Posts Tagged ‘Guy Harvey Research Institute’

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

For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com

 

Feb 10, 2012

Sailfish Mecca; Isla Mujeres Tagging Project

The sailfishing around Isla Mujeres attracts anglers from around the world

“Hold it, hold it….steady…OK… GO! GO! GO NOW!” Captain Anthony Mendillo gave us our marching orders and we dropped into the big blue swells of the western Caribbean swimming hard and looking up at the surface to check my position occasionally with the signature flock of frigate birds overhead. There they were….flashes of silver against the blue, large silhouettes moving rapidly, changing direction and in the middle of all these bodies, a large glinting shadow. Bait fish on the move. Sailfish and sardines…the ultimate open ocean diving experience and I was right in the middle of them shooting the amazing interaction of predator and prey.

The bait school was quickly consumed and the sailfish all went into cruise mode, dorsal fins tucked down, pastel colors and they looked like javelins, propelled by their large forked tails and headed off into the blue toward the main bait school invisible to me, but they knew where to go.

Back on the boat for a much needed rest and change of air tanks we, were elated and discussed the feeding behavior, the coloration changes of the sailfish and effectiveness of the feeding method by the group of sailfish. We rejoined the group of fifty or so sailfish and bait for more footage before going into catching mode.

The main goal of the expedition was to catch and tag twelve healthy sailfish and deploy Pop-up Archival Tags on these fish so researchers could get some information about where the sailfish go after leaving this area of the Yucatan. The Guy Harvey Research Institute was working with Dr. Molly Lutcavage of the Large Pelagics Research Centre http://tunalab.org/(University of Massachusetts Amherst). The GHRI purchased twelve mini-PATs for the study. Molly is best known for her research work on bluefin tuna in the northeast USA and Canada. The mission statement of the LPRC is to “work closely with fishermen using state of the art technology in conducting biological and ecological research on pelagic species including tunas, billfish sharks and sea turtles. LPRC endeavors to develop scientific understanding that supports effective ecosystem-based management strategies for these highly migratory Atlantic marine species.” Our ride for the expedition was the beautiful 48 foot Cabo “Chachalaca” owned by Lawrence Berry of Texas, and run by well-known local Captain Anthony Mendillo, who were very kind in supporting the GHRI/LPRC research efforts.

Isla Mujeres is a famous location for large numbers of sailfish attracting anglers from around the world from January to May each year. This is a catch and release fishery, circle hooks and dead bait are mandatory and anglers can expect 30 to 50 bites per day with many multiple hook ups. However no-one knows where the sailfish spend their time for the rest of the year. The attraction to the area is clearly the abundance of bait. The dominant species is the common sardine sardinella aurita, a round bodied fish attaining ten inches. Typically, these fish school near the bottom in 80 – 100 feet of water on the continental shelf. Just to the east of the shelf is the deep water and the strong north flowing current of the Gulf Stream.

For Mexico, the sailfish is a sustainable source of income for local business as anglers travel great distances, stay in hotels, eat in local restaurants, use taxis, shop and generally spend money. The socio-economic value of the living sailfish is very high throughout its range in the western north Atlantic. Current Mexican laws allow for one sailfish to be taken per day, but catch and release is the main appeal. Local fishermen target food species such as tuna, bonitos, mackerel and bottom fish rather than sailfish.

PSAT tag in the shoulder of a Sailfish

Over the years a great many conventional spaghetti tags have been placed in sailfish caught here by recreational anglers. The system depends on the tag card being returned to the tagging agency (here it is The Billfish Foundation, TBF) but it depends on the sailfish being recaptured and the tag cut out and sent back to TBF. The result is a straight line displacement that shows where it was tagged, where it was recaptured but cannot provide information about where the fish spent that time or how it used the habitat.

Using 20 pound test, trolled dead ballyhoo bait rigged with a 7/0 circle hook and chin weight, Anthony pulled two dredges (imitation bait schools as teasers) and we fished an area 6 to 12 miles north of the island looking for telltale vortices of frigate birds to show us where the concentrations of sailfish were located. When the sailfish were hooked, fought and brought to the boat, our mate Ruben Garrido grabbed the bill of the sailfish and flipped it into the boat onto a plastic covered foam mat. The fish eyes were covered with a wet cloth and the deck hose placed in its mouth. The sailfish was measured by Molly and assistant Eric Jacquard, the mini-PAT was placed carefully in the right shoulder and the fish was jetted back into the water in less than 50 seconds. We have much more control over the tag placement when the sailfish is in the boat as opposed to trying to tag the fish in the water. They move around a lot, are hard to control on a light leader, so correct placement of these expensive tags was a priority.

Now we wait for 6 months to hear from these tags. Each one costs about $4,000 so we are taking a gamble as anything can happen between release and the tag detaching from the sailfish and floating to the surface. No news is good news, as to hear from a tag early would mean the fish did not survive or was eaten by a predator. Large mako sharks frequent the area as well and have the gear and speed to take on a sailfish.

If you would like to have an awesome experience sailfishing, swimming with sailfish schools or with whale sharks then please visit http://www.islamujeressportfishing.com/ and stay in the Mendillo’s well appointed hotel, just walking distance from the dock http://playamedialuna.com/.

Fish responsibly, dive safely, have fun….the adventure continues.

— Guy Harvey

For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com

 

 

 

Jul 28, 2011

Cayman Island Creates New Artificial Reef with Sinking of the ex-USS Kittiwake

Guy and Alex on the deck of the Kittiwake, posing in front of the Flag of the Cayman Islands

The Cayman Islands’ newest artificial reef – the ex-USS Kittiwake – now rests 64ft. below the surface of Grand Cayman’s Seven Mile Beach. The sinking of the ship was an 8 year project and was sponsored in part by the Guy Harvey Research Institute.

The wreck is now open for business – and the diving is great! The ship sits perfectly upright and has already attracted a great deal of marine life. You can check out pics and videos at the links below, but the best way to appreciate this great new artificial reef is to come to Grand Cayman and see it in person!

Photos of the Harvey Family’s First Dive on the ex-USS Kittiwake

For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com

Jun 30, 2011

Guy Harvey Ocean Foundation Donates $100,000 to Guy Harvey Research Institute at NSU

The Guy Harvey Ocean Foundation recently presented a $100,000 donation to the Guy Harvey Research Institute (GHRI) at Nova Southeastern University during a ceremony at the new Guy Harvey Inc. world headquarters in Davie, FL. A significant part of these funds were raised from the sale of Guy Harvey sportswear.  You may not know this, but you, the Guy Harvey customer helped provide these funds with your last Guy Harvey clothing purchase. Money is raised for ocean conservation efforts from the sale of every Guy Harvey shirt, Guy Harvey sandal, Guy Harvey hat, Guy Harvey belt, Guy Harvey jacket and all Guy Harvey clothing items.  This $100,000 will be used to support the ongoing fishery research projects at the GHRI.

 

Photo, from left to right: Dr. Mahmood Shivji, Director of the Guy Harvey Research Institute; Guy Harvey; Dr. George Hanbury II, President & COO of NSU; Steve Stock, President of Guy Harvey Inc. and the GHOF; John Santulli, VP Facilities Management, NSU; Dr. Richard Dodge, Dean of NSU’s Oceanographic Center

For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com

Apr 1, 2011

OF SHIPS AND TIGERS

It was a beautiful winter day with a light north easterly wind, providing for calm conditions in the protection of West Bay, anticipating the deployment and sinking of the USS Kittiwake here in Grand Cayman.  Accompanied by Jessica and Alexander, my kids who are both keen divers, we anchored outside the perimeter marked off by the Department of Environment and the Marine Police.  Regular updates on the VHF radio gave us an idea of the history of the ship and the projected sinking schedule. The details of the ship’s construction and service can be found on a number of dedicated websites.

Pumping sea water into the hold began around 10:30 a.m.  At approximately 2:25 p.m. she started sinking rapidly, stern going down and listing sharply to port.  I bet a number of people were holding their breath as it seemed she would topple over in spite of all the preparations, and then appeared to sink upright as air rushed from the port holes and open hatches.

GHRI and GHOF collaborate with other research organizations to better understand tiger sharks

I am a great supporter of artificial reefs, even in a coral reef environment such as ours.  Socio economic studies of artificial reefs in Florida demonstrate hundreds of thousands of dollars generated by individual artificial reefs from diving and sport fishing activity each year.  As it took about 8 years for this project to be executed, perhaps we, the diving community, the Cayman Island Tourism Association and the Cayman Island Government should immediately start the search for another suitable ship for an artificial reef to be the successor to the “Kittiwake”.  I will put my money where my mouth is and volunteer my Guy Harvey Ocean Foundation (GHOF) to assist in locating and funding the next ship.

Talking of mouths, the tiger shark has a big, wide mouth adapted to ripping large chunks out of dead, decaying marine mammals and has large serrated teeth, with re-curved tips designed like a can opener to feed on turtles.  Tiger sharks have been of great interest to me and my research arm, the Guy Harvey Research Institute (GHRI).  We have tagged or sponsored the electronic tagging of 41 tiger sharks in the north western Atlantic in the last two years.  Each SPOT (Smart Position or Temperature Transmitting) tag deployed to the dorsal fin of the shark costs about $2,500 and then another $500 for the satellite time and monitoring. We have tagged tigers: 28 in Bermuda, 7 in the United States Virgin Islands, 4 in the Bahamas and just recently two in Grand Cayman.

The GHRI and GHOF collaborated with a number of research organizations in each of these island territories, which is why the project has been so successful.  Tiger sharks, we are now discovering, make seasonal migrations spending much of the warm summer months cruising in the open ocean, often in very deep water, looking for migrating turtles and feeding opportunistically on dead floating animals such as dolphin, whales, fish and sea birds.  In the winter, they move into the reef environment around oceanic islands in the Caribbean and Bahamas and will come into very shallow water targeting rays, fish and lobsters.

The Overseas Territories Environmental Programme, with assistance from the DoE, has sponsored a shark population analysis study in the Cayman Islands.  Being particularly interested in tiger sharks here, the GHOF sponsored SPOTs when the team caught and tagged two tigers in early December 2010.  Both were caught at night in North Sound and successfully released bearing an internal sonic tag and external SPOT attached to the dorsal fin.  Each time the animal swims at the surface, the tag sends a signal to a satellite giving its position very accurately.  The team was also able to tag Caribbean reef sharks, black tip sharks and nurse sharks—all caught at night in North Sound.

Divers and photographers have been safely interacting with tiger sharks for decades and have watched in horror as their numbers and those of other pelagic migratory sharks have been annihilated for the last three decades in the shark fin trade that threatens to clear all sharks from the planet.

If you are lucky enough to see one of the tiger sharks we have tagged, please send me or the DoE a photo of the animal.  If you happen to catch one while out fishing, then please release the animal alive (as you should release all sharks alive) responsibly.  In time, all shark species around Cayman will receive the protection they surely need under the new Conservation Law.

Fish responsibly, dive safely.

— Guy Harvey

 For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com

Feb 24, 2011

The Misunderstood Tiger Shark Shows Remarkable Migratory Behavior

The stripy and pug-nosed tiger shark gets little coverage or respect in the world of media shark stories compared to the idolizing attention showered on species such white sharks and whale sharks.  And when they do receive the occasional mention, tiger sharks bear the brunt of disparaging descriptors such as “garbage cans of the sea” just because a few individuals of the many thousands killed around the world have been found with indigestible, man-made objects such as a beer bottle, tin cans, chicken wire in their stomachs.  Tiger sharks do indeed have broad diets and are opportunistic feeders, but the reality is they consume almost entirely their normal prey of fishes, turtles, marine mammals, and even large invertebrates.  The discovery of man-made objects in their diet is rare, and it does a magnificent apex predator injustice to assume tiger sharks make a habit of wandering around near human population centers focused on scooping up our garbage that ends up in the sea.  On the contrary, ongoing research being conducted at the Guy Harvey Research Institute and Guy Harvey Ocean Foundation (GHRI/GHOF) on tiger shark migrations is shedding new light on how remarkable and environmentally flexible these amazing sharks are.

An important requirement for the proper management and conservation of any shark species is a robust understanding of its migratory patterns, how it uses its environment, and identification of what is termed its “critical habitat” – areas that are key to successful reproduction and feeding.  To understand tiger shark movements and aid in conservation efforts, the GHRI/GHOF in collaboration with the Bermuda Shark Project and with financial support from AFTCO is investigating tiger shark movements in the western North Atlantic in a long-term study.  The sharks’ movements are being studied by employing satellite tags that relay information on where the tiger shark is and/or its depth in the ocean.

 What have we found so far?

Sharks that we outfitted with satellite tags in Bermudian waters are providing exceptional information about their long-term migratory behavior.  We have been fortunate to be able to follow these tiger sharks for a record length of time (12-17 months and counting), and are discovering fascinating information about their seasonal movements.  The migratory tracks of two sharks are shown as examples.  Please visit the GHRI web site:  http://www.nova.edu/ocean/ghri/tshark.html to see long-term tracks for other tiger sharks.

In brief, the sharks left Bermuda in the fall of 2009 as the waters cooled and made notably direct pathways to the Bahamas or Caribbean, where they spent 6-8 months in close association with island habitats.  Then starting in the spring of 2010, the tiger sharks reversed course showing highly directed migrations northwards, moving beyond and often east of Bermuda and staying well out in the open ocean. In two instances, the batteries on the tags have lasted over 17 months and have revealed a consistent migratory pathway back to the Bahamas starting in the fall of 2010.  What is also amazing is that after their pelagic sojourn these sharks have returned to locations in the Bahamas really close to where they were hanging out a year ago!  Who gave them a GPS? 

These migratory patterns makes one wonder what the sharks are doing so far out in the Atlantic Ocean after spending approximately half a year acting like reef sharks tightly associated with island habitats in the Bahamas and Caribbean.  Something must be seasonally attracting these sharks into the deep open-ocean far offshore.  We’re guessing it is not indigestible man-made garbage.  Are they out in nearly the middle of the north Atlantic for 2-4 months for mating? For feeding on migratory prey such as turtles?  It’s still an open question.  Notably, however, these tiger sharks are displaying a remarkable ability to drastically switch their habitats comfortably, using shallow, coral reef environments for part of the year and completely open-ocean, deep environments for the other part with rapid travel in-between.  Few other shark species show this flexibility in the habitats they can use.

Based on these initial but novel findings, we are continuing this study in additional places to get a more detailed picture of tiger shark movements in different parts of the world.  Our hats are off to these stripy, majestic fishes for their astonishing migratory abilities!

For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com

Sep 17, 2010

Guy Harvey Gulf Fund Raising Effort Featured on CNN

We were honored to be featured on CNN recently for our Save Our Gulf fund raising effort.  Guy Harvey and AFTCO Bluewater are dedicated to keeping our oceans and waterways clean and safe for marine wildlife.  CNN picked up on the fact that our cause marketing efforts are authentic and part of the DNA of who we are.  The following copy is text from CNN’s blog.

Every year, companies spend billions of dollars on good causes. But in this challenging economy, corporate giving is taking on a new level of importance.

“Cause Marketing” is a term coined in the 1980s. But today, it’s becoming a popular method for companies to get through tough times, and build their brands.

We are accustomed to big companies like Pepsi and Nike getting behind global causes, but smaller businesses can get in on the action as well.

I profiled a small company, Guy Harvey Inc., that reports record revenues in 2008/2009, at the height of the recession, and management credits Cause Marketing with the success.

A pioneer in this field, Harvey says the cause started as an authentic desire to save the world’s oceans, and became a business strategy much later on.

“Sometimes you need to have money to do the good,” says Harvey, “and I feel good to be in this position now, to have the influence to really make a difference.”

Carol Cone, an expert on marketing and the author of “Breakthrough Nonprofit Branding” says companies spent more than $9 billion in 2001 on charitable causes. The challenge, she says, his ensuring they meet their business objectives at the same time.

According to Cone, recent surveys show six out of 10 consumers say they are more loyal to a company that backs a cause. Social media is an important factor in the success of cause marketing. Cone says, “By word of mouth and social media, consumers can find out what a company truly stands for. Consumers want to be in control, they want to feel empowered to be good, so this really resonates.”

For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com

Sep 8, 2010

SHARKS — Do We Really Need Them?

For the longest time after the 1975 blockbuster “JAWS” gave us a spine-tingling ride, there was an often used saying that “the only good shark is a dead shark”.  This man- against-beast thriller and its many progeny shark horror flicks still pervade the public’s psyche, anointing all sharks as human-eaters and keeping many beach-goers out of the ocean.

The public and media’s morbid fascination with sharks as killing “machines” continues today. There is a steady stream of media coverage when fishers catch and drag back a large shark for photo-ops.  In some minds, catching and killing a large shark is almost heroic and fashionable, and a testament to man’s superiority in the “battle” against the beast.

Meanwhile, the enormous toll taken on shark numbers worldwide due to indiscriminate fisheries continues unabated.  All this shark killing causes some to wring their hands in anguish about longer-term ecological impacts.  Others say “what’s the big deal if sharks are killed?”

Who’s right?  Should we care if many of the oceans large sharks are exterminated?  Is there really enough of an impact on the marine environment to worry about?

New studies show that sharks also influence the behavior of their prey. Photo credit: B. Watts

It seems intuitively reasonable that sharks, as top-level predators, play an important role in maintaining stability in the ocean’s food chain.  Most people objectively or “in their gut” understand that life on earth is a series of complex interactions, with connections through food webs.  Simply put, species at the top of the food chain eat species in the middle of the food chain which in turn eat species on the bottom of the food chain.  And therefore, changes in the abundance of one community segment will affect the other segments.  In fact, recent studies have indeed documented that overfishing of large sharks (the apex predators) has resulted in numerical increases in populations of their normal prey such as smaller sharks and rays (known as mid-level predators or mesopredators) in a phenomenon called “predator release”.  In turn, the mesopredators are overeating their own smaller prey such as bay scallops and bony fishes even lower on the food chain.  Scientists call such effects that ripple down the food chain “trophic cascades”.

Still, will it really matter all that much if we overfish sharks?  Won’t some other large predatory species, such as billfish and barracuda, take over for sharks at the top of the food chain and keep the food webs functioning normally?

If only the interconnections of life were that simple…….

New studies in Shark Bay, Australia by Dr. Mike Heithaus and his team at Florida International University are showing that in addition to playing important roles in the food web by direct predation (or lethal) effects, including keeping prey population sizes in check, sharks also play a large role in maintaining the normal functioning of marine ecosystems by— get this— influencing the behavior of their prey!

How does this prey behavior to ecosystem function connection work?

Let’s take the seagrass ecosystem as an example.  Recreational fishers and patrons of the marine outdoors know that seagrass beds are critically important nursery areas for juveniles and sometimes even adults of all types of fishes and invertebrates.  The health of seagrass ecosystems is woven into an intricate balance with larger animals such as sea-cows, sea turtles and birds that obtain their sustenance in seagrass beds, either by directly grazing on the seagrass or eating smaller creatures living on the seagrass or in the surrounding sediment. These large animals (mesopredators) are in turn, prey for tiger sharks.

Let’s connect the ecosystem dots: Dr. Heithaus and colleagues have documented that sea-cows, sea turtles and birds avoid hanging out in seagrass beds when tiger sharks are seasonally present in Shark Bay, and jump right back in to devour their favorite foods after the sharks leave in winter.  Makes survival sense doesn’t it?  What this shows is that the presence of tiger sharks causes the mesopredators to change their habitat-use behavior to avoid the risk of being eaten. And this risk-avoidance behavior keeps the seagrass beds and their inhabitants from being over-consumed.

The take home message is that sharks keep the marine ecosystem in balance not just by directly eating their prey — the role that gets the most attention, but also indirectly by altering the behavior of their prey.  The importance of this indirect ecosystem role of sharks is just beginning to be recognized.

We at the Guy Harvey Research Institute, Guy Harvey Ocean Foundation and AFTCO hope that you will keep in mind the delicate balance required to keep our oceans healthy. Please enjoy our marine environment with respect for all of its remarkable life forms.  If you catch a shark, enjoy its magnificence, keep its important ecosystem role in mind – and let it swim away.

For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com

Aug 19, 2010

Grabbing Tigers By the Tail — A Return to Bermuda —Part II

Guy Harvey Ocean Foundation Expedition: Bermuda – Part II

The 2010 expedition to Challenger Bank began on July 24, just a couple of weeks earlier in the year than last year’s trip. Much of the crew from the 2009 expedition were on hand again: Neil and Choy – the “local boys” from Bermuda; Mahmood and Brad, our resident scientists; my children, Jessica and Alex; and Capt. James Robinson, whose boat Wound Up once again served the dual role of catch boat and support vessel.

Neil shows the attachment of a 3-year SPOT to the dorsal fin of a 12 foot tiger

For this year’s trip, the GHRI provided thirteen SPOT (Smart Position or Temperature Transmitting) tags and Neil purchased four three-year SPOTs with assistance from Bermudian sponsors, some of whom rode along with Capt. James on the Wound Up. Neil and Choy were doing a great job in Bermuda in getting local businesses involved in the tagging project and the production of a documentary that was created to educate the public about the success of their work.

The expedition’s plan called for Neil and Choy to take us to Challenger Bank to tag as many tiger sharks as possible over the course of six days. The week started fairly slow, with just one shark caught on each of the first three days. However, things heated up in the second half of the week as we caught and tagged 9 more sharks over the three remaining days.

Chumming was the key to catching the sharks. Luckily, we had ample supplies of fish heads, and we added to the chum mix by catching bonitos, ocean robins (local name for an abundant mackerel scad), blackfins, wahoos and barracudas while we were on the Bank. While the sharks were definitely attracted to all of the fish we served up, they seemed to have a preference for one in particular – fresh barracuda, which proved to be irresistible to the tigers.

We fished for the tigers primarily from the Wound Up. When a shark was hooked, Capt. James would transfer it to the Bones and then return to the mooring to continue fishing. Meanwhile, Neil and crew would safely secure the caught shark, apply a tag to the its dorsal fin, and then release the shark unharmed. Our crew was very experienced at tagging sharks and had gained a lot of knowledge during last year’s expedition, so the entire process – from the initial hook up to the final step of releasing the shark – was well planned and executed, which resulted in all of the sharks being released without harm.

While James was fishing with 130s we put out a quarter inch rope line cable leader and 20/0 circle hook, which was baited with barracuda and suspended from a large buoy. We caught four sharks using this method. One of these was pulled in by Alex, and at 8 feet long, it was the smallest shark we had caught so far.

Brad and Neil decided this shark was small enough to pull into the boat for tagging, so the crew hauled the shark on board, then covered its eyes with a wet towel and ran two deck hoses through its gills for ventilation. With the smaller shark secured in the boat, Neil was able to deploy a 3-year SPOT tag on this young male in just a few minutes.

Alex Harvey works hard on a tiger on the rope line

Interestingly, while on board, this small tiger shark regurgitated several squid beaks, and the horn of the foot from a benthic gastropod (like a conch). This indicates opportunistic bottom feeding and mid-water feeding on pelagic squid (one of the big 12 footers regurgitated the remains of a seabird and lots of feathers).

Unfortunately, we didn’t catch any of the sharks that we tagged last year, nor did we catch any tigers that had been tagged previously by Mahmood and Brad in the U.S.Virgin Islands over the past two years. A somewhat disappointing result, but it suggests that the tiger shark population around Bermuda is comparatively healthy. Of course, we do not know what the population numbers were before the commercial fishing industry exploited this and other species over the last three decades, so it’s difficult to determine just how stable the population has been over time.

Impact of the Guy Harvey Ocean Foundation Expedition: Bermuda

Earlier in July, Brad presented our most up-to-date results at the annual conference of the American Elasmobranch Society, and the results of our comprehensive study amazed the scientific community. The tags applied in 2009 have lasted and stayed attached much longer than expected, and the regular reporting by the sharks (over a year now) is shedding new light on their behavior and migration in the Atlantic. Perhaps the biggest finding so far is that tigers are not the coastal dwellers that they were believed to be. Instead, they appear to make extensive oceanic journeys, and have an oceanic existence for much of the year.

It appears that the majestic tiger shark, which can grow to eighteen feet long, seems just as content in six feet of water chasing stingrays on the Bahamian sand flats as it is lurking near an oceanic bank 2000 miles offshore, hoping to detect and zero in on a dead floating sea bird or loggerhead turtle. This knowledge has serious management implications: since the sharks have been shown to make extensive migrations – passing through the 200 mile Exclusive Economic Zones of several countries in a given year – no country can consider these animals “their resource”.

The GHRI left several SPOT tags in Bermuda with Neil and Choy in the hope that some female tiger sharks would show up later in the year. Oddly, of all the animals tagged so far, only one has been female. This leads us to another question: “Why are there so many males at Challenger Bank at this time of year?” A question perhaps best answered by making another expedition.

Acknowledgements:

I wish to thank Rehanna Palumbo and the staff at the Fairmont Hamilton Princess Hotel in Hamilton, Bermuda for her assistance with accommodation. This is a beautifully appointed 5-star hotel in a wonderful setting on the Hamilton waterfront close to great shopping and restaurants. Well worth the visit.

Thanks to Neil and Choy for getting us together in the collaborative research effort, and for the chance to swim with these magnificent animals. Thanks to James Robinson and his family for his commitment to the project.

It is our collective responsibility to conserve the marine environment and maintain the biodiversity of the planet. Fish responsibly, dive safely.

Cheers….Guy Harvey PhD.

For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com

Aug 13, 2010

Grabbing Tigers By the Tail — A Return to Bermuda —Part I

With the dramatic declines in shark populations caused by shark-finning and other forms of commercial fishing, the need for protection of shark species worldwide has reached a critical point.  To this point, the Guy Harvey Ocean Foundation is aggressively supporting several fisheries management studies that are gathering crucial data that can be used to design and implement protective measures.

One of these studies is an ongoing project to track tiger shark migratory patterns in the western Atlantic.  For the past two summers, representatives from the GHOF and the Guy Harvey Research Institute have helped tag and track almost twenty tiger sharks off the coast of Bermuda.  The expeditions have produced previously unknown data about the tiger sharks in that region, information which may very well lead to new fisheries management practices in the western Atlantic and Caribbean.

Guy Harvey Ocean Foundation Expedition: Bermuda – Part I

Mahmood Shivji and Brad Wetherbee measuring a tiger shark on Challenger Bank, Bermuda

Mahmood Shivji and Brand Wetherbee measuring a tiger shark on Challenger Bank, Bermuda

In August of 2009, the staff of the Guy Harvey Ocean Foundation and the Guy Harvey Research Institute collaborated with the Bermuda Shark Project on an expedition to tag and track adult tiger sharks a few miles southwest of Bermuda.  We concentrated our efforts in a location known as Challenger Bank, which is a known as a hot spot for tiger shark activity.  The area certainly lived up to its reputation – by the end of the week, we had caught, tagged and safely released seven adult tiger sharks with PSAT and SPOT electronic tags.

The tagging project was being led by two Bermudians, Dr. Neil Burnie and Choy Aming, with the representatives of the GHOF and GHRI providing assistance in the form of tag provision and deployment, as well as follow-up analysis of the sharks’ migration patterns through the western region of the north Atlantic.  Dr. Mahmood Shivji, Director of the GHRI, and Dr. Brad Wetherbee of the University of Rhode Island – both of whom have extensive experience working with tiger sharks in the Bahamas and the USVI – were on hand to calibrate the tags and assist with deployment.  And, my children Jessica and Alex – both of whom are world-class fishermen with several IGFA records between them – rounded out the team as our expert tiger shark wranglers.

We used Neil’s 34’ Prowler, Bones, as the expedition’s work boat while Captain James Robinson’s Wound Up served as the catch boat.  The sharks were caught on 20/0 circle hooks with no barb and130# gear, then tail roped and restrained by a harness that kept them snug to the boat while Neil drilled small holes in the shark’s dorsal fin to attach the SPOT tags.  On average, the process was usually completed in about 15 minutes, during which time the shark’s head remained submerged in the water so it could ventilate normally.

Once the tag had been securely fastened, the tail rope and harness were released and the sharks would swim away at a rapid clip.  I was in the water to film the hook removal and rope/harness release, while my professional camera team of Rick Westphal and Dee Gele filmed all the action for a tiger shark documentary I am producing.

The results of last year’s expedition were successful beyond our expectations. Using the tags, we were able to track the sharks’ migration as they moved away from Bermuda when seawater temperatures dropped in October, during which time they migrated south towards the Bahamas, Turk and Caicos Islands, and the Virgin Islands.  The tracks showed the sharks were not wandering aimlessly but were actually headed in a more-or-less straight line, as if they knew where they were going.  Based on their amazingly direct movements, it’s highly likely the individual animals have taken this migratory path before.

Guy Harvey catching a tiger shark to tag

For the rest of the winter months, the tiger sharks behaved like reef sharks, tracking the edges of deep island drop-offs.  Presumably, they were feeding opportunistically along the way.  As they searched for food at or near the surface, their dorsal fins would be exposed above the water line, which would allow the Argos satellites to pick up the signal from the tags and pinpoint the shark’s location (NOTE: The SPOT tag technology is more suited for attachment on air-breathing mammals and reptiles that constantly interact with the surface. Only a few ocean-going sharks exhibit the necessary type of behavior needed to use the SPOT tag for tracking. For example, my friend Dr. Michael Domeier uses the same equipment in his ongoing research of white shark populations in the Pacific).

As the seawater temperatures started to rise in April and May, the tiger sharks began a northward migration, with some aiming directly for Bermuda.  As they approached the island, they began to veer off on an easterly track that led them well north of Bermuda and into the north Atlantic, where some have stayed for most of the summer (Katrin, the only female tagged last year, is currently on a latitude adjacent to New York!).

This pattern of migration away from the island and in to open water raises some big questions: “What are they doing out in the middle of the Atlantic Ocean?”, “Are they feeding, and if so, on what – turtles, dead sea birds, squid?”, “Or, are they perhaps breeding?” These are serious questions that need to be answered in order for our research to have any practical or meaningful conclusions. So, we decided to once again mount an expedition to Bermuda to see exactly what is going on with these perplexing tiger sharks.

See our next week’s blog for Part II

For a complete list of our other featured blog posts and to see the full line of Guy Harvey Sportswear, please visit: www.guyharveysportswear.com