Oceanographic perspectives on: 1) size and maturity at age in fishes and 2) the biomass spectrum in the Northumberland Strait

海洋学视角：1) 鱼类的大小和成熟度；2) 诺森伯兰海峡的生物量谱

• 批准号: RGPIN-2015-05102
• 负责人: Taggart, Christopher
• 金额: $ 1.53万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=678492
• 关键词: Oceanographic; perspectives; size; maturity; age

This proposal has two foci representing two oceanographic themes that my lab has been pursuing for well over a decade. The first (1) focuses on the growing-degree-day metric (GDD - the thermal integral) and its ability to diagnose size and maturity changes in fish that result from size-selective fishing. The second (2) focuses on zooplankton biomass spectrum models that can explain variation in the ecological functioning of regional oceans.******1) We have shown that ~92% of length-at-age (LaA) variation in fish can be explained by the GDD metric among many fish species in both the wild and in controlled studies and others have since confirmed the utility of the metric among other species. We have also demonstrated that deviations from the expected LaA-GDD relation can be used to diagnose size-selective fishing effects on exploited fish stocks that include reduced size-at-age and earlier maturation. These effects have negative consequences on recruitment potential due to reduced fecundity and reduced egg and larval quality. Others have also shown that this may have genetic consequences that place new demands on sustainable fishery management. Working with a PhD student, we will use the GDD metric to diagnose size-selective fishing effects across a range of exploited marine stocks in the north Atlantic, and do so in collaboration with researchers in Norway. For those stocks that depart from expectation, we will examine the anomalies under the hypothesis that they are most easily explained by size-selective fishing. We will then address the consequences on recruitment expectations in relation to sustainable fisheries management.***2) Zooplankton are the trophic link between phytoplankton and fish production. The zooplankton biomass size spectrum can be used to quantify the structure and function of zooplankton communities because it reveals processes not readily apparent using conventional taxonomic approaches. Variations among spectra can be used to estimate the time and space transfer of energy from primary production through the zooplankton community to the fish community. Working with an MSc student, we will focus on the zooplankton component via time and space variation in the biomass spectrum and its association with variation in water mass structure. As our test case, we will rely on optical plankton counter and in situ net sample data coincident with conductivity, temperature and depth data collected in the Northumberland Strait. The spectrum - a species-independent measure of the Strait ecosystem - will help us in determining the energy transfer and transport in time and space. These data and analyses will also be used to contribute to a global study involving several researchers and institutions around the world where the focus is on using the size spectrum as an innovative method for estimating zooplankton growth, predation and production as food for fish and as well as improving ecosystem models.***********

这项提议有两个焦点，代表了我的实验室十多年来一直追求的两个海洋学主题。第一个(1)侧重于生长度-日指标(GDD--温度积分)及其诊断选择性捕捞引起的鱼类大小和成熟度变化的能力。第二(2)集中于浮游动物生物量光谱模型，可以解释区域海洋生态功能的变化。*1)我们已经表明，在野生和对照研究中，许多鱼类物种中约92%的年龄长度(LAA)变化可以用GDD度量来解释，其他物种已经证实了该度量在其他物种中的实用性。我们还证明，偏离预期的LAA-GDD关系可以用来诊断对已开发鱼类种群的大小选择性捕捞影响，包括年龄减少和成熟提前。由于繁殖力下降、卵和幼虫质量下降，这些影响对招募潜力产生了负面影响。其他人也表明，这可能会产生遗传后果，对可持续渔业管理提出新的要求。与一名博士生合作，我们将使用GDD指标来诊断北大西洋一系列已开发海洋种群的大小选择性捕捞影响，并与挪威的研究人员合作进行这项工作。对于那些偏离预期的种群，我们将在以下假设下检查异常情况：它们最容易被选择性捕捞解释。然后，我们将讨论与可持续渔业管理有关的对招募预期的影响。*2)浮游动物是浮游植物和鱼类生产之间的营养联系。浮游动物生物量大小谱可以用来量化浮游动物群落的结构和功能，因为它揭示了使用传统分类方法不太明显的过程。光谱之间的差异可以用来估计初级生产力通过浮游动物群落向鱼类群落传递的能量的时间和空间转移。与理科硕士学生合作，我们将重点研究浮游动物成分通过生物量光谱的时间和空间变化及其与水团结构变化的关系。作为我们的测试案例，我们将依靠光学浮游生物计数器和现场净样本数据，这些数据与在诺森伯兰海峡收集的电导率、温度和深度数据一致。光谱--一种独立于物种的海峡生态系统衡量标准--将帮助我们确定能量在时间和空间上的转移和传输。这些数据和分析还将被用于一项全球研究，该研究涉及世界各地的几名研究人员和机构，重点是使用尺寸谱作为一种创新方法来估计浮游动物的生长、捕食和作为鱼类食物的产量，以及改进生态系统模型。