LOBSTERS AND CORAL IN HOT WATER IN THE KEYS
Welcome to the hottest summer in the history of Earth. High temperature records –for both the air and the sea floor– seem to tumble daily. And nowhere are the super heated conditions being monitored more closely than in the Florida Keys where lobster harvest season opened on Aug. 6.
So far at least, adult spiny lobsters seem to be doing okay, despite water temperatures measured in the 90s on both ocean reefs and inshore bays. According to Tom Matthews, who heads the Florida Fish & Wildlife Research Institute’s Marathon marine lab, these full-grown crustaceans are capable of traveling more than three miles per night to seek deeper, cooler waters and areas with strong currents. He said there was no indication of losses of legal-sized lobsters during the two-day recreational lobster mini-season in July. Lots of sport divers managed to score limits of six per person per day.
However, with the weather expected to grow even hotter this month, Matthews and his colleagues are deeply concerned about the long-term outlook for juvenile lobsters which live in and around sponges on the sea floor. If sponges die, then those finger-sized animals are in peril of losing food and shelter that could ultimately impact their populations. Matthews said those effects, if any, would show up in the fishery in about a year.
Meanwhile, hard corals which make up the foundation of ocean ecosystems throughout the globe and provide habitat for a quarter of Earth’s marine creatures, also are suffering severe heat stress –especially in the Lower Keys. Formerly vibrant and colorful animals, many are being bleached a pure white when the hot water causes them to expel protective algae in their tissues. Bleaching doesn’t always kill them and they can recover, but the stress makes them more susceptible to disease.
The unusual heat wave couldn’t come at a worse time for the Keys because the island chain has lost about half of its living coral cover in less than a decade, scientists say. Despite efforts by the state’s research institute and other coral scientists to grow more resilient corals in nurseries for transplantation onto the natural reef tract, those young colonies are in big trouble. Most are bleached and some have died, prompting an emergency rescue operation in late July. The scientists collected as many live corals from the nursery as possible and moved them to tanks on land, pending cooler weather.
Corals aren’t the only creatures getting stressed out by the heat in the Keys; a series of fish kills have been reported to the state hotline: grunts, pinfish, hogfish, mangrove snapper, and several other species. (If you observe dead fish, call the hotline at 800-636-0511.)
“It is getting harder and harder to restore the reef to expectations of a healthy reef,” Matthews said.
But back to the lobster situation: about 100 miles north of the Keys in the Fort Lauderdale area, ocean conditions were completely different. Deerfield Beach lobster-catching guru Jim “Chiefy” Mathie said he and his five mini-season scuba diving companions encountered cooler than usual water temperatures on the reef about 40 feet deep. Mathie said surface waters were in the normal 83-85 degree range, but closer to the bottom, the temperature gauge on his regulator plunged to a relatively chilly 78 degrees.
“Pretty rare,” Mathie said of the bottom temperature. “We see thermoclines like that in the beginning of the summer in May and June. But to have it at the end of July? The currents were screwy. Viz was crappy. It was a weird, strange mini-season.”
But conditions couldn’t have been TOO bad in Fort Lauderdale. Mathie said he and his fellow divers saw little coral bleaching and no dead fish. The divers caught their limit of 12 lobsters per person both days– a big haul.
“Be interesting to see what happens in August,” Mathie said.