The lobster Panulirus argus is a species belonging to the crustacean order Decapoda, family Palinuridae, which inhabits the waters of the western Atlantic Ocean, especially in the Caribbean Sea and the Gulf of Mexico, although it is possible to find specimens from the coasts of North Carolina to Brazil. They are also present in isolation in the eastern Atlantic Ocean, in the Canary Islands and Cape Verde. They generally inhabit relatively shallow waters up to 50 meters deep, although there are records of specimens found at greater depths. During the day they recover in rocky hollows, reefs or any other type of structure that gives them some protection, such as the inside of large barrel sponges.
As its common name indicates, the body of Panulirus argus specimens has a multitude of spines along the exoskeleton from the cephalothorax or carapace to the rostrum and the base of the antennae. Another distinctive feature of this species is the presence of two pairs of whitish spots on the second and fourth abdominal segments. The carapace of Panulirus argus has a reddish to beige color, depending on the bottom in which they live and their diet. The spiny lobster, like other crustaceans, has an exoskeleton that covers, protects and supports its soft body. With the development of the animal, this exoskeleton is shed with certain frequency, a moment that is used to generate a new, slightly larger exoskeleton that allows the specimen to grow.
There is a clear sexual dimorphism between male and female specimens in Panulirus argus. Males have the second pair of legs longer and more robust than the rest of the legs, while in females the fifth pair of legs ends in a small pincer. There are also differences in the abdominal appendages, called pleopods. Females have more developed double pleopods. If we look closely, we will observe in the pleopods structures formed by elongated bristles, whose function is to retain the eggs when the females reach sexual maturity.
During the reproduction of Panulirus argus, the male specimen attaches a sperm sac (called plastron) to the female in the lower region of the female cephalothorax. This sperm sac is easily recognizable as it has a tarry black coloration. Sexually mature females (approximately 2-2.5 years of age) use the molting of their exoskeleton to migrate the eggs from their ovaries to the abdominal part of the tail. During this process, the eggs are rubbed against the oesprmatic sac to fertilize them. Once fertilized, the eggs adhere to the filaments that the females have on their pleopods. A lobster can carry up to 1.3 million eggs in the lower part of its abdomen. This mass of eggs will change color over the course of about a month, from bright orange to dark brown, indicating maturation. As the eggs mature, the females move into deep water to release their eggs once they hatch.
The larval stage of Panulirus argus involves two periods, one in which it is part of the plankton, and a second benthic period of longer duration. During the planktonic stage, the larvae (called phyllosomes) are translucent and are dispersed over long distances by currents. During the benthic stage, the larvae prefer benthic macroalgae, marine phanerogams and mangroves as their habitat.
Both juveniles and adults are carnivorous, feeding on sedentary or slow-moving organisms. Preferences for crustaceans, molluscs and coralline algae have been reported in the diet of Panulirus argus. Some molluscs such as Strombus gigas, clams, crustaceans (crabs), echinoderms (starfish and sea urchins) and polychaetes (marine worms) are also reported as food. Lobsters eat at night and take refuge during the day. The main predators of Panulirus argus include some species of sharks, particularly catsharks (Gynglimostoma cirratum), rays, large species of snappers (Lutjanus) and groupers (Epinephelus), as well as octopuses, dolphins and turtles.
The estimated lifespan of a spiny lobster is 17 years, and it can weigh more than 6 kg.Photos: