istration’s fisheries service. Enforcement and penalties vary, and
some countries still allow trade within their borders.
The real impetus behind the CITES listing and ongoing
research is not only to limit trade in sawfish, but also to foster
the species’ recovery. The United States has been developing a
recovery plan for its domestic smalltooth sawfish. The plan will
focus on current knowledge about the animal in an effort to identify habitat that needs to be saved,
educate fishers to recognize and
release any sawfish that they
might pull in, and coordinate further research.
Recently, several researchers
have been studying sawfish genetics. For instance, Demian Chapman, head of the Pew Institute for
Ocean Science’s shark program at
the University of Miami, is cataloging portions of the smalltooth-sawfish genome where snippets
of DNA repeat many times. These
genetic bits, known as DNA
microsatellites, are highly susceptible to mutation over short periods of time, says Chapman, so
biologists can compare them to
determine how closely related individuals are.
Without harming a captured fish, biologists can take a tiny plug
of tissue and send it to an analyst such as Chapman. By comparing microsatellite profiles in two fish at up to 15 spots along the
specimens’ DNA, he hopes to tell whether or not the fish come
from the same population.
Even if research shows that small communities of sawfish develop
with little interbreeding, the DNA data should fill some basic
research gaps. The information could explain, for instance, how
many discrete breeding populations remain in any area.
“Our goal is to develop enough of these markers that we can
recognize kin,” says Chapman. If done over several years, such testing might also identify distinct broods, which could reveal how
frequently females give birth.
Although the microsatellites that Chapman is studying come
only from U.S. smalltooth sawfish,
“there’s every chance that some of
these markers will work for other
sawfish [species],” he says. That
would speed efforts to understand
what’s happening among those
declining populations as well.
In Fortaleza, Brazil, Vicente Faria
of the National University of Ceará
is studying the genetics of hundreds
of sawfish specimens from around
the world to identify species. Many
sawfish that look similar may represent subspecies or entirely different species. Knowing how many
distinct genetic groups exist will
prove important to their management, since each group would need
to be conserved individually.
Faria is also investigating the degree of genetic variability that
exists within populations, which may indicate how well a particular population might adapt to a changing environment.
Unfortunately, the bounty paid for sawfish offers a strong economic incentive for poachers to undermine conservation efforts.
As one Kenyan biologist explained at the CITES meeting in June,
the high value of a single large rostrum means that some indigent fishers in Africa “can retire after catching one sawfish.” ■
J. O’DONNELL
TOOTHY TROPHY — A new international-conservation
listing will soon trigger prohibitions on U.S.-domestic and
country-to-country trade in sawfish and their parts, such as
this nearly meter-long Pristis perotteti snout. The former
museum piece sold on eBay in mid-June.
