Innovative Tagging Technique May Help Researchers Better Protect Fish Stocks


August 7, 2007

Marine Protected Areas (MPAs) are often hailed as a way to
halt serious declines in the abundance of marine species that have been over-fished.
But even as nations begin to set aside protected parcels of ocean for marine
reserves, the effectiveness of the approach as a fisheries management tool remains
unclear.

Simon Thorrold, a fish ecologist from the Woods Hole Oceanographic
Institution (WHOI), would like to put MPAs to the test with a novel technique
for tagging fish.

Through a new
research grant from the David and Lucile
Packard Foundation, Thorrold and colleagues plan to use harmless chemical tags
to track the dispersal of the larvae of coral reef fishes in the western Pacific Ocean. The Packard Foundation’s Conservation and Science Program has
granted Thorrold and colleagues more than $480,000 for three years to study the
population dynamics of grouper and snapper in the waters around the Great
Barrier Reef and Papua New
Guinea.

Through a new technique known as TRAnsgenerational Isotope
Labeling (TRAIL), the researchers will introduce
an artificial tag—a stable isotope of barium—into the tissues of mature female
fish just before spawning. That chemical tag is then passed to the female’s
offspring and becomes a chemical signature within the ear bones (otoliths) of the
next generation of fish.

Researchers can then track the dispersal of the
tagged larvae across reefs and large stretches of open ocean. This chemical tagging approach has been successfully tested
in limited studies with clownfish and butterflyfish.

Now, Thorrold and
colleagues want to attempt one of the first large-scale, empirical tests of the
effectiveness of marine protected areas. The scientists will attempt to assess
how far and how effectively the larvae spawned within protected areas are
contributing to populations outside of their human-described borders.

Most management and conservation strategies assume that fish
populations may be connected across broad areas, and that protecting them in
one location will allow for sustainable fisheries outside of the reserve
boundaries. But such theories are mostly untested and do not necessarily
account for how long and how far larvae may or may not drift in the open ocean.

The new research program will be led by Thorrold, an
associate scientist in the WHOI Department of Biology. Co-investigators include
Glenn Almany, Geoffrey Jones, and Garry Russ of the ARC Centre of Excellence
for Coral Reef Studies and James Cook University
(Australia),
and Rick Hamilton of The Nature Conservancy.

The
David and Lucile Packard Foundation was created in 1964 by David
Packard, cofounder of the Hewlett-Packard Company, and Lucile Salter
Packard. The Foundation’s Conservation and Science Program seeks to
protect and restore our oceans, coasts, and atmosphere, and to enable
the creative pursuit of scientific research.

The Woods Hole Oceanographic Institution is a private,
independent organization in Falmouth,
Mass., dedicated to marine
research, engineering, and higher education. Established in 1930 on a
recommendation from the National Academy of Sciences, its primary mission is to
understand the oceans and their interaction with the Earth as a whole, and to
communicate a basic understanding of the ocean’s role in the changing global
environment.