Fishing, Trophic Cascades, and the Process of Grazing on Coral Reefs

Mumby, Peter J.; Dahlgren, Craig P.; Harborne, Alastair R.; Kappel, Carrie V.; Micheli, Fiorenza; Brumbaugh, Daniel R.; Holmes, Katherine E.; Mendes, Judith M.; Broad, Kenneth; Sanchirico, James N.; Buch, Kevin; Box, Steve; Stoffle, Richard W.; Gill, Andrew B.

doi:10.1126/science.1121129

Cited by 761 publications

(650 citation statements)

References 17 publications

Supporting

Mentioning

620

Contrasting

Unclassified

Order By: Relevance

“…3), supporting the finding that coral reef ecosystems with high top predator levels can also support high levels of herbivores (Mumby et al 2006). Two possible mechanisms could account for the high herbivore biomass on apex predator-dominated reefs.…”

Section: Resultssupporting

confidence: 70%

“…However, this explanation seems unlikely for the Line Islands, where the biomass of intermediate consumers did not differ significantly among islands. Alternatively, high biomass of herbivores at Palmyra and the NWHI may be a direct result of reduced fishing at all trophic levels (Micheli et al 2004;Mumby et al 2006). Parrotfishes and other lowtrophic level species that are caught by residents of Fanning and Christmas Islands (personal observations) may benefit directly from protection at Palmyra.…”

Section: Resultsmentioning

confidence: 99%

“…Depletion of apex predators can induce changes to the structure of marine communities as effects cascade through lower trophic levels (Stevens et al 2000;Bascompte et al 2005;Mumby et al 2006). …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

High apex predator biomass on remote Pacific islands

et al. 2006

Self Cite

View full text Add to dashboard Cite

Abstract. On coral reefs in Palmyra-a central Pacific atoll with limited fishing pressure-total fish biomass is 428 and 299% greater than on reefs in nearby Christmas and Fanning Islands. Large apex predators -groupers, sharks, snappers, and jacks larger than 50 cm in length-account for 56% of total fish biomass in Palmyra on average, but only 7% and 3% on Christmas and Fanning. These biomass proportions are remarkably similar to those previously reported for the remote and uninhabited Northwest Hawaiian Islands (NWHI) and densely populated Main Hawaiian Islands (MHI), although Palmyra's reefs are dominated in biomass by sharks (44% of the total), whereas the NWHI by jacks (39%). Herbivorous fish biomass was also greater on Palmyra than on Christmas and Fanning (343% and 207%, respectively). These results and previous findings indicate that remote, uninhabited islands support high levels of consumers, and highlight the importance of healthy coral reef ecosystems as reference points for assessment of human impacts and establishment of restoration goals.

show abstract

Section: Resultssupporting

confidence: 70%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

High apex predator biomass on remote Pacific islands

et al. 2006

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recent analyses suggest that marine protected areas may promote local processes, such as herbivory and coral recruitment (39,40), that limit macroalgal proliferation and promote coral recovery, thereby bolstering coral resilience to large-scale disturbance (7,8,11,41,42). However, because several allelopathic macroalgae (e.g., Dictyota, Chlorodesmis, Galaxaura, Lobophora, Halimeda, Ochtodes) also contain toxins that deter some herbivores (43), developing effective marine reserves may require protecting a diverse herbivore guild that includes species that consume chemically defended macroalgae (18,33,43).…”

Section: Discussionmentioning

confidence: 99%

Macroalgal terpenes function as allelopathic agents against reef corals

Rasher

Stout²,

Engel³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

212

269

View full text Add to dashboard Cite

During recent decades, many tropical reefs have transitioned from coral to macroalgal dominance. These community shifts increase the frequency of algal-coral interactions and may suppress coral recovery following both anthropogenic and natural disturbance. However, the extent to which macroalgae damage corals directly, the mechanisms involved, and the species specificity of algal-coral interactions remain uncertain. Here, we conducted field experiments demonstrating that numerous macroalgae directly damage corals by transfer of hydrophobic allelochemicals present on algal surfaces. These hydrophobic compounds caused bleaching, decreased photosynthesis, and occasionally death of corals in 79% of the 24 interactions assayed (three corals and eight algae). Coral damage generally was limited to sites of algal contact, but algae were unaffected by contact with corals. Artificial mimics for shading and abrasion produced no impact on corals, and effects of hydrophobic surface extracts from macroalgae paralleled effects of whole algae; both findings suggest that local effects are generated by allelochemical rather than physical mechanisms. Rankings of macroalgae from most to least allelopathic were similar across the three coral genera tested. However, corals varied markedly in susceptibility to allelopathic algae, with globally declining corals such as Acropora more strongly affected. Bioassay-guided fractionation of extracts from two allelopathic algae led to identification of two loliolide derivatives from the red alga Galaxaura filamentosa and two acetylated diterpenes from the green alga Chlorodesmis fastigiata as potent allelochemicals. Our results highlight a newly demonstrated but potentially widespread competitive mechanism to help explain the lack of coral recovery on many present-day reefs.allelopathy | chemical ecology | competition | phase shift C orals are structurally complex foundation species that generate and maintain tropical reef biodiversity. However, the direct and interactive effects of climate-induced coral bleaching (1, 2), ocean acidification (2, 3), coral disease (4), coastal overfishing, and eutrophication (5-8) have led to coral decline over wide areas. On many reefs, dramatic declines in coral cover have co-occurred with significant increases in fleshy macroalgae (9-11). Once established, macroalgae can inhibit coral recruitment and decrease herbivore grazing, producing negative feedbacks that reinforce phase shifts and further diminish reef function (12-14). Thus, local (e.g., overfishing) and global (e.g., climate) stresses may interact in complex ways to suppress coral cover, promote algal proliferation, and compromise reef resilience; such complexities provide both challenges and opportunities for managing these dynamic ecosystems (11, 13).As corals decline and macroalgae proliferate, the frequency of algal-coral interactions will increase, potentially affecting the survivorship, growth, and reproduction of remnant adult corals and new coral recruits (12, 13). However, the consequences ...

show abstract

“…Greenaway and Gordon-Smith, 2006). Yet, the regulating influence of intense herbivory on macroalgae (Mumby et al, 2006) may be quite general, including some inshore reefs (Hughes et al, 2007). In such consumer-controlled localities, concerns about future climate tend to focus on the management of overfishing via marine protected areas (e.g.…”

Section: Consumer Vs Producer Effectsmentioning

confidence: 99%