Ecology and Evolutionary Biology, University of California, 130 McAllister Way, Santa Cruz, CA 95060, USA.
Integr Comp Biol. 2020 Aug 1;60(2):522-534. doi: 10.1093/icb/icaa061.
The effectiveness of marine protected areas (MPAs) on the general health and conservation of species, habitats, and community interactions is of great interest to researchers, managers, and recreationalists. However, the ecological and behavioral diversity of vertebrate predators of southern California kelp forests limits our ability to make general conclusions about MPA effectiveness across a variety of species. Identifying and studying species with extreme feeding habits or prey-capture strategies may offer greater insight into predator-prey relationships and reveal the trophic importance of an animal in the larger community. Moray eels (family Muraenidae) have been shown to have morphological and behavioral adaptations that allow them to consume large prey whole, identifying them as important predators. From 2015 to 2018, we studied the health and feeding behavior of a long-lived, elusive, and benthic kelp forest predator, the California moray eel (Gymnothorax mordax). We trapped eels inside and outside of Blue Cavern Onshore State Marine Conservation Area, an MPA on the northwest side of Santa Catalina Island, CA which prohibits the take of any species. Over 4 years, we captured 1736 eels. Overall, we found that morays were longer, older, heavier, had higher body condition, and were found in greater abundance within the MPA. Although fish comprised the majority of their summer diet, morays outside of the MPA were consuming a more diverse set of fish, while kelp bass comprised more than half of the diet for morays inhabiting the MPA. Additionally, we found that morays within the MPA had larger relative vertical gape distances (VGDs) and narrower heads. Our recapture data support the high site fidelity of morays, indicating that their diet and morphology are influenced by their local community. While the majority of morays are thriving in the MPA, as suggested by their robust sizes and longevity, high abundance appears to result in higher frequencies of cannibalism, the presence of an undescribed disease, and lower growth rates. Our results suggest that the MPA affects the life history of morays and may select for an alternative feeding strategy in which eels develop larger VGDs, smaller adductor muscles, and a specialized diet which is presumably influenced by the local environment. In addition, observations of cannibalistic behavior and species-specific disease provide us with important insight into natural factors that may still regulate populations removed from anthropogenic disturbances such as fishing.
海洋保护区 (MPAs) 对物种、生境和群落相互作用的总体健康和保护的有效性引起了研究人员、管理者和休闲爱好者的极大兴趣。然而，南加州巨藻林的脊椎动物捕食者的生态和行为多样性限制了我们对各种物种的 MPA 有效性做出一般结论的能力。确定和研究具有极端摄食习惯或猎物捕获策略的物种，可以提供更多关于捕食者-猎物关系的深入了解，并揭示动物在更大群落中的营养重要性。海鳝（Muraenidae 科）具有形态和行为上的适应性，使它们能够整体吞食大型猎物，这使它们成为重要的捕食者。从 2015 年到 2018 年，我们研究了一种长寿、难以捉摸的底栖巨藻林捕食者——加利福尼亚海鳝（Gymnothorax mordax）的健康和摄食行为。我们在加利福尼亚州圣卡塔利娜岛西北侧的蓝洞陆上州立海洋保护区（MPA）内外捕捉海鳝，该保护区禁止捕捞任何物种。在 4 年多的时间里，我们捕获了 1736 条海鳝。总的来说，我们发现海鳝在 MPA 内的体长更长、年龄更大、体重更重、身体状况更好，而且在 MPA 内的数量更多。虽然鱼类是它们夏季饮食的主要组成部分，但在 MPA 外的海鳝正在食用更多种类的鱼类，而在 MPA 内栖息的海鳝的饮食中则有超过一半是巨藻鲈。此外，我们发现 MPA 内的海鳝的相对垂直张口距离（VGD）更大，头部更窄。我们的再捕获数据支持海鳝的高度栖息地忠诚度，表明它们的饮食和形态受到其当地群落的影响。虽然大多数海鳝在 MPA 中茁壮成长，这从它们的强壮体型和长寿中可以看出，但高丰度似乎导致了更高频率的同类相食、一种未描述疾病的存在以及生长速度降低。我们的研究结果表明，MPA 影响海鳝的生活史，并可能选择一种替代的摄食策略，其中海鳝的 VGD 增大、内收肌变小、以及专门的饮食，这可能受到当地环境的影响。此外，对同类相食行为和特定物种疾病的观察为我们提供了重要的见解，了解可能仍然调节从捕鱼等人为干扰中移除的种群的自然因素。
