Fishing, trophic cascades, and the process of grazing on coral reefs.
Since the mass mortality of the urchin Diadema antillarum in 1983, parrotfishes have become the dominant grazer on Caribbean reefs. The grazing capacity of these fishes could be impaired if marine reserves achieve their long-term goal of restoring large consumers, several of which prey on parrotfishes. Here we compare the negative impacts of enhanced predation with the positive impacts of reduced fishing mortality on parrotfishes inside reserves. Because large-bodied parrotfishes escape the risk of predation from a large piscivore (the Nassau grouper), the predation effect reduced grazing by only 4 to 8%. This impact was overwhelmed by the increase in density of large parrotfishes, resulting in a net doubling of grazing. Increased grazing caused a fourfold reduction in the cover of macroalgae, which, because they are the principal competitors of corals, highlights the potential importance of reserves for coral reef resilience.
Mumby
Peter J
PJ
Marine Spatial Ecology Lab, School of BioSciences, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, UK.
Dahlgren
Craig P
CP
Harborne
Alastair R
AR
Kappel
Carrie V
CV
Micheli
Fiorenza
F
Brumbaugh
Daniel R
DR
Holmes
Katherine E
KE
Mendes
Judith M
JM
Broad
Kenneth
K
Sanchirico
James N
JN
Buch
Kevin
K
Box
Steve
S
Stoffle
Richard W
RW
Gill
Andrew B
AB
D000818:Animals; D037421:Anthozoa / Q000254:growth & development; D001444:Bahamas; D018533:Biomass; D049628:Body Size; D003247:Conservation of Natural Resources; D017753:Ecosystem; D005398:Fisheries; D005399:Fishes; D010473:Perciformes / Q000033:anatomy & histology; D011156:Population Density; D011157:Population Dynamics; D011235:Predatory Behavior