Depczynski Martial, Bellwood David R
ARC Centre of Excellence for Coral Reef Studies, School of Marine Biology, James Cook University, Townsville 4811, Australia.
Ecology. 2006 Dec;87(12):3119-27. doi: 10.1890/0012-9658(2006)87[3119:epaiiv]2.0.co;2.
Life history theory predicts a range of directional generic responses in life history traits with increasing organism size. Among these are the relationships between size and longevity, mortality, growth rate, timing of maturity, and lifetime reproductive output. Spanning three orders of magnitude in size, coral reef fishes provide an ecologically diverse and species-rich vertebrate assemblage in which to test these generic responses. Here we examined these relationships by quantifying the life cycles of three miniature species of coral reef fish from the genus Eviota (Gobiidae) and compared their life history characteristics with other reef fish species. We found that all three species of Eviota have life spans of < 100 days, suffer high daily mortality rates of 7-8%, exhibit rapid linear growth, and matured at an earlier than expected size. Although lifetime reproductive output was low, consistent with their small body sizes, short generation times of 47-74 days help overcome low individual fecundity and appear to be a critical feature in maintaining Eviota populations. Comparisons with other coral reef fish species showed that Eviota species live on the evolutionary margins of life history possibilities for vertebrate animals. This addition of demographic information on these smallest size classes of coral reef fishes greatly extends our knowledge to encompass the full size spectrum and highlights the potential for coral reef fishes to contribute to vertebrate life history studies.
生活史理论预测，随着生物体体型增大，生活史特征会出现一系列定向的一般反应。其中包括体型与寿命、死亡率、生长速率、成熟时间以及终生繁殖输出之间的关系。珊瑚礁鱼类的体型跨越三个数量级，提供了一个生态多样且物种丰富的脊椎动物组合，可用于检验这些一般反应。在此，我们通过量化三种微小的埃氏鳚属（虾虎鱼科）珊瑚礁鱼类的生命周期，研究了这些关系，并将它们的生活史特征与其他珊瑚礁鱼类物种进行了比较。我们发现，所有三种埃氏鳚属鱼类的寿命均小于100天，每日死亡率高达7 - 8%，呈现快速的线性生长，且成熟时的体型比预期的要小。尽管终生繁殖输出较低，与其小体型相符，但47 - 74天的短世代时间有助于克服个体繁殖力低的问题，这似乎是维持埃氏鳚种群数量的关键特征。与其他珊瑚礁鱼类物种的比较表明，埃氏鳚属鱼类生活在脊椎动物生活史可能性的进化边缘。这些关于最小体型类别的珊瑚礁鱼类的人口统计学信息的补充，极大地扩展了我们的知识范围，使其涵盖了整个体型谱，并突出了珊瑚礁鱼类对脊椎动物生活史研究做出贡献的潜力。
