Monday, October 19, 2009

Brazil - Blue Shark Nursery?

With Blue shark (Prionace glauca) stocks plummeting worldwide, new discoveries like this one off the coast of Brazil might help turn the tide.

If protections can be put in place in time:

New evidence suggests a blue shark nursery exists in the Southwest Atlantic
near Southern Brazil, according to a paper accepted for publication in the
journal Fisheries Research.

Scientists Santiago Montealegre-Quijano and Carolus Vooren of the
Universidade Federal do Rio Grande monitored the composition and magnitude
of blue shark accidental catches by longline fishery operations off the
coast of Brazil. (At least something positive can come from such data.
Bycatch has really put a dent in shark populations worldwide.)

The researchers determined that large adult blue sharks were not present in
the suspected nursery region, only juveniles. Size appears to be very
important to life stage shifts in these sharks, as the small juveniles were
found to remain at the site until they reached lengths of around 4 feet or

"After that stage," the scientists conclude, "the large juvenile males
disperse northwards, whereas the large juvenile females move to the south,"
and wind up going all the way to the southeast Atlantic off Africa.

The scientists added, "The subadult females move northwards in late summer
(March) to areas beyond latitude 25°S."

Complete Story

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