At Sea, Gulf of California
One of the great advantages of the alliance between Lindblad Expeditions and the National Geographic Society is the partnership in research. Since our ships travel all over the world, they present many opportunities to researchers funded by the National Geographic Society to serve as platforms from which to carry out their research programs.
Such an activity is currently underway using the National Geographic Sea Bird in the Gulf of California to support the research of Dr. William Gilly on the Humboldt squid. These giant squid enter the Gulf every year and support a large fishery around the town of Santa Rosalia. When the squid come into the Gulf they are followed by sperm whales such as those we saw on Thursday south of Isla San Pedro Mártir. The squid themselves feed on small myctophid fishes, such as lantern fish, which are able to survive in water which is extremely poor in oxygen.
All over the eastern Pacific there is a layer of oxygen poor water, called the “oxygen minimum layer.” This layer is produced when the rich organic matter sinks from the light-lit waters near the surface and decomposes, removing oxygen from the deeper water (around 300 meters). During the past decade, at least, the oxygen minimum layer seems to be shoaling in the eastern Pacific and extending farther north, into the Gulf of Alaska. The squid have followed it north and are now seen occasionally in Alaskan waters. Dr. Gilly would like to find out how all this works.
To do this research Dr. Gilly uses an instrument package which measures temperature, salinity, chlorophyll concentration and oxygen abundance, as well as pressure as a measure of the sampling depth of the instrument. By sampling all these variables about once a second as the package, or “fish,” is lowered to depths of about 400 meters in the deep areas of the Gulf, we can determine the behavior of the oxygen minimum layer throughout the season of Lindblad Expeditions’ operations in the Gulf. This is a perfect marriage of Lindblad Expeditions’ longstanding interest in the health of the waters of the Gulf of California, and the work of a National Geographic research scientist on a very important aspect of that health.
Today we lowered Dr. Gilly’s instrument off the west coast of Isla Santa Catalina. On our way to the drop site we were escorted by a wonderful pod of bottlenose dolphins. After the drop we went ashore on the island for a very full afternoon of snorkeling, kayaking, and hikes, topped off by a lovely beach barbecue dinner as the sun set over the Sierra de la Giganta.
