(Image: NOAA)
Scientists Santiago Montealegre-Quijano and Carolus Vooren of the Universidade Federal do Rio Grande monitored the composition and magnitude of blue shark catches by longline fishery operations off the coast of Brazil.
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 more.
"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."
Males and females seem to keep their distance from each other, save for in March, when the two groups meet presumably for mating season. Their offspring wind up in the nursery, and the whole cycle repeats itself.
Every so often we hear about such shark nursery discoveries. It's always good news, as the information can be used by conservationists to help identify areas that should be protected and monitored more closely.
comments ( )