spawning hawkfish

8/15/2019 Spawning Hawkfish

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Environmental Biology of Fishes Vol. 24, No. 4, pp. 295-300, 19890 Kluwer Academic Publishers, Dordrecht.

Pelag ic spawning of the hawkfish Oxycirrhites typus (Cirrhitidae)Terry J. Donaldson 1,4& Patrick L. Colin2,3 Section of Ichthyology, Museum of Natural Science and Department of Zoology and Phys iology, 119 FosterHall, Louisiana State University , Baton Rouge, LA 70803, U.S.A.2Motupore Island Research Station, Universi ty of Papua New Guinea, Papua New Guinea3 Present address: Caribbean Marine Research Center, cfo Florida State University Marine Laboratory, Rt. 1,Box 456, Sopchoppy, FL 32358, U.S.A.4Reprint requests.Received 30.3.1988 Accepted 22.7.1988

Key words: Behavior, Courtship, Eggs, Habitat availability, Site-attachment, Social group, Spawning ascentSynopsisPelagic spawning of the deep slope coral-dwelling cirrhitid Oxycirrhites typus was observed for two socialgroups at Papua New Guinea. This species was previously reported to be a demersal spawner in an aquarium.Courtship in social groups consisting of a single male and one or two females commenced just prior to or aftersunset among the branches of gorgonian or antipatharian corals. Males and females occupied separate corals;males either visited females at their corals or met them at an adjacent coral just prior to courtship. Courtshipwas sequential and consisted of two or more bouts with each female that culminated in a rapid ascent into thewater column and the release of floating eggs. Ferti lized eggs, taken from a third social group, were sphericaland averaged 0.69 mm in diameter. Spawning pairs sought refuge in their resident corals or in the coral wherecourtship occurred immediately after spawning was completed.

IntroductionThe long-nosed hawkfish Oxycirrhites typus is adistinctive tropical to sub-tropical cirrhitid distrib-uted from Baja California, Mexico west to the RedSea. This species is typically found on deep slopesof coral and rocky reefs and inhabits gorgonian andantipatharian corals at depths of 25-100 m (Randall1963). There is some published information con-cerning its reproductive behavior. Takashita (1975)and Tanaka et al. (1985) briefly described apparentcourtship behavior in aquaria. Another observa-tion suggested the possibil ity that this species mightlay demersal eggs (reviewed in Thresher 1984).This suggestion has been cited elsewhere (i.e. Ran-dall 1985).

Thresher (1984) questioned demersal spawningof this species as a result of field observations ofpelagic spawning by another cirrhitid, Cirrhitich-thys oxycephalus, in the Gulf of California. Hebelieved the existence of two modes of spawningwithin a small, monophyletic family of 34-35 spe-cies was unlikely. Additional species of cirrhitidshave been spawning pelagic eggs, including Cirrhit-ichthys falco (Donaldson 1986, 1987), C. aprinus(Donaldson, unpublished), C. aureus (Y. Yogo,personal communication), and Paracirrhites arca-tus, P. forsteri and Cirrhituspinnulatus (Donaldsonunpublished). Recently, we observed courtshipand pelagic spawning of Oxycirrhites typus nearMotupore Island, Papua New Guinea, where thisspecies occurred in relatively shallow (20-26m)depths.


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296Methods and study sitesObservations of courtship and spawning weremade using scuba between 6-15 November, 1986 attimes to include sunset and dusk (1730-1830 h).Additional observations of behavior and habitatuse were made during occasional daylight diveswithin these dates. Data were recorded on plasticslates, and underwater photographs of courtshipand spawning were taken. Time of sunset was de-termined from meteorological tables. Water vis -ibi lity was estimated from known distances to sub-jects at approximately 20-25 m. Spawning was ob-served at two sites located about 16 km SE PortMoresby. The first site was located on the slope of abroad fringing reef ca. 500m south of Loloata Is-land at a depth of 22-23 m. This site had poor watervis ibility, ca. 3-6m and water temperatures be-tween 2627 C. The second site was located at partof the Papuan Barrier Reef, locally called Horse-shoe Reef, ca. 6 km south of Motupore Island.Water temperature was 285C.

Body sizes were estimated in the field by mea-suring the distance between two points on the sub-stratum relative to the observed position of the tipof the snout and the edge of the caudal fin for agiven individual. Fertile eggs were obtained by col-lecting adults with quinaldine-alcohol solutionshortly before (within one hour) spawning. Fishwere returned to the laboratory alive, their bodysizes measured, and their gametes stripped by gen-tle hand pressure shortly after sunset (when theywould have naturally spawned) the same evening.Gametes were mixed in a petri dish containingseawater and later embryos that hatched were mea-sured using an ocular micrometer. Eggs, embryosand larvae were preserved in 3% formalin andspecimens deposited in the Australian Museum,Sydney (AMS) .

ResultsThree social groups were studied. Courtship andspawning were observed from a group consisting ofa male (72 mm TL) and two females (71 and 67 mmTL, respectively) at the Loloata Island site and

from a pair (male- 65 mm TL; female- 55 mm TL)at the Horseshoe Reef site. In the former group,the male and the largest female lived among thebranches of separate antipatharian corals; thesmaller female lived on a large Subergorgia sp. seafan located less than 0.5m away from the largerfemales coral. In the latter group, both male andfemale were observed at 23-26m in two Suber-gorgia sp. sea fans, located 3m apart. Gameteswere taken from a second pair collected from anantipatharian coral near the Loloata Island site(male- 99.5 mm TL; female- 92 mm TL). Courtshipand spawning of 0. typw was observed off LoloataIsland on five consecutive nights, 6-10 November,1986 and at Horseshoe Reef, 15 November. Court-ship began 23 minutes before to 22 minutes pastsunset at Loloata Island and 13 minutes past sunsetat Horseshoe Reef.

The male at the Loloata Island site left his coraland made his way, either swimming between thecoral branches or along the bottom, to the firstfemale, located less than 0.5 m away. Once there,he waited, dorsal fin erect, until the female arrivedfrom the upper branches of her coral. Occasional-ly, the male swam into the upper branches of thecoral in search of the female. As the male ap-proached, the female swam toward him, dorsal finerect. Daily courtship consisted of several bouts ofactivity during a period which ranged from 12-19(x = 5.3) minutes in duration. Generally, the maleand female circled horizontally or vertical ly aroundone another among the branches of the coral andoccasionally settled upon the branches to rest. Thepair rested by aligning their bodies l-3 cm apart inparallel or anti-parallel position (see Donaldson1986, 1987, for description of cirrhitid motor pat-terns). As courtship progressed, the female led themale in short swimming movements (lead and fol-low; Donaldson 1987) through the branches of thecoral, each movement separated by periods, 3-5seconds in duration, of parallel or anti-parallel rest.During rest periods of longer duration the malemoved his body close to the female and nudged herabdomen or flank below the dorsal fin with hissnout (Fig. 1). Then the male often mounted thefemale by placing his body along her upper flank,adjacent to or touching her dorsal fin; balance was


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297

Fig. 1. Nudging behavior by a male O xycirrhites typus (the ma le is the lower f ish).

Fig. 2. Descent after pelagic spawning by a pair of Oxycirrhires fypus.The female is partially obscured by the edge of the coral.


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298maintained by extending a pectoral fin against herbody while he beat his caudal fin vigorously. Themale also swam from his position parallel to thefemale, looped to pass in front of her and exposedhis flank perpendicularly to her snout, before com-ing to rest parallel to her opposite flank. Just priorto spawning, the pair assumed parallel or near-parallel positions, lifted their snouts upward byraising their bodies with extended pelvic fins,raised their dorsal fins and fin spines, and quicklyswam up or out from the coral to a point 20-25 cmaway. There, they turned their snouts downward,flexed their bodies rapidly, and released a smallcloud of gametes, which remained visible for 2-3seconds in the fading light; no egg predation wasobserved although egg predators, usually poma-centrids, were present nearby. Immediately afterspawning, the pair quickly swam back to thebranches of the same coral (Fig. 2) and brieflyassumed a position parallel to one another beforethe male departed.

After spawning with the first female, the maleswam to the second female on the upper edge of theSubergorgiu sea fan OSm away. Daily courtshipbouts with the second female commenced 4-12minutes past sunset and lasted 2.1-9.7 minutes be-fore spawning occurred. On one occasion, the firstfemale did not spawn with the male and in turn hedid not join the second female, who remained onthe edge of the sea fan until total darkness hadfallen (ca. 1840 h). Courtship and spawning behav-ior was the same as with the first female, althoughfewer bouts of courtship (x = 3.3) were observedper period before spawning. On one exception (6November), however, the male and the secondfemale were observed at parallel rest, their bodies1 cm apart, on the edge of the sea fan. There, theypositioned their vents out past the edge over openwater and both quivered together during three pe-riods of l-2 seconds each over the space of oneminute. Gametes may have been simultaneouslyreleased by each during these brief periods. After-wards, the pair repositioned themselves a few cmaway and repeated the behavior four more times insuccession without ascending into the water co-lumn.

Large predatory fishes were observed in close

proximity to the courting 0. typus, and it is possiblethat the pair spawned from the edge of the sea fanrather than making a spawning ascent above thecoral and exposing themselves to the risk of preda-tion. Alternately, these behaviors may merely havebeen a demonstration of male responses to an ap-parent lack of readiness on the part of the female,

After spawning had been completed with thesecond female, the male slowly swam back to hiscoral by way of the first females coral; the secondfemale sought shelter within the sea fan.

Courtship and spawning behavior of 0. typus atHorseshoe Reed was similar, although the onset ofcourtship was after rather than before sunset. Priorto the onset of courtship, both male and femalerested and fed in separate Subergorgia sea fans.Sometime just after 1730 h (32 minutes before sun-set), the female moved slowly from her sea fan andswam upward along the reef slope, past the malessea fan and two adjacent but shallower sea fans,and eventually moved into the branches of a largeantipatharian coral ca. 6 m from her starting posi-tion. This coral was located at the base of a steepreef face at 23 m depth. At 1800 h the male tracedthe females path to the large antipatharian coralwhere the female was sitting. However, the malesprogress was much slower as he moved from onepoint of cover to the next before arriving at 1812 h.

Courtship commenced at 1815 h (13 minutes pastsunset) when the male ascended into the upperbranches of the coral and joined the female. Court-ship consisted of two bouts, each in separate partsof the coral, and was brief (3 minutes and 4 secondstotal duration) compared with courtship durationsof the Loloata Island social group. After thespawning ascent, the male and female moved intoshelter within the branches of the coral.

Ferti lized eggs taken from the third social groupwere spherical and averaged 0.69mm in diameter(+ 0.23; N = 17), slightly larger than that of ripeova of C. oxycephalus reported in Thresher (1984).Eggs taken later from a fourth group, collected 5May, 1987 and stripped at 2000 h, hatched after 15hours incubation at 27C. Attempts to rear theembryos were unsuccessful.


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299DiscussionCourtship and spawning behavior of 0. typus wassimilar to that described from field studies for thecirrhitids (Thresher 1984, Donaldson 1986, 1987).Aspects in common included: (1) onset of courtshipjust before or after sunset with spawning after sun-set, (2) successive courtship and spawning by themale in social groups containing one or more fe-males, (3) courtship and spawning at a site commonto both the male and female or at a site locatedwithin the females home area, (4) pelagic spawn-ing with a rapid but relatively short ascent into thewater column by both male and female, (5) thereturn of the male and female to resident coralsafter spawning, except at Horseshoe Reef wherethe pair moved into shelter in the same coral usedfor courtship. Pelagic spawning at or near dusk isfound among many tropical reef fishes. Spawningascents into the water column above the substra-tum allow the release of planktonic eggs some dis-tance above the bottom, minimize immediate eggpredation by benthic organisms, and facilitatetransport of eggs away from the spawning site (seeThresher 1984 for review). Spawning adults are atrisk from piscivores, but this threat may be reducedby rapid dashes to minimal heights where eggs canbe released (Moyer 1987). Oxycirrhites typusspawning was rapid (ca. l-2 seconds in duration)and ascent lengths were relatively short (


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ported by an award from the Coypu Foundation.Field operations were funded by the UniversityResearch Committee, University of Papua NewGuinea.

References citedDonaldson, T.J . 1986. Courtship and spawning behavior of the

hawkf ish Cirrhitichthys f&o at Miyake-jima, Japan. Jap. J.Ichthyol. 33: 325L333.

Donaldson, T.J . 1987. Social organization and reproductivebehavior of the hawkfish Cirrhitichthys falco (Cirrhitidae).Bull. Mar. Sci. 41: 531-540.

Moyer, J.T . 1987. Quantitative observations of predation dur-

ing spawning rushes of the labrid f ish Thalassoma cupido atMiyake-jima, Japan. Jap. J. Ichthyol. 34: 76-81.

Randall, J.E. 1963. Review of the hawkfishe s (Family Cirrhiti-dae). Proc. U.S . Nat. Mu s. 114: 389-450.

Randall, J.E. 1985. Guide to Hawaiian reef f ishes. HarrowoodBooks , New ton Square. 70 pp.

Takashita, G .Y. 1975. Long-snouted hawk fish. Mar. Aquarist6(6): 27-31.

Tanaka, Y., Y. Shiobara, T. Ohyam a, I. Ozaki & M. Moriya.1985. Spawning behaviour, eggs and larvae of the hawkfish,Oxycirrhites typus, in an aquarium. Advance Abstracts forthe 18th Annual Meeting of the Ichthyological Society ofJapan, No. 58 ( in Japanese).

Thresher, R.E . 1984. Reproduction in reef f ishes. TFH Publi-cations, Neptune City. 339 pp.

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