Mako Madness

MAKO CHRONICLES

BY DR. MAHMOOD SHIVJI & DARYL CARSON

Tracking one of the fastest sharks in the world.

For any angler who has tangled with a shortfn mako, they know the power of Commercially, makos are most often taken as bycatch in longline and drift gillnet these incredible sharks. The largest animals reach a length of more than 12 feet, operations, where they are kept for their high quality meat and fns. The number and makos are known for impressive acrobatics during a fght, often putting of makos killed per year around the world is unknown, but fshing pressure on on a series of leaps that can take them 10 to 20 feet out of the water. Makos are their populations is believed to be huge. Research by the Guy Harvey Research also considered among the fastest, if not the fastest, of sharks. Although there is Institute (GHRI), in collaboration with Dr. Shelley Clarke, has estimated that a no defnitive answer, various researchers have estimated these torpedo-shaped median of about half a million mako sharks were utilized in the global shark fn animals can reach a top speed between 30 and 65 mph when accelerating to trade as of the year 2000. capture prey. For the record, that’s faster than Congress can vote itself a pay raise. Despite the heavy commercial bycatch of makos and their popularity among

But makos seem to be designed for high speed swimming—they have sport fshermen, good information on the biology of these sharks to aid in a highly streamlined shape with a conical snout, large gills for efcient gas management is surprisingly sparse. However, current research does suggest exchange and a prominent fattened keel at the posterior end of the trunk that mako numbers in parts of their range are in decline. This is of concern for that is believed to strengthen the Researchers are amazed at not many reasons, including the fact that makos are clearly toplevel predators in the ocean, likely giving them an important tail for powerful only the incredible distances ecosystem role. Stomach content analysis has shown that smaller movements. Unlike sharks, swordfsh, billfsh, turtles and bony fshes are all part of most sharks, makos Carol has traveled, but also the the mako diet. and their kin (e.g., Just like other highly migratory species, the efective white sharks, travel pattern itself. management of makos is a challenge, because it increases salmon sharks) have the difculty of assessing population numbers, and because adaptations that allow them to maintain parts of their body, including muscles, at applying conservation measures requires the coordinated eforts of multiple temperatures several degrees above ambient seawater. This is believed to be part nations or user groups. Details of mako migratory patterns in diferent parts of the reason why makos can achieve such high swimming speeds. And, not to of their global range remain largely unknown, adding to the difculties of carry the political analogy too far, but unlike some politicians, this suggests makos formulating efective management and conservation plans. The good news is that are not completely “cold blooded.” information coming in from new tracking studies is helping to solve this problem.

From a fshing and conservation perspective, makos are no less intriguing. In New Zealand, a study co-sponsored by the GHRI, New Zealand National With a global range, and a high quality meat, these sharks are popular in both Institute of Water and Atmospheric Research and New Zealand Ministry for commercial and sport fshing. They have been referred to as one of the great Primary Industries placed a satellite “SPOT” tag on a six-foot juvenile female mako gamefshes of the world due to their feisty nature when hooked on rod and reel. dubbed “Carol.” Carol has provided almost daily, good quality detections for her

Carol the New Zealand Mako has amazed researchers with the speed and distance of her travels.

Check out Carol’s track at nova.edu/~johnmatt/makosharks.htm and her round trip from New Zealand to Fiji.

whereabouts for more than eight months now (and counting) providing a highresolution view of her travels. Researchers are amazed at not only the incredible distances Carol has traveled, but also the travel pattern itself. She has covered over 13,000 km. (over 8,000 miles) in about eight months, showing speeds of up to 60 miles per day. And none of this travel was at taxpayer’s expense.

Tagged of the northern New Zealand coast, Carol swam north for two weeks, covering half the distance to Fiji, before doubling back and hanging out in Kiwi waters for almost two months and before re-launching and completing her trip to Fiji then returning to eastern coast of New Zealand in just two and a half months. Carol’s remarkable movements can be followed on the interactive GHRI

tracking website (www.nova.edu/~johnmaƩ/makosharks.htm).Based on the success of this pilot study with Carol, GHRI and New Zealand collaborators are expanding this study by tagging more makos here to get a solid idea of their migratory patterns in relation to New Zealand’s territorial waters.

Somewhat closer to home, the GHRI team has also been tracking makos to understand their movement behaviors in our part of the world. As part of this study, Dr. Guy Harvey recently deployed two pop-up satellite tags on makos of Isla Mujeres, Mexico. The tags stayed on for two-and-a-half and fve months, and showed both sharks migrating into the western and northern Gulf of Mexico, respectively. Additional SPOT and pop-up tags will be deployed of Isla Mujeres this spring with Captain Anthony Mendillo of Keen M International, and of Maryland this summer with Captain Mark Sampson of Fish Finder Adventures.

These global combined studies should provide an interesting, comparative view of mako movements. The information should increase our biological knowledge of these amazing sharks and help provide regulators with the information they need for efective management and conservation eforts. And, with continued success, perhaps similar tracking techniques can be applied to a few worthy public servants.

Fiji

New Zealand