Collaborative research: physiological limits to vertical migrations of the pelagic, jumbo squid, Dosidicus gigas in the Gulf of California

近岸和远洋(远洋)鱿鱼是所有无脊椎动物中最健壮的。它们是高度活跃的喷气式游泳者，代谢率很高，在短短一到两年的生命中以惊人的速度增长。这种鱿鱼在世界上所有的海洋中都很丰富，它们作为主要的捕食者在生态上扮演着重要的角色。成年鱿鱼是许多顶级捕食者的基本猎物，包括鲨鱼、金枪鱼、长嘴鱼和海洋哺乳动物。此外，鱿鱼在世界范围内的商业渔业中正变得越来越重要，因为它们取代了生长缓慢的鱼类，特别是在这些种群正在枯竭的地方。巨型乌贼，也被称为巨型乌贼或洪堡乌贼，是一种真正的巨型乌贼，全长可达2-3米，质量超过50公斤。它广泛分布在东太平洋，从智利到加拿大，几乎到赤道的夏威夷。它构成了一个主要商业渔业的基础，目前是墨西哥第三大商业渔业。尽管石斑潜蝇具有重要的生态和经济价值，但人们对它的生活史、行为或生理知之甚少。其庞大的面积和开阔的海洋栖息地使传统的野外和实验室研究变得复杂。该项目的重点是利用最近开发的促进这类研究的技术，对加利福尼亚州海湾的巨藻进行综合实地和实验室研究。试验性标记研究表明，大金鱼白天在寒冷、深水、耗氧水(约10摄氏度，300米处)中度过，晚上迁徙到可达30摄氏度的浅水充气表层水域。频繁的夜间快速潜水到白天深度在几分钟内覆盖数百米。这些新陈代谢活跃的大型鱿鱼如何在深处忍受长期白天低氧的压力，这是一个谜。相反，温暖的表层水域也可能会造成压力，限制鱿鱼在这一区域停留的时间。这项提议将使用电子标签来跟踪这种中上层捕食者的垂直迁徙，并监测不同深度的自然喷射和呼吸。根据这些数据确定的耗氧量，加上实验室游泳洞实验提供的校准和厌氧代谢的生化指标，将为鱿鱼本身提供真实的能量成本的衡量标准。极端弱光视频方法将揭示典型垂直迁徙范围内的自然行为，无论是白天还是黑夜。因此，这个项目将揭示这种非凡的鱿鱼在其海洋栖息地做什么，它为什么这样做，以及什么生理和生化适应在某些深度允许这些行为，在另一些深度阻止它们。这项研究将极大地促进我们对巨藻生物学的了解，并为研究其他中上层捕食者的生态生理学提供一个综合方法的模型。它还将建立一个生命历史框架，这最终将是在墨西哥和其他地方在生态系统层面管理这一渔业所必需的。它包括培训一名博士后研究员和两名研究生，以及与两名墨西哥科学家和他们的学生合作。头足类动物，特别是大型鱿鱼，具有魅力并吸引公众，该项目具有通过各种媒体进行大规模公众宣传的巨大潜力。

Inshore and open-ocean (pelagic) squid are the most athletic of all invertebrates. They are highly active, jet-propelled swimmers, have high metabolic rates and grow at a prodigious rate throughout their short life spans of one to two years. Such squid are abundant in all the world's oceans where they play important ecological roles as major predators. Adult squid serve as essential prey for many top predators, including sharks, tuna, billfish and marine mammals. In addition, squid are becoming increasingly important in commercial fisheries worldwide as they replace slow-growing fish, particularly where these stocks are being depleted. Dosidicus gigas, also known as the jumbo or Humboldt squid, is a true giant, reaching 2-3 m in overall length and over 50 kg in mass. It is widely distributed over the eastern Pacific, ranging from Chile to Canada and nearly to Hawaii at the equator. It forms the basis of a major commercial fishery, presently the third largest in Mexico. Despite the ecological and economic importance of D. gigas, little is known about its life history, behavior or physiology. Its large size and open-ocean habitat complicate traditional field and laboratory studies. This project focuses on integrative field and laboratory studies of D. gigas in the Gulf of California using recently developed techniques that facilitate such studies. Pilot tagging studies have revealed that D. gigas spends the daytime in cold, deep, oxygen-depleted water (~10 deg C at 300 meters) and migrates at night to shallow, aerated surface waters that can reach 30 deg C. Frequent rapid dives at night to daytime depths cover several hundred meters in minutes. It is a mystery how these large, metabolically active squid can tolerate the stress of chronic daytime hypoxia at depth. Conversely, warm surface waters also may present a stress that limits the time squid can spend in this zone. This proposal will employ electronic tagging to track vertical migrations of this pelagic predator and to monitor natural jetting and respiration at different depths. Oxygen consumption determined from these data, with calibrations provided by laboratory swim-tunnel experiments and biochemical indices of anaerobic metabolism, will provide a measure of the true energetic costs to the squid itself. Extreme low-light video methods will reveal natural behaviors over the range of a typical vertical migration, both day and night. Thus, this project will reveal what this remarkable squid is doing in its oceanic habitat, why it is doing it, and what physiological and biochemical adaptations permit these behaviors at some depths and preclude them at others. This study will greatly advance our understanding of the biology of D. gigas and provide a model for an integrated approach to studying the ecological physiology of other pelagic predators. It will also establish a life-history framework that will ultimately be necessary to manage this fishery at the ecosystem level in Mexico and elsewhere. It includes training of a postdoctoral fellow and two graduate students, and collaboration with two Mexican scientists and their students. Cephalopods, particularly large squid, are charismatic and appealing to the public, and this project has significant potential for mass public outreach through a variety of media.