Thursday, September 11, 2014

It's not only Overfishing - one more Paper!

A baited remote underwater video station showing details of the removable bait arm, plastic camera housing and pegs for placement of ballast on the frame (a). Images of Carcharhinus amblyrhynchos (b), C. albimarginatus (c) and Galeocerdo cuvier (d) in the BRUVS field of view.

Remember this post? :)

For Sharks, the principal threat is overfishing.
But of course it only stands to reason that no Shark can survive if we destroy its habitat. We often talk about how healthy Shark populations preserve habitat, e.g. via those trophic cascades - but of course the principal effect is not top down but bottom up, which is actually so trivial that most researchers and conservationists don't even bother to mention it. Methinks that both effects are linked via feedback loops, meaning that negative effects at either side of the equation can quickly lead to a self-reinforcing downward spiral, but of course I'm speculating.

Long story short?
Species protection alone does not work - you need to also protect critical habitats.
That's why we protect the whole of Shark Reef and not only the Sharks, and that's why we continue to investigate the nurseries in the rivers!

The above is obviously particularly evident in those Reefies.
Several species like the Whitetip, Blacktip and Grey Reef Shark are highly associated with and resident in coral reefs, meaning that their dependency on the health of those reefs is likely very high. Other more transient species with a wider range of habitats like the Tigers, Bulls and Great Hammers, likely less so.

This appears to be one of the findings of this paper.
It really is fantastic stuff, the result of ten years of data collection via BRUVS, much like what the volunteers of Projects Abroad are currently doing in Beqa Lagoon. The paper is thankfully open access, meaning that there's no need for citations.
Plus, you can find a great synopsis here - inclusive of highly complimentary comments by other researchers which is really nice to see.

Well done - very impressive indeed!

1 comment:

Anonymous said...

Hell of a read; and I agree 100%! Thanks for posting! - Susana N.