An investigation of patterns of deep-sea demersal fish metabolism and feeding rates

深海是地球上最大的栖息地。许多关于深海动物的研究记录了它们的摄食习性以及与区域和深度相关的生物量、丰度和群落组成模式。现在，对深海底栖生物群落的关键需求是代谢率的信息。代谢率决定了资源利用、生长和繁殖等许多过程的速度，进而影响许多生态过程。这些信息的普遍缺失一直是构建动态食物网的障碍，而动态食物网有助于海洋学界更好地提出有关深海如何运作的问题。人们提出了两种一般的假设来预测生物体的代谢率。最近有争议的生态学代谢理论声称，仅用温度和体重就可以解释新陈代谢的大部分变化。然而，对许多深海中上层动物群体的研究表明，随着深度的增加，代谢率显著下降，这无法用该模型来解释。另一个模型，视觉相互作用假说试图将代谢率的下降解释为持续运动能力的进化选择压力下降的结果，这是大多数鱼类共同的特征，由于光线水平下降和捕食者与猎物之间的反应距离。用于评估这些模型的深海底栖动物或底栖动物数据非常少。事实上，关于深海鱼类的代谢率或这些鱼类在深海食物网的能量流动中所起的作用的数据很少。在这个项目中，将收集一个独特的深海鱼类数据集来评估它们的代谢率，并看看上面描述的哪种模型可以用来合理地估计它们的能量需求。为此，将使用新型原位呼吸计测量100-4000米深度鱼类的代谢率，并使用这些数据量化它们的能量需求。底栖鱼类是一个理想的研究群体，因为它们中的许多是顶级捕食者，通过控制猎物数量，从而影响深海食物网的能量流，在各种海洋群落中起着至关重要的作用。由于人类活动对深海物种环境的影响不断扩大，深海渔业继续开发底栖鱼类，因此尽快收集深海物种的关键能量信息非常重要。代谢率与生长率相联系，它们一起是估计鱼类种群生产力的组成部分。通过开发食物网的信息，这项研究还可以揭示这些渔业如何通过消除顶级捕食者来影响生态系统。调查人员还将参与对本科生和研究生的培训，并提供海上教师机会，以加强参与者的课程发展。

The deep sea is the largest habitat on earth. Many studies of deep-sea animals have documented feeding habits and regional and depth related patterns in biomass, abundance, and community composition. Now, the critical need for deep-sea benthic communities is information on metabolic rates. Metabolic rate sets the pace of many processes such as resource utilization, growth, and reproduction which in turn affect many ecological processes. The general absence of this information has been an obstacle to constructing dynamic food webs which then help the oceanographic community to ask better questions about how the deep sea works. Two general hypotheses have been advanced with which to predict the metabolic rates of organisms. The recent, and controversial, Metabolic Theory of Ecology claims to explain the majority of variation in metabolism using temperature and body mass alone. However, studies of many deep-sea pelagic animals groups, show significant declines in metabolic rates with depth that cannot be explained by this model. Another model, the Visual Interactions Hypothesis attempts to explain these declines in metabolic rate as the result of the decrease in the evolutionary selection pressure for sustained locomotory capability, a feature common in most fishes, due to declining light levels and reaction distances between predators and prey. Very little data for deep-sea benthic or demersal animals are available with which to evaluate these models. In fact, very little data is available on the metabolic rates of deep sea fishes or the role that these fish play in energy flow through the deep sea food web. In this project a unique dataset for deep sea fishes will be collected to assess their metabolic rate and see which of the models described above can be used to reasonably estimate their energetic demands. To do this the metabolic rates of fishes from 100-4000 m depth will be measured using novel in situ respirometers and the data will be used to quantify their energetic demands. Demersal fishes are an ideal group to study as many of them are top predators which play a vital role in various marine communities by controlling prey populations and therefore influencing energy flow through the deep sea food web. It is important to gather key energetic information on deep-sea species soon because of expanding human activities in their environment as deep-sea fisheries continue to exploit demersal fishes. Metabolic rates are tied to growth rates and together they are integral to estimating the productivity of fish stocks. By developing information for food-webs this study could also shed light on how these fisheries will affect the ecosystems by removing top predators. The investigators will also be involved the training of undergraduate and graduate students as well as providing teacher-at-sea opportunities to enhance curriculum development for the participants.