Spot-fin porcupinefish are found in the Pacific Ocean from San Diego, California to Chile, including the Hawaiian and Galapagos Islands, and the western Atlantic Ocean from Massachusetts to the northern Gulf of Mexico, as well as Bermuda, the Caribbean, and Brazil. They are also found around the Azorean and Seychelles Islands, as well as in the western Indian Ocean, off the coast of Kenya, Mozambique, Somalia and South Africa. Additionally, these fish can be found in the Mediterranean and Red Seas and off the coast of New Zealand. (Bailly, 2012; Leis, 1977; Luna and Ortañez, 2012; Patton, 1999)
Adults are generally found in holes and crevices in inshore areas including lagoons, caves, shipwrecks, reefs, and ledges, and are also found in seamount areas. They are found at depths up to 50 meters, most commonly between 3 and 20 meters. Juveniles are pelagic until reaching 20 cm in length, becoming benthic thereafter. ("Encyclopedia of Animals", 2006; Bailly, 2012; "Encyclopedia of Animals", 2006; Luna and Ortañez, 2012; Patton, 1999)
Spot-fin porcupinefish have round, expandable, slender bodies with small fins. These fish lack pelvic fins, and the rounded dorsal and anal fins are positioned near the caudal fin. They have 22-25 pectoral fin rays, 14-17 dorsal fin rays, and 14-16 anal fin rays. They are covered in long spines, which lie flat along their bodies when they are not inflated, including a longitudinal row of spines (14-20) between their snouts and dorsal fins, as well as small spines covering their caudal peduncle area. Body color varies, but they are generally uniformly dull brown to green with the body covered in small dark spots and markings, with a pale belly that is surrounded by a dusky ring. Their fins do not have spots. These fish have large eyes and wide, flattened mouths. Their teeth are fused together and they have very strong jaws. Spot-fin porcupinefish can grow up to 91 cm, with an average of 40 cm, and have a maximum recorded weight of 2.8 kg. There are slight differences in body shape and color between males and females. (Bailly, 2012; Debelius, et al., 2006; "Encyclopedia of Animals", 2006; Luna and Ortañez, 2012; Patton, 1999)
Spot-fin porcupinefish eggs are buoyant, pelagic, spherical, and 1.9-2.1 mm in diameter. About five days after fertilization, eggs hatch and larvae, which average 2.6 mm in length, float in the open ocean near the surface. Hatchlings have large amounts of yolk still attached to them. Within two days after hatching, larvae have formed fully functional mouths and their eyes have become fully pigmented. Body coloration is mainly orange and they are more highly pigmented dorsally. Larvae maintain a thin shell until they have reached about 5 mm in length (at about 10 days old). At this time they metamorphose into spiny juveniles. Within 3 weeks, fins, fin rays, and teeth have formed. Juvenile spot-fin porcupinefish become olive to brown in color with dark spots on their ventral sides, camouflaging them in the mats of seaweed where they hide until moving inshore, usually when they reach at least 20 cm in length. (Debelius, et al., 2006; Leis, 1977; Luna and Ortañez, 2012; Patton, 1999)
This species is a broadcast spawner; males and females mate promiscuously during spawning events. Although mating behavior has not been observed for this species, in captivity or in the wild, it has been observed for captive Diodon holocanthus, a closely related species. Breeding begins when water temperatures reach approximately 25°C, likely from May through August. Multiple males approach a female at a time, bringing her up to the surface of the water where, if she has ripe eggs, she will release them. All of the males (usually 4-5) contribute sperm. (Sakamoto and Suzuki, 1978)
Spot-fin porcupinefish breed when water temperature reaches approximately 25°C, typically from May-August. It is unknown how many offspring are produced by these fish at a time or what their age at sexual maturity is. Eggs usually hatch within 2 days of fertilization. (Leis, 1977; Patton, 1999)
As this species is a broadcast spawner, there is no parental investment. Planktonic larvae develop independently in the water column. (Leis, 1977)
Porcupine fish are known to survive at least 10 years in captivity. Lifespan in the wild is unknown. (Luna and Ortañez, 2012)
When spot-fin porcupinefish are threatened, they inflate their bodies by swallowing water. Their integument is very flexible, allowing expansion of the body to up to three times its original size. When no longer threatened, excess water is expelled and the fish returns to its normal size. These fish are typically solitary, outside of breeding, and are nocturnal, hiding during daylight hours. (Debelius, et al., 2006; Patton, 1999)
There is no information to indicate that this species maintains territories, and the home range is currently unknown.
As in other bony fishes, Spot-fin porcupinefish use their eyes to see, nares to sense dissolved chemicals, and a lateral line to detect vibrations and movement via changes in water pressure. (Debelius, et al., 2006)
Spot-fin porcupinefish are durophagous and carnivorous, having strong jaws and teeth that are fused together, specializations for eating hard-shelled creatures. Their beaked mouths can catch and crush sea urchins, crabs, snails, and clams while their large, rubbery lips protect them from being injured by spines and broken shells. These fish commonly scavenge and search for prey in sandy areas, crevices, and caves. (Bailly, 2012; Patton, 1999)
Spot-fin porcupinefish are well-known for their defensive ability to inflate their bodies by swallowing water, causing their spines to extend outwards and preventing most predators from swallowing them. They also secrete dermal toxins that are poisonous to many species. They do have some known predators, however, mainly large-bodied fishes. (Debelius, et al., 2006; Leis, 1977; Luna and Ortañez, 2012; Patton, 1999)
Spot-fin porcupinefish are an intermediate link in the reef food chain, serving both as nonspecific predators of benthic invertebrates and as prey for higher order predators. Like other fish, this species is host to numerous endo and ectoparasites. (Bailly, 2012; Balakrishnan, 1969; Debelius, et al., 2006; Quilichini, et al., 2010; Radhakrishnan and Nair, 1981)
This species is sold in the home aquarium trade. While the internal organs of this species are extremely toxic, it is customary in Japanese culture to eat the flesh of these fish as a type of sushi, called fugu. Spot-fin porcupinefish bodies are also made into souvenirs for tourists in tropical areas: after a porcupinefish is killed, it is inflated. It is then made into a lamp or wall display. Traditionally, the hardened bodies were also used as war helmets, by the Gilbertese people on the Gilbert Islands. (Patton, 1999; Debelius, et al., 2006; Patton, 1999)
Except for occasional cases of fugu poisoning in Japan, there are no known adverse effects of these fish on humans. (Patton, 1999)
Spot-fin porcupine fish are not considered endangered or vulnerable to extinction, according to the World Conservation Union. However, information is lacking about their natural history in their oceanic environment. (IUCN, 2012; Patton, 1999)
Amber Baker (author), San Diego Mesa College, Ashley Koser (author), San Diego Mesa College, Paul Detwiler (editor), San Diego Mesa College, Jeremy Wright (editor), University of Michigan-Ann Arbor.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
fertilization takes place outside the female's body
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
eats mollusks, members of Phylum Mollusca
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
the business of buying and selling animals for people to keep in their homes as pets.
an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.
mainly lives in oceans, seas, or other bodies of salt water.
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
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Quilichini, Y., J. Foata, J. Justine, R. Bray, B. Marchand. 2010. Ultrastructural study of the spermatozoon of Heterolebes maculosus (Digenea, Opistholebetidae), a parasite of the porcupinefish Diodon hystrix (Pisces, Teleostei). Parasitology International, 59(3): 427-434.
Radhakrishnan, S., N. Nair. 1981. Tetrochetus coryphaenae (Digenea: Accacoeliidae) infection of Diodon hystrix (Pisces: Diodontidae). Proceedings of the Indian National Science Academy, B47/1: 47-52. Accessed February 18, 2013 at http://www.dli.gov.in/rawdataupload/upload/insa/INSA_2/20005a0c_47.pdf.
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