FORT PIERCE, FLA., -- The R/V SEWARD JOHNSON is enroute from HARBOR BRANCH Oceanographic Institution in Fort Pierce, Florida, to the Gulf of Maine, embarking upon the first phase of a 3-year, multi-seasonal science mission aimed at evaluating the ecological importance of zooplankton predation by a gelatinous midwater animal.
From August 25 to 15 September, 2001, HARBOR BRANCH research scientist Dr. Marsh Youngbluth and a team of collaborators will remain in the Gulf of Maine studying the predation habits of Nanomia cara, a species of colonial, jellyfish-like animal belonging to the same group of animals (called Siphonophores) as the familiar Portuguese man-of-war. In past years, the organism has occurred in sufficient abundance within the Gulf of Maine to foul the nets of commercial fishermen.
Dr. Youngbluth and a co-investigator from the Monterey Bay Aquarium Research Institute first determined that it was Nanomia that was responsible for the mass of unidentifiable slime coming up in fishing nets a couple of years ago. More importantly, the pair also made the discovery that the siphonophore was feeding almost entirely on the over-wintering stage of a planktonic copepod, Calanus finmarchicus.
These copepods form an important part of the diet of young cod and other commercially important fishes in the Gulf of Maine region. A key goal of the current mission is to determine the extent to which the predatory activity of Nanomia effects food availability for other animal populations in the Gulf of Maine.
The research is being accomplished using the JOHNSON-SEA-LINK (J-S-L) manned submersible, which allows scientists to gain a better understanding of the distribution and behavior of pelagic animals that are too delicate to be adequately studied with traditional approaches.
The mission is being covered on the HARBOR BRANCH @ Sea website http://www.at-sea.org, where remote multimedia dispatches from Dr. Youngbluth and his science team are being posted regularly during the mission. Extensive mission background information can also be found on the website.
The above post is reprinted from materials provided by Harbor Branch Oceanographic Institution. Note: Materials may be edited for content and length.
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