Algal turf consumption by sea urchins and fishes is mediated by fisheries management on coral reefs in Kenya

Rapid and unprecedented ecological change threatens the functioning and stability of ecosystems. On coral reefs, global climate change and local stressors are reducing and reorganizing habitat-forming corals and associated species, with largely unknown implications for critical ecosystem functions such as herbivory. Herbivory mediates coral–algal competition, thereby facilitating ecosystem recovery following disturbance such as coral bleaching events or large storms. However, relationships between coral species composition, the distribution of herbivorous fishes and the delivery of their functional impact are not well understood. Here, we investigate how herbivorous fish assemblages and delivery of two distinct herbivory processes, grazing and browsing, differ among three taxonomically distinct, replicated coral habitats. While grazing on algal turf assemblages was insensitive to different coral configurations, browsing on the macroalga Laurencia cf. obtusa varied considerably among habitats, suggesting that different mechanisms may shape these processes. Variation in browsing among habitats was best predicted by the composition and structural complexity of benthic assemblages (in particular the cover and composition of corals, but not macroalgal cover), and was poorly reflected by visual estimates of browser biomass. Surprisingly, the lowest browsing rates were recorded in the most structurally complex habitat, with the greatest cover of coral (branching Porites habitat). While the mechanism for the variation in browsing is not clear, it may be related to scale-dependent effects of habitat structure on visual occlusion inhibiting foraging activity by browsing fishes, or the relative availability of alternate dietary resources. Our results suggest that maintained functionality may vary among distinct and emerging coral reef configurations due to ecological interactions between reef fishes and their environment determining habitat selection.

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Grazing Effects of Fish versus Sea Urchins on Turf Algae and Coral Recruits: Possible Implications for Coral Reef Resilience and Restoration

Journal of Marine Biology ◽

10.1155/2011/960207 ◽

2011 ◽

Vol 2011 ◽

pp. 1-8 ◽

Cited By ~ 17

Author(s):

Leor Korzen ◽

Alvaro Israel ◽

Avigdor Abelson

Keyword(s):

Coral Reef ◽

Coral Reefs ◽

Sea Urchins ◽

Benthic Algae ◽

Herbivorous Fish ◽

Grazing Impact ◽

Turf Algae ◽

Coral Reef Resilience ◽

Drastic Increase ◽

The Impact

Herbivory is an important structuring factor in coral reefs, influencing seaweed abundance, competitive interactions between seaweeds and corals, and coral reef resilience. Despite reports of a drastic increase in the cover of benthic algae and turf dominancy in the coral reefs of Eilat, Red Sea, very little is known about the factors responsible for this phenomenon or the possible effects of herbivory on turf algae and coral recruits. Here, we examine the effects of herbivory by experimentally exposing turf algae and coral recruits to grazing activities of herbivorous fish and sea urchins. Using remote video cameras to document removal of algae and coral spats, we show that the main grazing impact is due to daily grazing by fishes, whereas the significant impact of sea urchins is mainly expressed in their adverse effect on the survival of coral recruits, with a relatively low effect on algal biomass. These findings contribute to our understanding of the factors influencing turf algae establishment and proliferation, and the survival of coral recruits on the coral reefs of Eilat. The clear differences between the impact of herbivorous fish and that of sea urchins, on the Eilat reefs, have critical implications for reef resilience and restoration measures.

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Changes in northern Tanzania coral reefs during a period of increased fisheries management and climatic disturbance

Aquatic Conservation Marine and Freshwater Ecosystems ◽

10.1002/aqc.1020 ◽

2009 ◽

Vol 19 (7) ◽

pp. 758-771 ◽

Cited By ~ 17

Author(s):

Tim R. McClanahan ◽

Nyawira A. Muthiga ◽

Joseph Maina ◽

Albogast T. Kamukuru ◽

Saleh A.S. Yahya

Keyword(s):

Coral Reefs ◽

Fisheries Management ◽

Northern Tanzania

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Spatial variation in sea urchins, fish predators, and bioerosion rates on coral reefs of Belize

Coral Reefs ◽

10.1007/s00338-006-0159-9 ◽

2006 ◽

Vol 26 (1) ◽

pp. 71-78 ◽

Cited By ~ 36

Author(s):

Jocelyn Brown-Saracino ◽

Paulette Peckol ◽

H. Allen Curran ◽

Martha L. Robbart

Keyword(s):

Coral Reefs ◽

Spatial Variation ◽

Sea Urchins ◽

Fish Predators

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Primacy of bottom-up effects on a butterflyfish assemblage

Marine and Freshwater Research ◽

10.1071/mf15012 ◽

2016 ◽

Vol 67 (8) ◽

pp. 1175 ◽

Cited By ~ 1

Author(s):

Susannah M. Leahy ◽

Garry R. Russ ◽

Rene A. Abesamis

Keyword(s):

Climate Change ◽

Water Quality ◽

Coral Reefs ◽

Fisheries Management ◽

Negative Association ◽

Feeding Guilds ◽

Top Down ◽

Management Tools ◽

Bottom Up ◽

Anthropogenic Stressors

The question of whether biological systems are maintained by top-down versus bottom-up drivers is a recurring one in ecology. It is a particularly important question to address in the management of coral reefs, which are at risk from a variety of anthropogenic stressors. Here, we explicitly test whether the abundance of different feeding guilds of coral-associated Chaetodon butterflyfishes are controlled by top-down or bottom-up drivers, and we assess the relative influence of all statistically significant drivers. We find that the abundance and species richness of Chaetodon butterflyfishes are predominately determined by bottom-up drivers. The abundance of corallivores is primarily driven by availability of branching and tabular live corals, whereas the abundance of generalists is most strongly influenced by a negative association with macroalgal cover. We also find evidence of weak top-down control on the abundance of corallivorous butterflyfish by gape-limited mesopredators, but no such effects on generalist butterflyfish. Our findings indicate that conservation of coral reefs for Chaetodon butterflyfishes must include management at a larger spatial scale in order to reduce the effect of coral reef stressors such as declining water quality and climate change, but should also include implementation of fisheries management tools in order to increase local herbivory.

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The near future of coral reefs

Environmental Conservation ◽

10.1017/s0376892902000334 ◽

2002 ◽

Vol 29 (4) ◽

pp. 460-483 ◽

Cited By ~ 62

Author(s):

Timothy R. McClanahan

Keyword(s):

Coral Reefs ◽

Sea Urchins ◽

Trophic Levels ◽

Current Status ◽

Toxic Substances ◽

Atmospheric Concentration ◽

Seawater Chemistry ◽

Generalist Species ◽

The Past ◽

Use Of Resources

In this paper the current status of coral reefs, predictions concerning the ecological state of coral reefs to the 2025 time horizon and the research needs that can help understanding and management activities that might alleviate detrimental ecological changes are evaluated and discussed. The present rate of CO2 emissions will produce an atmospheric concentration in 100 years not experienced during the past 20 million years and water temperatures above those of the past interglacial 130 000 years before present. Human influences on water temperatures, seawater chemistry (toxic substances, nutrients and aragonite saturation), the spread of diseases, removal of species and food web alterations are presently changing reef ecology. A significant ecological reorganization is underway and changes include a reduction in calcifying and zooxanthellae-hosting organisms, their obligate symbionts, and species at higher trophic levels, with an increase in generalist species of low trophic level that are adapted to variable environments. Late-successional fleshy brown algae of low net productivity or non-commercial invertebrates such as sea urchins, starfish and coral-eating snails will dominate many reefs. These changes will be associated with a loss of both net benthic and fisheries production and inorganic carbonate deposition; this will reduce reef complexity, species richness, reef growth and increase shoreline erosion. To avert these changes management is needed at both global and local levels. Both levels need to reduce greenhouse gases and other waste emissions and renew efforts to improve resource management including restrictions on the use of resources and globalization of resource trade, run-off and waste production, and balancing potential reef production and resource consumption.

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Echinometra sea urchins on Caribbean coral reefs: Diel and lunar cycles of movement and feeding, densities, and morphology

Journal of Experimental Marine Biology and Ecology ◽

10.1016/j.jembe.2020.151430 ◽

2020 ◽

Vol 530-531 ◽

pp. 151430

Author(s):

M.J. Shulman

Keyword(s):

Coral Reefs ◽

Sea Urchins ◽

Lunar Cycles ◽

Caribbean Coral ◽

Caribbean Coral Reefs

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Hubungan Kepadatan Bulu Babi (Echinoidea) dan Tutupan Terumbu Karang pada Kawasan Intertidal Pantai Sanur

Journal of Marine and Aquatic Sciences ◽

10.24843/jmas.2017.v3.i02.134-141 ◽

2017 ◽

Vol 3 (2) ◽

pp. 134

Author(s):

Tiara Permata Sari ◽

Abd. Rahman As-syakur ◽

Yulianto Suteja ◽

Dwi Budi Wiyanto

Keyword(s):

Coral Reef ◽

Coral Reefs ◽

Sea Urchins ◽

Coral Cover ◽

Intertidal Area ◽

Positive Direction ◽

Community Activities ◽

Cruise Tourism ◽

The Many ◽

The Relationship

Marine intertidal region is an area that is affected by the mainland. One of the ecosystems found in the intertidal area is the coral reef ecosystem. Urchin is one that lives on these ecosystems. Sanur Beach area has coral reefs and the intertidal zone is quite extensive. The many activities and cruise tourism in Sanur Beach will indirectly affect the life of coral reefs and associated animal in it in this case urchins. The purpose of this study was to determine the relationship density of sea urchins and coral reefs cover percentage in the intertidal area on Sanur Beach. Research done during low tide. Coral reef data collection method and the density of sea urchins using 5x5m quadratic transects were analyzed using Pear Person bivariate correlations. Urchin densities ranging between 0-2.04 ind/m2. The percentage cover coral reefs ranged from 0.1- 17.9%. High and low density of sea urchins and the percentage of coral reefs affected allegedly incompatibility place their lives and because of pressure from community activities in Sanur. The density of sea urchins and the percentage of coral cover has a significant relationship with a strong degree of correlation is 0.79. Positive direction on that relationship means that the higher percentage of coral reefs, the higher density of sea urchins. This assume in which they live almost the same that is in need of a hard substrate and urchins use of coral reefs as a shelter.

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