Jumbo Squid in Oxygen-Poor Zones: new study shows ability to expand territory and evade predation

New research adds further insight into the ability for the Humboldt, or jumbo, squid to expand its territory and become even more of a destabilizing predatory influence along the coast of the Eastern Pacific. In the latest issue of Progress in Oceanography, researchers from the University of Lisbon, Portugal, and the University of Rhode Island, U.S., studied the squid's metabolic rates in water with different oxygen levels - duplicating the oxygen-poor environment found in waters several hundred meters deep and also the oxygen-rich environment of relatively shallower depths.

Dr. Ruis Posa, of Portugal's Center for Oceanography, posed the question, "Jumbo squid display oxygen consumption rates that are among the highest in the oceans. This high energy demand reflects the low efficiency of jet propulsion. So the question is how can they survive in these deep, cold and oxygen depleted zones?"

According to Dr. Rosa, from Portugal's Center of Oceanography, the squid displayed the ability to shut down its metabolism by as much as 80% in the oxygen minimum layer (OML). This enables the squid to find a safe haven during the day beyond the reach of many of its predators. During the night, the squid rejuvenates itself in shallower waters where its metabolic demands increase dramatically as it hunts for food using its jet propelled speed coupled with tentacles laced with tooth-lined suction disks.

As mankind continues to alter the marine environment, we are finding more and more areas of lower-than-normal or even near-depleted oxygen levels in the oceans, thereby providing the voracious Humboldt squid with the capability of expanding its range. An animal's territorial range can be maintained by a variety of factors, some of which are based on the quality of its environment and on the predators that help keep the population in check. With this newly studied metabolic ability, the Humboldt squid can utilize spreading OMLs to its advantage, avoiding predators during the day and causing havoc amongst commercially fished species at night.

Read the study in Progress in Oceanography. Read more about the study in BBC News. Watch video below from Google Earth/Ocean.

Growth of oxygen-poor zones in the Pacific Ocean

On 05/18/08, RTSea wrote: Interesting but disturbing article in the Los Angeles Times regarding the growth of oxygen-poor zones (http://latimesblogs.latimes.com/unleashed/2008/05/threatening-mar.html). Noting the expansion of the Pacific's zone along Mexico/Central America/South America, these zones are typically deep water but have been increasing in size, extending further north and south and becoming more shallow. These zones are different from equally dangerous "dead zones" caused by fertilizer-fed algae blooms, but have the same effect on sealife, pushing fish populations into different regions or oceanic stratas that can impact their health or expose them to a greater potential for over-fishing as their numbers increase in shallower waters.

The culprit behind this expansion, according to scientists from Germany to California, is global warming. As ocean temperatures increase due to the accumulation of greenhouse gases in the atmosphere, the water's ability to retain oxygen is compromised. One more domino effect that we must address and that proves that the health of the oceans is undeniably linked to our actions on the land.