September 21, 2021

Makos: Tracking one of the fastest sharks in the world

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lilsurface-e1393272502194By Dr. Mahmood Shivji and Daryl Carson, From Guy Harvey website

The following article originally appeared in the Spring 2013 issue of Guy Harvey Magazine.

For any angler who has tangled with a shortfin mako, they know the power of these incredible sharks. The largest animals reach a length of more than 12 feet, and makos are known for impressive acrobatics during a fight, often putting on a series of leaps that can take them 10 to 20 feet out of the water. Makos are also considered among the fastest, if not the fastest, of sharks. Although there is no definitive answer, various researchers have estimated these torpedo-shaped animals can reach a top speed between 30 and 65 mph when accelerating to capture prey. For the record, that’s faster than Congress can vote itself a pay raise.

But makos seem to be designed for high speed swimming—they have a highly streamlined shape with a conical snout, large gills for efficient gas exchange and a prominent flattened keel at the posterior end of the trunk that is believed to strengthen the tail for powerful movements. Unlike most sharks, makos and their kin (e.g., white sharks, salmon sharks) have adaptations that allow them to maintain parts of their body, including muscles, at temperatures several degrees above ambient seawater. This is believed to be part of the reason why makos can achieve such high swimming speeds. And, not to carry the political analogy too far, but unlike some politicians, this suggests makos are not completely “cold blooded.”

From a fishing and conservation perspective, makos are no less intriguing. With a global range, and a high quality meat, these sharks are popular in both commercial and sportfishing. They have been referred to as one of the great gamefishes of the world due to their feisty nature when hooked on rod and reel. Commercially, makos are most often taken as bycatch in longline and drift gillnet operations, where they are kept for their high quality meat and fins. The number of makos killed per year around the world is unknown, but fishing pressure on their populations is believed to be huge. Research by the Guy Harvey Research Institute (GHRI), in collaboration with Dr. Shelley Clarke, has estimated that a median of about half a million mako sharks were utilized in the global shark fin trade as of the year 2000.

Despite the heavy commercial bycatch of makos and their popularity among sport fishermen, good information on the biology of these sharks to aid in management is surprisingly sparse. However, current research does suggest that mako numbers in parts of their range are in decline. This is of concern for many reasons, including the fact that makos are clearly top-level predators in the ocean, likely giving them an important ecosystem role. Stomach content analysis has shown that smaller sharks, swordfish, billfish, turtles and bony fishes are all part of the mako diet.

Just like other highly migratory species, the effective management of makos is a challenge, because it increases the difficulty of assessing population numbers, and because applying conservation measures requires the coordinated efforts of multiple nations or user groups. Details of mako migratory patterns in different parts of their global range remain largely unknown, adding to the difficulties of formulating effective management and conservation plans. The good news is that information coming in from new tracking studies is helping to solve this problem.

In New Zealand, a study co-sponsored by the GHRI, New Zealand National Institute of Water and Atmospheric Research and New Zealand Ministry for Primary Industries placed a satellite “SPOT” tag on a six-foot juvenile female mako dubbed “Carol.” Carol has provided almost daily, good quality detections for her whereabouts for more than eight months now (and counting) providing a high-resolution 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 off 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. 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 off Isla Mujeres, Mexico. The tags stayed on for two-and-a-half and five months, and showed both sharks migrating into the western and northern Gulf of Mexico, respectively. Additional SPOT and pop-up tags will be deployed off Isla Mujeres this spring with Captain Anthony Mendillo of Keen M International, and off 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 effective management and conservation efforts. And, with continued success, perhaps similar tracking techniques can be applied to a few worthy public servants.

Click below to subscribe to Guy Harvey Magazine, and be sure to follow GHM on Facebook.

Click HERE at https://www.facebook.com/guyharveymagazine?fref=ts to learn more about the GHRI and HERE at http://www.nova.edu/ocean/ghri/ to view the shark tracking web site.

For more on this story go to: http://www.guyharvey.com/uncategorized/mako-chronicles-tracking-one-fastest-sharks-world/#sthash.WHxqzB8I.dpuf

 

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