Written by John Sargent
The Sandbar shark, also known as the brown shark, thickskin shark, or by the Latin name Carcharhinus plumbeus, is a native species to the waters surrounding Fishers Island. Sandbar sharks are estimated to live approximately 30 years, with both males and females reaching maturity around 13 to 14 years old. After 8 to 12 months of gestation, females give birth to live young in shallow, nearshore nursery grounds. Sandbar shark pups measure around 2 feet at birth. As adults, they can measure up to 8 feet long and weigh as much as 200 pounds.
Sandbar sharks are opportunistic feeders that eat bony fish, smaller sharks, octopuses, squid, eels, skates, rays, shrimp, and crabs. While visually similar to more aggressive species such as bull sharks, Sandbar sharks pose virtually no threat to humans.
The recent increase in shark sightings around the island is not the result of a population boom within Sandbar sharks, but rather a result of the changing food web on which they rely.
One of the primary forages for Sandbar sharks is bunker, also known as menhaden or pogies. This species of oily baitfish has suffered a noticeable population decline due to overfishing and climate change in the last decade. As bunker and other baitfish species become less prevalent in open water, it is believed that larger predators, such as Sandbar sharks, move closer to shore in order to seek out alternative food sources. Many also believe that the increase in Sandbar sharks in the waters of the Northeast is an indirect result of declining striped bass populations. Because there are fewer stripers in historically abundant waters, their numbers and overall biomass have become concentrated into smaller pods, which eventually draws the attention of predators already suffering from a lack of forage. I should be clear, this topic is complicated, and there is a great deal of nuance that I am not trained to speak on. However, for the sake of simplicity, you can boil it down to this: Lack of abundance of other species will slowly increase shark sightings close to shore as they seek out alternative food sources.
The waters on the south side of Fishers Island, specifically Isabella, Chocomount, and South Beach, are ideal shark habitat for a number of reasons. The water is cooler, bait is more prevalent, and there is direct access to the waters of the Atlantic. While no one should feel deterred from swimming, surfing, or other forms of recreation on these beaches, we must treat these animals with the respect they deserve. Sandbar sharks have been on Earth for nearly 14 million years. These waters are their home. While their seemingly increased presence may feel alarming, it is a byproduct of mismanaged fisheries and ecological disruption. Learning to coexist with them is going to be our new normal until a balance is struck. For better or for worse.
It should also be noted that Sandbar sharks are federally protected, meaning there is no recreational fishery. If a fisherman catches one unintentionally, they must release it immediately, with minimal injury, and without removing it from the water. This also means that culling, harming, or otherwise attempting to lower the Sandbar shark population is illegal.
Please exercise caution when fishing with bait at night from the beaches. Striped bass are fun to catch and locally abundant in our waters, even if their population is in crisis, but a poorly revived striped bass is an easy meal for a Sandbar shark. Get your catches in quickly, and release them even quicker to avoid unwanted encounters.
For more information, check out NOAA’s website, or reach out to any local conservation group specializing in sharks and shark behavior.