2018-02-01 / Nature

Replenishing the Waters ‘Gives Back’ to the Wild

By Charles Avenengo

Destined for eventual release into the wild, skates share the tank with another breeding project, chain dogfish. Save the Bay Exploration Center breeds and then releases the fish back into local waters. (NTW file photo) Destined for eventual release into the wild, skates share the tank with another breeding project, chain dogfish. Save the Bay Exploration Center breeds and then releases the fish back into local waters. (NTW file photo) Elasmobranchs is a biological name used for non-bony fish, the cartilaginous sharks, rays, stingrays and skates.

Everyone knows about the big, bad sharks. Likewise, rays are impressive. The largest, the manta ray, stretches more than 20 feet from wingtip to wingtip. At places in the tropics, when they leap out of the water, they crash back in with a report that is heard from miles away. Major League Baseball’s Tampa Bay Devil Rays, now called the Rays, were named after them.

Stingrays are the smaller cousins to the manta rays. The iconic Corvette Stingray car is named after them, and there was a former professional developmental league soccer team in Rhode Island called the Stingrays.

But no one seems to love the lowly skates. They lie at the bottom of the cartilaginous chain of respect. Although the 280 species of skates worldwide are an ancient form of fish, with fossils dating back 150 million years, their presence barely raises eyebrows. Even in restaurants, they aren’t found on menus. No one would choose skate as a dining option, so instead their meat is sometimes fraudulently billed as “scallops.” Likewise, the trawlers that catch them sell them for the lowest of market prices as bait for lobsters.

No one seems to respect skates, except for Adam Kovarsky at the Save the Bay Aquarium on Easton’s Beach. In his decade-plus of manning the tanks at the beachside aquarium, the Exploration Center manager has seen lots of fish come through the doors. But all aquarists have a little husbandry in them, and in addition to receiving visitors and keeping the inhabitants of the fish tanks well-fed and happy, Kovarsky has been breeding little skates. Normally, this would be de rigueur, as zoos and aquariums worldwide replenish their viewing specimens with captive breeding programs. But in the case of the little skates, Kovarsky and his charges have been releasing them back into the wild.

“As of this winter we are up to about 50 little skates released back into the local food web,” he said.

Ordinarily, such an undertaking might be overlooked. However, many little skates are pulled out of local waters. According to the Rhode Island Department of Environmental Management, a commercial fisherman is allowed an annual possession limit of 62,000 pounds of little skates. According to the DEM Fisheries Division, the total allowable landings of little skates in the state in 2018-19 will be 4,408 metric tons.

In a National Oceanographic and Atmospheric bulletin entitled, “What We’re Doing to Learn More About Skates,” it states that the most sought after of these species is the little skate, which is used for bait in other commercial fisheries such as lobster.

It also states that although the bait fishery is based principally in Point Judith and Tiverton, fishermen in Connecticut, Massachusetts, New York, New Jersey and Maryland also harvest skates for bait.

Nonetheless, the population of little skates appears stable.

During a recent visit to the aquarium, Kovarsky explained the process of breeding and releasing the skates. The aquarium rotates three fecund female little skates in its tanks. Each lays two to three egg cases a week. These egg cases are the familiar “mermaid purses” seen by virtually every beachcomber in Rhode Island. Once laid, the eggs go into the incubation tank and begin a development period that extends to nine months. During this time, in addition to receiving the professional care and nurturing, they are housed in a predator-free environment.

“In the wild, they would have a half-percent chance of surviving. Here they marinate until they pop out,” Kovarsky said.

As they near hatching, guests can hold the live egg cases, and by putting the eggs to the light, they can actually see the pulsating embryos and tell if the egg is fertile.

When they are born, another time-consuming process takes place as the little skates are put into a second juvenile tank for one to two years until they reach a size where they can be released into the wild.

During this lengthy process, as 25,000 guests visit the aquarium annually, they are educated about the perils of little skates and other aspects of Narrangansett Bay’s marine life.

“The real message is we’re not just taking away, but we are also having fun releasing them back into the wild.” Kovarsky said. “Although this is a relatively stable population, we are very happy to be able to make the difference we can.”

Naturalist Charles Avenengo has been chasing Aquidneck Island wildlife for more than 40 years.

Elasmobranchs found in Rhode Island waters.

Sand tiger
Thresher shark
Basking shark
White shark
Shortfin mako
Chain dogfish
Dusky shark
Sandbar shark
Tiger shark
Blue shark
Smooth dogfish
Scalloped hammerhead
Smooth hammerhead

Spiny dogfish
Atlantic angel shark
Atlantic torpedo ray
Thorny skate
Barndoor skate
Little skate
Winter skate
Smooth skate
Clearnose skate
Roughtail stingray
Spiny butterfly ray
Devil ray
Cownose ray

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