A UNE researcher known as ‘Dr. Shark’ develops a method that allows fish data collection without killing the specimens.

A decade ago, when James Sulikowski first came to the University of New England, scientists who studied shark reproduction had to kill and gut their specimens to unlock the secrets of how these elusive fish gave birth.

Sulikowski wanted to learn more about the reproductive process in hopes of bolstering shark numbers, and didn’t like the idea of having to kill pregnant sharks and their unborn young to do it. That study method also made it impossible to study the reproductive habits of endangered sharks, such as the basking, hammerhead or tiger shark, even though information about how these threatened groups lived and loved would have helped policymakers protect their mating or pupping grounds and possibly help stabilize their populations.

Scientists had begun using blood samples to supplement their shark necropsies, measuring hormone levels to establish the stage of pregnancy, but Sulikowski, a father of three, thought researchers could go further. About five years ago, he turned to the same kind of sonogram technology that doctors use to monitor pregnant women – complete with a transducer, an image screen and conductive jelly – and adapted it for use on pregnant sharks, as well as other elusive or endangered fish species, such as sturgeon.

“There is so much that we still don’t know, like where different species of sharks go to give birth,” Sulikowski said, “and so much that we think we do know, like the length of gestation for our local spiny dogfish that we are just now learning through the use of this technology and tagging that is just plain wrong. I love that. I love challenging accepted science. For me, it’s always about being inquisitive, testing what we think we know, asking what we don’t and figuring out new ways to come up with answers to questions we didn’t even know to ask just a few years ago.”

ADAPTING SONOGRAM TECHNOLOGY

Sulikowski, 47, is something of a rock star on the UNE campus, and his prominent role on the opening night of Discovery Channel’s Shark Week 2016 will add to the mystique of the professor who students call Dr. Shark. After enduring some criticism in recent years for sensationalism, Discovery has decided to open this year’s shark extravaganza with some science. It will focus its Sunday episode on research that Sulikowski did on pregnant tiger sharks in the warm, shallow waters off Tiger Beach in the Bahamas with University of Miami professor Neil Hammerschlag.

The researchers employed a portable sonogram, this one equipped with goggles to see the intrauterine ducts, to study tiger sharks hooked, lassoed and hauled aboard their 66-foot research boat from 2011 to 2014. They were trying to figure out why the waters off what has come to be known as Tiger Beach were drawing such a high number of large tiger sharks. When Hammerschlag noticed that many of the tigers were females, he guessed it might be a pupping ground, but he couldn’t know for sure without confirmation. That’s when he called Sulikowski.

Animal breeders have been using portable sonograms for years, adapting the large, stationary units developed for human medicine more than half a century ago into portable, high-resolution machines that can be used in the field. Sulikowski needed to develop a method to keep the sharks calm and alive, so researchers could study the dual uterine tracts and count and measure the young without injuring the sharks or the scientists. For large sharks, that meant hauling them aboard, holding them down on a submerged platform and pumping oxygenated saltwater over the shark’s gills to keep them calm for the 20-minute examination.

ACCURATE, NON-LETHAL RESEARCH

Sulikowski had been practicing on spiny dogfish and other smaller shark species in the Gulf of Maine to perfect his method. These fish were harvestable, so for the first year of his sonogram studies he compared the results of what he learned from the sonogram with the hormone levels documented in blood samples and the results of traditional necropsies, or animal autopsies. But by year two, with the necropsies repeatedly confirming what he saw in his sonograms, the UNE team started to rely almost exclusively on sonogram images to provide immediate, accurate, non-lethal results.

The sonogram images are crisp and clear, just like the ones performed in doctor’s offices across the developed world. On a trip out Thursday to Tantas Ledge, about 10 miles off the coast of Biddeford, Sulikowski caught two small spiny dogfish, both of which were pregnant. While his 8-year-old daughter, Kendall, and a UNE neuroscientist, David Johnson, held them down on the top of a wet cooler, Sulikowski pointed out the young that lined the mothers’ two tracts, and found their hearts and the outlines of their small gaping mouths, before tossing them back into the sparkling sea.

“You can see, they really are quite beautiful,” Sulikowski said. “We learn so much from each look, but without hurting the mother or babies.”

STUDY EXAMINES 65 SHARKS

This was the technique that Sulikowski employed for the Bahamian study to be featured this Sunday on Shark Week, much to the delight of his research team and UNE officials eager for the widespread exposure.

They caught 65 sharks over the span of the three-year study. Of those, 59 were female. They and a team of graduate students used the sonogram to check for pregnancies and to document what they found. Some were pregnant, but the team also found young females, even though there was very little for the sharks to eat in those calm, warm waters, Sulikowski said.

There were no babies and very few males, most likely because of the lack of food, he said. The data suggests female tiger sharks prefer the relatively male-free waters, and pregnant tiger sharks may experience increased fetal growth in warmer waters.

But Sulikowski said the data also suggests that habitat protection can help threatened sharks grow their numbers. Tiger Beach is located in a protected zone in the Bahamas, he said. Their numbers are declining globally, but are rising in the Atlantic, he said, and it may be because of what’s happening at Tiger Beach. That gives Sulikowski reason to believe that a combination of sonograms and satellite tagging could help scientists and policymakers mount successful conservation campaigns for other endangered shark species.

DOGFISH STUDY MAKES A DIFFERENCE

However, his dogfish sonogram practice has ended up being more than simply a warmup for the Tiger Beach work. Sulikowski said the research has led him to believe that dogfish gestation, or the period of time between conception and birth, is shorter than the previously accepted 18 to 20 months, although there is still work to do before he can say exactly how much shorter. His team also has located the species’ first identified pupping area off the coast of Rhode Island. Both of these are big discoveries, but it was the dogfish’s prolific breeding habits that first came to Sulikowski’s attention.

In 2011, Sulikowski used two grants totaling about $500,000 to study the dogfish life cycle in reaction to conservationists’ claims that dogfish were in need of protection. His results, which echoed what Maine fishermen had been saying for years, led the Marine Stewardship Council to declare the spiny dogfish fishery a sustainable one in 2012, which allowed the species to be shipped overseas and federal authorities to raise the harvest quotas on the species.

“We challenged the accepted thinking and got to the truth,” Sulikowski said. “That’s what everybody wants, really, scientists and fishermen alike.”

 

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