Extent and Speed of Lionfish Spread Unprecedented

Invasive Marine Fish May Stress Reefs

The rapid spread of lionfish along the U.S. eastern seaboard, Gulf of Mexico and Caribbean is the first documented case of a non-native marine fish establishing a self-sustaining population in the region, according to recent U.S. Geological Survey (USGS) studies."Nothing like this has been seen before in these waters," said Dr. Pam Schofield, a biologist with the USGS Southeast Ecological Science Center in Gainesville, Fla. "We've observed sightings of numerous non-native species, but the extent and speed with which lionfish have spread has been unprecedented; lionfish pretty much blanketed the Caribbean in three short years."More than 30 species of non-native marine fishes have been sighted off the coast of Florida alone, but until now none of these have demonstrated the ability to survive, reproduce, and spread successfully. Although lionfish originally came from the Indo-West Pacific Ocean, there are now self-sustaining populations spreading along the western Atlantic coast of the U.S. and throughout the Caribbean.It is not yet clear exactly how the new invasive species will affect reefs in this part of the world. Foremost on the minds of scientists is the lionfish's predatory behavior, which may negatively impact native species in the newly invaded ecosystems. They have already been observed preying on and competing with a wide range of native species.Invasive lionfish were first reported off Florida's Atlantic coast in the mid-1980s, but did not become numerous in the region until 2000. Since then, the lionfish population has spread rapidly north through the Atlantic Ocean and south throughout most of the Caribbean. The spreading population is now working its way around the Gulf of Mexico.Schofield spent years compiling and verifying sightings of lionfish, reaching out to local experts such as biologists, museum curators, natural resource managers, divemasters and citizens groups to collect detailed records of specimen collections and sightings throughout the region. The records were compiled in the USGS Nonindigenous Aquatic Species database and used to map the fish's spread.

No one knows for sure exactly how the predecessors of the current population first made it into the Atlantic and Caribbean, but Schofield believes the invasion serves as a warning of the dangers posed by introductions of non-native fishes into an ecosystem."This invasion may constitute a harbinger of the emerging threat of non-native marine fishes to coastal systems," Schofield said.In the Florida Keys, Schofield and her team are working closely with partners from the National Oceanographic and Atmospheric Administration (NOAA) in Beaufort, N.C., and Reef Environmental Education Foundation (REEF) in Key Largo, Fla., to analyze lionfish diets, an important first step in understanding their impact on reef ecosystems. Eradication of lionfish is probably not possible, admits Schofield. Yet, local control efforts may be able to keep the population tamped down, releasing pressure on the native ecosystem. Many Caribbean countries, such as Bermuda and the Cayman Islands, have begun lionfish control programs. In the U.S., REEF held a series of lionfish derbies in the Florida Keys that resulted in the removal of more than 600 lionfish from the Florida Keys National Marine Sanctuary.For More InformationRead Schofield's most recent paper, "Update on geographic spread of invasive lionfish in the Western North Atlantic Ocean, Caribbean Sea and Gulf of Mexico," was published in the Dec. 2010 issue of Aquatic Invasions; it updates a 2009 article published in the same journal.

USGS Lionfish FactsheetNOAA's Lionfish WebsiteREEF's Lionfish Research Programs Contact Pam Schofield of the USGS - See more at: http://www.alertdiver.com/Lionfish_Spread_Unprecedented#sthash.OfeTsROx.dpuf

Nautilus Explorer Seeks Relief Engineer

 

 More Nautilus Explorer news
 More DNW Works JOBS news

Florida Dive Center Seeks Full-Time Manager

 

Job Title:
Dive Shop Manager

Summary: Looking for an experienced scuba diver who would like to help run a local growing dive center.

Job Duration
Full Time

Location
Sarasota Florida USA

Company Description: PADI 5 STAR Instructor Development Center (IDC) and SCUBAPRO Platinum Dealer. We are an active dive center with a full retail showroom, equipment service, recreational, technical and instructor level training and dive travel.

Job Description
Looking for an experienced scuba diver who would like to help run a local growing dive center. Duties include inventory, daily upkeep, sales, marketing and scheduling. The position relies heavily on technology so experience with Office is required. This is a 40 hour a week position with some overtime during busy seasons. We are looking for somebody that is very self motivated and can help us make our great customer service even better. If interested, please send a resume and include your scuba diving history as well (current certifications, number of dives, places you have been diving, etc). We look forward to hearing from you.

Qualifications
Certified diver, Retail Experience. Marketing, inventory control, scheduling would be a plus

Salary Range
$12/hour plus commission

How to Apply
Send resume and contact information to This email address is being protected from spambots. You need JavaScript enabled to view it." target=_blank>This email address is being protected from spambots. You need JavaScript enabled to view it.

 More news
 More DNW Works JOBS news

Go Easy on the Ears

By Marty McCafferty

A seemingly mild injury can lead to serious symptoms.

The diver was a 36-year-old female who had done four dives in the two months since her certification. She was physically fit and in good general health but reported having had intermittent difficulty equalizing during her certification dives.

The Dives

On a Saturday in June, the diver did a series of three dives to a maximum depth of 64 feet in a freshwater quarry. Her bottom times were within her computer's no-decompression limits, and she had a minimum surface interval time of an hour between each dive. Her last dive of the day was to 45 feet for 45 minutes. She reported trouble equalizing during her first descent and increasing difficulty on subsequent descents. She did not complain of pain or any other significant symptoms, but she did report a feeling of "fullness" in her left ear. She didn't dive for the next two days, and the sensation of fullness decreased but did not resolve completely.

After the two days the diver believed she would be able to equalize effectively despite the fullness, and she decided to dive again at the same location. Unfortunately, this time she found equalization difficult and uncomfortable as she descended. The discomfort persisted to her maximum depth of 55 feet. She continued to dive for about 20 minutes, but when she could no longer tolerate the discomfort she signaled her buddy, and they initiated their ascent. At approximately - 20 feet, the discomfort had intensified to the point of pain. This distracting pain, combined with the diver's inexperience, caused her failure to vent her BCD, and she made an uncontrolled ascent to the surface, during which the pain increased dramatically.

She had not done a safety stop, so she and her buddy attempted to descend to 15 feet to perform the missed stop. As they descended she was unable to equalize, and she made a forceful attempt at approximately 10 feet. She reported feeling and hearing a "pop," and the pain in her ears became very sharp. The diver aborted the descent and managed to return safely to the surface, but she required assistance getting back to shore. Once ashore she was observed staggering and unable to walk without aid. She also became very nauseated and vomited several times. She found she could not tolerate lying flat or any movement of her head, both of which provoked nausea and vomiting. The diver's buddy called emergency medical services (EMS), which arrived soon afterward and transported her to the local hospital.

The DiagnosisUpon examining the diver, the doctor observed nystagmus (rapid involuntary eye movements) in addition to the acute nausea and vertigo she reported. Additionally, the diver complained of diminished hearing and a continued sensation of fullness in the left ear. Examination of the ears revealed slight redness of the right tympanic membrane (ear drum) with no other abnormalities. The left tympanic membrane, however, was markedly red and bulging, and an accumulation of fluid and blood was observed behind the membrane. These signs indicated an injury to the middle ear, but the diver's symptoms indicated something more serious. The evaluating physician contacted DAN® for consultation.

Based on the diver's difficulty equalizing, her relatively conservative dive profiles and her forceful equalization attempt, some type of ear barotrauma was the most likely explanation of her symptoms. The severity of the symptoms seemed to indicate inner-ear barotrauma in addition to that of the middle ear. Inner-ear barotrauma means a perforation of either the round or oval window, the two membranes of the inner ear. This injury is usually treated with bed rest with the head elevated, avoidance of lifting or straining, stool softeners (to further minimize straining) and medication to relieve the nausea. The purpose of these therapies is to give the perforated membrane a chance to heal, and most individuals recover without complications or other interventions, as this diver did.

Discussion Middle-ear barotrauma is the most common injury resulting from diving. It is a consequence of inadequate pressure equilibration between the middle ear and the ambient pressure of the external environment. During descent the Eustachian tube, which is normally closed, may fail to open if the diver does not make effective attempts to equalize or if congestion is present. Failure of the Eustachian tube to open can create negative pressure within the middle ear, which further closes the Eustachian tube and may draw fluid and blood from the surrounding soft tissues into the middle ear space. All of these factors can make subsequent efforts to equalize more difficult. Symptoms of middle-ear barotrauma include sensations of fluid or fullness in the ears, muffled hearing, mild tinnitus, dizziness and mild to moderate vertigo.

Early in our dive training we are taught we should never dive with congestion, a head cold or allergy symptoms, as these can interfere with equalization. Unresolved symptoms of middle-ear barotrauma — even mild ones — should also be considered reasons to suspend diving. The fluid, inflammation and closed Eustachian tubes will complicate equalization and place divers at increased risk for more serious injuries such as inner-ear barotrauma. Sudden pressure changes due to rapid ascents, rapid descents or forceful equalizations further elevate this risk.

Remember, if you encounter any equalization difficulty, stop descending, ascend a few feet and attempt to equalize again. If you cannot equalize, do not make a forceful attempt; abort the dive instead. Neither middle- nor inner-ear injuries are inherently life threatening, but nausea, vomiting and especially vertigo while submerged can place a diver at great risk and may even be fatal. Don't be complacent when it comes to equalization, and don't ignore ear discomfort while diving. Despite expenses paid or plans made, our hearing and lives are much more valuable. By discontinuing diving as soon as symptoms appear and staying out of the water until they resolve completely, divers can avoid increasingly serious injuries and prolonged recovery times.

Want To Know More?

Check out the "Diver's Complete Guide to the Ear" on www.DAN.org.© Alert Diver — Fall 2011 - See more at: http://www.alertdiver.com/Go_Easy_on_the_Ears#sthash.wEMsWneZ.dpuf

Nature at it's Awesomest (is that a word?)