Chesapeake Bay Rays and Sharks
Sharks and Rays
they're out there
Eight exhausted teenagers doze in the shade on Jefferson Island, part of the Poplar Island chain. Working for the Youth Conservation Corps, their mission that day was to stabilize an eroding shoreline. Shovel by shovel, they unloaded a barge full of oyster shell onto the shore. Now they slept on the grass, wanting nothing more than to rest.
Suddenly, this lethargy was interrupted by the sound of churning water. Curiosity overwhelmed the group and they raced to the end of a pier, scanning the water's surface of Eastern Bay. There, about 20 feet away, the water frothed and a brown fin broke the surface then quickly disappeared. It was the summer of 1979 and I had encountered my first school of cownose rays.
Rays, as well as sharks and skates, belong to a group of primitive fishes, known as elasmobranchs, which do not have a bony skeleton. Instead, the bodies of these ancient creatures are made up of cartilage. Unlike most fishes, some species of elasmobranc hs are able to give birth live.
Skates and rays are commonly described as flat sharks. Their distinct triangular shape sets them apart. Their pectoral (side) fins are flattened and enlarged to look more like wings. This shape is appropriate to these creatures as they seem to fly rather than swim through the water. They are adapted to life at the bottom. The mouth and gills are on the underside of the body. They forage the bottom for mollusks, crustaceans and occasionally small fish that they crush between their teeth. Since the mouth is often buried in the sand, skates and rays have spiracles on the tops of their heads to take in water. Rays have whip-like tails while skates are characterized by their thicker tails. Rays and skates possess spines in their tails that, if stepped on, could inject a painful, though rarely life-threatening, poison.
The cownose ray is the most common of all elasmobranchs in the Chesapeake. Adult cownose rays may be up to 45 inches wide and weigh up to 50 pounds. They have a brown back, whitish belly and a deep notch in the head, giving a double-headed appearance. From above, the head looks like the muzzle of a cow. The cownose ray rarely rests on the bottom so stepping on the spine at the base of the tail Please see RAYS - page 15 is unlikely.
Voracious feeders, cownose rays prefer soft clams. Moving in schools of 5-20 individuals, they churn up the bottom to uncover food. Cownose rays are migratory, moving north along the Atlantic Coast during warmer months and south during cooler months. Many cownose rays spend their summers in Chesapeake Bay, arriving in May and remaining until September or October.
Cownose rays give birth live. Ray pups are born in June and the female is re-fertilized within 10 days. Cownose rays are 11-18 inches wide at birth. They emerge tail-first so as not to harm the mother.
In contrast, skates lay eggs in a hard, thorny capsule often called a mermaid's purse. This purse is attached to vegetation and the young emerge from it. The clearnose skate, common to the Bay, gets its name from the two transparent patches on either side of its pointed nose. Brown to gray in color, the clearnose skate has a row of spines down the middle of its back. The tail also has spines and two fins at the end.
The most common shark species seen in the lower Bay during summer and fall is the sandbar shark. The Chesapeake is a nursery ground for them so most sandbar sharks seen here are juveniles. The young range from 2 to 3 feet in length and adults are up to 8 feet long. Sandbar sharks are dark gray above and white below. A ridge runs between the two dorsal fins. The bullnose shark is similar to the sandbar but lacks the ridge between the two dorsal fins. Although bullnose sharks can grow up to 12 feet, those visiting the Bay are usually less than 6 feet.
Two smaller sharks in the Bay are the smooth dogfish and spiny dogfish. Both species are only 2 to 3 feet long and travel in schools. The smooth dogfish is gray to brown in color and both dorsal fins are about the same size. Spiny dogfish is quickly recognized by the spine in front of each dorsal fin. For the most part, sand and dogfish sharks pose little, if any, danger to humans.
Sharks, rays, and skates in the Chesapeake are found mostly in the lower Bay but some species do travel into the brackish water of the middle Bay.
Most people probably think that the closest they will ever come to observing such ancient and exotic looking animals is on the television or at an aquarium. The dual origins of the Chesapeake, the influx of both freshwater and seawater, provides the oppo rtunities to see things we may never have seen before. Sometimes we just have to sit up and take notice.
Sharks and Rays
Article from Bay Journal