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

这个建议有两个焦点，代表了我的实验室十多年来一直在追求的两个海洋学主题。第一个（1）侧重于生长度日指标（GDD -热积分）及其诊断因选择性捕捞造成的鱼体大小和成熟度变化的能力。第二（2）部分着重于可以解释区域海洋生态功能变化的浮游动物生物量谱模型。 1)我们已经表明，在野生和对照研究中，许多鱼类中~92%的年龄长度（LaA）变化可以用GDD度量来解释，其他人已经证实了该度量在其他物种中的实用性。我们还表明，偏离预期的LaA-GDD关系，可用于诊断大小选择性捕捞对已开发鱼类种群的影响，包括年龄和成熟期的减少。这些影响对招募潜力产生负面影响，因为繁殖力降低，卵和幼虫质量降低。其他研究也表明，这可能产生遗传后果，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尺寸选择性捕捞效应，并与挪威的研究人员合作。对于那些偏离预期的种群，我们将根据最容易用大小选择性捕捞来解释的假设来审查异常情况。然后，我们将讨论与可持续渔业管理有关的招聘预期的后果。 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用于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容易明显的过程。光谱之间的变化可以用来估计能量从初级生产力通过浮游动物群落到鱼类群落的时间和空间转移。与一名硕士学生合作，我们将通过生物量谱中的时空变化及其与水体结构变化的关联来关注浮游动物成分。作为我们的测试案例，我们将依靠光学浮游生物计数器和原位净样本数据与诺森伯兰海峡收集的电导率，温度和深度数据相一致。光谱-海峡生态系统的一种独立于物种的测量-将帮助我们确定能量在时间和空间上的转移和运输。这些数据和分析还将用于一项全球研究，该研究涉及世界各地的几个研究人员和机构，重点是使用大小谱作为估计浮游动物生长、捕食和作为鱼类食物的生产以及改进生态系统模型的创新方法。

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.