Tuesday, September 20, 2011

The Taming of the Lionfish

The lionfish is a hot item in SCUBA current events. Though beautiful to observe, the lionfish has infiltrated a marine ecosystem it does not belong to, causing devastating effects to coral reef systems in the Atlantic along the eastern cost of the US and the Caribbean. Local government and environmental agencies are beseeching SCUBA divers to actively hunt and kill the lionfish, which as it turns out, is a rather tasty fish that can be prepared in a variety of ways. So what’s the big deal about lionfish?

Lionfish is the common name for a genus of fish called Pterois, which features about 15 different species. There are 2 species which have invaded the Atlantic and Caribbean: P. volitans and P. miles. Originally from the waters of the Indo-Pacific region, lionfish have been a very popular choice for aquarium enthusiasts in the US for quite some time. There are several theories as to how the lionfish came to be in the local environment. One such theory is that the invasion was facilitated through the destruction of a southern Florida aquarium during Hurricane Andrew in 1992. Another tells of lionfish being accidentally released following the hurricane, and yet another proposes aquarium owners were deliberately releasing them into the sea, unsatisfied with the way the lionfish performed in the aquarium. Still others claim to have spotted the lionfish on local reefs even before Hurricane Andrew.

The lionfish has been able to reproduce at such profuse levels due to certain crucial factors:
Lionfish have no natural predators on the reefs of the Atlantic and Caribbean. Any creature that sits at the top of the food chain, unchecked by nature, will enjoy the privilege of populating an area with its own species. But this can have disastrous implications for the area as the system becomes more imbalanced.

Lionfish have a voracious, unbiased appetite for reef species. The lionfish is an indiscriminate predator, feeding on invertebrates, small fish, mollusks, and juvenile species in large amounts. Up to 6 species of fish have been found in a lionfish stomach at one time. They are aggressive and skilled hunters, using specialized characteristics of their bodies to stalk and overtake prey, which they do in one giant swallow.

Lionfish spawn at a highly accelerated rate. The female lionfish releases clusters of 2,000 to 15,000 eggs at one time, which are then fertilized by the male, and hatch 36 hours later. Within 3 days they are competent swimmers, and capable of capturing and consuming small prey. Within 20 – 40 days, the lionfish begins its metamorphosis to adult. Lionfish females can repeat this process on a monthly basis with no set breeding season, and the typical lionfish lives between 5 and 15 years.

Lionfish are hostile and venomous. The lionfish is covered in long, venomous spines that serve as a deterrent to predators in its natural environment, and are incorporated into the capture of some prey. The effect of the venom on prey is fatal, whereas the effect on humans is painful, and can bring about symptoms of nausea and fever, but is very rarely fatal. They are extremely aggressive toward other reef species, either chasing them away from the reef or consuming them in a territorial play.

According to research, lionfish are responsible for wiping out up to 80% of reef species in the Atlantic and Caribbean. A few studies have shown the Caribbean grouper to be a predator of the lionfish, but due to overfishing, there are not enough grouper to contain the wild spread of lionfish populations. That’s where SCUBA divers, snorkelers, and anglers come in.

If you live in these areas or will be traveling to one soon, check into local programs dedicated to controlling lionfish populations. Although complete eradication is deemed unrealistic, people with SCUBA training can be of immense assistance in keeping reef ecosystems from being ravaged by this most unwelcome visitor.

Photos via NOAA’s National Ocean Service, mtarlock, Serge Melki

thanks to Book Your Dive and Creedence

Kathy Dowsett
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Saturday, September 17, 2011

Scuba diving may benefit those with spinal cord injuries

Tracts of the spinal cord.Image via Wikipedia

A preliminary study finds that scuba diving may help improve muscle movement, touch sensitivity and post-traumatic stress disorder symptoms in people with spinal cord injuries.

The small pilot study, presented Saturday at the Paralyzed Veterans of America conference in Orlando, Fla., involved 10 wheelchair-dependent disabled veterans who had suffered spinal cord injuries an average 15 years earlier and who underwent scuba diving certification. Pre-dive tests checked the participants' muscle spasticity, motor control, sensitivity to light touch and pinpricks, plus depression, obsessive-compulsive disorder and post-traumatic stress disorder symptoms. Eight people completed the program and the study also included nine health controls who served as dive buddies.

Among the disabled vets, researchers found an average 15% drop in muscle spasticity, an average 10% increase in light touch sensitivity and an average 5% jump in sensitivity to pinprick. No one in the control group experienced any neurological changes.

On the mental health side of things, post-traumatic stress disorder symptoms decreased an average 80%, all of which could not be attributed to the fact that the scuba training was done in a lovely Caribbean setting.

"What we saw in the water strongly suggests there is some scuba-facilitated restoration of neurological and psychological function in paraplegics," said study co-author Dr. Adam Kaplin in a news release. Kaplin is an assistant professor of psychiatry and behavioral services at the Johns Hopkins University School of Medicine in Baltimore.

While cautioning that these are preliminary results and more study needs to be done, Kaplin has some theories on why water and weightlessness promote positive effects in people with spinal cord injuries. Water may provide buoyant resistance training they can't find on land, and when in the water, breathing isn't hindered by sitting in a chair. The participants may have also benefited from tissues being extra oxygenated from pressurized air, possibly causing improvements in muscle tone and sensitivity.

"There's a signal," said Kaplin of the results, "but only by repeating these results and showing significant improvements can we establish that. It's too early to know for sure."

The idea for the experiment came from Cody Unser, founder of the Cody Unser First Step Foundation, a New Mexico-based nonprofit raising money and awareness for those with spinal cord-related paralysis. At the age of 12 Unser contracted transverse myelitis, an inflammation of the spinal cord that can cause muscle weakness or paralysis as well as pain or sensory issues. Unser, who is paralyzed from the chest down, has been treated at Johns Hopkins and told Kaplin that she and others in wheelchairs recovered some feeling in their legs after scuba diving.

Thanks to Jeannine Stein, Los Angeles Times

Kathy Dowsett

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Sunday, September 4, 2011

Going to great depths to save ocean life

Scott Cassell already holds the record for longest non-stop dive but is ready to break it again while trying to preserve ocean life.

On September 17, the explorer and combat/commercial diver will attempt a 30-mile (48-kilometre) non-stop SCUBA dive from Catalina Island to Los Angeles, gathering information about shark population and what the ocean actually holds, a task that only human effort can accurately collect.

“[The ocean] is where monsters dwell,” says Cassell, who has spent more than 13,000 hours under water in his lifetime, “Where man’s imagination can become reality because it truly does have the most magnificent animals to ever have existed.”

From 1,000 ft. to 3,000 ft., he will be diving through two great white shark strike zones, and an area that has been known to contain very large Mako sharks, to calculate how many sharks there are in Southern California.

Aside from sharks, other dangers Cassell is prepared to face include hypothermia, decompression sickness, extraordinary currents, equipment failure, and physical exhaustion.

For this diver, however, his safety, although important, is not top priority.

“Every dive is a mission,” says Cassell. “And the mission is always first.”

Cassell considers himself a man who takes responsibility for everything in his world. In this case, that's the ocean and the animals that dwell underneath.

“If we, as humans, were to see the devastation, in chronological form, that has occurred in the ocean, as if it were on land we would be horrified,” he says.

To call this a successful dive, he says he needs to make it from point A to point B non-stop, collect observations, and report his findings.

At the end, he plans to produce a documentary and lecture series to expose this information to the public.

A Vancouver crew of producers and filmmakers has joined him in the mission, helping raise money for Cassell’s conservation work and documenting the record-breaking attempt.


Kathy Dowsett

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Friday, September 2, 2011

All About Going Pro (Scuba that is!!)

Self modified from via Wikipedia

Going Pro, The Prequel

Welcome fellow Scuba enthusiasts! My name is Luis Sidonio, and in 3 weeks time,( as of July 2011) I will be embarking on a 3-month adventure of a lifetime. I am about to do a Divemaster Internship in the Caribbean and become a PADI Pro. Over the new few months my blog will be a communication tool, to tell you guys exactly what it is like continue reading here and keep up on Luis adventure

Thanks to Luis for keeping us updated!!!

Kathy Dowsett

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Thursday, September 1, 2011

Divers find Northwest Passage discovery artifacts

Critical position of HMS Investigator on the n...Image via Wikipedia

A musket and other artifacts from HMS Investigator, the ship abandoned in the Canadian Arctic in 1854 during the hunt for Sir John Franklin’s lost expedition, have been recovered by divers. The ship is credited with discovering the Northwest Passage.

Shoes, a musket, a copper sheet, and parts of the ship’s rigging were among the items brought up over nine days this July from the wreck discovered last summer in Mercy Bay, off Banks Island in the Northwest Territories. Divers were lucky enough to find the usually ice-covered bay largely open water during the expedition.

Marc-AndrĂ© Bernier, the Parks Canada scientist who led the expedition, said that “to dive on that shipwreck that is literally frozen in time... with artifacts on the deck” was the highlight of his career of more than 20 years.

Archeologists photographed and mapped the ship using sonar and video to determine its state of preservation.

"Although the hull is basically survived up to the main deck, the main deck is a litter of timbers,” Bernier said at a news conference.

The ship continues to be damaged by ice, he said, but there was a lot of sediment within the interior of the ship.

“This is basically the best conditions to preserve artifacts,” he added.

The buried artifacts were left untouched, but about 16 lying outside and on the deck were recovered because they were exposed, and researchers feared they could become damaged before an expedition could return to the site.

Bernier said the most exciting was the copper sheeting, which protected the ship's hull from marine organisms. That's because the copper can be chemically tested and compared to copper found at other sites to figure out whether those pieces originally came from HMS Investigator, or compared to the copper on other ships.

He added that some of the items, such as the shoes, are of interest because they appear to include waterproofing or other modifications for use in the Arctic.

Researchers also conducted land surveys as part of the expedition, collecting an inscribed wooden barrel top, an arrow and a tin can near a cache linked to Robert McClure, the captain of HMS Investigator.

They identified four new archeological sites, including a small aboriginal camp and rock cairn.

At one point, the researchers responded to a search and rescue call that brought them near a previously known archeological site believed to have been used as an observatory by Franklin's crew between 1846 to 1848. There, they checked up on the site and collected artifacts that included bottle glass, copper nails, twine or rope, tent canvas, and pieces of tobacco smoking pipes.

However, as previously announced, they did not manage to locate HMS Erebus and HMS Terror, Franklin's long-lost ships, in the third year of a three-year hunt for them.

Environment Minister Peter Kent gave his assurances that government-funded expeditions will continue to visit the Arctic each summer to continue the search and map the Arctic waters that are becoming increasingly ice-free and navigable.

"Certainly, I can assure you that this will be an ongoing project," he said.

Kent noted that while HMS Investigator was trapped in a bay, where it stayed put, HMS Erebus and HMS Terror may have drifted very long distances to two very different sites, based on Inuit oral history indicating their locations.

Bernier said the area that needs to be searched is enormous, but that large swaths are ruled out each year.

"“We are getting closer because we have covered more territory,” he said.

HMS Erebus and HMS Terror are considered by Parks Canada to be National Historic Sites, Bernier added.

"They are the only National Historic Sites for which we don’t know the location," he said, adding that the department has the mandate and the responsibility to find them.

Thanks to MSN News

Kathy Dowsett
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