Collaborative Research: Incorporating Disease Information Into Abundance Models of Alaska Pacific Herring Populations

合作研究：将疾病信息纳入阿拉斯加太平洋鲱鱼种群的丰度模型

• 批准号: 9901351
• 负责人: Terrance Quinn
• 金额: $ 3.06万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-02-01 至 2002-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9901351&HistoricalAwards=false
• 关键词: Collaborative; Research; Incorporating; Disease; Information

Quinn 9901351Pacific herring (Clupea pallasl) are schooling fish that range throughout coastal regions of the North Pacific. They are an important component of the ecosystem as secondary consumers, they serve as high-quality prey for many marine mammals and birds, and in Prince William Sound, Alaska, they comprise an important seasonal commercial fishery.Models to estimate fish populations commonly integrate many variables, including age, length, sex composition, fishing mortality, and indices of abundance such as catch per unit effort and survey biomass. For Pacific herring in Prince William Sound, population biomass has been modeled and estimated since the early 1970s. Natural mortality is usually treated as a constant in these models because it is difficult to estimate mortality without comprehensive information about disease and predation. Recent evidence from Prince William Sound, however, indicates that use of a constant mortality in such models can lead to large errors in stock assessment estimates. In 1993, estimates based on age-structured population models led biologists to predict that over 1 00,000 metric tons of Pacific herring would spawn. However, only 20,000 metric tons actually returned to spawn. When viral hemorrhagic septicemia virus was isolated from several herring sampled from the population, it was hypothesized that a disease epidemic was responsible for the unexpectedly large natural mortality.This project will evaluate the role of disease in Pacific herring by focusing on two specific objectives: 1) to determine prevalence and severity of disease in a free ranging Pacific herring population; and 2) to determine, through modifications of an age-structured assessment model, the contribution of disease in explaining Pacific herring population fluctuations. To assess disease-produced mortality, adult Pacific herring from Prince William Sound will be sampled each year in April and October. These will be examined to determine standard length and a variety of assays for general physiological condition and the presence of pathogens will be performed. Prevalence of potential pathogens will be statistically linked to histopathologic lesions and changes in blood chemistry to determine significance of disease to individuals, and prevalence will be linked to population models of abundance to determine population-level significance.Disease is a fundamental biological process that ultimately affects the longevity of most individuals, and any process that affects individuals will also impact populations. This study will investigate the ecological significance of disease in a pelagic marine schooling fish species and will be the first to model the link between enzootic disease and population change. Results from this study will answer basic questions about how season, gender, spawning condition, and age may affect disease processes cycling through a population.

太平洋鲱鱼(Clupea Pallasl)是生活在北太平洋沿海地区的鱼群。作为次级消费者，它们是生态系统的重要组成部分，是许多海洋哺乳动物和鸟类的高质量猎物，在阿拉斯加的威廉王子湾，它们是一种重要的季节性商业渔业。估计鱼类种群的模型通常结合了许多变量，包括年龄、长度、性别组成、捕捞死亡率和丰度指数，如单位努力产量和调查生物量。对于威廉王子湾的太平洋鲱鱼，自20世纪70年代初以来一直在对种群生物量进行建模和估计。在这些模型中，自然死亡率通常被视为一个常数，因为在没有关于疾病和捕食的全面信息的情况下，很难估计死亡率。然而，最近来自威廉王子湾的证据表明，在这类模型中使用恒定死亡率可能会导致库存评估估计的巨大误差。1993年，基于年龄结构种群模型的估计导致生物学家预测将有超过10万公吨的太平洋鲱鱼产卵。然而，实际返回产卵的只有2万吨。当从种群中的几个鲱鱼样本中分离出病毒出血性败血症病毒时，假设疾病流行是导致出乎意料的大量自然死亡的原因。本项目将通过两个具体目标来评估疾病在太平洋鲱鱼中的作用：1)确定自由活动的太平洋鲱鱼种群中疾病的患病率和严重程度；2)通过修改年龄结构评估模型，确定疾病对解释太平洋鲱鱼种群波动的贡献。为了评估疾病造成的死亡率，威廉王子湾的成年太平洋鲱鱼将在每年的4月和10月进行采样。将对这些进行检查，以确定标准长度，并对一般生理条件和病原体的存在进行各种分析。潜在病原体的流行将在统计上与组织病理损害和血液化学变化联系起来，以确定疾病对个人的意义，流行程度将与种群丰度模型联系起来，以确定群体水平的意义。疾病是一个基本的生物过程，最终影响大多数人的寿命，任何影响个人的过程也将影响人群。这项研究将调查疾病在一种远洋海洋鱼群鱼种中的生态学意义，并将首次模拟地方性疾病与种群变化之间的联系。这项研究的结果将回答有关季节、性别、产卵条件和年龄如何影响在种群中循环的疾病过程的基本问题。