Curator calls museum’s skates and rays ‘fascinating’
They might not be as cute and cuddly-looking as the star-of-the-show otters at the Calvert Marine Museum, but David Moyer, curator of estuarine biology, says there is much guests can learn from the museum’s skates and rays.
“I think the most interesting thing … is that people have misunderstandings of them,” Moyer said.
The skates and rays are the first living creatures visitors to the marine museum encounter by way of an exhibit with a large round pool in the center. The exhibit started out as a temporary one a decade or so ago, but the creatures were so popular that the exhibit, called “The secrets of the mermaid’s purse,” became permanent, Moyer said.
Visitors get the chance to interact and touch the skates and rays from time to time, unlike the other critters who live at the museum. However, a trained person has to be manning the exhibit for this to occur. During the rest of the time, visitors should obey the “don’t touch” signage.
“They’re just fascinating to watch,” Moyer said.
Skates and rays look alike and are managed very similarly, but have some key differences. First of all, skates lay eggs, while rays give birth to their young. The egg casings laid by skates are called mermaid’s purses and can commonly be found while beach-combing, even along the Chesapeake Bay.
Skate babies take eight to 12 weeks to develop and hatch, and staff at the Calvert Marine Museum can shine a light on the mermaid’s purses to see how the young skate inside each one is developing. To do the same for a ray, an ultrasound would be required. Next to the large round tank where the adult skates and rays swim, there’s a smaller tank containing mermaid’s purses as well as some young skates, so all stages of the skate’s life cycle are on display at once.
Another big difference between skates and rays is that only the rays have the ability to sting, which tends to give them a bad reputation, especially after a large species of ray killed the “Crocodile Hunter” Steve Irwin.
But rays will only sting when threatened. Most stinging incidents happen when humans accidentally step on rays that are hanging out on the bottom. While a jellyfish sting is a surface sting on the skin, the stinging of a ray is from a sharp barb that breaks the skin and causes internal damage.
The rays at the Calvert Marine Museum periodically get their barbs trimmed, as they’re made of a fingernail-like material. Trimming the sharp tip of the barb means it can’t easily break skin. Throughout their lives, rays will grow multiple stingers and shed them.
The misconceptions of the rays extend beyond the stingers. Moyer said oystermen tend to think cownose rays are problematic, but the reason behind the problem is that other people are killing sharks, which are the main predators of cownose rays. In recent years, cownose ray hunting contests have been at the center of controversy.
To restore the shark population to a state where the ray population gets back under control would take about 30 years, Moyer said.
“The problem is not the cownose rays, the problem is humans … taking out top level predators … The reality is, we are the problem. We’ve disrupted the food web and we get mad,” Moyer said.
Above, a ray swims along in the main exhibit tank at the Calvert Marine Museum. Below, skates lay eggs in “mermaid’s purses,” pictured here, while rays give birth to their young.
Skates lay eggs in “mermaid’s purses,” pictured here, while rays give birth to their young.
A smaller viewing tank allows visitors to see unhatched mermaid’s purses as well as young baby skates.
David Moyer, curator of estuarine biology at the Calvert Marine Museum, watches skates and rays in the exhibit tank.