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

近海和公海（远洋）鱿鱼是所有无脊椎动物中运动能力最强的。它们是高度活跃的、喷气推进的游泳者，代谢率高，在它们一到两年的短暂生命中以惊人的速度生长。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扮演着重要的生态角色。成年乌贼是许多顶级捕食者必不可少的猎物，包括鲨鱼、金枪鱼、长嘴鱼和海洋哺乳动物。此外，鱿鱼在全球商业渔业中变得越来越重要，因为它们取代了生长缓慢的鱼类，特别是在这些鱼类资源正在枯竭的地方。Dosidicus gigas，也被称为巨型或洪堡鱿鱼，是一个真正的巨人，全长可达2-3米，体重超过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。它构成了墨西哥目前第三大的主要商业渔业的基础。尽管gigas具有重要的生态和经济意义，但人们对其生活史、行为和生理知之甚少。其庞大的体型和开阔的海洋栖息地使传统的野外和实验室研究复杂化。这个项目的重点是利用最近开发的技术，在加利福尼亚湾对D. gigas进行综合实地和实验室研究，以促进这类研究。试点标记研究表明，D. gigas白天生活在寒冷，深层，缺氧的水中（300米~10摄氏度），晚上迁移到可达30摄氏度的浅水，通风的表层水。频繁的夜间快速潜水到白天深度，几分钟内覆盖数百米。这些新陈代谢活跃的大鱿鱼是如何忍受深海慢性日间缺氧的压力的，这是一个谜。相反，温暖的水面也可能会限制鱿鱼在这个区域度过的时间。这项提案将采用电子标签来追踪这种远洋捕食者的垂直迁徙，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，加上实验室泳道实验提供的校准值和无氧代谢的生化指标，将为鱿鱼本身的真正能量消耗提供一个衡量标准。极弱光的视频方法将揭示在一个典型的垂直迁移范围内的自然行为，无论是白天还是晚上。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，为什么这样做，以及生理和生化适应在某些深度允许这些行为，在其他深度阻止它们。该研究将极大地促进我们对巨虾的生物学认识，并为综合研究其他远洋食肉动物的生态生理学提供一个模型。它还将建立一个生命史框架，最终将在墨西哥和其他地方的生态系统一级管理这种渔业。它包括培训一名博士后和两名研究生，并与两名墨西哥科学家及其学生合作。头足类动物，特别是大型鱿鱼，对公众具有魅力和吸引力，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.