Monthly Archives: May 2014
A favorite among beachgoers, sea stars are one of the most popular and recognized echinoderms found in Florida. Like other echinoderms such as brittle stars, sea lilies, urchins, sand dollars, and sea cucumbers sea stars are characterized by a calcareous endoskeleton composed of separate plates, which gives them their rough or “spiny skin” appearance. Sea stars display radial symmetry and possess a vascular system that uses hydraulic pressure to operate tiny tube feet; these tube feet aid a sea star’s movement and feeding.
While a sea star makes a popular souvenir for many beachgoers, it is important to be aware of and follow appropriate harvesting regulations to stay legal and avoid potential fines. Sea stars fall under Florida Fish and Wildlife Conservation Commission’s marine life (aquarium) species regulations. Where recreational harvesting is permitted, a valid saltwater fishing license is required. Other requirements include that the organisms be kept alive and that they are kept in a continuously circulating live well with an aeration or oxygenation system of adequate size to maintain these organisms in a healthy condition. There is also a bag limit of 20 organisms per person per day; only 5 of any one species is allowed within the 20-organism bag limit unless otherwise noted in the regulations. These rules apply in both state and federal waters. To view other restrictions pertaining to harvesting sea stars and other marine life visit: http://myfwc.com/fishing/saltwater/recreational/sea-shells/.
Every spring they appear in force, growing through the summer and then they seem to diminish in late fall. “They” are tunicates, affectionately known as sea squirts and sometimes sea pork.
Tunicates are invertebrates, meaning they lack a backbone. Invertebrates are a very large and diverse group of organisms that include crabs, sea urchins, jellyfish, sponges, worms, spiders and insects, just to name a few.
Tunicates come in many shapes, sizes and colors. They can be solitary, colonial or pelagic. And, they are all marine organisms. There are no freshwater tunicates, but some species can be found in fairly low salinity brackish waters. All tunicates are filter feeders. As such, they all have two siphons. The first takes in water, particles are extracted as a food source and then the water is expelled out the second siphon. Tunicates get their name from their “tunic” or outer covering that protects them from predators. The tunic is made of cellulose, a long chain of linked sugar molecules. Cellulose is more common in plants and is the substance that gives wood its strength.
As filter feeders, tunicates benefit water quality by removing particulates and excess nutrients from the water. Good water quality is important to all marine life and us humans too, but water quality may not be the only way tunicates benefit us. Researchers have been studying various properties of tunicates and have learned that they may possess important anti-cancer properties.