Monday, March 30, 2009

From Bermuda News: Turtles survive horrific boat strikes

Turtles survive horrific boat strikes

By Amanda Dale
Royal Gazette
Monday March 30, 2009

Tough turtle: Mark Outerbridge and Patrick Talbot remove barnacles and algae from a boat struck Green Turtle which was found in Jews Bay on Wednesday. The turtle is missing a large portion of shell but is still alive.
Photo: Mark Tatem

Boat users are being urged to slow down after two more injured turtles were recovered from the water this week.Both Green Turtles are both lucky to be alive, according to Bermuda Aquarium, Museum and Zoo (BAMZ) head aquarist Patrick Talbot.

The first was found floating in Jews Bay and the second was recovered from St. George's Harbour."We are amazed they are still alive," said Mr. Talbot.The turtles are now being rehabilitated at BAMZ, but need daily care to clean out their wounds.

The first, estimated at between 20 and 30 years old, was spotted by a member of the public on Wednesday in Jews Bay. The turtle was severely injured and Bermuda Turtle Project coordinator Mark Outerbridge had to jump in the water to retrieve it.Mr. Talbot said: "His injuries are such that it is as if someone has taken a big ice cream scoop and taken a chunk the size of a quarter of his body away.

"The wounds however, are starting to heal, and Mr. Talbot said this points to the incident happening a couple of weeks ago."The staff here are all amazed this turtle is still alive," he said. "We are hoping we will be eventually able to release him back to the wild, but at the moment he needs daily care."It's the same with the one today. It also needs daily cleaning of its wounds."He said a St. George's resident reported seeing the turtle in the middle of the harbour last Friday.

"It had just been hit and was still bleeding," said Mr. Talbot, who described the injuries as "the size of a large dinner plate".He said the turtle's shell had gaping holes in both the top and bottom, indicating it had been struck by the prop of a boat.

The turtle is thought to be between five and ten years old."We want people to be more aware," said Mr. Talbot. "Last year we had a number of turtles killed from boat strikes in a short space of time."There are signs up close to shore, so please obey the laws. Anyone within 100 yards of shore has to be travelling at five knots or no wake."If you can imagine the amount of force it takes to punch through a turtle's shell, if that was done to a human being, the damage would be so horrific the human wouldn't survive."

Mr. Talbot added it was important to protect these animals as Bermuda is a "major staging ground" in the Atlantic for growing juvenile and sub-adult Green Turtles.

From August to November of last year, five turtles were killed in boat collisions, whereas from August 2007 to August 2008, six were killed over the course of a year. Experts say the rise in boat strikes is a worrying trend.Anyone finding a dead or injured turtle should take it to the staff at BAMZ. Contact BAMZ at: 293 2727.

Friday, March 27, 2009

Mangroves: Back to Bermuda’s Roots

By: Jessie Hallett - BZS

Two views across The Lagoon at Ireland Island showing the fringing mangroves and neighbouring seagrass habitats. These natural areas are critical habitat for juvenile snappers and grunts which eventually leave and live as adults out on the coral reefs.

While we tend to think of marine habitat restoration as something modern – I have found two instances where healthy mangrove forest were created over decades and centuries ago.

During the last few months, I have been comparing extant marine and coastal habitats around Bermuda to those that were present two hundred years ago. I have been doing this by comparing recent aerial photos of the coast and reefs to the same areas charted by Thomas Hurd between 1788 and 1797. Throughout my work, I have been striving to determine what changes have occurred to these habitats, whether the changes have benefited the environment or not, and whether they are natural or anthropogenic. While in many cases, the environmental changes that have occurred over the past two centuries have been negative, two positive changes have occurred inadvertently due to human perturbations. Both these cases involve the creation of mangrove swamps where none existed before.

With a thicket of roots that hang like slender fingers into the water, mangrove trees may look ominous, but they are an important habitat to many fish species, as well as aquatic and terrestrial invertebrates, and birds. These trees have adapted to live in one of the most extreme and variable habitats in tropical marine systems: brackish marshes where salinity, temperature, nutrients, and sunlight can all be highly erratic. Unlike most plants, mangroves are halophytes, which means they are specially adapted to thrive in salty conditions. Mangroves are important because their roots help to stabilize coastlines, preventing erosion by expediting sediment deposition, and they also help recycle nutrients throughout seagrass and reef communities. The complex structure created by their roots also provides an ideal nursery habitat for juvenile reef fish, including many of the commercial fish species we like to eat.

Many mangrove habitats in Bermuda have disappeared entirely in the past two centuries. Many of Bermuda’s wetlands were in-filled as garbage dumps, or drained in the 19th Century when marsh-breeding mosquitoes spread deadly diseases such as yellow-fever. Since we have already lost so many mangrove areas, any remaining habitat where mangroves are thriving should be protected.

Over the past two centuries, human modifications to the coast has inadvertently created thriving mangrove marshes – at Morgan’s Point, and The Lagoon on Ireland Island.

Morgan’s Point was originally a group of islands called “The Brothers”, each surrounded by seagrass and patches of coral reefs. When the islands and surrounding area was reclaimed to create the US Naval Base during the 1940’s, a small inlet on the north side of the point was also formed, in order to provide a safe berth for small boats. Today the coastline of this man-made inlet is dominated by mangroves, and acts as a miniature estuary that provides habitat for herons and juvenile fishes.

An aerial image of the North Inlet at Morgans Point

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Another “accidental” mangrove swamp was created in the lagoon located on the south side of Ireland Island. Two hundred years ago, this lagoon was an larger inlet and open completely to the sea. When the Dockyard was built in the early 1800’s, the lagoon was enclosed by boulders except for a small cut through the rock out to the western side of the island, and a second pass between the boulders that connected to the Great Sound on the east side. These connections to the sea were excavated to prevent the lagoon waters going stagnant. By making the lagoon so sheltered - the workers who created it inadvertently also created a shallow sheltered area which is ideal for mangroves.

An aerial image of The Lagoon

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Presently, the Dockyard Lagoon and the inlet at Morgan’s Point both have healthy populations of mangroves, and the adjacent waters are dotted with propagules - the seeds with which mangroves reproduce. Both these areas are currently facing the possibility of development: a resort hotel on Morgan’s Point, and housing near Dockyard. Hopefully, these habitats will be spared if the regions are developed, as without protection Bermuda’s remaining mangrove forests may disappear.

Since local research has show reef fishes start their life in mangrove forests, losing these critical intertidal areas will have negative consequences that will resonate across the entire reef platform. These two "manufactured" habitats provide Bermuda’s mangrove population a chance to re-establish itself, and to restore the island with a healthy abundance of this vital coastal habitat.

Monday, March 16, 2009

Transplanting Corals - Restoring a Reef

BREAM Scientist Dr. Thad Murdoch prepares finger corals
for attachment on the reef being restored.

BREAM and the Bermuda Government Department of Conservation Services have been working together to transplant corals from an old sunken barge at Dockyard to restore a nearby coral reef damaged by a cruise ship grounding in 2006.

The 100-yr old wreck of one of the barges used to build the King's Wharf at Dockyard is located next to the new cruise ship pier. An RG article about the wreck can be read here: link.

While the wreck is deep enough to be left in place, except for a single spindle, or mast, the corals on the wreck are likely to be damaged by the currents generated by the ships' propellors and by the silt they kick up each time the ships approach or leave the pier.

For this reason we felt it best to remove the corals. The most suitable place to transplant the corals is the nearby reef that was struck by the Nordic Crown in 2006 [link].

With the use of Conservation Services research vessel the R.V. Calamus, team members Dr. Philippe Rouja (Custodian of Wrecks), Anson Nash and Mandy Shailer from Conservation Services, Dr. Thad Murdoch, Jessie Hallett and Robert Fisher from BREAM, Bermuda Zoological Society, and Jeff Porter, Aquarist at BAMZ/BZS moved corals on Thursday and Friday (12,13 March), and are going to finish the task after the 18th March, when weather clears.

BREAM research assistant Jessie Hallett
removes a coral from the mast of the wreck.

To move the corals, Rouja, Fisher, Hallett and Murdoch dived the wreck on SCUBA. Hallett and Murdoch carefully detached corals from the wreck, either with a hammer and chisel or by hand. This can be done because the bottom side of the corals is dead skeleton, not live tissue. While Rouja documented the process on video and still cameras, Hallett and Murdoch passed the corals to Fisher, who placed them in crates attached to ropes and pulleys and then winched the corals up to the Calamus above them. Shailer, Porter and Nash then carefully removed the corals and placed them in large seawater-filled containers to keep them wet during the removal phase.

BREAM volunteer Robert Fisher raises
a crate filled with corals to the boat above.

Once all containers were filled the team moved the Calamus to the ship grounding reef location. After anchoring over the location we lowered the containers of corals to the sea floor and transported the bins to the restoration site. Corals were carefully placed along the scarred reef in preparation for attachment.

Once all corals were in place Hallet, Rouja, Murdoch and Fisher then cemented the bases of each coral to the bare rock - being carefull to give each coral space to grow.

A transplanted finger coral, held in place
by a special blend of cement.

Once the transplantation process is finished the BREAM and DCS team will monitor the transplanted corals to see how well they coped with the move.

The close collaborative relationship between the Department of Conservation Services and the BREAM team at the Bermuda Zoological Society was crucial in this conservation effort. We were able to both save corals from damage and return corals to an area in need of restoration - two wins for Bermuda's marine environment!