EA1314, BPR4, 98851, Noumea, New Caledonia.
Institut de recherche pour le développement (IRD), UMR ENTROPIE, Laboratoire Excellence LABEX Corail, Noumea, New Caledonia.
Sci Rep. 2019 Feb 27;9(1):2897. doi: 10.1038/s41598-018-37145-x.
Reef sharks are vulnerable predators experiencing severe population declines mainly due to overexploitation. However, beyond direct exploitation, human activities can produce indirect or sub-lethal effects such as behavioral alterations. Such alterations are well known for terrestrial fauna but poorly documented for marine species. Using an extensive sampling of 367 stereo baited underwater videos systems, we show modifications in grey reef shark (Carcharhinus amblyrhynchos) occurrence and feeding behavior along a marked gradient of isolation from humans across the New Caledonian archipelago (South-Western Pacific). The probability of occurrence decreased by 68.9% between wilderness areas (more than 25 hours travel time from the capital city) and impacted areas while the few individuals occurring in impacted areas exhibited cautious behavior. We also show that only large no-entry reserves (above 150 km²) can protect the behavior of grey reef sharks found in the wilderness. Influencing the fitness, human linked behavioral alterations should be taken into account for management strategies to ensure the persistence of populations.
礁鲨是易危的掠食者，其种群数量严重减少，主要是由于过度捕捞。然而，除了直接捕捞之外，人类活动还会产生间接的或亚致死的影响，如行为改变。这种改变在陆地动物中是众所周知的，但在海洋物种中记录甚少。本研究使用了 367 个经过广泛采样的立体诱饵水下视频系统，沿着从新喀里多尼亚群岛（西南太平洋）到人类的隔离程度明显的梯度，展示了灰礁鲨（Carcharhinus amblyrhynchos）的出现和觅食行为的变化。在荒野地区（距离首府超过 25 小时的行程）和受影响地区之间，出现的可能性降低了 68.9%，而在受影响地区出现的少数个体表现出谨慎的行为。我们还表明，只有大型的禁入保护区（超过 150 平方公里）才能保护在荒野中发现的灰礁鲨的行为。考虑到与人类相关的行为改变会影响适应度，在管理策略中应该将其纳入考虑，以确保种群的持续存在。
