Five years ago, a marine biologist from Clemson University made an interesting discovery involving a species of nemertean worm that affects Caribbean spiny lobsters. Antonio Baeza, an associate professor in the Department of Biological Sciences, stumbled upon this new worm while studying the parental behaviors of the spiny lobster Panulirus argus in the Florida Keys. In a light-hearted gesture, Baeza named the worm Carcinonemertes conanobrieni after comedian Conan O'Brien, due to its physical characteristics of being long-bodied, pale, and slightly tinted orange.
This worm has been found off the coast of the Colombian and West Indies. Caribbean spiny lobsters, known for the forward-pointing spines covering their bodies, inhabit tropical and subtropical waters in the Atlantic Ocean. Their range extends as far north as North Carolina, encompassing the Caribbean Sea and the Gulf of Mexico. These lobsters are ecologically significant and economically valuable species in the Caribbean.
Over the past decade, the landings of Caribbean spiny lobsters have declined, and scientists have been investigating the reasons behind this trend. Potential causes include overfishing, declining water quality, global climate change, and environmental degradation. A recent study published in BMC Zoology suggests that the worm discovered by Baeza may also be a contributing factor.
To assess the impact of C. conanobrieni on spiny lobsters, artisan fishers captured 90 egg-bearing lobsters near Pueblo Viejo, Magdalena, Colombia. The study aimed to determine the effects of the worm on embryo mortality, fecundity, and reproductive output in brooding females. Out of the 90 lobsters examined, nearly 88% had either nemertean worms or worm cysts and egg masses.
Infected gravid female lobsters displayed embryo mortality ranging from 0% to 43.81%, as indicated by empty capsules and dead embryos. Non-infected gravid females did not show any signs of embryo mortality. The presence of the worm was also found to impact reproductive output.
Baeza mentioned that the effect of the parasite varies among individual females, with some being heavily affected while others are not. The extent of the overall population-level impact is still unknown, and further data is required to determine whether it will be detrimental or catastrophic.
Carcinonemertes worms have previously caused the collapse of crustacean fisheries on the west coast of North America. Caribbean spiny lobsters play a vital role in the marine ecosystem as prey for various predators such as sharks, large fish (e.g., grouper and snapper), turtles, and octopuses. They also act as predators themselves, feeding on snails, crabs, and clams. When lobsters consume clams, they connect different tropic chains, facilitating energy flow throughout the entire ecosystem.
Baeza emphasized the importance of Caribbean spiny lobsters to the fishing industry and coastal communities across the entire Caribbean basin. Understanding the prevalence of the egg predator and its effects could enable researchers to develop models that predict future landings. This information would be valuable for fishery managers, helping them minimize adverse effects and make informed decisions.
The study involved the participation of Clemson graduate student Natalie Stephens, as well as researchers from Colombia and Chile.
Source: Clemson University