Halichoeres bivittatus
| Ecological Descriptors |
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| Habitat | Size (cm) | Diet | Behaviour | Sex |
| Co, R (S) | 25 | Pisc, Ech, Cru, Mol, Wor (Cle) |
I | PGH |
Description:
Terminal phase (Males): Shades of green, with pink lines from eye to snout, nape and back, and upper edge of operculum, and from mouth across center of operculum.May have dark triangular corners on tail. Green/ yellow (or black/ pink) bicoloured spot above pectoral fin/ upper corner of operculum. Can have dark grey stripe from operculum to tail base. Dorsal and anal fins pink, with a central green stripe. Tail fin greenish blue with 3 pairs of pink stripes that converge at end of fin from its upper and lower borders.
Initial Phase; Colours and markings vary from green to medium brown. Can look like Terminal Phase but less strongly coloured, or can be similar to juveniles, but more robust. Green/ yellow (or black/ pink) bicoloured spot above pectoral fin/ upper corner of operculum.. Marked horizontal pinkish red "V"on tail.
Juvenile Phase: Cream or whitish body undercolour with longitudinal dark stripe (can be series of spots). Upper body pale brown. Often a small black, or large blue spot on mid-dorsal fin. Most have a dark spot at the rear base of the pectoral fin.
Ecology
Found in habitats ranging from the more common rocky and coral reef areas to the less common sea-grass beds. Depths of 0-50m (0-160ft). They are considered diurnal due to their reduced motion or sensitivity during the night. According to a study done in Panama, the Slippery Dick showed size segregation in different zones of habitat such as: smaller juveniles and intermediates occurred in low-complexity zones (sand rubble and turf algae), whilst there was an increase in size proportions from intermediate to high-complexity zones (rocky and fire coral areas).
Feeds on benthic organisms, e.g. crabs, sea urchins, polychaetes , gastropods , brittle stars and other fishes. Juveniles often in large groups and will follow benthic fishes, or divers, if they disturb the bottom, searching for displaced food items ( “following behaviour”. They also act as cleaners.
Gets its unique name from the slippery mucus it excretes to help it evade predators.
Life Cycle:
It is a protogynous hermaphrodite, with some IP females becoming TP males. Sex reversal is completed in more than 3-4 weeks. IP males aso exist along with the IP females. Before spawning, terminal males aggregate into leks by gathering and taking part in a competitive show. They do this to demonstrate their male prowess and to attract female partners for spawning. They are pelagic spawners; males and females swim above the reef together and release their gametes simultaneously. Fertilized eggs drift in currents until they hatch. Spawning tends to take place during daylight.
IP males reproduce differently, by interfering (sneaking in) in the spawning at the site of gamete release, a behaviour known as “streaking”.
Fertilized eggs are 0.6mm in diameter and buoyant while unfertile eggs were not buoyant. Hatching occurs ~23 hours after fertilization and the larvae measure 1.6mm and possessed a spherical oil globule and an ovoid yolk sac.
Terminal phase (Males): Shades of green, with pink lines from eye to snout, nape and back, and upper edge of operculum, and from mouth across center of operculum.May have dark triangular corners on tail. Green/ yellow (or black/ pink) bicoloured spot above pectoral fin/ upper corner of operculum. Can have dark grey stripe from operculum to tail base. Dorsal and anal fins pink, with a central green stripe. Tail fin greenish blue with 3 pairs of pink stripes that converge at end of fin from its upper and lower borders.
Initial Phase; Colours and markings vary from green to medium brown. Can look like Terminal Phase but less strongly coloured, or can be similar to juveniles, but more robust. Green/ yellow (or black/ pink) bicoloured spot above pectoral fin/ upper corner of operculum.. Marked horizontal pinkish red "V"on tail.
Juvenile Phase: Cream or whitish body undercolour with longitudinal dark stripe (can be series of spots). Upper body pale brown. Often a small black, or large blue spot on mid-dorsal fin. Most have a dark spot at the rear base of the pectoral fin.
Ecology
Found in habitats ranging from the more common rocky and coral reef areas to the less common sea-grass beds. Depths of 0-50m (0-160ft). They are considered diurnal due to their reduced motion or sensitivity during the night. According to a study done in Panama, the Slippery Dick showed size segregation in different zones of habitat such as: smaller juveniles and intermediates occurred in low-complexity zones (sand rubble and turf algae), whilst there was an increase in size proportions from intermediate to high-complexity zones (rocky and fire coral areas).
Feeds on benthic organisms, e.g. crabs, sea urchins, polychaetes , gastropods , brittle stars and other fishes. Juveniles often in large groups and will follow benthic fishes, or divers, if they disturb the bottom, searching for displaced food items ( “following behaviour”. They also act as cleaners.
Gets its unique name from the slippery mucus it excretes to help it evade predators.
Life Cycle:
It is a protogynous hermaphrodite, with some IP females becoming TP males. Sex reversal is completed in more than 3-4 weeks. IP males aso exist along with the IP females. Before spawning, terminal males aggregate into leks by gathering and taking part in a competitive show. They do this to demonstrate their male prowess and to attract female partners for spawning. They are pelagic spawners; males and females swim above the reef together and release their gametes simultaneously. Fertilized eggs drift in currents until they hatch. Spawning tends to take place during daylight.
IP males reproduce differently, by interfering (sneaking in) in the spawning at the site of gamete release, a behaviour known as “streaking”.
Fertilized eggs are 0.6mm in diameter and buoyant while unfertile eggs were not buoyant. Hatching occurs ~23 hours after fertilization and the larvae measure 1.6mm and possessed a spherical oil globule and an ovoid yolk sac.
Slippery Dick (Intermediate Phase)
372
(C) Robertson & Van Tassell
Slippery Dick (Terminal Phase)
Slippery Dick (Intermediate Phase)
Slippery Dick (Juvenile Phase)
576
373