Spiny Lobsters: Characteristics, Conga Lines, Mating and Fishing

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20120519-spiny lobster TucacasBajoMeroPanulirusArgus.JPG
spiny lobster
There are two main types of lobsters: 1) those with large claws, like the American lobster; and 2) spiny-type lobsters without big claws. Spiny-type lobsters including the Caribbean spiny lobster; Rock lobsters or crayfish, associated with Australia, are similar to these. Spiny lobsters are found in tropical oceans while those with claws are generally found in colder water

Caribbean spiny lobsters (Scientific name: Panulirus argus) have a reddish brown shell , marked with occasional dark spots on the body and two large, yellowish cream-colored spots on the top of the second segment of the tail. It is estimated that these lobsters live 12 to 20 years in the wild, but there is uncertainty here as estimating their age is difficult. Age is typically estimated by size. These lobsters are harvested for their tail meat. Items marketed as “lobster tail” are usually from spiny lobster.[Source: NOAA]

Also known as crawfish, rock lobster, bug, Florida lobster and Langosta espinosa, Caribbean spiny lobsters get their name from forward-pointing spines that cover their bodies to help protect them from predators. They have long, horn-like antennae over their eyes that they wave to scare off predators, and smaller antennae-like “antennules” that sense movement and detect chemicals in the water. Unlike the American lobster, they lack large front claws.

Spiny lobsters are commonly harvested for commercial purposes. They are second only to shrimp in commercial importance in Florida fisheries. They are also a popular catch among snorkelers and scuba divers. They are categorized as "Data Deficient" by the International Union for Conservation of Nature (IUCN) Red List. They have no special status according to the Convention on the International Trade in Endangered Species (CITES). [Source: Nadine Seudeal, Animal Diversity Web (ADW) /=]

Websites and Resources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Fishbase fishbase.se ; Encyclopedia of Life eol.org ; Smithsonian Oceans Portal ocean.si.edu/ocean-life-ecosystems

Spiny Lobster Habitat and Where They Are Found

20120519-Lobster_300.jpgCaribbean spiny lobster are found in the western Atlantic in tropical and subtropical waters along the continental shelf of the southeastern United States from North Carolina to Texas, in Bermuda, throughout the Caribbean Sea and Gulf of Mexico, and as far south as Rio de Janiero, Brazil.

Caribbean spiny lobster are often found in reefs and live in shallow waters to depths of 90 meters (295 feet), and occasionally deeper. They are benthic creatures that live on or near the bottom of the sea. Larvae are pelagic (open ocean) creatures, moving into nearshore habitats as get older. Juveniles are found in vegetation, particularly in seaweed areas, sea grass beds and occasionally among large sponges. Adults are found offshore, often in coral reefs, rocks, and eelgrass beds. [Source: Nadine Seudeal, Animal Diversity Web (ADW) /=]

Caribbean spiny lobster as their implies are associated with the Caribbean Sea. In U.S. waters, there are above target population levels in St. Thomas-St. John, St. Croix, and Puerto Rico. The population levels are unknown in the South Atlantic and the Gulf of Mexico, but presumed stable. [Source: NOAA]

Spiny Lobster Physical Characteristics

Caribbean spiny lobsters are cold blooded (ectothermic, use heat from the environment and adapt their behavior to regulate body temperature),, bilateral symmetry (both sides of the animal are the same). They range in weight from 0.5 to 6.8 kilograms (1.12 to 15 pounds) and reach lengths of 45 centimeters (18 inches), with their average length being 20 centimeters (7.87 inches). and individuals close to 60 centimeters long have been reported. In regards to sexual dimorphism (differences between males and females): Males and females have different shapes.[Source: Although males and females are typically the same length, males tend to have longer carapaces. Nadine Seudeal, Animal Diversity Web (ADW) /=]

Caribbean spiny lobster

Caribbean spiny lobsters grow by molting — they vacate their old shells while simultaneously absorbing water, expanding their body size. They molt about 25 times in their first 5 to 7 years of life, and once per year when they’re older. It takes them about 2 years to grow to the 3-inch carapace (shell) legal-harvesting size. They grow throughout their lives. After molting new shell shows signs of hardening within 12 days but does not completely harden until around 40 days after the old one was shed.

According to Animal Diversity Web: Adults have two long antennae (longer than the carapace), antennules (small antennae, about two-thirds of the body length), and large eyes at the front of the head. They have pleopods, which aid in swimming, and claws (quite different from the large, pinching claws of Atlantic lobsters (Homarus americanus)). Caribbean spiny lobsters range from red to brown and blue in color. Adult lobsters have brown, white, or yellow spots on their tails and orange-yellow and black stripes on their tail fans. Their legs are striped with blue. Juveniles are purple in color. /=\

Spiny Lobster Behavior and Conga Lines

Spiny lobster are nocturnal (active at night), motile (move around as opposed to being stationary), migratory (make seasonal movements between regions, such as between breeding and wintering grounds), sedentary (remain in the same area) and solitary. [Source: Nadine Seudeal, Animal Diversity Web (ADW) /=]

range of the Caribbean spiny lobster

Spiny lobster spend most of their time in caves or crevasses in the reef, with only their antennae protruding. Often characterized as being solitary loners, they are actually quite social, preferring to hang out in caves with others nearby. They fight a lot though and often vent their anger by peeing at their rivals using a bladder that is on their head.

Spiny lobsters in coral reefs off Florida and the Bahamas form massive conga lines with up to 50 individuals and migrate to relatively warm water when the first autumn storms stir up the water. The lobsters march across the sandy sea floor in a single file, head to tail, head to tail, and so on, heading towards deep water where they are safe from churning water of the storm. They maintain contact through touch with their antennae or sight of the lobster in front of them. This migration may be in order to locate more favorable temperatures or food sources. Forming lines helps them avoid getting knocked around, reduces drag and provide protection from predators. Those that get left behind are munched on by parrot fish or triggerfish.

Spiny lobsters generally spend the day hiding in rock or coral crevices. After they have just molted they are extremely vulnerable to predation, so they stay hidden in the reef to avoid predators. Molting patterns vary depending on locality. Some go through four molts a year. Off of Florida, these lobsters molt twice a year, from March through July and from December through January; Motling frequency decreases with age and size.

Spiny Lobster Perception and Communication

Caribbean spiny lobsters communicate with vision, touch, sound and chemicals usually detected by smelling. They also employ pheromones (chemicals released into air or water that are detected by and responded to by other animals of the same species) and vibrations and sense using vision, touch, vibrations, magnetism and chemicals usually detected with smelling or smelling-like senses. [Source: Nadine Seudeal, Animal Diversity Web (ADW) /=]

rock lobster of Australia and New Zealand

Caribbean spiny lobsters use their antennules to sense water movements. They also use olfactory cues. Females detect levels of pheromones (chemicals released into air or water that are detected by and responded to by other animals of the same species) produced by developing embryos to judge time to hatching. Their large compound eyes sense light, color, and movement. These lobsters can also detect magnetic fields, which they may use for navigation purposes during migrations.

Spiny lobsters produce a rasping noise when threatened by conger eel by rubbing their hard antennae along a toothed spike that projects from their head between their eyes. All lobsters who hear the noise take cover in their caves. In colder, deeper water the body temperatures of lobsters drops. This helps them conserve energy and lower their food needs at a time of the year when food supplies are low.

Spiny Lobster Food, Eating Behavior and Predators

Young spiny lobsters feed on soft-bodied plankton (tiny floating plants and animals). Juveniles and adults are carnivores, preying on gastropods (snails), bivalves (clams), chitons (kinds of molluscs) and crabs. They also eat carrion and other organisms like crustaceans, worms, and sea urchins. They are considered omnivores and have been observed occasionally eating vegetation. They typically hide away during the day and forage for food at night. When feeding on animals with shells, these lobsters use their front legs to bring prey close to their mouth and crush the shell with their mandibles.[Source: Nadine Seudeal, Animal Diversity Web (ADW) /=]

Many predators feed on juvenile and adult spiny lobster, including groupers, snappers, sharks, skates, turtles, octopuses, rays, sea turtles, moray eels, crustaceans, and fishes. Humans like to catch eat these lobsters. Their main known predators are nurse sharks, bonnethead sharks, loggerhead turtles, bonefish, toadfishes, gray snappers and triggerfishes.

Caribbean spiny lobsters avoid predation by hiding in crevices or spaces in reefs. When predators approach these lobsters, they use their antennae to defend themselves. According to Animal Diversity Web: They rub a plectrum, which is a nub like structure found on their antennae, against plates below their eyes. The result is a screeching sound that plays a role in their defense against predators, possibly scaring them away. This is known as the "stick and slip" mechanism. Additionally, they may flip their tails forward, thrusting them quickly in another direction, if threatened. This behavior is known as a "tail flip," and is usually only seen in open areas. [Source: Nadine Seudeal, Animal Diversity Web (ADW) /=]

Spiny Lobster Mating, Reproduction and Offspring

in East Asia and Oceania: spiny lobster in yellow and rock lobster in blue

Spiny lobsters are iteroparous (offspring are produced in groups such as litters multiple times in successive annual or seasonal cycles) and engage in seasonal breeding. Reproduction is external, meaning the male’s sperm fertilizes the female’s egg outside her body. They use delayed fertilization in which there is a period of time between copulation and actual use of sperm to fertilize eggs, and employ sperm-storing (producing young from sperm that has been stored, allowing it be used for fertilization at some time after mating).[Source: Nadine Seudeal, Animal Diversity Web (ADW), NOAA]

Caribbean spiny lobsters mate at least once a year. If they mate a second time, it is typically one week after a brood of eggs hatches. The breeding season is March-June or June-November, depending on location. The number of offspring ranges from 230,000 to 2,600,000 each time they spawn, depending on the size of the female that releases them. The average gestation period is one month. On average males and females reach sexual maturity at two years. After fertilization, female Caribbean spiny lobsters carry fertilized eggs on their pleopods until hatching, at which time larvae are independent. Males do not exhibit any

Females can reproduce when they reach 7 to 7.6 centimeters (to 2.75 to 3 inches) carapace length in the southeastern United States, and 9 centimeters (3.6 inches) in the Caribbean. They spawn from March through August in the Florida Keys on offshore reefs, and spawn throughout the year in the Caribbean. The male spiny lobster deposits sperm packets on the underside of the female. She scratches them to release sperm as she releases her eggs The female carries the fertilized eggs beneath her tail, and is referred to as “berried.” The eggs hatch in about three weeks. Increasing embryonic pheromone levels indicate readiness to hatch and trigger more vigorous respiratory pumping by the female, helping the eggs to hatch.

Caribbean spiny lobsters are polygamous. Males mate with many females, while the females only mate with one male during a single reproductive event. episode. If a female does mate a second time in a season, she does not necessarily mate with the same male. According to Animal Diversity Web: A male seeks out a female and when he finds her, he uses his front legs to gently coax her out of her shelter. The lobsters then lie belly-to-belly and the male releases a spermatophore onto the female's tail or underside of her belly. She breaks the spermatophore open when the eggs are ready to be fertilized. When eggs are ready to be fertilized, a female will scratch open the spermatophore deposited by the male, resulting in external fertilization (some consider this a form of delayed fertilization).

Spiny Lobster Development

During the pre-fertilization and pre-birth stages provisioning and protecting is done by females. Eggs are bright orange and darken in color as embryos develop. They usually hatch within three weeks of fertilization. Until they hatch the eggs adhere to the female's pleopods. The female keeps her eggs well aerated and cleaned by using a pumping action of her pleopods. [Source: Nadine Seudeal, Animal Diversity Web (ADW), NOAA]

Flat, leaf-shaped planktonic phyllosoma larvae hatch from the eggs and are propelled away from the female by flexation of her abdomen. Larval spiny lobster float in the water column and ocean currents ideally move them into shallower areas with seagrass. Most of the spiny lobster larvae found in U.S. waters are from upstream sources in the Caribbean.

California spiny lobster

California spiny lobster breeding and development timing

The larvae migrate vertically throughout the day, into shallower waters at night and deeper waters during daylight hours. As they grow, they swim to nearshore habitats and settle in dense vegetation, especially among seaweed and sea grass. They live there until they reach about 1.5 to 2 centimeters (0.6 to 0.8 inches), when they seek shelter in crevices provided by large sponges, rocks of soft corals. When they reach 5 to 8 centimeters (2 to 3.15 inches), they travel from their nearshore nursery habitat to shallow banks in nearshore waters. As mature adults, they inhabit bays, estuarine areas, coral reefs and other offshore habitats, but are found on softbottom and seagrass during migratory periods. Adults move along shore and offshore seasonally, migrating in single-file lines to deeper water to escape cold and turbid waters..

It is estimated that spiny lobsters reach maturity by two years of age when they are 7 to 8 centimeters (2.7 to 3.1 inches) in length. According to Animal Diversity Web: Larvae undergo 11 distinct phyllosoma stages, by which they metamorphose into pueruli, which resemble adults but are smaller (about 34 millimeters at metamorphosis), colorless, and do not feed or possess hard exoskeletons. After approximately six months, they molt and metamorphose into juvenile lobsters. Juveniles are solitary and usually benthic (living on or near the bottom of the sea).

Spiny Lobster Fishing

In 2021, the total commercial catch of Caribbean spiny lobster in U.S. waters in the Gulf of Mexico and South Atlantic totaled 2.1 election kilograms (4.7 million pounds) and were valued at $42 million, according to the NOAA Fisheries commercial fishing landings database. Recreational anglers harvest spiny lobsters primarily by snorkeling or scuba diving. Undersized lobsters must be released unharmed immediately without removal from water. [Source: NOAA]

Commercial fishermen harvest spiny lobsters either by diving, bullynetting, or using wooden, plastic, or metal traps. Bullynetting is conducted in shallow waters at night when lobster are foraging for food or migrating offshore. A vessel uses a spotlight to find the lobster and then uses a “bullynet” to harvest the lobster. Commercial traps are weighted with cement and must have a degradable escape panel to prevent “ghost fishing” (when a lost or abandoned trap continues to capture lobsters or other species). Buoys are attached to each trap, or if stringing a trap line, at each end of the trap line. The State of Florida runs two programs dedicated to removing lost and abandoned traps from state waters and has the authority to expand those programs into federal waters.

Fishermen generally use undersized lobster (known as “shorts”) as bait to attract legal-sized lobsters into their traps. Mortality of these undersized lobsters is around 10 percent. Traps sometimes incidentally catch reef fish and ornamental fish, but most are released alive. Threatened or endangered species, such as sea turtles and corals, occasionally become entangled in trap lines. Lobster trap closures are in place in some areas to prevent damage to ocean bottom habitat. Regulations are in place to minimize bycatch.

There are four stocks of Caribbean spiny lobster: 1) the South Atlantic-Gulf of Mexico stock, and three stocks in the Caribbean— 2) the Puerto Rico, 3) St. Thomas/St. John, and 4) St. Croix stocks. According to the most recent stock assessments are not subject to overfishing and not overfished.

Fishermen must have a permit to harvest spiny lobster. Annual catch limits in place. There are bag limits for commercial and recreational fishermen, depending on where they are harvested. The fishing season closed from early April through early August off Florida and the Gulf states to protect spiny lobsters during peak spawning season. There is a prohibition on harvesting and importing egg-bearing females or females that have been stripped of eggs. Minimum size limits exist on harvested and imported lobsters to allow them to spawn before they are harvested.

There are also prohibitions on spears, hooks, piercing devices, explosives, gillnets, trammel nets or poisons to harvest spiny lobster. Non-wooden traps must have biodegradable escape panels. Harvest is prohibited at all times in several marine protected areas. Traps, pots, buoys, and boats should be identified and marked and all traps must have biodegradable escape panels.

Image Sources: Wikimedia Commons, NOAA

Text Sources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Wikipedia, National Geographic, Live Science, BBC, Smithsonian, New York Times, Washington Post, Los Angeles Times, The New Yorker, Reuters, Associated Press, Lonely Planet Guides and various books and other publications.

Last Updated April 2023

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