Posts Tagged ‘Research’

Oct 5, 2012

Stingray Census, Grand Cayman, July 2012

The annual census of the stingray population in Grand Cayman was conducted the week of July 10 – 13, 2012. The research work was done by personnel from the Guy Harvey Research Institute in collaboration with the Cayman Island Dept. of Environment. The difference this year was that three veterinarians from the Georgia Aquarium visited to assist with analyzing the health of the stingrays.

The situation at the Sandbar in North Sound is unique, with a large number of rays, which are wild animals that are not fenced or contained but inhabit the shallow clear water with accessibility every day of the year. The socio-economic value of the rays to the Cayman economy is enormous. Rays are slow growing long lived animals, a close relative of sharks. Each animal may generate USD 500,000 in revenue per year therefore in its life time assuming they live more than 20 years, may generate USD 10,000,000 in a lifetime.

From a historical perspective, it is worth setting out the track record of research work conducted on the population of stingrays in Grand Cayman. Research was started by the GHRI in 2002 when all the stingrays that frequent the two main sites were caught by hand and tagged with a PIT (passive integrated transponder) at the base of the tail where it meets the disk on the left side of the animal. Tag retention remained at 100%, so many animals tagged ten years ago still have their PIT today. This has been a very simple and valuable tool to track the life history and growth rates of these animals.

For the period 2002-2003, one hundred rays were sampled each month over a three day period at the Sandbar. One hundred sixty-four rays were tagged, weighed and measured at the Sandbar over two years. There was never any difficulty in catching a hundred animals. The same situation was experienced in a subsequent census conducted by GHRI in 2005 and in 2008. There was recruitment of new (untagged) rays to the Sandbar and loss of individuals due to migration, natural mortality and possibly some predation. The sex ratio of 90% females to 10% males has remained historically skewed in favor of the larger females.

From 2010, tour operators and casual observations indicated a sudden decline in the number of rays at the Sandbar. The GHRI conducted a census in January 2012 and sampled only 61 rays in the standard three day research period at the Sandbar which represents a significant (38%) decrease in number of rays compared to the last census in 2008. Now that we had some facts, the next step was to find out why? What was causing the decrease in numbers? How would this affect the tourism value of the interactive programme? What action would the Dept. of Environment and therefore the CI Government take to learn more about this potential problem?

The numbers of rays have been constant since research was started in 2002 with recruitment and mortality being well balanced. GHRI personnel ruled out predation by sharks in the January census due to lack of evidence of shark bites (near misses) and the corresponding demise of sharks in the last ten years. However, some tour operators have reported seeing rays injured by sharks from time to time but no more than normal. Fishing mortality (intentionally or by accident) is a consideration. I say this because outside of the Wildlife Interactive Zones (WIZ) this species has no protection and can be removed and consumed by residents. There is no national protection for stingrays.

The health of the rays was another consideration, which is why the GHRI enlisted the support of the Georgia Aquarium veterinary staff. The research work was now becoming much more technical. Dr. Tonya Clauss (Director Animal Health, Georgia Aquarium), Dr. Lisa Hoopes (Nutritionist, Georgia Aquarium) and Nicole Boucha (Senior Veterinary Technician, Georgia Aquarium) all arrived here loaded with equipment to take blood and store these precious samples in liquid nitrogen until analysis could be achieved back in Georgia.

Over three days, the team sampled 57 rays (only 5 males) at the Sandbar (down from 61 in January) with assistance from DoE staff and several volunteers. The team spent a day at the original Stingray City and sampled 11 rays (2 males) and caught 3 rays (1 male) at Rum Point bringing the total to 71 rays sampled. The low number of males generally is cause for concern.

Each ray was caught by hand and transferred to the pool in the work boat where they were measured, tagged and then blood was taken from the underside of the base of the tail. Some of this blood was immediately centrifuged to make counts of white blood cells. The rest was frozen in liquid nitrogen for shipment back to the lab in the Georgia Aquarium.

From the blood samples the vets will be able to determine if the (monotonous) diet of squid fed the rays by the majority of tour operators is affecting the animal’s health. The processing of samples and data will take several weeks. At the end of this process we will have more knowledge about these valuable creatures and how better to manage their supplementary diet and well being.

Overall, a long term plan of monitoring the numbers of rays and their health is required. Everyone in the Cayman Islands benefits from the presence of this unique marine interactive site. Every advertising campaign or tourism related article featuring the Cayman Islands has these iconic animals up front and prominently displayed. It is time the CI Government returned the favor by supporting ongoing research of the stingrays’ population status and wellbeing by releasing funds in the Environmental Protection Fund collected for this purpose.

More updates to come.

Fish responsibly, dive safely.

Guy Harvey

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Mar 14, 2012

Neurotoxins in shark fins: A human health concern

This article was originally published by EurekAlert! global news service.

University of Miami study shows alarming accumulation of BMAA neurotoxins in shark fins; may pose a threat to shark fin consumers

MIAMI – Sharks are among the most threatened of marine species worldwide due to unsustainable overfishing. Sharks are primarily killed for their fins alone, to fuel the growing demand for shark fin soup, which is an Asia delicacy. A new study by University of Miami (UM) scientists in the journal Marine Drugs has discovered high concentrations of BMAA in shark fins, a neurotoxin linked to neurodegenerative diseases in humans including Alzheimer’s and Lou Gehrig Disease (ALS). The study suggests that consumption of shark fin soup and cartilage pills may pose a significant health risk for degenerative brain diseases.

“Shark fins are primarily derived through finning, a practice where by shark fins are removed at sea and the rest of the mutilated animal is thrown back in the water to die,” said co-author Dr. Neil Hammerschlag, research assistant professor of Marine Affairs & Policy and director of the RJ Dunlap Marine Conservation Program (RJD) at UM. “Estimates suggest that fins from as many as 70 million sharks end up in soup. As a result, many shark species are on the road to extinction. Because sharks play important roles in maintaining balance in the oceans, not only is shark fin soup injurious to the marine environment, but our study suggests that it is likely harmful to the people who are consuming them.”

Seven species of shark were tested for this study: blacknose, blacktip, bonnethead, bull, great hammerhead, lemon, and nurse sharks. Samples were collected from live animals in waters throughout South Florida.

“The concentrations of BMAA in the samples are a cause for concern, not only in shark fin soup, but also in dietary supplements and other forms ingested by humans, ” says study co-author Prof. Deborah Mash, Director of the University of Miami Brain Endowment Bank. The Bank supports basic and clinical research and holds one of the world’s largest collection of postmortem human brains encompassing a wide range of neurological disorders. In 2009, Prof. Mash and her co-authors published a study in the journal Acta Neurological Scandinavica, demonstrating that patients dying with diagnoses of Alzheimer’s Disease and ALS had unusually high levels of BMAA in their brains up to 256 ng/mg, whereas normal healthy aged people had no BMAA, or only trace quantities of the toxin present. “BMAA was first linked to neurodegenerative diseases in Guam, which resulted in the progressive loss of structure and function of neurons.”

The shark study found a similar range and even higher BMAA in the fins tested. The new study found levels of between 144 and 1836 ng/mg of BMAA, which overlapped the levels we measured in the brains of Alzheimer’s and ALS victims. Surprisingly, this level fits with the BMAA levels in fruit bats examined by Paul Cox, animals which concentrate BMAA from their diet of cycad seeds. He linked ingestion of fruit bats to the severe ALS/Parkinsonism dementia that afflicted many people in Guam.

“Not only does this work provide important information on one probable route of human exposure to BMAA, it may lead to a lowering of the demand for shark fin soup and consumption of shark products, which will aid ocean conservation efforts,” added Hammerschlag.

Guy Harvey & tiger shark – Bahamas. Photo courtesy of Neil Hammerschlag.

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Feb 2, 2012

San Juan IGFA Great Marlin Race: All Tags Report and a Record is Broken






FOR IMMEDIATE RELEASE February 1, 2012 Contact: Jason Schratwieser, Conservation Director 954-924-4320

The blue marlin from the IGFA Great Marlin Race traveled 4,776 nautical miles in 120 days

During the inaugural IGFA Great Marlin Race (IGMR) six satellite tags were deployed at the Club Nautico de San Juan’s 58th Annual International Billfish Tournament (IBT) that was held in San Juan, Puerto Rico on September 5-11, 2011. Since that time anglers have waited patiently to see when and where the tags would pop up and start reporting information.

The first tag to pop up and report was from a fish caught by Norman Pichardo on IGFA Trustee Pepe Anton’s boat Amirita. Pichardo’s tag popped up October 23, 2011, 419 nautical miles (nm) from where it was tagged near the island of Aruba. Although the tag popped up early, this fish demonstrated an important lesson in the importance of proper revival techniques. Pichardo’s marlin had become tail-wrapped during the fight and was reeled in tail first. Because marlin must continually swim in a forward direction to properly have water flow over their gills so that they can breathe, the fish came up browned-out and in bad shape. First mate David Hernandez and IGFA Conservation Director Jason Schratwieser spent close to 10 minutes reviving the fish by holding on to it as the boat slowly idled forward to get water flowing over its gills. In time the fish’s color came back and it began to beat its tail, after which the fish was quickly tagged and swam off on its own, recording data with its satellite tag as it went.

The next four tags popped up over the course of the next month. Tag number two belonged to a 150 lb blue marlin caught by Charles Donato on the Islamar and popped up on November 20th, 178 nm southeast of where it was caught. December 7th saw two more tags report. Father and son team Antonio and Jaime Fullana landed a blue marlin on September 8th aboard the Bolita. When the tag popped up and reported, the Fullana’s fish had traveled east 589 nm from where it was tagged, putting them solidly in first place. The day after Fullana’s fish was tagged, lady angler Mariana Fuster hooked and landed a blue, which she dubbed “Vic,” on the Lucky Dog that was tagged by Jorge Rivera. Vic traveled 497 nm from where it was tagged which, at the time, placed Mariana in second place for the race. Rounding out 2011 on December 20th, the tag placed by Gerald Torres in the 80 lb marlin caught by Moises Torrent aboard the Batichica popped up 206 nm from its point of deployment – a fourth place finish at the time.

After Torrent’s tag reported, things were quiet and 2011 came to a close. At this point the only tag that had yet to report belonged to a sizeable 575 lb blue that was caught by Mike Benitez on the Sea Born and tagged by Eneau Agusta on September 7, 2011. Then it happened. On January 5, 2012 – exactly 120 days after it was deployed—Benitez’s fish’s tag popped off and began transmitting information. Dr. Randy Kochevar at Stanford University codirects the IGMR with IGFA and was stunned when he began reviewing the data. Benitez’s fish had traveled southeast some 4,776 nm from where it was tagged and crossed the equator to have its tag pop off near the coast of Angola, Africa.

“These are the kind of results we dreamed about when we first launched the Great Marlin Race program back in 2009,” said Kochevar. “This may be one of the longest, if not the longest, marlin tracks ever recorded on an electronic tag. To have a marlin swim from the Caribbean all the way across the Atlantic and across the Equator to Africa reminds us how remarkable these animals are and how much we still have to learn from them.”

Travelling more than eight times farther than any other fish, Benitez’s fish became the clear winner of the San Juan IBT race. Unfortunately, Mike Benitez never got to hear the news. A beloved captain in Puerto Rico and the first tournament recipient of the IGFA-Chester H. Wolfe Outstanding Sportsmanship Award, Mike passed away in Boston just two days before his tag reported; he was 79 years old.

Anglers worldwide can view all the results of the IGMR on the interactive map at  The next tournament in the IGMR will begin in February of 2012 in South Africa at the South African Deep Sea Angling Association Classic. For more details and sponsorship information, contact Jason Schratwieser at or 954-924-4320.

For further information, contact the IGFA Fishing Hall of Fame & Museum, 300 Gulf Stream Way, Dania Beach, Florida 33004; phone 954-927-2628, fax: 954-924-4299, website:


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Dec 21, 2011

Guy Harvey On— The Queen Angelfish

Every time I go for a dive in the Cayman Islands I am always on the lookout for the most beautiful of all Caribbean reef fishes, the queen angelfish. If followed too closely, they sneak into a hole and then turn to look at you, but never give you a good profile shot. However, I know that they feed a great deal on sponges, and occasionally you can be lucky and find a hawksbill turtle chowing down on a sponge at a reasonable depth giving you decent bottom time. The turtle is a sloppy eater and there are lots of loose pieces of sponge and scraps to be had, a perfect size for the angelfish’s small mouth. 

Queen angelfish are also present at cleaning stations, particularly the juveniles,and will clean parasites off larger predators like groupers and jacks. In the tropical eastern Pacific, a close relative, the king angelfish will be a major player at cleaning stations and along with the barberfish (a butterflyfish species) will cover scalloped hammerheads as they come close to the stations to be cleaned. In such exotic locations as Cocos Island and in the Galapagos, these angelfish form large schools and the sight of them cleaning a large shark is quite a spectacle.

Apart from sponges, the queen angels consume a wide variety of tiny invertebrates, soft corals and tunicates in their normal depth range from the shallows down to one hundred meters.  Their mouths are protractible and have fine, brush-like teeth. Typically, one finds them slowly browsing along the reef picking at minute bits of coral tissue, and invertebrates that are lurking in crevices.

This species is found throughout the Caribbean and Gulf of Mexico, to Bermuda, so may be considered sub tropical and tropical. By no means the largest of the angelfish species, they grow to a maximum of forty centimeters, and weigh just a couple of pounds. Because of its vivid blue and yellow colour, gorgeous face markings and unique shape, it is widely used to advertise dive shops and exotic dive destinations in numerous publications. Easily identifiable from a distance because of their flattened rhomboid shape and brilliant colours, the queen angelfish is truly the queen of the reef and a great subject for an underwater painting.

It is likely the angelfish has a protracted spawning season as pairs can stay together over many months. Other similar, but larger species, such as the gray angel and French angel, may pair for life. Following spawning, as with most tropical species, eggs hatch within twenty four hours and the larvae are planktonic, feeding and growing rapidly and then settling on a new coral reef habitat as juveniles. They are protective of their patch of reef and often engage in cleaning other fish and rays. The colouration of juvenile is different from the adult, but just as spectacular and combined in the same image make a wonderful work of art.

Queen angelfish are long lived and may be encountered in the same reef for many years. They are common but not abundant having few predators. Only man has exploited them to any great extent. For defense, they rely on their ability to fit into crevices in the coral to evade predators. Also, they have two very large backward facing spines on their pre-operculum, which they use to good effect with violent head shakes when held. In some Caribbean islands, they are harvested in fish traps or by spear fishing for food. In other locations, they are taken mostly as live animals for use in the aquarium trade but are not yet considered over exploited anywhere in their range.

So the next time you encounter a queen angel browsing along the reef, try to get the best shot ever of this magnificent creature while you wonder why it evolved with such striking markings and coloration.

It is our collective responsibility to conserve all marine creatures and maintain the biodiversity of this planet. Safe diving!

Guy Harvey 

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Nov 16, 2011

We Still Need MORE Tagging

I recently found an old story I wrote while looking up some information about tagging and its benefits. When “Migratory Movements, Depth Preferences, and Thermal Biology of Atlantic Bluefin Tuna” was published in the 17 August 2001 issue of Science there were some great stories to tell. Stories that had to be kept as secrets until the paper was published in Science.

The data presented, and conclusions drawn from them by a team headed by Dr. Barbara Block from Stanford University (and including scientists, anglers and crew making up a who’s who of tuna angling , research and management) created shocks waves across the Atlantic.

National Public Radio, National Geographic News as well local, regional and national newspapers, had already discussed the ramifications of having tuna tagged off Hatteras, cross the Atlantic Ocean, and even enter the Mediterranean Sea in larger numbers than any previous estimates could imagine. This threw a monkey wrench into all management plans and conservation attempts, based on earlier theories, that eastern and western populations of bluefin tuna were separate and need to be managed separately.

Giant Atlantic Bluefin Tuna, each weighing over a quarter-ton — Photo by Guy Harvey

Two types of tags were used in the study, surgically applied internal “archival” tags and pop-up satellite archival tags (PSAT tags in the article’s jargon). Both showed that fish from the west cross over into the eastern Atlantic. These tags, plus captured fish with conventional spaghetti tags, raised the thorny issue of North American fishermen (commercial and recreational) accepting low catch quotas in order to allow the overfished tuna populations to recover, only to have the fish massacred in huge numbers in the Mediterranean and eastern Atlantic. (East of longitude 45 degrees West twenty metric tonnes of bluefin tuna were being caught for every tonne caught in the west!)

The Science paper is fascinating but takes some serious reading! It is not something you can glance at and retain. Some highlights, with some input from me from information gleaned during the tagging process, include:

There were 377 electronic tags in this study. Electronic tags were recovered from a few days to 3.6 years later, AND the TAG program continues to produce amazing results. Internal archival tags totaled 279 with 49 tuna being recaptured. This 18% return rate is extremely high and by itself suggests overfishing.

The 90% data acquisition rate from pop-up tags is a marvel of both technology and tuna survival rates. The return rate is higher since the fish does not have to be recaptured and the data is downloaded through the Argos satellite system. Although, the percentage of recovery is higher less information per tag can be retrieved, because of the high energy needed to send a radio signal, not just burn data onto a chip.

There were 7065 conventional spaghetti tags applied by Carolina tuna fishermen between the years 1994 and 2000. There were 292 recoveries (4.1%). This is a high rate in itself and valuable information was added, but it is obvious that trained scientific teams with top anglers and crews are more successful than the general public in properly applying tags. (One reason for non-return is probably mortality where a dead fish sinks or is eaten by sharks and the tag cannot be recovered.)

Some tags could record depth (through pressure) and location (by measuring the levels of light). Sunrise and sunset were the “most significant light events” and with an accurate electronic clock allow extremely precise east/west location and reasonable north/south estimates. It became apparent that Western tuna breed later in their lives than originally thought- another huge consideration in conservation and management.

Deep dives to over 500 fathoms (1000 meters) sometimes resulted in lowered internal body temperatures that experiments at the tuna lab showed to probably be the result of feeding on cold squid or fish living at those depths (Block fed captive yellowfins cold bait and measured cold internal temperatures.)

My question is “HOW DO THEY KNOW?” You can dive half a mile in most parts of the ocean and NOT find a meal!

In the field, the emotional highs and lows were enormous! The successful signal reception of the first pop-up tag started a major round of toasts and celebrations. Shortly after, on a rough and stormy night when the second pop-up tag failed to report in on its scheduled time, long faces abounded- until the weather eased and in calm water the tag sang like a bird to the overhead satellite. This alone allowed an adjustment, low tech but important, in additional buoyancy for subsequent tags.

Dr. Block was reduced to tears on the flying bridge one rough day when a large sea lifted the boat and one rudder hit and killed a tuna we were trying to tag. “I’m trying to save them- not kill them!” she sobbed.

The cooperation of anglers and crews, and their donations of time and money were an extremely important factor in the amazing success of this study and along with dozens of scientists and technicians all involved are to be highly congratulated! For more information get a copy of Science (17 August 2001). .

Recently, Paxson Offield was initiated into the IGFA Hall of Fame and a high light of his career and work in conservation was an ongoing program of PSAT tags in marlin. Currently, the internationally noted artist Dr. Guy Harvey is also a leader in not only tagging but other conservation initiatives.

We need people like Dr. Block, Dr. Harvey and Mr. Offield to help conserve our precious stocks of “Marine Megafauna”. AND we all need to do our part to help out.

See my next column in Marlin Magazine for a story of a Sportfishing CLUB gone BAD and becoming a detrimental group of swordfish killing amateur professionals.

Peter B Wright

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Oct 26, 2011

How fast can fish swim?

I seriously question the speeds often given for any fish, especially when Wikipedia and some reputable some encyclopedias claim that sailfish are supposed to be the fastest fish and can hit 60 miles per hour.

I once went to several references and online sites looking for Orca speeds. I found a range of speeds from 25 to 35 miles per hour (from here on shortened to mph) on the publications and web sites. None were anywhere near as fast as some the speeds some fish can supposedly attain.

Since Orcas can run down, catch, and eat, blue fin tuna, I question all the old, unsubstantiated fish speeds. I believe the speed of most fish is highly exaggerated by anglers, especially fishing writers. How excited can a reader get when reading about a bonefish tearing line off a reel at 15 mph, which is slower than many humans can run? In my youth, I could run down a beach in shallow water fast enough to avoid losing line to even a big bone.

Billfish, like this jumping Blue Marlin, are considered to be some of the fastest swimming fish in the sea. Photo by Richard Gibson

As a long time big game fishing guide, part time and ex Biological Oceanographer with decades of personal experience, ( called anecdotal evidence by scientists) I am positive no marine fish can exceed about 25 mph. I often chase large marine fish (tuna and marlin) with a boat and quickly catch them at 20 mph.

In addition, if a fish jumped straight up at 60 mph (88 ft/sec), simple math shows that after one sec the force of gravity (32ft/sec/sec) would have slowed the fish to 38 mph (88ft/sec -32ft/sec = 56ft sec which is 38 mph) The height of the fish at the end of that one second would be 72 ft and it would still going up at 38 mph. Height equals AVERAGE velocity times one second. Average V would be 88 + 56 divided by 2 giving a height of 72 feet.

Last but not least, there is the study AFTCO did decades ago which showed how much frictional drag there was on given lengths of line being pulled through the water. If any fish could go even 30 mph, they would break off before any crew could clear the lines and merely backing up would not make enough difference to avoid breaking the line.

Big fish eat little fish and the biggest predatory fish are the fastest. I doubt very much any fish can go 30 mph — it is too easy for Orcas to catch them for fish to obtain that kind of speed and no one says Orcas can hit 60!

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Sep 16, 2011

GHOF Funding Sawfish Studies in Florida Bay, Florida Keys, the Tortugas and Indian River Lagoon

The sale of Guy Harvey Sportswear supports the marine resource in many different ways with its sale of each Guy Harvey product, a contribution is made to the GHOF

In October 2010, the Guy Harvey Ocean Foundation and Hell’s Bay Boatworks donated a custom boat and trailer valued at more than $50,000 to the Florida Program for Shark Research. FPSR director and world-renowned shark expert Dr. George Burgess recently filed this report detailing the ongoing sawfish studies he is conducting in the waters around south Florida:

During the spring sampling season, three ongoing projects of the Florida Program for Shark Research at UF’s Florida Museum of Natural History, one in collaboration with researchers from Florida State University (FSU), focused on the distribution and movements of adult and subadult sawfishes in the southern portion of its Florida range.

We produced a survey of the waters surrounding U.S. Navy properties in the Key West region in order to determine the current status of sawfishes in those areas for the U.S. Navy/U.S. Army Corps of Engineers.  Because of obvious security constraints, we were the first fish biologists to sample in these waters in decades.

Concurrently, in conjunction with Dean Grubbs and fellow FSU scientists and the John Carlson of the National Marine Fisheries Service, we sampled the middle and lower Keys and Tortugas region and Florida Bay, catching and satellite tagging eleven sawfishes.  Satellite tags give long time and distance of movement information and we hope our tagging will help us better understand seasonal horizontal (up and down the coast) and vertical (depth) movements of the critters.

We also caught and multiple tagged two large adults in Florida Bay, the tags being traditional “spaghetti,” satellite, and active acoustic models.  The last allowed us to manually track the minute to minute movements using a receiver held under the boat.  Our first saw was “lost” within the first hour or so as it gave us the slip by scooting over a shallow bank, then boogying before we could detect its signal.  Having learned our lesson, on our second capture we got in 38 hours of tracking over three days, including day-night comparisons.  The sawfish moved about in deeper channels by day, then moved onto shallow, seagrass beds by night.  It chose the same shallow grassy area on successive nights, demonstrating some short-term site fidelity.  Next spring we plan to initiate placement of underwater listening stations on the bottom and tag the sawfishes with passive acoustic tags.  These tags will leave a unique “bleep” on any receiver as the sawfish swims near, allowing us to track localized movements over longer periods and larger areas.  We also will continue to satellite tag these and other sawfishes.

While sampling for sawfishes we also caught many sharks and rays.  All of these animals also were measured, sexed, sampled (tissue for DNA) and tagged as part of ongoing studies of their biology and movement patterns.  We also continued our work in Indian River Lagoon (IRL), where we began tagging young bull sharks with spaghetti and passive acoustic tags in a “new” region for us, the St. Lucie River estuary.  This work is being done with our colleague, David Snyder, of Continental Shelf Associates.  We also continue to download data from our underwater array of receivers in Mosquito Lagoon, Banana River and the northern IRL, where tagged bull sharks and rays still roam.

During this time period we put 5000 miles in land travel on the Guy Harvey adorned Hell’s Bay and God only knows how many sea miles on our faithful vessel!

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May 24, 2011

Dr. Guy Harvey PSAT Tags a Blue Marlin Underwater

A fully-clothed and SCUBA-equipped Dr. Guy Harvey dives down 40 feet to PSAT tag a blue marlin

Dr. Guy Harvey recently placed a Pop-Up Satellite Archival Tag (PSAT) in a blue marlin by diving in the water with scuba gear, and placing the PSAT in the hooked fish as it swam 50 feet underwater.  This was an impromptu move by Guy in an effort to tag the fish before it could escape or be fatigued on the light tackle on which it was being fought.  When the fish was close to the boat, Guy quickly donned his scuba equipment and dove in fully clothed with tag stick and PSAT in hand!

This was similar to the episode back in January of 2005 in Panama, where Guy was able to dive in and attach a second leader to the swivel of the estimated 1200lb female black marlin being fought by Neil Patrick and me.  This allowed us to leader the fish quickly and place a PSAT in the huge black.  The photos and video of this monster marlin were later seen by millions on Discovery, National Geographic, You Tube and in every major saltwater magazine and website around the world. She was tracked by PSAT for 8 weeks as she traveled over 1200 miles in her journey out into the Pacific and back to the tagging location just south of Tropic Star Lodge in Pinas Bay, Panama

The estimated 175lb blue marlin in the photos below was hooked while fishing off the 12-Mile Bank in Grand Cayman back in April of 2011.  The fish bit a tuna chunk fished on 80lb leader with a light-wire size 7/0 circle hook.  Guy was afraid the leader would break or the hook would straighten if they tried to leader the fish in close for the shot with the PSAT.  Rather than risk losing the opportunity to place one of the valuable PSATs in the blue marlin, Guy thought the best tag placement could be made with the marlin still swimming on the leader.  This would also prevent the marlin from possibly sustaining an injury while being leadered alongside the boat.  The marlin was still very active, and was rapidly swimming 40 feet below the surface after being fought on 80lb tackle for 50 minutes by angler Alex Harvey.  Remarkably, Guy was able to swim far enough and fast enough to catch up with the still very-alive blue marlin, and perfectly place the PSAT in the dorsal area of the fish.

Dr. Guy Harvey inspects the PSAT before taking the plunge

Well known film maker George Schellenger was aboard with his underwater camera gear and took these phenomenal photos of Guy tagging the blue with the PSAT.  This may be the only time a hooked marlin has ever been PSAT tagged by a diver while still swimming on the line!

This is a classic example of Dr. Guy Harvey’s intense desire to do all he can to place these PSATs in billfish so that information can be gathered at a later date for the benefit of billfish research.  To date, Guy has placed 60 of the $4000 PSATs in pelagic gamefish, in cooperation with the Pfleger Institute of Environmental Research (PIER) in Oceanside, CA and other research institutions such as The Billfish Foundation, The Offield Center, Virginia Institute of Marine Science (VIMS) and others .Designed for use in learning more about the movements of pelagic gamefish in the world’s oceans, the PSAT’s sophisticated transmitter records data on depth, water temperature and location.  Following a programmed length of time, the tag pops to the surface and uploads the data to a satellite, and then down to the scientists at PIER.


May 6, 2011

Blue Marlin Fishing After Filming Grouper Documentary- Part I

Following the incredible Cayman Islands Squash tournament April 3 – 9, I got going on finishing the Grouper Moon documentary which I started in mid- February. By way of a recap, producer/cameraman George Schellenger and I spent 6 days in Little Cayman shooting the research work being done by the REEF personnel (please visit and volunteers along with staff from the Department of Environment, Cayman Island Government.

The timing was such that we experienced the dusk spawn of about 2500 Nassau groupers a few days after the full moon in February. We shot all the daytime census-taking and measuring of adults (using lasers mounted on underwater cameras) gathered for the spawn. We conducted many interviews with the different interest and user groups. It was a very comprehensive shoot.

So… on to Grand Cayman. In order to show all the marine conservation interests at work, I scheduled a four day shoot around Grand Cayman. I wanted to show what Grand Cayman has to offer on and under the water. We started out with an hour long helicopter tour with Jerome and Natalie of Cayman Helicopters, who run a superb heli-experience which can be customized, depending on what you want to see and achieve. That afternoon we dived the Kittiwake and were lucky as a huge school of horse-eye jacks enveloped the superstructure making an awesome scene in the 100 foot viz water.

Andi is hooked up

In addition, there were bar jacks, rainbow runner, squid, tons of juvenile squirrelfish, copper sweepers, blue tangs and other grazing reef fish taking advantage of the new growth of algae up and down the steel hull. An 80 pound goliath grouper has also adopted the wreck. George and I then went to the sandbar to get some stingray footage before heading out to Hammerhead Hill, one of my favorite north wall dives. We encountered groups of spotted eagle rays, a hawksbill turtle, six different species of groupers, and a big hogfish being cleaned by some mini wrasses. Just too cool! Enough for one day of action packed diving.

Day 2 and 3, we were aboard the “Hit ‘n’ Run”, a well maintained 40 foot Luhrs, owned and captained by Derrin Ebanks. I coerced, friend and restaurant owner, Andi Marcher (of “Ragazzi” and “Luca” fame) to come along with my son Alex to be anglers. In two days they each caught two fine blue marlin. The weather was just perfect…it never gets too calm for me, particularly when you are blue marlin fishing.

Day 2 started early. While we waited for the charter boat to arrive, we were amazed at the eagle rays, big sting rays, tarpon and bonefish that were rooting around in the sand by the dock. We left Morgan’s Harbour at the crack of 8 a.m. and trolled about a mile off the coast heading west toward the 12 mile bank all the time looking for frigate birds that would signal the presence of dolphin or marlin. We missed a couple of them, one was a cheap shot but the second was a ripper that had captain Derrin doing a dance on the flybridge.

Blue Marlin, just prior to release

I saw her come in fast from the right side as she crashed the short right lure, then came back around in a swirl for the bite with dorsal and bill out. The big marlin did not come tight and again came in on the same lure. The hair on the back of my neck was standing up when I saw the height of her dorsal fin. She ate this time, was hooked and started jumping straight away going off to the right and then (as a blue marlin can) turned around and headed off to the left like a jetski on steroids. Unfortunately, she crossed the left rigger line and that reel also started howling. Somehow…. the hook came out and after a series of fabulous grey-hounding jumps ….she said goodbye. Lots of great action but no results… and it was only 11 a.m.

We trolled down to 12 mile Bank, and worked the NE tip of this seamount before heading to the SW tip as the current was coming from the NW. This three mile long seamount comes up from 3,500 feet to 90 feet from the surface. You need to fish on that end when the current is coming from the west. A yellowfin tuna popped up chasing flying fish, then a couple more. Cool. This was the place to be. Where there are tuna frolicking, a marlin will be nearby. Sure enough, the right rigger went down, but no hook-up. The marlin blazed over to the left rigger and we were tight. Andi was the angler on 30# test which is ideal tackle for a marlin of 125#. After lots of jumps far away, Andi got the marlin to the boat and I deployed the PSAT(Pop-up Satellite Archival Tag) in the marlin’s left shoulder. I got my gear on and jumped in to film the release. Very good. It was carrying a 3-month PSAT, and headed into the blue. No more bites for the day as we trolled home in perfect weather. That evening, we had a couple of beers at the little restaurant on the Morgan’s Harbour dock. A perfect end to the day.

See our next week’s blog for Part II

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Apr 22, 2011

The Lovely Menace: Invasion of the Lionfish

The colorful and charismatic lionfish are proliferating on the coral reefs of Bermuda, Florida, the Bahamas, and the Caribbean. Although non-native to the Atlantic, it’s becoming hard to miss them in many areas.  That’s good, you might be thinking.  Divers spend a lot of money to travel to coral reefs in the Indo-Pacific where these fishes are native and provide visual delights for underwater photographers.  Whip out those cameras — an added attraction has shown up to add zing to the diving experience on Atlantic coral reefs, you say.

Unfortunately, like most invasive species scenarios – recall the ecological and economic mess created by the infamous zebra mussel – the lionfish introduction and rapid geographic spread is proving far from ecologically harmless to Atlantic coral reefs.  In fact, scientists are quite concerned that lionfish may be completely reinventing the western north Atlantic coral reef ecosystem – permanently!

What are these lionfish doing in the Atlantic in the first place and what’s going on?  Here’s some background: Lionfish belong to the scorpionfish family (which includes the venomous scorpionfish and stonefish).  Even if you don’t dive you’ve likely seen them as they are very popular in the aquarium trade.

Two species are now known to occur in the western Atlantic: the red lionfish (Pterois volitans) and the devil firefish (Pterois miles), with the former occurring in much greater numbers.  The two species are similar looking and it took DNA evidence to confirm that there are indeed two species that have invaded the Atlantic.  They’ve been around for a while, with the first observation in the Atlantic occurring near Fort Lauderdale, Florida in 1985!  Considered a rarity at first, lionfish populations have exploded over the past 25 years and especially over the past decade, spreading far north and south.  They now range at least from Bermuda to Venezuela.  It’s really worth tracking their remarkable and disconcertingly fast spread at:  If you dive in the Bahamas you’ll know that they are over running the reefs.

So what’s the worry?

Invasive Lionfish in the Bahamas. Photo: Courtesy of B. Watts

It’s an ecological nightmare.  In spite of a mountain of unknowns, researchers agree on a few key points: lionfish are voracious predators and prolific breeders.  They devour the young of other reef fish species, including several commercially important species, and even crustaceans such as newborn lobsters.

In addition to their own direct impact on reducing other fish populations by predation, lionfish are outcompeting native fishes for food.  Not a good scene for native fishes.  Lionfish can suck up about 80% of all small or immature fish in a section of reef in only five weeks.  Their predation on young herbivorous fish also means reduced control of algae, which can overgrow and kill coral.

How bad is it? There are enormous concerns that lionfish will completely change and possibly destroy Atlantic coral reefs by overrunning them and shrinking their native biodiversity, and that the ongoing damage is severe and possibly irreparable.  So far, there is no known quick-fix, and the problem is escalating exponentially.

Lionfish are the lions of the Atlantic reefs; they sit enthroned near the top of the food web where almost nothing eats them.  Scientists don’t fully understand why lionfish have no natural predators in the Atlantic. Observed cases of lionfish being eaten by other fish are so few that they can be counted on one hand. Would-be predators seem to shy away from the lionfish’s poisonous appearance – even when lionfish are in their larval stage. Possibly for this reason, invasive lionfish have encountered practically no natural opposition since their introduction, when the first individuals were probably dumped into the Atlantic as unwanted aquarium pets. Without effective population control, the lionfish – also called the red firefish – spread like, well, wildfire.

It’s easy to see why. Lionfish reach sexual maturity in only about one year. For the rest of their adult lives, female lionfish lay batches of 25,000-30,000 eggs almost twice a week (about every four days). Do the math, and you will quickly discover what this means. Each year, there are easily over two million eggs for each female lionfish. These eggs quickly develop into living vacuum cleaners. Each lionfish eats fish up to two-thirds of its own size, and lionfish stomachs stretch up to thirty times their normal size when feeding.

Ironically, studies are showing that lionfish are now present in higher densities in some Atlantic regions than they are in their native Indo-pacific habitats! Maybe the Atlantic environment is just making female and male lionfish more romantic. Or maybe it’s a lack of predator thing. Or maybe their Atlantic prey have fewer defenses?

So, what can be done? Many scientists think that the rapid pace of lionfish population growth and geographic spread means that nothing can completely stop the destruction by this invading beauty. But perhaps the momentum can be slowed if control measures are quickly and widely implemented.

Lionfish meat is excellent in taste and texture, and lionfish dishes have been added to the menus of many exclusive restaurants. In fact, the US federal government’s chief fisheries management agency, the National Oceanic and Atmospheric Administration (NOAA) has developed an “Eat Lionfish” campaign to increase the public’s awareness of the issue and create a consumer market for this tasty invader. Several coastal communities host fishing events called lionfish derbies where prizes go to the anglers who catch the most, and an enormous celebratory barbecue comes at the end of each derby. Many recreational anglers would attest that, after a long day of fishing, grilled lionfish with a cold beer is a hard treat to beat!

These triumphs, however, are small ones. Fishing alone cannot solve the lionfish problem. It will also take both education and dedication. As an increasingly prominent marine “poster child” against non-native species release, the lionfish example further proves that release can have unpredictable, unprecedented, and literally dire consequences. Please never release your exotic pets. A simple desire to let one animal “have a better life” in the wild can so easily create an irreparable ecosystem and economic mess.

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