Thoughtful Thursdays: Chesapeake Bay Lined Seahorses
Published November 01, 2012
Many people don’t realize that there is a species of seahorse that calls the Chesapeake Bay its home. The lined seahorse, hippocampus erectus, lives in shallow eel grass beds during the summer and moves to deeper submerged aquatic vegetation during the winter. It can typically be found in the lower to middle Chesapeake Bay and, in particularly dry years when the water is saltier, as far north as Kent Island and the Bay Bridge.
Lined Seahorse at National Aquarium, Baltimore
Photo courtesy of Michael Bentley
The lined seahorse varies drastically in both coloration and ornamentation. Individuals can range from a yellowish color all the way down the spectrum to a nearly black color. Some may have intricate ornamentation on their backs and their heads. Additionally, they can change color slightly to match their surroundings. As with all seahorses, males carry a pouch which they use to hold their young after breeding. Breeding itself is complicated, it includes a drawn-out ritual of dancing and clicking between the male and female. At the end of the courtship, females deposit their eggs into the male’s pouch where they are fertilized and held until ready to be released (about 2 weeks).
Lined seahorses vary in color, pattern and ornamentation
Seahorses as a whole are ineffective swimmers. They only use three of their fins (two pectoral fins and one dorsal fin) to swim. They beat these fins rapidly to provide propulsion, but it is not enough to keep them stationary in even the most gentle of currents. It is because of this that they require something to hold on to. For our local lined seahorses in the Chesapeake, that something is often eel grass, as well as other submerged aquatic vegetation. These grasses are vital to the seahorses' ability to hunt, breed and just plain survive. Seahorses are ambush predators and so they need something to anchor themselves to while hunting. As they hide, prehensile tails attached to the eel grass, they wait for prey to float by their snouts.
Lined seahorses have very small fins, making it hard for them to swim.
Unfortunately, eel grass is in trouble in the Chesapeake Bay. Nutrient pollution from farms, sewage and other human activities often leads to large algal blooms, which grow near the surface of the water and block light that the grasses need to grow. Additionally, destructive fishing techniques like bottom trawling can rip up huge swaths of submerged aquatic vegetation, causing wide-spread loss of habitat. Because they are so specialized in their habitat needs, lined seahorses have little hope of successfully hunting and breeding without the grasses. These pressures are threatening seahorses worldwide. As a result of these and other conservation pressures, it is estimated that the world's lined seahorse population has declined by at least 30 percent in the past 10 years. We must begin to take steps to preserve the local habitat, or we risk losing this very interesting and important Chesapeake Bay species.
What you can do to help: Reduce waste runoff, which pollutes waters like the Chesapeake Bay.
- Control insects using natural controls instead of pesticides. Americans directly apply 70 million pounds of pesticides to home lawns and gardens each year and, in so doing, kill birds and other wildlife and pollute our precious water resources.
- Dispose of motor oil and anti-freeze through a local service station or recycling center. A one-quart container of oil disposed of at the local landfill can contaminate up to 2 million gallons of drinking water and the water home of our seahorse friends.
- Don't pour anything down storm drains because they lead to the bay, which connects to the ocean. Most sewer systems and wastewater treatment plants do not remove poisonous cleaners, and yard and car-wash chemicals make their way into local waterways, and, eventually, into our ocean, harming animals along the way. You wouldn't want to swim in those chemicals, and neither do animals!
- Learn more!
To find out more about the lined seahorse and the troubles threatening them in our area, listen to this special seahorse edition of WYPR's Environment in Focus with Tom Pelton