Atlantic Pearlfish are not listed or have not yet been evaluated by any specific conservation initiative. Individuals are technically "protected" when their sea cucumber hosts live within a protected reef zone, such as the Florida Keys National Marine Sanctuary.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
These fish are well protected from predation by their hosts, sometimes even feeding while still halfway inside their hosts. They are able to take advantage of their hosts' anti-predator adaptations, such as their Cuverian tubules; these are not activated when an Atlantic pearlfish enters and these fish also have a higher tolerance to sea cucumber toxins than other reef fish do. Potential predators include other fishes, including conspecifics and other ophidiiform species.
Known Predators:
This species is characterized by a short predorsal region and a dorsal fin which is longer than the anal fin, extending along the body and meeting at the ends of the tail. The anus is located anteriorly, close to the throat. The body is scaleless and eel-like in appearance, being long and laterally compressed. There are no enlarged dentary or premaxillary fangs, spaces between their teeth. Pectoral and pelvic fins are also absent. These fish have constricted, two-chambered swim bladders, as well as visceral cradles and elaborate pre-dorsal bones. They have small conical teeth all along their jaws, as well as cardiform teeth on the frontal, external regions of the premaxillary bones. Coloration is typically silver and white, with red markings. Adults range in length from 15 to 24 cm total length, though individuals found at extreme depths have been noted to be both larger and darker in color. Vexillifer larvae (the first stage of metamorphosis) of this species are relatively deep bodied, with a short predorsal body region.
Range length: 15 to 24 cm.
Other Physical Features: ectothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
Using otolith data, the average lifespan of this species in the wild has been estimated to be 3 years.
Average lifespan
Status: wild: 3 years.
Atlantic pearlfish are tropical and subtropical marine benthic teleosts. They are primarily commensal, commonly being found living inside the bodies of sea cucumbers (Holothuroidea) or occasionally other marine intervebrates. These fish tend to be associated with coral-dominated communities or shallow sea grass beds, and are most common at depths of 1-34 meters, although they have been found in waters up to 235 meters deep.
Range depth: 1 to 235 m.
Habitat Regions: tropical ; saltwater or marine
Aquatic Biomes: benthic ; reef ; coastal
Atlantic pearlfish are native to tropical western Atlantic waters from Bermuda to Brazil, including southern Florida, the Gulf of Mexico and the West Indies. Larvae of this species have also been found in the Gulf of Maine.
Biogeographic Regions: nearctic (Native ); neotropical (Native ); atlantic ocean (Native )
Atlantic pearlfish are nocturnal carnivores, capturing the vast majority of prey while outside of their hosts; Caridean shrimps are their main source of food and they also occasionally feed on other small decapods, isopods, annelids, copepods, and fish remains. They are nonspecific generalists, eating whatever food is most abundant and easily attainable. They may cannibalize smaller conspecifics.
Animal Foods: fish; carrion ; mollusks; aquatic or marine worms; aquatic crustaceans; other marine invertebrates; zooplankton
Primary Diet: carnivore (Eats non-insect arthropods)
Atlantic Pearlfish affect their benthic marine ecosystems by regulating populations of their prey, including small crustaceans. They have a well-known commensal relationship with sea cucumbers, using their hosts for protection. This does not generally adversely affect individual sea cucumbers or their populations.
Species Used as Host:
This species does not have any economic value or other benefit to humans.
There are no known adverse effects of this species on humans.
Although its complete life history and development have yet to be described, it is assumed that eggs of this species follow a similar pattern to a closely related species, Carapus actus. Eggs are laid in a gelatinous flat that floats freely in open waters. After hatching from elliptical, planktonic eggs, larvae undergo two separate growth phases. In the first phase, the larvae develop into vexillifers, which are characterized by a branched dorsal filament called the vexillum. As the vexillifers continue to grow, they lose their vexilla and enter the tenuis stage. Atlantic pearlfish larvae in this stage are very long (7-8 cm) and thin, transparent, and develop a long caudal filament. At this stage, these fish become demersal and may enter a host or remain free-swimming. Once they have entered a host (tail first, through its anus), they transform into their definitive forms, shrinking to about one third of their tenuis length, beginning to grow again after transformation is complete. This larval period is estimated to last for three months.
Development - Life Cycle: metamorphosis
Atlantic pearlfish are able to produce sounds, which are structured in regular pulse emissions and are heard over long distances from within their hosts. These sounds signal their sex to conspecifics. In sexual encounters, sounds are reduced to a single pulse emission. Sound emissions can be divided into two groups: stridulatory (non-harmonic sounds created by rubbing body parts against each other, such as teeth and pectoral fins) and swim bladder vibrations (sounds from vibration of the swim bladder against a deformation of its wall). These vibrations are detected by other Atlantic pearlfish through their lateral line systems. These fish locate potential hosts primarily using chemical cues as well as through vision, olfaction and rheotaxis (sensation of water currents).
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: vibrations
Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical
Little is known of the reproductive behavior of Atlantic pearlfish. While many carapids pair sexually, this speices is thought to be an open-water broadcast spawner, with females scattering eggs over substrate and males releasing sperm over them.
Mating System: polygynandrous (promiscuous)
Atlantic pearlfish are dioecious and breed via broadcast spawning throughout the year; larvae in both vexillifer and tenuis stages, as well as adults, can be found at any time of year. Following external fertilization, eggs hatch within one or two days. It is unknown how many eggs are released at a time or what age these fish are when they reach sexual maturity, as time to adulthood has not been recorded.
Breeding interval: Atlantic pearlfish breed multiple times throughout the year.
Breeding season: Breeding is year-round
Average number of offspring: unknown.
Range gestation period: 1 to 2 days.
Average time to independence: unknown minutes.
Average age at sexual or reproductive maturity (female): unknown minutes.
Average age at sexual or reproductive maturity (male): unknown minutes.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); broadcast (group) spawning; oviparous
As broadcast spawners, adults of this species show no parental investment.
Parental Investment: no parental involvement
