Mesophotic Coral Ecosystems

MESOPHOTIC CORAL ECOSYSTEMS – A LIFEBOAT FOR CORAL REEFS?

MCEs are often considered to be buffered from many

large-scale impacts known to directly affect shallow coral

ecosystems, such as warm-water bleaching and tropical

storms. Furthermore, by virtue of their depth, and in many

cases their remote offshore locations, some MCEs are

afforded greater protection from direct human impacts,

such as overfishing and land-based runoff. However, there is

increasing evidence to suggest that MCEs are vulnerable to

environmental disturbances, such as climate change impacts,

overfishing, bottom fishing gear, capture of aquarium fish,

precious coral trade, land-based pollution and invasive species

(Table 6.1). Despite these threats, many MCEs are in good

condition in comparison to their shallower counterparts.

Strong management responses could mitigate at least some

documented threats, thereby preventing future degradation

of MCEs.

Threats to mesophotic coral

ecosystems and management

options

6.1.

Introduction

Chapter 6.

Dominic Andradi-Brown

, University of Oxford, UK

Jack Laverick

, University of Oxford, UK

Ivonne Bejarano

, University of Puerto Rico at Mayagüez, USA

Thomas Bridge

, Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University; Australian Institute of Marine Science, Australia

Patrick L. Colin

, Coral Reef Research Foundation, Palau

Gal Eyal

, Tel Aviv University; The Interuniversity Institute for Marine Sciences in Eilat, Israel

Rachel Jones

, Zoological Society of London, UK

Samuel E. Kahng

, Hawai‘i Pacific University, USA

John Reed

, Harbor Branch Oceanographic Institute — Florida Atlantic University, USA

Tyler B. Smith

, University of the Virgin Islands, USA

Heather L. Spalding

, University of Hawai‘i at Mānoa, USA

ErnestoWeil

, University of Puerto Rico at Mayagüez, USA

ElizabethWood

, Marine Conservation Society, UK

Table 6.1.

Comparison of the major anthropogenic threats facing shallow-water reefs and MCEs.

Shallow-water coral reef ecosystems

• Fishing (overfishing, destructive fishing with dynamite and

poison and damage from lost fishing gear)

• Thermal stress (bleaching) from ocean warming

• Diseases

• Pollution (land-based)

• Invasive species

• Tourism and recreation

• Anchor damage

• Coral mining (for aggregate and lime)

• Coastal development

• Marine aquarium trade

Mesophotic coral ecosystems

• Fishing (overfishing and damage from lost fishing gear)

• Thermal stress (bleaching) — reduced exposure to warm water

stress

• Diseases

• Pollution — reduced exposure to land-based sources; exposed

to deep-water sewage outfalls and dredging spoils

• Invasive species

• Tourism and recreation (reduced exposure)

• Anchor damage (reduced exposure)

• Coral mining (reduced to negligible exposure)

• Marine aquarium trade

• Oil and gas exploration

• Cables and pipelines