NY Aquarium discovers shark nursery ground in New York waters
Scientists and veterinarians working for the Wildlife Conservation Society’s (WCS) New York Aquarium in Coney Island have discovered something noteworthy in the near shore waters of Long Island’s Great South Bay: a nursery ground for the sand tiger shark, a fearsome-looking but non-aggressive fish.
The discovery was made by researchers who have collected a wealth of information on sharks in local waters over the past four years through the use of acoustic tags, devices that enable scientists to remotely track marine animals as they swim through their environment. The data have helped the scientists confirm the existence of the nursery in Great South Bay, one of the rich estuaries found along Long Island’s southern shore. Only a handful of sand tiger shark nursery grounds have been identified, one of which is in the waters of Massachusetts.
“The discovery of a shark nursery is fantastic news for local conservationists seeking to learn more about sharks and other species in the New York Bight,” said Jon Dohlin, vice president and director of WCS’s New York Aquarium. “Through field projects and outreach efforts by the New York Aquarium and other organizations, we hope to raise awareness about our local marine environment and the need to manage our natural wonders.”
The team received the first indications of a potential nursery ground in Great South Bay in 2011 when one of the scientists received a picture of a dead juvenile sand tiger shark from one of the marinas. Follow-up conversations with local anglers and boaters revealed that people had been catching these small sharks in the bay for years. The scientists then initiated the tagging study using acoustic transmitters in Great South Bay and have been catching and releasing only juvenile sharks since that time. Ten of the 15 were individual sharks tagged this year, and five individuals tagged in previous seasons returned to the same section of the bay, a behavior known as “site fidelity.”
Data gathered from the sharks’ movements are helping scientists learn more about the migratory behavior of sand tiger sharks and their habitat needs. The discovery of the Great South Bay shark nursery in particular is important because the sand tiger shark has been heavily depleted by fishing and is listed as a “Species of Concern” by the U.S. National Marine Fisheries Service. Fishing for sand tiger sharks has been prohibited in state and federal waters since 1997. The species has a low reproductive rate — a female shark gives birth to only one or two pups every two years — so it will take this sand tiger shark population many years to rebuild. Protecting the nursery will help promote sand tiger shark recovery in the coastal waters of the eastern U.S.
Growing up to 10 feet in length, the sand tiger shark is widely distributed and found in the temperate water and subtropical waters of many of the world’s coastlines. Although it is not known how many sand tiger sharks remain, the species is listed as globally “Vulnerable” on the IUCN’s Red List of Threatened Species, while populations in parts of Australia and Argentina are classified as “Critically Endangered.” The NY Seascape program is collaborating with WCS shark scientists from Argentina to improve the understanding of sand tigers in the Southwest Atlantic, which have been severely depleted by overfishing.
The work is part of an initiative by WCS’s NY Seascape program based out of WCS’s New York Aquarium to study and protect sharks and rays in the New York Bight, the region between Long Island’s Montauk Point and New Jersey’s Cape May that extends out to the continental shelf and over the Hudson Canyon. More than 40 species of sharks and rays are known to occur in these waters.
In addition to the sand tiger study, NY Seascape researchers attached archival satellite tags to two blue sharks in the waters south of Long Island in 2015. These tags will gather data for six months before they are scheduled to pop off and begin broadcasting archived location data back to the research team. They also tracked three juvenile shortfin mako sharks and one blue shark tagged with near real-time satellite monitoring tags in 2014.
Sharks will be the central focus of “Ocean Wonders: Sharks!”, a 57,000-square-foot exhibit building currently under construction at the New York Aquarium. The building will house more than 115 marine species, including sharks, skates and rays.
-Information from the Wildlife Conservation Society
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