Wednesday, September 17, 2014

A Coastal Triathlete: Brown Pelican

Photo taken by Cindy Elder
If you've ever taken an auto trip, you've probably seen bicyclists riding closely behind each other in a straight line. This technique, called a "pace line," allows the riders an opportunity to "draft" the cyclist just in front, cutting down wind resistance for subsequent riders. And if you've walked one of our beaches you probably have seen brown pelicans, Pelecanus occidentalis, flying in a similar formation. What those pelicans do instinctively takes most bicyclists weeks or months to perfect. For a brown pelican that can weigh up to 15 pounds, it's truly an energy-saving technique, allowing these birds to ride the marine air currents, rising and falling with the waves, with minimum effort.

Brown pelicans can be found from the coasts and estuaries of the mid-Atlantic and around the Gulf of Mexico. Some groups may migrate several hundred miles during the year, while others live their lives around the same shorelines. Whether they migrate or not, pelicans are never far from land and relatively shallow water depths. These are the areas in which they feed and breed. And if you think the pelican pace line is a pretty savvy way to get around, you'll be impressed at their fishing technique. A pelican's method of catching fish can be compared to a defensive end's approach to tackling the runner in a football game. Both dive right at their target with head tucked, and in the case of the pelican, with a slight rotation to the left (to protect the trachea on the right side of the bird's neck). The impact of the hit stuns the target (in the football game it at least shuts down the ball's advance toward the goalposts). The pelican's goal is to consume the fish knocked unconscious by the force of its collision with the water. Both the defensive end and the pelican have their protective equipment. Shoulder pads and a helmet for the man, air sacs beneath the pelican's skin that inflate like little air bags.

P. occidentalis is not a dainty eater; it expands its trachea, quickly taking in both fish and water before the fish recover from the blow. Nearby seagulls flock to the dive site, knowing the pelican must open its bill upon surfacing in order to rid itself of the water before swallowing its meal. The gulls will attempt to literally snatch the food out of the pelican's mouth; the ensuing scramble is reminiscent of the post-play pile-ons so commonly seen in football. Considering how last Sunday's game went against the Eagles, our Jacksonville Jaguars might benefit from a lesson in tackling given by P. occidentalis.

Come to the GTM Research Reserve's Family ecoMENTALITY National Estuaries Day on September 27 and you'll be able to watch this triathlete's skill: flying, and fishing, and the diving play-by-plays of pelican vs. gull right at the estuary's line of scrimmage.


Wednesday, September 3, 2014

All about that bass, no treble...hooks

Sciaenops ocellatus: Fried, Baked, or Blackened

If you saw this notation on a restaurant menu, would you order it? If you said, "yes," you know your redfish! Red Drum, commonly called, "redfish," "channel bass", or "spot tail," are popular restaurant faire, and no Cajun restaurant would open its doors without offering it to customers. This local fish is also a favorite of saltwater sports fishermen - so much so that states set annual catch limits to protect it from being overfished. Whether you like to catch it or eat it, you should thank your local estuary for its role in this fish's life cycle.

Red drum females mature at 4.5 years of age. The males do so around 3.5 years. Between August and December the drums leave their coastal habitat to gather at the mouths of inlets to spawn. The males use muscular contractions to vibrate their swim bladders, making a drumming sound. Apparently the females enjoy the noise; they can release up to 1.5 million eggs per batch. That's an enthusiastic response. Fertilized eggs are carried by the tides into an estuary (like the GTM Research Reserve estuary) to spend the next three or four years eating small crustaceans and marine worms. When mature, S. ocellatus heads out to join the other adults at the coastal "drumming session". Both sexes "drum" their swim bladders when agitated; that behavior has earned them the fisherman's name of drum.
The redfish you'll see listed on a restaurant menu are probably not wild caught. Red drums are typically grown as aquaculture. If you want to see one in the wild, but don't want to get a license and a fishing pole, sign up for a Family Seining activity as part of National Estuaries Day, Saturday, September 27, at the GTM Research Reserve. Maybe you'll find a juvenile in your net!