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Artificial reefs to boost fish supply

ARTIFICIAL reefs are to be built in local waters to boost fish supplies which have been depleted by over-fishing, pollution, dredging and dumping.

The Agriculture and Fisheries Department yesterday announced it was investigating sites for the reefs and had received $1.6 million from the Royal Hong Kong Jockey Club to start the project.
Reefs provide nursing and feeding grounds for all sorts of marine life including larger fish sold in local markets.
Fisheries officer David Cook said it was hoped local stocks would be boosted and the diversity of marine life in Hong Kong would increase with the reefs.
”We see that there’s a need to provide some level of redress for the perceived damage that’s occurring to the marine environment,” he said.
Fishermen and environmentalists have stepped up campaigns in the past year to call attention to the destruction caused by dredging and dumping for the airport projects. Silt is stirred up that can smother corals and drive away fish.
But overfishing is also a concern and Mr Cook said fishing around the reefs would be restricted.
He said fishermen in Malaysia and Thailand had abided by fishing restrictions around artificial reefs in their waters because they increased fish production by up to 400 times in some cases.
It was impossible to say how much impact the scheme would have on Hong Kong fisheries as this would be proportional to the scale of the project, he said.
But fish stocks are expected to increase when the first reefs are set up in soon-to-be-established marine parks where legislation already restricts fishing, he said. The first park is expected to be declared later this year, probably in the eastern waters.
But the declaration of the parks is likely to be slow and cover only a limited area, and any large-scale setting up of artificial reefs will require about $65 million.
The Jockey Club’s $1.6 million contribution will be used towards setting set up the first few reefs and determine the best reef sites.
The programme is separate from trials being carried out on an artificial reef made from coal ash in Hoi Ha Wan, which is still underway. Until results are available on its safety, the reefs will be made from more expensive reinforced concrete.
It is also hoped to use sunken ships, possibly some of the hundreds of vessels destroyed by the Marine Department each year, as these can provide the solid surface and nooks and crannies needed for a successful reef.
Hong Kong’s natural coral reefs are in the eastern waters and many have been damaged by dredging and pollution and by a mysterious water current last month that killed everything in a 40-square-kilometre area.
Most of the rest of the sea bottom is flat and soft, and the reefs will provide a place for marine organisms to grow, providing food for larger animals.By KATHY GRIFFIN
Mr Cook said. Dozens of unique habitat models at fishiding.com

Artificial Reefs and Seagrass

Article of the Week 2 – Artificial Reefs

Posted by laymanc

Coastal ecosystems may be the most anthropogenically-altered on the planet.  Habitat loss, over-fishing, nutrient loading, and many other impacts have fundamentally changed the structure and function of these systems.  Many of these impacts operate over rather large spatial scales (think global warming or the loss of migratory fishes); however, most marine ecology actually is conducted at the smallest scales.  Foundational ecological theory took root in experiments conducted in coastal intertidal zones, often at scales of a meter or less.  But ecologists now are challenged to develop approaches that better fit the large scales at which human impacts are altering coastal ecosystems.

In terrestrial systems, “landscape” ecology is a well-developed sub-discipline.  Yet tenets of this are rarely applied in marine systems.  This study was among the first to do so and to use manipulative approaches as we constructed a series of artificial reefs in the Bight and specifically chose locations within different “seascape” contexts.  This allowed us to examine the importance of relatively large-scale (hundreds of meters) features in determining local fish community structure.  That is, instead of just examining small-scale aspects of the reef itself, we included much larger scale factors (such as seagrass cover) and used these to explain the makeup of fish communities.

See the dozens of unique artificial fish habitat models, fish attractors and fish cover used at fishiding.com, the leader in  science based, proven, fish protection.

We found that the amount of seagrass at large spatial scales was one of the most important features determining to number and identity of fishes using these artificial reefs.  Specifically, reefs that had more seagrass within 100 m had more fishes.  This may be explained by the fact that many reef species like grunts, snapper and lobster that use reefs during the day migrate out into the surrounding seagrass at night to feed.  However, not all species of fish responded to the amount of seagrass in the same way.  For example, the number of white grunts increased with more seagrass cover within the seascape, but the number of French grunts decreased.  This means that changes in the cover of seagrass within large areas surrounding reefs can affect both the number and types of fishes using reefs.  Human activities that cause even subtle changes to seagrass habitat can impact reef fish communities even before the complete loss of seagrass habitat.

Residents fear shoreline project will smother reef

Structures a home for sea creatures

Three acres of coquina and worm rock could be covered by a beach renourishment project.
Three acres of coquina and worm rock could be covered by a beach renourishment project. / Photos courtesy of Karen Holloway-Adkins

A new beach renourishment project is in the works for Brevard County, and conservation-minded residents are worried that trucking in the sand will bury a local treasure.

The Brevard County Mid Reach Shore Protection Project aims to dump 573,000 cubic yards of sand onto the 7.8-mile section of beach between Patrick Air Force Base and Indialantic. By adding up to 20 feet of beach, three acres of coquina and worm rock reef will be smothered.

But marine biologist Karen Holloway-Adkins knows the reef is more than just a pile of rocks.

See the dozens of unique artificial fish habitat models, fish attractors and fish cover used at fishiding.com, the leader in  science based, proven, fish protection.

“Worm rock doesn’t get much credit. A lot of people don’t even know what’s out there.” said Holloway-Adkins. “It’s a full-on living reef.”

The large, cauliflower-shaped boulders are not rocks, but the protective sand structures secreted by colonies of bristle worms of the family Sabellariidae (pronounced “SAH—bell—AIR– I—dee”).

But the worms are just a small piece of the reefs’ complexity.

“The algae growing on the reef provides food for turtles and fish.

“The structure is excellent habitat for crabs, blennies, sheepshead, snook, pompano and more,” said Holloway-Adkins, who lives in Indialantic. “I’ve even seen an octopus under one of the ledges.”

Holloway helps run a nonprofit research company, East Coast Biologists, Inc., and was hired by the County to aid in an Environmental Impact Assessment for the project.

Her work revolves specifically around the green sea turtles which feed almost exclusively on the red, green and brown algae growing on the reef. She’s logged countless hours snorkeling the reefs in the Mid Reach zone — when the underwater visibility permits it.

“The juvenile greens will forage and hang around the intertidal zone, sometimes in less than two feet of water.”

The high-energy intertidal zone — the area dappled with small tide pools near shore — is threatened most by the filling project.

“Those pools are important for gamefish,” Holloway-Adkins said. “That’s where you’ll see schools of baby pompano. It’s an important nursery.”

The threat to gamefish and the local ecology has Space Coast fishing authority, Captain Rodney Smith, reeling with concern.

“It’s an extremely unique habitat because this reef is also part of the Indian River Lagoon estuary,” said Smith, a fishing guide for over 20 years and founder of Coastal Angler Magazine. “It’s all connected ecologically. It’s such a treasure.”

Smith conducts guided surf-fishing clinics and recognizes the significance of the reefs for the recreational fishery. As one who makes his living from the area’s natural splendor, he empathizes with business and home owners who are faced with protecting their assets on the beach.

“Change is definitely difficult,” Smith said. “But the quality of life drops during these projects, the beach as we love it is destroyed and the degradation to the habitat is profound.”

As far as the economics of the fill, Smith would like to see changes in how these projects are carried out. With Florida’s dynamic coastline of shifting sand dunes, replenished beaches can be stripped away by hurricanes and strong storms.

“Millions of taxpayer’s dollars are swept into the ocean in a day,” Smith said.

“It’s like throwing sand into a volcano. We need to reassess how we’re managing our beaches.”

Smith’s wish may somewhat come true.

Mike McGarry, the Beach Project Coordinator for Brevard, says that the Mid Reach project is a one-of-a-kind operation designed by the Army Core of Engineers.

“The Mid Reach project is vastly different from a typical beach renourishment. We’ve made sure a large weight has been placed on the environmental consequences.”

Sand will be harvested offshore, stockpiled in Port Canaveral and placed on the beach by dump truck. There won’t be any rusty pipes snaking through the sand from offshore pumping barges, as in previous filling ventures.

“Less than 10 percent of the rocks in the Mid Reach zone will be covered, allowing 90 percent of the habitat to remain,” McGarry said.

“We don’t discount that there won’t be an impact to the environment, but we’ve taken all the steps possible to minimize that impact.”

To mitigate for any damage to the reef that can’t be avoided, the county and the ACOE have devised an artificial reef system that will be placed in parts of the Mid Reach stretch.

Coquina rocks embedded in concrete-block grids will be laid by crane in 12-15 feet of water — after the fill is completed.

The reef habitat in the Mid Reach zone has been designated as an “Essential Fish Habitat” by the National Marine Fisheries Service, which requires the involved parties to take precautions to ensure the health of the ecosystem, including the design of these ‘mitigation reefs’.

But they’re still not the real, living thing.

And although keeping the surf-side infrastructure intact is vital to the area’s economy, Rodney Smith feels that healthy reefs are a part of our culture that can’t be bought.

“You can’t destroy a natural reef and then try to fix it,” Smith said. “They’re priceless.”

Written by
Matt Badolato
For FLORIDA TODAY
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