Mercurial Grey Sharks Dive Deep Under a Full Moon
by Megan Gannon
Over the course of nearly three years, researchers from Australia observed 39 mostly female gray reef sharks (Carcharhinus amblyrhynchos) living near coral reefs in Palau, Micronesia, east of the Philippines.
In the winter, the sharks stayed closer to the surface, at an average depth of 115 ft (35 m), where water was consistently warmer, the team found. Meanwhile, the sharks plunged deeper when seasonal temperatures started rising in the spring, averaging depths of 200 ft (60 m).
The sharks also changed their behavior in sync with the lunar cycle, diving deeper during the full moon but sticking to the shallows with the new moon. Previous tagging studies showed that other open-water predators — including swordfish, yellowfin and big eye tuna — also go to greater depths as the lunar cycle progresses. This suggests the moon’s brightness might sway the movements of many big fish…
(read more: Live Science) (photo: P. Ayotte)
Cinderella animals: endangered species that could be conservation stars
A cursory look at big conservation NGOs might convince the public that the only species in peril are tigers, elephants, and pandas when nothing could be further from the truth. So, why do conservation groups roll out the same flagship species over-and-over again?
Simple: it is believed these species bring in donations. A new paper in Conservation Letters examines the success of using flagship species in raising money for larger conservation needs, while also pointing out that conservation groups may be overlooking an important fundraising source: “Cinderella animals.
“Too much focus on “flagship species”?
Flagship species are animals used by conservation groups to raise funds; these species are almost always mammals, large, and appealing to the general public, often defined as ‘cute.’ This trend has long faced criticism: some researchers argue that in an age of mass extinction focusing on a few mammals trivializes the scale of the problem and leaves the bulk of the world’s threatened species without targeted protection…
(read more: MongaBay)
(photos: T - Pygmy Raccoon by Scott Camazine; TR - Pennant’s Red Colobus Monkey by Richard Bergl; B - Somali Wild Ass by Bigstock)