Unique coral reef system discovered at the mouth of the Amazon

APRIL 23, 2016

by Chuck Bednar

With tales of widespread bleaching and the ill effects of climate change dominating headlines, there’s finally some good news involving coral reefs : researchers have discovered an entirely new, previously undetected reef system at the mouth of the Amazon River.

The unexpected find, which is detailed in the April 22 edition of the journal Science Advances, was rather unexpected because larger rivers that flow into the oceans in areas known as plumes often have gaps in the reef distribution along their tropical shelves, the authors explained.

However, a team of scientists from the University of Georgia and the Federal University of Rio de Janeiro found a broad reef ecosystem hidden beneath a plume of river water, which according to Discovery News is what kept it hidden for so long. They discovered the reef through a process known as multibeam acoustic sampling, and collected samples to confirm their find.

“There were some studies back in the 1950s that suggested the presence of reefs,” senior author Fabiano Thompson, an oceanographer and professor of marine biology at the Federal University of Rio de Janeiro, told the site, “but none pinpointed the reef bodies, dimensions, locations, and compositions.”

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More coral babies staying at home on future reefs

Date:

April 29, 2014

Source:

ARC Centre of Excellence in Coral Reef Studies

Summary:

Increasing ocean temperatures due to climate change will soon see reefs retaining and nurturing more of their own coral larvae, leaving large reef systems less interconnected and potentially more vulnerable. "We found that at higher temperatures more coral larvae will tend to stay on their birth reef," says the lead author of the study.

Continued

Young parrotfish explore, while adults stay at home

Young parrotfish rapidly expand their coral reef home range but only until they reach adulthood, scientists have found.

Researchers in Australia mapped the movements of individuals from very young juveniles to mature adults.

They found that small parrotfish quickly expanded their range as soon as they settled on a reef.

This expansion stopped when the fish matured, and their final home range was unrelated to adult body size.

The results are published in the journal Proceedings of the Royal Society B.

Most animals move within a home range; the size of which is driven by avoiding predators, finding food and reproducing.

"In many studies which look at coral reef fish movements, we see a significant relationship reported between body size and home range," explained lead researcher Justin Welsh from James Cook University, Australia.

The team identified 75 individual fish by size, colour markings and scars from three species of parrotfish.

Continued

Fiji fishing experiment – It doesn’t take long to trash fish stocks

Fiji fishing fundraiser breaks the coral reef "bank"
March 2012. A protected coral reef in Fiji briefly opened for an intensive five-week fishing season was largely depleted of its fish populations and has been slow to recover, according to a study by the Wildlife Conservation Society.

In the first study of its kind, conservationists with WCS's Marine Program examined the environmental impact of an intensive fishing event-conducted by three villages in 2008 to pay for both school and church fees and provincial levies-on a formerly protected reef system.

Commercial fish almost disappeared
Predictably, the research team found that the reef's populations of large-bodied, commercially valuable species (surgeonfish, parrotfish, snapper, grouper, etc.) were severely depleted during the harvest, which lasted for five weeks, and some species were fished out entirely (the target of 12,000 Fiji dollars was achieved in the first day, but the fishing continued). Other species, the team speculated, may have simply fled to an adjacent reef outside of the fishing area.

After returning a year later, the marine scientists recorded a significantly lower fish biomass (a tally of all species based on visual surveys) in the reef than the previous year before the harvest. The findings also suggested that fishers may have continued to fish even after the fishing ban was reinstated.

Fishing to pay bills
The idea for the study was prompted by an announcement from the residents of the three villages on Kia Island. Seeking to raise funds to pay for needed services and taxes, the villagers temporarily opened a coastal no-take zone with a goal of generating 12,000 Fiji dollars (approximately $7,500) in fish and sea cucumbers. WCS researchers had surveyed the reef sites just prior to the announced harvests.

"We realized this would be a once-in-a-lifetime opportunity to directly assess the impacts of a huge harvest event in a coral reef normally closed to fishing," said Dr. Stacy Jupiter, lead author of the study. "Many studies have examined the vulnerability of reef systems to overfishing. In this instance, we had a baseline in what was a protected area, followed by a survey of the site one month into the harvest and then a year later to gather evidence of recovery."

Read on:  http://www.wildlifeextra.com/go/news/fiji-reefs.html