Thursday, August 12, 2010
Thallasia Thursday in the Sun
The day started with a lesson on mangroves, which make up an important ecosystem in the tropics. These specialized trees, the red, black, white and gray mangroves, help to protect the islands, stabilize sediment and serve as nurseries for the coral reef. Our snorkel along the red mangroves delivered a snapshot at this amazing, but often unprotected area. Seen by some as nuisance plants that are bulldozed to make sandy beaches, the mangrove community that we experienced showed us oysters, colorful worms, small fishes and even a problematic invasive…the lionfish! These fish have made their way from its native Pacific to home aquaria where they have been released to the wild. Roatan saw its first lionfish last year and already we have seen this venomous invader on several of our dives/snorkels. Fortunately, our dedicated dive-master, Alson, was prepared to capture and eliminate the 3 lionfish that the group spotted on our snorkel. Shouts of “lionfish” sent Alson over to rid the area of this dangerous fish. More than just a threat to unknowing snorkelers or divers, this Pacific invader has a huge mouth and a voracious appetite for small reef fish. Some biologists believe they can eats dozens of small fishes each day, which has the potential to impact fish communities on the reef.
After lunch, Helen gave a lecture that compared/contrasted the fishes of the Great Lakes with marine fish. COSEE Great Lakes teaches about ocean literacy through this course, but since the teachers call the Great Lakes home, it is important for them to realize there can be a connection between fish species. Body-shapes, fin structure, coloration and reproductive strategies can be compared/contrasted between the two distinctive environments.
The evening ended with a night dive for part of the group. These dives offer a unique experience to be on the reef during an important transition time from daylight to night, when the reef comes alive with creatures not seen during the day.