Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute of Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada.
PLoS One. 2019 Apr 18;14(4):e0215747. doi: 10.1371/journal.pone.0215747. eCollection 2019.
Exploitation and changing ocean conditions have resulted in altered species interactions and varied population dynamics within marine fish communities off northeast Newfoundland and southern Labrador, Canada. To understand contemporary species interactions, we quantified the isotopic niches, niche overlap, and ontogenetic niche change among seven dominant fish species using stable isotope analyses. Analyses used fishes from three regions differing in fish and prey diversities. Differences in fish and diet composition diversity among regions were found using Simpson's inverse diversity index. The regions of lowest diversities had higher instances of niche overlap and higher percentage of niche overlap area. The region of highest diversity had the widest spread of niches with greater distances from the community centroid. Ontogenetic shifts were observed such that larger individuals shifted towards the community centroid with the exception of Atlantic cod. Atlantic cod in particular was found to consistently be the top predator of the analyzed species. Our results reveal: (a) overlap in isotopic niches and spread within niche space was correlated with fish and diet diversity; (b) ontogenetic shifts are important when considering a species' niche and quantifying spatial variation in community niche profiles.
加拿大纽芬兰岛东北部和拉布拉多省南部沿海水域的海洋条件变化和过度捕捞，改变了海洋鱼类群落中的物种相互作用和种群动态。为了了解当代物种相互作用，我们使用稳定同位素分析量化了 7 种主要鱼类的同位素生态位、生态位重叠和个体发育生态位变化。分析使用了来自三个在鱼类和猎物多样性方面存在差异的区域的鱼类。通过辛普森逆多样性指数发现了区域间鱼类和饮食组成多样性的差异。多样性最低的区域具有更高的生态位重叠和更大的生态位重叠面积百分比。多样性最高的区域的生态位分布范围最广，与群落质心的距离也更大。观察到了个体发育的转变，即除了大西洋鳕鱼外，较大的个体向群落质心移动。特别是大西洋鳕鱼被发现一直是分析物种的顶级掠食者。我们的研究结果表明：（a）同位素生态位的重叠和生态位空间内的分布与鱼类和饮食多样性有关；（b）当考虑一个物种的生态位并量化群落生态位分布的空间变化时，个体发育的转变很重要。
