This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Editor's Note: William Gilly, a professor of biology at Stanford University's Hopkins Marine Station, embarked on new expedition this month to study jumbo squid in the Gulf of California on the National Science Foundation–funded research vessel New Horizon. This is his eighth blog post about the trip.
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SEA OF CORTEZ—Back in the Guaymas Basin east of Isla Tortuga by sunset, we get a good jigging session in after sunset and restock our squid-condo with fresh animals. Fortunately, the squid are again small, and they fit nicely into our tubes in our temperature-controlled, squid condo. Each squid gets its own tube with flowing, chilled seawater to keep it from interacting negatively with vertical tank surfaces and other squid. They eagerly eat one another in captivity, and this really complicates husbandry effort. In the morning all the squid are alive and well—it would appear that the red tide problems of Salsipuedes are over—and that there really was some toxic agent in the water in that region.
Experiments continue day and all night. We are trying to determine how the combined condition of low oxygen and low, like that the squid experiences in the depths of the Oxygen Minimum Zone (OMZ), impact swimming performance. Our tagging results suggest that squid can forage all day long in the OMZ, but this leads to more questions. Do squid move more slowly in the OMZ? Their decrease in metabolic rate under OMZ conditions (Brad is studying this) would seem to require slowing down. But by how much? The organisms that the squid forage on during the daytime in the OMZ are probably also slowed down, so sacrificing speed may not be such a penalty in prey capture.
But what happens when the predator becomes the prey? A main predator of squid in the OMZ is the sperm whale, a deep-living leviathan that carries its own oxygen supply and temperature regulator. Impairment of a squid's strong swimming, sensory capabilities, reaction times or coordination of complex motor outputs could all act to compromise performance during an escape response. An escape response may be a fairly rare event in the life of a squid, but you don't get a second chance—failure means death. Impairment of escape response under OMZ conditions may therefore be an ecologically critical problem for a squid.
Our previous tagging studies suggested that this was the case—sperm whales seemed to prefer to hunt squid at daytime depths of the OMZ even at night, when most squid were much shallower. To test this idea further, we would like to challenge the squid in the laboratory under temperature and oxygen conditions that mimic those in the OMZ.
To do this, we assay the escape response. Our experimental setup is conceptually simple, but in reality it's a Rube Goldberg nightmare. This creation gradually emerged during the time onboard, and photos will help maintain our memory of how it actually worked and lead the way to its recreation at home in the lab.
Basically, we have a squid in a tank and subject it to controlled temperature and oxygen regimes while monitoring escape responses that are stimulated through a sensitive structure that monitors head-position, the "neck organ." It seems that this organ is also strongly connected to the neural circuitry that controls escape responses, at least in Dosidicus.
Escape jetting in squid is far from simple, but it has really been studied in only one species, the much smaller California market squid, Doryteuthis (previously Loligo) opalescens. We did much work on that species years ago in the lab, and now we are trying to see how Dosidicus compares. It's always useful to have some sort of established framework to describe results in a new system. With data from this cruise in hand, we will return to the lab in Pacific Grove and re-test market squid in the identical way. We already know there are major differences between these two species. For example, a strobe flash invariably triggers an escape response in loligo but causes no reaction in Dosidicus. We never noticed the functional connection between the neck organ and escape responses with loligo, but we never really looked. But right now, we are trying to make sure we get enough replicates of our experiments here. Repetition may be boring, but it is critical to building a convincing case.
Unfortunately there is just not enough time right now to do experiments and analyze the data, and this is a huge problem: You don't really know what you've done until you get home. But then it's too late to repeat critical manipulations, to double-check something. Indeed, once we are off the ship, this predicament will be captured by Joni Mitchell's lyrics "Don't it always seem to go ... That you don't know what you got till it's gone." But there is a way around this dilemma—bring the squid home with you.
Last year I reported on developing a collaboration with a new technical college here, the Instituto Tecnologico Superior de Mulegè, or ITESME. The overall goal is to create a program of research and education focused on the basic ecology of the Guaymas Basin and adjacent Baja peninsula, a huge area that has includes Mexico's largest wildlife refuge, the Vizcaíno Biosphere Reserve of more than 55,000 square miles. Santa Rosalia is the perfect portal to this vast treasure, and this region has largely escaped commercial (tourist) development. Much rugged, remote wilderness remains, and we need to learn more about all aspects of it if we are to use its resources in intelligent and sustainable ways.
As we again parallel the coast off Santa Rosalia on our last days of acoustic transects, the need for a shore-based lab to do experiments on squid and other marine organisms remains. Developing such a lab is a primary goal of the ITESME collaboration, and we are making progress toward realizing such a creation. During the past year we have had several meetings with Mexican scientists, government agencies and non-governmental organizations that have been extremely helpful and encouraging.
Our project is now a Program (with the requisite acronym of course)—Approvechamiento Sustenable e Investigacion de Centro del Mar de Cortez (ASIMAR), or its English version, Sustainable Use and Research of the Central Mar de Cortez (SURMAR). Its mission will be to develop a holistic understanding of the region, including its human inhabitants and their interactions with the environment, from scientific, social and commercial viewpoints. The physical laboratory component, where we and others will be able to work, will be the Centro de Investigacion Vizcaíno del ITESME (CIV), or Vizcaíno Research Center (VRC). This facility will be located on the nine-acre ITESME campus south of Santa Rosalia.
We have lots of ideas about education and outreach as well as research. An important component of this program will involve training through involvement of students, both from ITESME and Stanford. We will directly involve ITESME students in our research projects, and these students can carry out thesis projects (a requirement for graduation) using the facility. An established Stanford teaching program will also visit the VRC/ CIV and interact with ITESME students in the classroom and field.
Finally, we are working towards incorporating the project into the Baja California conservation efforts of The Ocean Foundation. We are excited about this affiliation and have been working for the last several months to bring it to fruition—we are almost there. And now all we need is a logo—any suggestions?
Photos: Support tube: Ian Wilson, Colorado State University
Squid Set-up at rest: W Gilly
Squid Neck Organ: Ted Uyeno, Northern Arizona University; adapted by W. Gilly
ITESME Aerial Photo: W. Gilly (Nov 2007)
ASIMAR/SURMAR draft logo: by W. Gilly