{"id":939,"date":"2013-03-01T12:27:00","date_gmt":"2013-03-01T17:27:00","guid":{"rendered":"http:\/\/ncseagrant.ncsu.edu\/coastwatch\/?page_id=939"},"modified":"2024-09-24T13:26:37","modified_gmt":"2024-09-24T17:26:37","slug":"naturalists-notebook-dinosaurs-in-the-rivers","status":"publish","type":"post","link":"https:\/\/ncseagrant.ncsu.edu\/coastwatch\/naturalists-notebook-dinosaurs-in-the-rivers\/","title":{"rendered":"NATURALIST’S NOTEBOOK: Dinosaurs in the Rivers?"},"content":{"rendered":"\n\n\n\n\n
A prehistoric species, Atlantic sturgeon were a common menu item along the East Coast in the 19th century. However, Atlantic sturgeon are making news these days for placement on a different list: the federal endangered species list.<\/p>\n\n\n\n
These fish date back 120 million years and even have dinosaur-like armor from five rows of bony plates, or scutes. The plates provide camouflage and protection from predators for the bottom-dwelling fish that can be 10 feet long and weigh 500 pounds.<\/p>\n\n\n\n
“They are really dinosaur-like in the way that they behave,” says Mary Moser. In the 1990s, the N.C. Fishery Resource Grant Program, administered by North Carolina Sea Grant, funded some of her sturgeon research. She is still considered an expert on its habitats in the state.<\/p>\n\n\n\n
“It always impresses me that they aren’t like other fish that get so frantic and panic when you handle them. They basically just wait for you to do whatever you are going to do to them. Then you will put them back into the water and they will slowly swim away,” she continues.<\/p>\n\n\n\n
Sturgeon are anadromous fish. They migrate into the freshwater coastal rivers to spawn but spend the majority of their lifetime in the sounds and ocean. In North Carolina, adult and juvenile Atlantic sturgeon can be found in the Roanoke, Chowan, Tar, Neuse and Cape Fear rivers during the spawning season.<\/p>\n\n\n\n
“Part of the reason why North Carolina has always been a haven for Atlantic sturgeon is that North Carolina has such an extensive estuary system where Atlantic sturgeon thrive,” says Moser, now a National Marine Fisheries Service biologist.<\/p>\n\n\n\n
With a life span of up to 60 years, their age of maturation, when they are ready to spawn, is much greater than other fish species \u2014 about eight to 10 years for males and up to 20 years for females.<\/p>\n\n\n\n
There are few predators for the species due to their protective covering and massive size. The main threats to Atlantic sturgeon are from human activity, such as boat strikes in coastal rivers. Poor water quality and habitat alteration or destruction also are leading issues.<\/p>\n\n\n\n
Sturgeon, Acipenser oxyrinchus, range up and down the East Coast and are broken into five distinct population segments. The National Marine Fisheries Service categorizes the different populations based on genetically unique differences, explains Michael Loeffler, N.C. Division of Marine Fisheries specialist on Atlantic sturgeon.<\/p>\n\n\n\n
The Carolina population was officially listed under the Endangered Species Act on April 6, 2012. This distinct population segment stretches from the Albemarle Sound southward to the Charleston Harbor in South Carolina, with accounts of sightings spanning centuries.<\/p>\n\n\n\n
Writing about North Carolina sturgeon in 1709, British explorer and naturalist John Lawson describes, “Of sturgeon we have plenty, all the fresh parts of our rivers being well stored therewith. The Indians upon and towards the heads and falls of our rivers, strike a great many of these, and eat them; yet the Indians near the salt-waters will not eat them. I have seen an Indian strike one of these fish, seven foot long, and leave him on the sands to be eaten by the gulls. In May, they run up towards the heads of the rivers, where you see several hundreds of them in one day. The Indians have another way to take them, which is by nets at the end of a pole. The bones of these fish make good nutmeg-graters.”<\/p>\n\n\n\n
In the late 1800s, fishermen began commercially fishing the abundant Atlantic sturgeon species. Dare County was known as a market hub.<\/p>\n\n\n\n
In 1907, Hugh M. Smith, author of The Fishes of North Carolina, described the changes of the 1880s.<\/p>\n\n\n\n
“Within a comparatively few years the fish, formerly regarded as of little value, has come into use on account of its eggs, which are made into caviar, and also on account of its flesh, which is now highly regarded and brings a good price.”<\/p>\n\n\n\n
Loeffler adds that during those years, “In some areas, the eggs could be sold for a couple thousand dollars an ounce.”<\/p>\n\n\n\n
But the economic lure for the large North Carolina commercial fishing industry of Atlantic sturgeon drastically diminished the population, Smith noted. “It is incumbent on the state to take prompt and radical measures to prevent the further diminution in the supply of this excellent fish, and to restore it to something like its original abundance, if this is now possible.”<\/p>\n\n\n\n
Those comments ring true today. “Sturgeon are their own worst enemy,” adds Joe Hightower, North Carolina State University fisheries biologist. “They take a long time to reproduce. Females are said to skip spawn, which means they only spawn every three to five years. They grow slowly and they are also a very predictable fish in that they come into the rivers every time they are going to spawn.”<\/p>\n\n\n\n
In his 1907 work that was Volume II of the North Carolina Geological and Economic Survey, Smith mentions that Atlantic sturgeon would move into the rivers to spawn in the spring. However, current research suggests a fall spawning period, Loeffler explains.<\/p>\n\n\n\n
Moser describes them as a “boom and bust” species. “They spawn multiple times in their lifetime and they live for a very long time, so they may have a lot of spawning events that don’t produce very many juveniles. But if everything lines up and they have a really good spawning event, then that group of sturgeon will carry the population for a really long time,” she explains.<\/p>\n\n\n\n