A 14-year study by the Wildlife Conservation Society in an atoll reef lagoon in Glover's Reef, Belize has found that fishing closures there produce encouraging increases in populations of predatory fish species. However, such closures have resulted in only minimal increases in herbivorous fish, which feed on the algae that smother corals and inhibit reef recovery.
Conservationists are hopeful that Belize's nation-wide fishing ban on parrotfish -- an important herbivorous species (pictured here) -- may help degraded reef systems rebound. Credit: Wildlife Conservation Society
The findings will help WCS researchers in their search for new solutions to the problem of restoring Caribbean reefs damaged by fishing and climate change.
The study appears in an online version of Aquatic Conservation: Marine and Freshwater Ecosystems. The authors include: Tim McClanahan, N.A. Muthiga, and R.A. Coleman of the Wildlife Conservation Society.
Specifically, the fishing closures have resulted in the recovery of species such as barracuda, groupers, snappers, and other predatory fish. Herbivorous fish such as parrotfish and surgeonfish, however, managed only slight recoveries, along with a small amount of the herbivory needed to reduce erect algae and promote the growth of more hard corals. This modest recovery of herbivorous fish has not been sufficient in reversing the degradation of the reefs by algae that have overgrown the reef and replaced the coral that once occupied 75 percent, but now represent less than 20 percent, of the seafloor cover. The authors note that a recent national-level ban by the Belizean government on the fishing of parrotfish—a widespread herbivorous species—may be the key to reef recovery, provided that the fishing ban is enforced and met with compliance. WCS provided valuable data through its monitoring program at Glover's Reef to justify the landmark measure to protect reef grazers.
"The fishing ban in the fully protected portion of the lagoon was expected to result in an increase in predatory fish and—more importantly—herbivorous fish such as parrotfish that in turn reverse the degraded condition of algal dominance in this reef," said Dr. Tim McClanahan, lead author of the study and head of WCS's coral reef research and conservation program. "What happened was a recovery of predatory fish, but not of the herbivorous fish, a finding that is forcing us to come up with a more effective model of reef management and recovery. If the nation-wide ban on parrotfish is successful, then we can see if this type of large-scale management is the only effective solution for protecting coral reefs."
According to the authors, a number of factors could be contributing to the unpredicted responses of fishing closures, which considerably complicates the understanding of coral reef ecology and management. The complex web of species interactions may produce unexpected cascading effects because of underestimates in the possible responses to bans on fishing. Other possible reason: the size of the closure may be too small to produce the desired effect, or there may be a failure of compliance with fishers following the ban. The authors also mention that environmental factors such as oceanographic oscillations and warming waters complicate any attempt to establish cause-and-effect relationships in these systems, as they noted a loss in coral cover across the 1998 El Niño that killed many corals worldwide.
"It is encouraging to see the recovery of large predatory fish such as groupers and snappers under significant pressure elsewhere in Belize, but the lagging herbivorous fish is a warning that there is no single solution to coral reef conservation," said Dr. Caleb McClennen, Director of WCS's Marine Program. "While no-take zones are critical, more comprehensive ecosystem-based management is essential throughout the range of targeted species for long term recovery of the entire Meso-American Barrier Reef."
From Fiji to Kenya to Glover's Reef, Dr. Tim McClanahan's research examines the ecology, fisheries, climate change effects, and management of coral reefs at key sites throughout the world. This work has been supported by the John D. and Catherine T. MacArthur Foundation and The Tiffany & Co. Foundation. WCS wishes to acknowledge the Oak Foundation and The Summit Foundation for their generous support of this study and our marine conservation work throughout Belize.
John Delaney | EurekAlert!
Further reports about: > WCS
Listening in: Acoustic monitoring devices detect illegal hunting and logging
14.12.2017 | Gesellschaft für Ökologie e.V.
How fires are changing the tundra’s face
12.12.2017 | Gesellschaft für Ökologie e.V.
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences