How to track a shark
Date:
April 5, 2022
Source:
University of Massachusetts Amherst
Summary:
An international team of researchers has compiled a massive dataset
that overlays years' worth of information on the position, migration
and interaction of sharks and game fish. This research has immediate
relevance for anglers, who have been reporting increased contact
with sharks over the years. The research gives us the clearest
window yet into complex ecological relationships and promises to
be a useful tool in ongoing conservation efforts.
FULL STORY ==========================================================================
An international team of researchers, led by the University of
Massachusetts Amherst, has compiled a massive dataset that overlays years' worth of information on the position, migration and interaction of sharks
and game fish.
This research has immediate relevance for anglers, who have been reporting increased contact with sharks over the years. The research, recently
published in Ecological Applications and which relies on an innovative
use of acoustic telemetry and machine learning, gives us the clearest
window yet into complex ecological relationships and promises to be a
useful tool in ongoing conservation efforts.
========================================================================== "It's so rare to observe multi-species interaction in the ocean," says
Lucas Griffin, the paper's co-lead author and a postdoctoral researcher
in environmental conservation at UMass Amherst. That's because species
such as the ones the researchers focused on -- great hammerhead and
bull sharks, permit and Atlantic tarpon -- can range over hundreds of
square miles of open ocean. There has long been anecdotal evidence from
the game-fishing community that instances of depredation -- when a shark
eats a fish that has been hooked -- are on the rise, but to date there's
been no hard data to support whether or not such encounters are indeed increasing and, if so, why.
For this study, the researchers focused on the coastal regions of the
Florida Keys. Over a three-year period, the collaborative team deployed
nearly 300 acoustic receivers and tagged 257 fish (including 73 sharks)
with transmitters.
Every time one of the tagged sharks or fish swam within range of
the receiver, its presence was recorded and tagged with the date
and time. This approach, called acoustic telemetry, gave the team
unprecedented access to the migratory, reproductive and feeding patterns
of sharks and gamefish. The team then ran their raw data through a
cutting-edge machine-learning algorithm to model the incredibly complex interplay of environmental factors, such as time of year, lunar cycle
and water depth and temperature.
"Combining acoustic telemetry and machine learning helped us to answer
a host of questions about predators and prey," says Grace Casselberry,
the paper's other co-lead author and a graduate student in the program
in marine sciences and technology in UMass Amherst's Department of Environmental Conservation. It turns out that tarpon and permit are
returning to the same spawning grounds, at the same times of year,
every year. Sharks know this: "they seem to remember where and when
the tarpon and permit aggregate," says Casselberry. So do anglers who,
through years of word-of-mouth reporting on when the fish are biting
where, wind up trying to hook the same fish that sharks feed on. Knowing
this, fisheries managers can tailor their management strategies to best
protect the interests of sharks, game fish and anglers.
Finally, the team's research is innovative not just for its methods,
but for its cooperation. A wide range of institutions shared data from
tagged fish, including research institutions, like the University of
Miami and the Bimini Biological Field Station in The Bahamas, to state agencies, like the Florida Fish and Wildlife Conservation Commission,
and the nonprofit environmental groups, Bonefish & Tarpon Trust. "We
also worked extensively with the local fishing-guide community to help
tag game fish and sharks, and figure out where to place the receivers,"
says Griffin. "Our lab very much embraces a collaborative and cooperative spirit," says Andy Danylchuk, professor of fish conservation at UMass
Amherst and one of the paper's senior authors. "We are grateful for our research partners and hope our science will help to hone conservation
and management strategies for both game fish and sharks."
========================================================================== Story Source: Materials provided by
University_of_Massachusetts_Amherst. Note: Content may be edited for
style and length.
========================================================================== Journal Reference:
1. Lucas P. Griffin, Grace A. Casselberry, Susan
K. Lowerre‐Barbieri,
Alejandro Acosta, Aaron J. Adams, Steven J. Cooke, Alex Filous,
Claudia Friess, Tristan L. Guttridge, Neil Hammerschlag, Vital
Heim, Danielle Morley, Mitchell J. Rider, Gregory B. Skomal,
Matthew J. Smukall, Andy J.
Danylchuk, Jacob W. Brownscombe. Predator-prey landscapes of large
sharks and game fishes in the Florida Keys. Ecological Applications,
2022; DOI: 10.1002/eap.2584 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/04/220405123907.htm
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