‘Coffee with a scientist’: stone crab stresses

March 16, 2018
By Marcy Shortuse

The second “Coffee With a scientist” event of the season sponsored by Mote Marine Laboratory was held on Wednesday, March 14 at the Boca Grande Mote office.
This week’s discussion was presented by Dr. Phil Gravinese.
During his talk, “Responding in a Pinch: Determining the Impacts of Man-Made Stressors on the Florida Stone Crab,” Gravinese pointed out that the life expectancy of a stone crab is about eight years, and it can take up to two years to regenerate a claw when they are removed by fisherman.
The marine biologist has spent the last several years researching the levels of stress stone crabs go through when harvesters remove their claws.
“The good news is that we are working with them and they are willing to learn about our research for sustainability purposes,” Gravinese said.
After years of teaching in Florida’s public schools and at Eastern Florida State College, Gravinese joined the Mote team in February 2017. His research interests focus primarily on determining how anthropogenic stressors, like ocean acidification and elevated seawater temperatures will impact the reproductive biology, development, and behavior of one of Florida’s most lucrative fisheries, the Florida stone crab.
During his research, he raised larval stone crabs from hatching in order to perform experiments that were designed to characterize how stone crab larvae control their swimming in response to endogenous and exogenous cues (light, pressure and gravity).
Stone crabs sit on the ocean floor, and they are preyed upon by pecking predators.
Research has shown that when someone breaks a claw, stress levels go up tremendously because it results in the inability to defend itself.
For sustainability purposes, it is suggested to only remove one claw at a time, but it is legal to remove both if it is of legal size.
“One of the greatest challenges for the management of crustacean fisheries is the inability to adequately correlate the success rate of larvae and juveniles recruiting back to the fishery with fine-scale environmental changes that occur within coastal habitats,” Gravinese said. “The research in the laboratory begins to address this challenge.”
His work interests include determining the mechanisms that underlie the recruitment and settlement behavior of larval crabs by assessing the role different environmental and chemical cues play during development, habitat selection and metamorphosis.
His lab is also attempting to characterize how combined stressors like elevated temperature and hypoxia (low oxygen) can impact stone crabs.
Recently, Dr. Gravinese has been conducting experiments to determine the stone crab’s tolerance during red tide events that usually occur along Florida’s west coast.
In 2012, he co-founded an international marine-science film-making competition for K-12 students called Youth Making Ripples. The program challenges the next generation of ocean enthusiast to promote marine conservation.
The next Coffee With a Scientist free event is scheduled for 9 a.m. on Wednesday, March 21 at 480 East Railroad Avenue on the island.
Dr. Jim Locasci, Mote’s Fisheries Habitat Ecology Research Program Manager, will speak about his recent research.
For more information, visit mote.org.