COMMERCE
Subscriber Services
Classified Ads
Subscribe
Advertise
NEWS
This Month
Editorial
Letters
F/V Safety
Past Issues
ABOUT US
Contact Us
Latest Issue
Subscribe
History
MORE CONTENT
CFN Archives
Links
Each month exclusively in the PRINT edition of CFN
Along the Coast
Ask the Lobster Doc
Bearin’s
Classifieds
Coming Events
Editorial
Enforcement Report
FISH SAFE
Fleet Additions
Letters
Lobster Market Report
New Boats
News Catch
Quahog Market Report
|
Commercial Fisheries News
Volume 36 Number 4
December 2008
Fish tagging offers new insights, questions
DURHAM, NH – Fish tagging technologies, both new and old, and their use in tagging studies were showcased at the Northeast Regional Tagging Symposium held Oct. 17 at the University of New Hampshire (UNH).
The symposium featured reports on eight specific tagging studies for species ranging from bluefin tuna and spiny dogfish to Pacific salmon.
Rachel Gallant-Feeney with the Northeast Consortium and Ken La Valley with the UNH Sea Grant College Program co-chaired and facilitated the event.
“The planning committee’s goal from the beginning was to host a meeting following the very formal and rigorous scientific review process that would give industry and fishery stakeholders an opportunity to hear from many of the tagging program scientists themselves regarding how their data has been used or could be used in stock assessments,” said La Valley.
He added that 140 people attended, far beyond the original expectation of 90 registrants.
The organizers invited David Welch, president of Kintama Research Corp. in Nanaimo, British Columbia, which has developed a wide variety of marine sensor systems, to be one of the event’s keynote speakers.
“He is at the forefront of acoustic fish tagging research and application,” La Valley said of Welch. “It was a great technology transfer opportunity, especially since acoustic tagging studies are being conducted on a small scale in the Gulf of Maine.”
Tracking fish
Welch talked about the cutting edge tagging program known as POST – the Pacific Ocean Shelf Tracking project.
He explained how his company has created an undersea wireless platform by anchoring battery-powered receivers extending over a 1,500-mile stretch from the Columbia River in Washington state to Alaska. He then surgically implanted four species of anadromous fish, including Chinook salmon and Cultus Lake sockeye salmon, with tags.
The acoustic tracking system, said Welch, is essentially a “fish EZ-pass,” referring to the automated system used throughout the country to collect highway tolls.
The receivers, which have a 10-year lifespan, were placed along the fishes’ path of migration where they were able to log the date and time each tagged fish passed within range. The data logged in the receivers were then compiled to reconstruct the fishes’ movements.
The ability to measure migration and survival over such huge distances without relying on the recapture of tagged fish is revolutionary.
“It’s never before been possible to do this. This is the first place in the world that this is happening,” said Welch.
POST was conceived in 2000. Today, Vemco Division, an acoustic telemetry company based in Halifax, Nova Scotia, manufactures 13 different types of tags that can be surgically implanted on fish as small as 10 cm in length, the size of a finger, with excellent survival rates.
“POST is giving us answers that were never before possible. It’s providing answers to questions that scientists didn’t know they needed to ask,” said Welch.
The Ocean Tracking Network, a $168 million dollar conservation project based at Dalhousie University in Halifax, is using $45 million to set-up POST arrays around the world.
As to the project’s implications for more funding for tagging work in the US, Welch said, “It will show the relevance of new questions to old problems.”
Improving management
Fisherman David Goethel of Hampton, NH has been involved in several cooperative research projects in the western Gulf of Maine. He observed that tagging technologies that depend on the recapture of fish involve four-to-five-year lag times before producing useful data.
Goethel said he hoped the new technology would allow greater use of tagging studies that, in turn, could prompt rethinking of current management practices.
“Part of the message here is to make new models – hopefully better models – based on this information. That’s the key from the management perspective,” said Goethel.
He gave Atlantic cod as an example of how tagging information can transform understanding of fish behavior.
“Fishermen had this original idea that there was a ribbon of cod traveling up the coast,” he said. “Now they know it’s more of an expansion and contraction from Ipswich Bay out to the feeding grounds.”
Whether or not management areas along the coast matched stock behavior also was a question that arose throughout the day. For several fish species, tagging results often contradicted existing area management practices.
According to Goethel, there is tremendous interest in cooperative research projects, particularly tagging studies, for two reasons.
“When you understand where the fish go, you can be a better fisherman,” he said.
And, Goethel added, the consensus among many fishermen is that management “hasn’t got it quite right.”
Closure implications
Tom Nies of the New England Fishery Management Council agreed that it’s important to consider management when planning this kind of research.
“When it comes to tagging studies, it’s smart to ask what scientists want and what management needs,” said Nies.
He explained that management measures are most easily based on geography and that most area closures were designed well before information from tagging studies was available.
“It takes a tagging study to evaluate whether closures are in the right spot or designed correctly. If we know about stock structures, measures can be taken to protect a weak stock,” he said.
Cod “corridors”
Shelly Tallack, Gulf of Maine Research Institute (GMRI) associate research scientist and program manager for the Northeast Regional Cod Tagging Program, said the program provided insights into cod behavior that raises questions about how managers currently view cod stocks.
With the help of 106 tagging vessels and 256 taggers, Tallack and partners used a simple T-bar tag to mark 114,473 cod. Of those, more than 6,500 fish were recaptured. Because the study depended on the recapture of fish, its results were highly influenced by fishing effort and location.
“Two core assumptions when defining a stock are that the stock is self-sustaining and that the neighboring stocks exist in isolation,” wrote Tallack in her presentation summary. “Considerable movements were observed between different management areas.”
Though this was expected, for management purposes it is important to understand the relative proportion of cod exchanges between areas, she explained, adding that this analysis continues.
Tallack said the tagging study provides evidence of these core “migration corridors”:
l Georges Bank cod moved northward seasonally into the Bay of Fundy;
l Bay of Fundy cod moved southward to Georges Basin and Georges Bank; and
l Gulf of Maine cod moved smaller distances following the coastline between New Hampshire and Maine.
Bluefin
Molly Lutcavage, director of the Large Pelagics Research Center at UNH, has been tagging bluefin tuna since 1997.
She has seen firsthand how the technology has grown in its ability to now store data at high densities and provide information to plot a fish’s geolocation.
Lutcavage described her most recent work tagging bluefin from the Great South Channel to the Gulf of St. Lawrence.
The big news was confirmation of what fishermen and Lutcavage have long believed: There likely are numerous bluefin spawning grounds.
Some fish entered a known spawning area in the Gulf of Mexico, while others “traveled to the Gulf Stream region, the Antilles, the Bahamas, and New England seamounts,” she said. “And several fish made round-trip, trans-Atlantic migrations before returning to their release location.”
Lutcavage’s findings offer a much broader view of bluefin tuna behavior and migration.
“With conventional tags, there was no way we could have figured out that these fish have such diverse dispersal patterns,” she said.
Other projects
Among the day’s other presenters were: Alexi Sharov of the Maryland Department of Natural Resources on striped bass tagging in Chesapeake Bay; Steve Cadrin of the National Marine Fisheries Service and the University of Massachusetts School for Marine Science and Technology on yellowtail flounder tagging; Lara Slifka of the Cape Cod Commercial Hook Fishermen’s Association on haddock tagging; and Graham Sherwood of GMRI on haddock tagging on Georges Bank.
Members of the symposium’s planning committee included La Valley, Cadrin, Gallant-Feeney, Tallack, and Gary Shepard of the Northeast Fisheries Science Center.
Lauren Simmons
Back to story list
|
|
Tell us what you think.
