Saturday, May 14, 2011

Belize Expedition: Sharks and Rays (from Pete)

Belize Expedition, 2011
Out here on Carrie Bow Cay, one of the questions that frequently comes up is, “Have you seen any sharks?”

The short answer is “yes,” but it is a far less exciting answer than it sounds. We have a couple of nurse sharks (Ginglymostoma cirratum) which inhabit the reef surrounding Carrie Bow. One of them even regularly resides beneath the dock where we launch our boats.

Moreso than sharks, we have seen a large number or their relatives, rays. Yellow rays (Urolophus jamaicensis) are found in the shallows around Carrie Bow in large numbers. While these animals are not aggressive in the least, we wade carefully through the shallows to avoid stepping on them, and perhaps avoid their defensive barb.

Also found in the shallows are Southern stingrays (Dasyatis americana). While the Southern stingrays that we typically see in the shallows are less than 1 meter in diameter, we have seen some rather large specimens in the 90-foot deep sand channel on the eastern edge of the island; sometimes even hiding in the sand. 

Another ray that we see with regularity is the spotted eagle ray (Aetobatus narinari). These striking creatures regularly exceed 2 meters from wingtip-to-wingtip, and seem to be curious about humans working on the ocean floor. As Jay was taking coral measurements on a dive, a large ray maneuvered within a few feet of him, paused for a moment, and then slowly lumbered away. Neither Jay nor I had ever seen a wild ray exhibit such careful scrutiny of a diver. Needless to say, both of us were quite impressed by the encounter.

One of the animals associated with sharks worldwide are the remoras (family Echeneidae). Over the course of the last couple of weeks we have all become very familiar with remoras [photo in this previous post]. Remoras regularly reach two feet in length, and have a disc shaped suction cup on their head. This suction cup allows remoras to attach themselves to larger animals, often sharks and rays, where the remora can then get a free ride around the reef in search of food.

Remoras, sensing large animals, in the water column often break from their typical hosts, and attach to our dive team while trying to conduct work underwater. It can be very distracting and disconcerting to try to count, measure, and identify fish and corals with a 1-meter grey torpedo attached to your leg. At times, during our ascent from the bottom, we would have upwards of 4 remoras circling our team. While they are an interesting and inquisitive creature I have really begun to dislike them.

Aside from nurse sharks, rays and remoras there are a few species of shark that inhabit the waters surrounding Carrie Bow. Each dive we hope to catch a glimpse of a 5-meter great hammerhead (Sphyrna mokarran), reefsharks (Carcharhinus spp.), or one of the huge whale sharks (Rhincodon typus) that are seen occasionally in the area. Unfortunately, we have not had the opportunity to see these magnificent creatures on this trip, but that just leaves us all wishing for one more dive.


1 comment:

  1. Well, Pete, I have to disagree with you--this is more exciting than it sounds!