Belize protected area boosting predatory fish populations

Herbivorous fish needed for reef recovery still lagging

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.

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.

Barracuda, grouper & snappers
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.

http://www.wildlifeextra.com/do/ecco.py/view_item?listid=1&listcatid=1&listitemid=12526

New Species of Ancient Predatory Fish Discovered

ScienceDaily (Sep. 12, 2011) — The Academy of Natural Sciences has announced the discovery of a new species of large predatory fish that prowled ancient North American waterways during the Devonian Period, before backboned animals existed on land.

Drs. Edward "Ted" Daeschler and Jason Downs of the Academy and colleagues from the University of Chicago and Harvard University describe the new denizen of the Devonian they named Laccognathus embryi in the current issue of the Journal of Vertebrate Paleontology.

The 375-million-year-old beast was discovered by the same group of researchers who discovered Tiktaalik roseae, the important transitional animal considered "a missing link" between fish and the earliest limbed animals. The fossil remains of the new species were found at the same site as Tiktaalik, on Ellesmere Island in the remote Nunavut Territory of Arctic Canada.

The Devonian Period (415 to 360 million years ago) is often described as the Age of Fishes because of the rich variety of aquatic forms that populated the ancient seas, lagoons and streams. Laccognathus embryi is a lobe-finned fish whose closest living relative is the lungfish. The creature probably grew to about 5 or 6 feet long and had a wide head with small eyes and robust jaws lined with large piercing teeth. "I wouldn't want to be wading or swimming in waters where this animal lurked," said Daeschler, co-author of the paper and the Academy's curator of vertebrate zoology. "Clearly these Late Devonian ecosystems were vicious places, and Laccognathus filled the niche of a large, bottom-dwelling, sit-and-wait predator with a powerful bite."

The researchers named the new species in honor of Dr. Ashton Embry, a Canadian geologist whose work in the Arctic islands paved the way for the authors' paleontological explorations.

The kind of fish known as Laccognathus (translates as pitted jaw) was previously only known from Eastern Europe. The discovery of Laccognathus embryi, the new species, extends the geographic range of Laccognathus to North America and confirms direct connection of the North American and European landmasses during the Devonian Period.

"This study is the culmination of a lot of work in the field, in the fossil lab, and in the office," said Downs, lead author of the study. Downs, an Academy research associate and a visiting professor at Swarthmore College, started studying fossils in high school as an Academy volunteer. "Our team collected the first fossils of Laccognathus almost 10 years ago, and the collection has grown with each subsequent field season. The quality and quantity of this collection will continue to shed new light on these unusual animals."

Other scientists who collaborated on the new discovery are Dr. Farish Jenkins Jr. of Harvard University and Dr. Neil Shubin of the University of Chicago. The research was funded by the National Science Foundation and the National Geographic Society.
http://www.sciencedaily.com/releases/2011/09/110912104834.htm