Written by Jen Finn
It's back to the drawing board for halibut iTags that will soon tell us more about where the fish travels than ever before.
The internal tags, which were deployed in 30 halibut two years ago, were the first to test Smart Phone geomagnetic advances to track the migrations of fish. The tags record magnetic field strength on three axes and have accelerometers and pitch and roll detectors, explained Tim Loher, a biologist with the International Pacific Halibut Commission.
"Without being able to tell whether or not your tag is horizontal, you can't really get the axis of the magnetism. The invention of the iPhone pointed the way to make the pitch and roll detectors small enough to put in fish tags," he said.
The geomagnetic tags, which can record data every 30 seconds for seven years, are designed to give real time, daily positions on halibut and track them without any need for light, acoustics or communication with GPS satellites - all the information will be onboard when the fishermen catch them.
But in the field tests, magnetism was the gut tags' undoing.
"The tags had some metal components inside them that were actually picking up magnetic charges and screwing up the calibrations," Loher said.
He added that a new metal-free version of the tags already has been developed, and will be deployed in Glacier Bay halibut later this summer by project associate Julie Nielsen, a graduate student at UAF/Juneau. Within a couple of years, the IPHC team plans to tag 1,000 or more halibut from Oregon to Attu.
"We've got a lot of migration issues and we are trying to set our quotas and determine exactly how to assess the stock," Loher said. "We know the halibut are moving but we are having trouble getting refined estimates of movement by size, age and regulatory area, so hopefully this will help nail that down. It's going to be a really powerful experiment."
The IPHC will pay a $500 reward for the return of any geomagnetic tags (which are accompanied by external wire tags). Rewards ranging from $50-$200 also are paid for returns of halibut containing darts or wire tags.
Read the full story at the Bristol Bay Times>>
National Fisherman Live: 3/10/15
In this episode, Online Editor Leslie Taylor talks with Mike McLouglin, vice president of Dunlop Industrial and Protective Footwear.
National Fisherman Live: 2/24/15
In this episode:
March date set for disaster aid dispersal
Oregon LNG project could disrupt fishing
NOAA tweaks gear marking requirement
N.C. launches first commercial/recreational dock
Spiny lobster traps limits not well received
The Mid-Atlantic Fishery Management Council has scheduled a series of scoping hearings to gather public input for a proposed action to protect unmanaged forage species.
The proposed action would consider a prohibition on the development of new, or expansion of existing, directed fisheries on unmanaged forage species in the Mid-Atlantic until adequate scientific information is available to promote ecosystem sustainability.Read more...
The National Marine Educators Association has partnered with NOAA this year to offer all NMEA 2015 conference attendees an educational session on how free NOAA data can add functionality to navigation systems and maritime apps.
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