Fish Feature: Atlantic Sturgeon
Our new Fish Feature series will share posts from New England Ocean Odyssey’s weekly “Fish Fridays.” New England Ocean Odyssey uses breathtaking images and captivating stories to highlight the amazing riches and diversity of New England’s ocean and bring attention to the issues facing it.
Let’s dive into this week’s feature: the threatened, yet resilient Atlantic sturgeon
This fish species looks like a creature from prehistoric times, and for good reason. Sturgeons (family Acipenseridae) are a group of primitive fishes that emerged about 70 million years ago during the Upper Cretaceous epoch. In fact, some of the best-preserved fossils were discovered in dinosaur stomachs! While sturgeons today have cartilaginous skeletons (as opposed to their bony ancestors), they have retained many primitive features. These include bony plates (called scutes) instead of scales, long “whiskers” (called barbels) covered in taste buds that dangle from the underside of their snouts, and the ability to shoot out their tubular mouths to inhale prey1.
Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) can be distinguished from other sturgeon species by their large size, small mouth, and distinct snout shape. They range from dark blue and black to olive green on their backs and have lighter bellies. Adults can measure up to 800 pounds and may reach 14 feet long!
They have been aged up to 60 years old and generally reach sexual maturity between 10 and 35 years old, although southern populations may mature faster. Males typically spawn every 1 to 5 years, while females will spawn every 2 to 5 years.
Atlantic sturgeon are anadromous fish, meaning they are born in fresh water, spend a majority of their adult lives in the ocean, and return to fresh water to spawn. In the spring (May and June in northern waters), Atlantic sturgeon migrate from their oceanic ranges into rivers along the Atlantic coast from Florida to Labrador, Canada, where they spawn at the border of fresh and salt water. This dependence on estuarine habitat, in combination with late spawning age, makes Atlantic sturgeon particularly vulnerable to human threats such as dams, water pollution, and overfishing.
In 1998, the Atlantic States Marine Fisheries Commission (ASMFC) and the federal government implemented a coast-wide moratorium on commercial harvest that remains in place today. While this prevents intentional harvest of Atlantic sturgeon, many factors continue to threaten stocks up and down the coast: dams prevent migration to spawning grounds, dredging ruins spawning areas altogether, water pollution (often due to coastal development) hinders juvenile development, and other commercial fisheries accidentally harvest Atlantic sturgeon as bycatch.
To address these additional threats, NOAA listed five populations under the Endangered Species Act (ESA) in 2012. The Gulf of Maine population was listed as threatened, while the Chesapeake Bay, New York Bight, Carolina, and South Atlantic populations were listed as endangered.
With money made available by the ESA listing, NOAA’s National Marine Fisheries Service was able to invest in research to determine human threats to Atlantic sturgeon populations and devise mitigation strategies, such as nets that will allow sturgeon to escape while still capturing smaller fish.
In the Gulf of Maine, multiple dams have been or will be removed, allowing Atlantic sturgeon to return to their historical spawning grounds. There have recently been reports of potentially higher catch-per-unit-effort than in the past – a sign that the population may be recovering.
There are still a lot of cards stacked against the Atlantic sturgeon; we have much left to learn about their distribution, and, at the moment, NOAA has little control over when and where dredging occurs. But, as conservation writer and editor Ted Williams says, “Maybe the greatest value of the Endangered Species Act — greater even than information it generates about how and where animals live and the threats they face — is the knowledge that it’s not too late to save them…Atlantic sturgeon didn’t make it for 70 million years without being resilient.”