Tuesday, February 16, 2016

Exploding Cownose Rays? Not so fast!


Remember those exploding Cownose Ray populations?
Proudly announced in 2007 as the first scientific evidence for Shark-mediated trophic cascades, the paper is a favorite argument of some quarters within the Shark conservation movement, and a frequent topic of increasingly critical posts on this blog, e.g. here, here and here.

Enter myth-buster Dean Grubbs, and I cite.
The lack of temporal correlations coupled with published diet data suggest the purported trophic cascade is lacking the empirical linkages required of a trophic cascade. 
Furthermore, the life history parameters of cownose rays suggest they have low reproductive potential and their populations are incapable of rapid increases. 
Hypothesized trophic cascades should be closely scrutinized as spurious conclusions may negatively influence conservation and management decisions.

Like I said, bingo.
The article is here, and required reading - and no, I really got nothing to add!

Actually, there IS something to add, so there.
Spurious conclusions is likely a euphemism for a load of horseshit. From what I can see, Grubb did not conduct any new field research but merely re-examined the info available at the time, and his findings are pretty much devastating in terms of the methodology and the illicit conclusions by Myers et al. 
Which obviously raises questions about the peer review process but also about the value of NGO-sponsored research (eg here) and according agendas and conflicts of interest.
And now, I can certainly leave it at that!

And then, throw those exploding Cownose Rays into the same incinerator as the Oxy Myth! Like I said back thenthe theory of correlations between trophic levels is sound - but much more when viewed bottom up! 

Synopses here and here - extensive blog post here!

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