Resource partitioning in the St. Lawrence estuary

圣劳伦斯河口的资源分配

• 批准号: 328300-2006
• 负责人: Dodson, Julian
• 金额: $ 4.21万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Ship Time
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=340560
• 关键词: Resource; partitioning; St.; Lawrence; estuary

The long term objective of this NSERC-supported research program has been to elucidate how the highly heterogeneous environments that characterise the estuarine transitional zone (where freshwater first mixes with seawater) influence the ecology and the evolution of estuarine fishes. We propose to pursue four major objectives. The first is to assess how the exploitation of the estuarine landscape during development generates the selective forces leading to independent phenotypic trajectories of two sympatric populations of smelt in the St. Lawrence estuary. We will sample two cohorts of smelt of both populations from hatching to reproduction (age 3+), thus providing a longitudinal developmental series for growth, morphological development, survival and sexual maturation as a function of depth, salinity and temperature gradients along transversal and longitudinal axes. The second specific objective is to test the hypothesis that tomcod, the most abundant fish of the ETZ, are morphologically specialized to exploit deep channel and shallow shoal habitat and exhibit a morphological divergence similar to that of the sympatric populations of smelt. Our third specific objective is to exploit this same sampling program to describe the spatial structure of the entire fish community as a function of the ETZ's physical gradients. The fourth specific objective is to focus on another tool with which we hope to reveal the partitioning of resources on a spatial and temporal scale. Stable isotope analyses of carbon, nitrogen and sulphur will be used to define the spatial extent of feeding of young-of-the-year and 1+ fishes. The same stratified sampling plan involving a grid of 30 stations spanning the environmental gradients of the ETZ will serve to map the distribution of all life history stages of all key transitional-zone fishes. These objectives are attainable thanks to the availability of a new sampling platform (the Lampsilis), which permits the sampling of shallow and deep-water habitat, and the use of a combination of innovative technologies including stable isotope analysis and molecular genetics.

这项由NSERC支持的研究计划的长期目标是阐明河口过渡带(淡水与海水首先混合的地方)的高度异质性环境如何影响河口鱼类的生态和进化。我们建议达致四大目标。第一个是评估开发过程中对河口景观的开发如何产生选择性力量，导致圣劳伦斯河口两个共域种群的表型轨迹独立。我们将对两个种群从孵化到繁殖(3+龄)的两组气味进行采样，从而提供生长、形态发育、存活和性成熟的纵向发育序列，作为横轴和纵轴上深度、盐度和温度梯度的函数。第二个具体目标是验证这样一种假设，即作为ETZ中最丰富的鱼类，大头鳕鱼在形态上专门开发深水航道和浅滩栖息地，并表现出与共域种群类似的形态差异。我们的第三个具体目标是利用同样的采样程序来描述整个鱼类群落的空间结构作为ETZ物理梯度的函数。第四个具体目标是侧重于另一个工具，我们希望用它来揭示资源在空间和时间尺度上的划分。碳、氮和硫的稳定同位素分析将用于确定年幼鱼和1+鱼的摄食空间范围。同样的分层抽样计划涉及30个站点的网格，横跨ETZ的环境梯度，将用于绘制所有关键过渡带鱼类的所有生活史阶段的分布图。这些目标之所以能够实现，是因为有了新的采样平台(Lampsilis)，可以对浅水和深水栖息地进行采样，并结合使用了稳定同位素分析和分子遗传学等创新技术。