Saturday, September 15, 2012

Stingrays


Stingrays are always a hit with families – kids and adults – at aquariums around the country.  This picture was taken at the Georgia Aquarium at their huge whale shark tank. Trust me, its worth a trip to Atlanta. 
This summer, I visited the Texas State Aquarium for the first time. They have a big touch tank where you can touch the fish and feed them. A few dollars gets you a tray of silversides, small fish that make a great stingray snack. 

I love visiting aquariums. I learn something new every time.

Like sharks, stingrays are fish made of cartilage – the same material as your earlobes and the tip of your nose. Their skin is covered in a layer of mucus that protects the stingrays from bacteria. This is why they feel a little slimy if you happen to touch one in an aquarium touch tank.
Stingrays get their name because of the barbs on their tails. The barbs are made from keratin, the same material as you hair and fingernails. They are covered in a toxin and can cause a painful wound.

These fish aren’t aggressive but they enjoy warm shallow water just like we do. They are also very good at camouflaging themselves in the sand. One way to take extra care is to do the “stingray shuffle” when you’re enjoying the beach. Instead of taking steps in the water, shuffle your feet back and forth in the sand as you move. The movement will scare the stingrays away and you both can enjoy your day at the beach.
On the rare chance you do step on a stingray, don’t pull out the barb! Run the area under hot water, as hot as you can stand. The heat will help denature the toxin. A doctor should remove the barb. Even if the barb is not intact, the wounds are easily infected because of the toxins and you might need antibiotics. Take a trip to the hospital to be safe.

Learn more about the stingrays of the Texas State Aquarium. They have Atlantic stingrays, southern stingrays, and cownose rays in the touch tank and a colorful electric ray inside the aquarium.  
Learn more about skates and rays in general at the FloridaMuseum of Natural History or head over to Animal Planet

Photos and video by Sara K. MacSorley 

Monday, September 10, 2012

Silversides


When I was in college I took a course about fish diversity. We learned about fish evolution and memorized a bunch of latin names. I enjoyed when species had the same genus and species name. The Atlantic silverside is one of those fish species, its latin name being Menidia menidia.

There is a whole set of fish called silversides. They have long slim bodies, big eyes, and shiny silver scales.

The old adage “safety in numbers” is true for silversides. Silversides often school, forming large masses like in this video taken during my semester abroad in Bermuda. Coming together as a school makes it harder for a predator to pick out individual fish for food.


Unfortunately for them, silversides are a delicious commodity. The small fish are common and are toward the bottom of the food chain. Predators include seabirds and larger fish like stingrays and striped bass (or rockfish as its fondly called back home).

In addition to being food in the wild, silversides are often used as baitfish and can be bought to feed larger fish in aquariums. Silversides are also sometimes used in toxicity studies. They are sensitive to environmental changes so these tiny fish are important on a much larger scale, as possible indicators of a changing climate. 

Here are several resources to learn more about silversides from the Maryland State Department of Natural Resources and the Marine Biological Laboratory. Check out this Sea Grant fact sheet to learn more about schooling. 

Video by Sara K. MacSorley