Sunday, June 04, 2017

Abundance and spatial Distribution of Reef-associated Sharks - Paper!

Shark Reef Marine Reserve: protecting the Sharks, their prey and their habitat! Great pic by Ozzie Sam!

And I cite.
Our study found shark abundance to be primarily driven by fish biomass amongst lower trophic levels and functional groups.
The importance of fish biomass in predicting shark abundance suggests the necessity of ecosystem level protection, involving all species and functional groups, rather than species-specific policies, such as shark sanctuaries, which might still permit on-going depletion of prey species.
Similarly, studies across a range of marine ecosystems have found that assemblages of top level predators such as sharks require both healthy environments in terms of prey availability, and a wide range of habitat zones to accommodate different species’ habitat preferences and to permit resource partitioning and ontogenetic changes in habitat use. Individual species or life stages preferentially use particular habitat zones or depth ranges, and, though often highly site-resident, reef shark species have been shown capable of making long movements between neighbouring reefs.
This implies that marine reserves that encompass a wide variety of habitats within the boundaries of the protected area may be more effective in preserving species diversity in the shark assemblage and providing the habitat niches required at different life stages. Very large MPAs such as the BMR, in contrast to more narrowly scoped or zoned protection regimes, have the additional advantage of protecting not only known and surveyed habitats but also the unknowns.
Like I've been stating for a while, e.g. here, we really need to shift away from the current narrow focus on species protection towards a much more holistic approach - and those mega-MPAs are an excellent way of achieving that aim.

Enjoy David and Jessica's paper!

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