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Opistognathus rosenblatti

(Blue-spotted jawfish)

Overview

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Family : Jawfishes ; Found in large colonies. Feeds on benthic and planktonic invertebrates . Covers its burrow entrance at dusk and rebuilds the opening each morning.

Common Names

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Click on the language to view common names.

Common Names in Danish:

Bl, Blåplettet kæbefisk

Common Names in English:

Blue-spotted jawfish, bluespotted jawfish

Common Names in Mandarin Chinese:

罗氏后颌鰧, 羅氏後頜鰧

Common Names in Spanish:

bocón manchas azules, Bocón azul, bocón manchas azules

Description

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Physical Description

Species Opistognathus rosenblatti

Bluespotted jawfish have squared heads , eel-like bodies, big mouths and long, continuous dorsal fins. Their eyes are overly large for their body size. Their heads are yellowish-brown, blending to a darker almost black body covered with blue spots. Their dorsal fins are yellow. Juveniles are yellow and do not have spots.

These fish reach a maximum length of just 10 cm (4 in).

The powerful jaws of the bluespotted jawfish have been adapted for use as a tool to scoop up sand , coral rubble , broken shells and pebbles to build their burrows. They are not above stealing supplies from a neighbor’s burrow to avoid work.

Habitat

Bluespotted jawfish are usually found on the ocean bottom at depths of 18-24 m (60-80 ft ), near cliff bases or rocky outcroppings of offshore islands. Juveniles can be found in waters sometimes as shallow as 4.6 m (15 ft).

Biome: Marine [1].

Ecology: The Bluespotted Jawfish is a demersal species, found in sandy rubble areas at depths of 5–25 m .  It can form colonies of up to several hundred fish.[1].

List of Habitats :

Biology

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Diet

This species sticks just their head outside their burrow, sits at the mouth of it, or hovers over the burrow to catch floating zooplankton .

Reproduction

At new or full moons during the spring through fall breeding season , the front halves of the almost black body of males changes to white. They perform a special mating display in which they dart up into the water column , hang motionless with all fins erect for a few seconds, then dart back into their burrows, repeating the display every few minutes. These displays can go on for hours. An interested female eventually leaves her burrow and follows the male back to his burrow or to a separate breeding burrow to lay her eggs , which the male then fertilizes.

Jawfish are mouth-brooders. Males generally have larger mouths than females adapted for this purpose. The male gathers the fertilized eggs, which are held together with mucous threads, into his mouth and carries them until they hatch . The only time the incubating eggs are spit out is when the male has to eat and then he carefully places them inside the burrow away from predators . When the eggs hatch and the fry are released, and his mouth is once more empty, the male is free to repeat his mating display.

Behavior

Bluespotted jawfish are normally found living in large colonies of several hundred individuals. Both males and females dig burrows, which are spaced 1-3 m (3.3-10 ft ) apart and can be as much as 30 cm (1 ft) deep. Every night these fish build covers for their burrows, and every morning they rebuild the openings again. They clean and repair their burrows, shoveling sand out almost constantly. They line the burrow tunnel with pebbles and shell fragments. These are also used to reinforce the roof to keep it from caving in. They stay in or very close to their burrows, defending their territories from intruders and their burrows from other thieving jawfish.

Taxonomy

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Notes

Name Status: Accepted Name .

Last scrutiny: Data last modified by FishBase 19-Jan-1999

Similar Species

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Members of the genus Opistognathus

ZipcodeZoo has pages for 41 species and subspecies in this genus:

O. alleni (Abrolhos Jawfish) · O. aurifrons (Yellowhead Jawfish) · O. brasiliensis (Darkfin Jawfish) · O. castelnaui (Blue-Spotted Jawfish) · O. robinsi (Bartail Jawfish) · O. cuvierii (Phantom Jawfish) · O. darwiniensis (Darwin Jawfish) · O. dendriticus (Tabangka) · O. elizabethensis (Elizabeth Reef Jawfish) · O. eximius (Harlequin Smiler) · O. galapagensis (Galapagos Jawfish) · O. gilberti (Yellow Jawfish) · O. inornatus (Black Jawfish) · O. jacksoniensis (Southern Smiler) · O. latitabundus (Blotched Jawfish) · O. leprocarus (Roughcheek Jawfish) · O. lonchurus (Moustache Jawfish) · O. macrognathus (Spotfin Jawfish) · O. macrolepis (Bigscale Jawfish) · O. margaretae (Halfscaled Jawfish) · O. maxillosus (Mottled Jawfish) · O. megalepis (Largesacle Jawfish) · O. melachasme (Yellowmouth Grouper) · O. mexicanus (Mexican Jawfish) · O. muscatensis (Jawfish) · O. nigromarginatus (Moustached Jawfish) · O. nothus (Yellowmouth Jawfish) · O. panamaensis (Panamanian Jawfish) · O. papuensis (Papuan Jawfish) · O. punctatus (Finespotted Flounder) · O. reticeps (Reticulated Jawfish) · O. reticulatus (Leopard Jawfish) · O. rhomaleus (Giant Jawfish) · O. robinsi (Spotfin Jawfish) · O. rosenblatti (Blue-Spotted Jawfish) · O. scops (Bullseye Jawfish) · O. seminudus (Halfnaked Jawfish) · O. solorensis (Variegated Jawfish) · O. stigmosus (Coral Sea Jawfish) · O. verecundus (Bashful Jawfish) · O. whitehursti (Dusky Jawfish)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal March 05, 2008:

Identifiers

Footnotes

  1. McCosker, J.E., Acero, A. & Espinosa, H. 2010. Opistognathus rosenblatti. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 03 February 2012. [back]
Last Revised: 2014-05-07