NOAA Ship Townsend Cromwell

Student Connection

Highlights From TC 02-02 Swordfish/shark tagging and biology

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Highlights from TC 02-02 Swordfish/Shark Tagging and Tuna Research

Aloha from the Townsend Cromwell!

The NOAA ship Townsend Cromwell just completed a month long research cruise to tag pelagic fish with archival pop-up satellite tags. We headed north towards swordfish grounds on April 1st and within a few days found ourselves 500 miles north of the main Hawaiian islands and in the thick of swordfish and blue shark waters. Over the course of the cruise we were able to deploy 48 pop up tags (Table 1). Having exceeded our expectations up north, we turned south and ran to to about 150 miles west of the big island of Hawaii in the vicinity of Cross Seamount which is known for its large concentrations of juvenile tuna. Near Cross we were able to tag bigeye thresher sharks and catch tuna for experimentation on live retinal tissues in a study on how pelagic fish use vision to survive in the ocean realm. Over the course of the cruise we were able to capture 244 fish and conduct eye experiments on swordfish, bigeye tuna, yellowfin tuna, longsnout lancetfish, escolar, and squid.

The pop up tags are due to jettison from the tagged fish in 8 months and this information will hopefully provide us with new insight into the daily behavior of fish in the pelagic environment.

Table 1. TC02-02 Pop up satellite archival tag totals 4/1/02-4/30/02