Article by Capt. Mark Sampson
Anyone who is really interested in sharks is probably aware of the now famous white shark “Mary Lee” that was tagged by the “Ocearch” research team last September off the coast of Massachusetts. The shark was baited, hooked then escorted to a large research vessel where it was lifted out of the water on a platform and fitted with a high-tech tag that communicates with satellites. The shark was tagged on September 17th and since then, her whereabouts have been anything but secret. Every time Mary Lee comes to the surface the tag sends information to satellites, and from then on the researchers and anyone else around the world with a computer and an internet connection can see on a Google map the track-line where the old girl has been swimming.
This is really cool stuff that has been providing a lot of eye-opening information about where white sharks go when they’re out in their natural environment doing their own thing. After being tagged, Mary Lee left the coast and went out beyond the continental shelf, then south to Florida where she stayed until almost mid-November. After that, the shark headed north and eventually meandered her way past Delmarva in late January.
As a fisherman who thought he knew a thing or two about sharks, I for one was blown away at the thought that a white shark could be off our coast in the middle of the winter when water temperatures are about as cold as they get. Just as baffling was the fact that the shark kept going north all the way up to Long Island, then it turned back south and by the end of February was off Bermuda and eventually back to Florida again. This up and down, up and down movement in a six-month period is a far departure from the “up in the spring, down in the fall” movements most fish seem to follow. That track came from just one shark, but the Ocearch team tagged two sharks off Massachusetts along with one off Jacksonville and a gang of them off South Africa. As long as the batteries last, a lot of tracking data is sure to follow from those sharks over the months ahead.
Such information will certainly be useful to help better understand and protect white sharks. But since most fishermen will never fish for - or even encounter a great white shark in their lifetime, observing their daily travels is likely more of an interesting thing to do than a real tool to help them better understand a fishery that they participate in. Imagine what could be learned if anglers and fishery managers could follow tuna or billfish in such a way. Unfortunately, at least for now, technology doesn’t easily allow us to track the day-to-day movements of such fish.
The tags that were used by Ocearch on Mary Lee and the other white sharks were known as “smart position and temperature” (SPOT) tags. Because they cannot communicate with the satellites through the water, SPOT tags are used only on animals that are commonly found at the surface of the water such as turtles, dolphins and some species of sharks. To save battery life they turn off while underwater but as soon as the tag breaks the surface they quickly turn on and transmit their location. At a few thousand bucks each, and an additional fee every time they report to a satellite, SPOT tags aren’t exactly cheap and researchers are not likely to use them unless they’re engaged in a pretty significant project. So last fall I was happy to learn that just such a project was in the works and a team of biologists from the University of Rhode Island, Guy Harvey Research Institute and the NOVA Southeastern University Oceanographic Center were planning to put SPOT tags on mako sharks off Ocean City. I was fortunate to be included in their plan as the captain who would steer them to the makos.
The project kicked off on Memorial Day and after four days of fishing we successfully tagged five makos that ranged in size from 75 to as much as 175 pounds. The process involved hooking and landing the sharks on sportfishing tackle and then lifting them out of the water in a specially designed sling that allowed our team to quickly attach the tag to the shark’s dorsal fin before returning it to the water. The entire process took 6-9 minutes per shark and we had a pump pushing saltwater over their gills the entire time. We were happy to watch each shark swim away with a tag but absolutely elated when every one “pinged” the satellite within 24-hours, many miles from the tagging site, thus confirming a healthy release.
Depending upon how many times the sharks surface, the SPOT tag batteries should last 1-2 years, and by the middle of June the public will be able to view the sharks progress online at http://www.nova.edu/~johnmatt/makosharks.htm (see map on right). Though makos are an incredibly important species to both recreational and commercial anglers, there is much about them that is still not known. Tracking their movements over time will provide valuable information that will help biologists and fishermen better understand the shark and assist fishery managers make policy decisions based on solid data.
We have three more tags to deploy, so if things go our way, over the next couple weeks there could be eight makos swimming off our coast with SPOT tags. This same group of tagged makos off New Zealand and Mexico but this is the first time makos have been SPOT tagged in the Atlantic. A lot of money and effort has been invested in this project that will hopefully provide valuable long-term data about the fish and the fishery. And even though the initial tracks of these fish showed that they wasted no time in scooting out of the area, it’s imperative that fishermen are aware that if they catch a mako sporting a transmitter and antenna on their dorsal fin it should be quickly released. These fish are too valuable to the fishery to end up in someone’s freezer!
Captain Mark Sampson is an outdoor writer and captain of the charter boat “Fish Finder”, docked at the Ocean City Fishing Center.
