Social Organization, Reproductive Behavior, and Zoogeography of Some Indo-Pacific Hawkfishes (Cirrhitidae) (original) (raw)
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Reclassification of the Indo-Pacific Hawkfish Cirrhitus pinnulatus (Forster)
2013
The hawkfish Cirrhitus pinnulatus Forster (in Bloch & Schneider 1801) was regarded as one wide-ranging Indo-Pacific species, from the Red Sea and east coast of Africa to the Hawaiian Islands and the islands of French Polynesia. Schultz (1950) resurrected the name C. alternatus Gill for the population in the Hawaiian Islands and Johnston Atoll, and described the Red Sea population as a new species, C. spilotoceps, based on morphological data. Randall (1963) confirmed the differences that Schultz used to separate Cirrhitus pinnulatus into three species, but preferred to regard them as subspecies. We examined more specimens, colour photographs, and used genetic comparisons to determine the validity of the three species recognized by Schultz (1950). Combining mitochondrial cytochrome oxidase I and cytochrome b sequence data from specimens of C. pinnulatus pinnulatus from the Indo-Pacific, C. spilotoceps from the Red Sea, and C. pinnulatus maculosus from Hawai‘i, we detected levels of sequence divergence (5–12%) that support the species-level designation of C. spilotoceps. We detected no genetic differentiation but maintain the subspecies designation of the Hawaiian form based on morphological and colour differences. We found a third genetic lineage in the Indian Ocean and Western Pacific that is 5% divergent from C. spilotoceps. We refrain from designating this group as a separate subspecies until further morphological and genetic study can be completed.
We observed spawning behavior of the hawkfish Paracirrhites forsteri on reefs of southern Japan. Spawning generally occurred after sunset, prior to the full and new moon with semi-lunar spawning peak periodicity. No egg predation was observed in spawning after sunset, and high tide often occurred at dusk in the lunar phases. Thus, diel timing and lunar synchronicity may increase larval survival. We found that the mating activity tended to start earlier in the day during early mating season than during mid-to-late mating season. The advantages of the earlier start of mating activity were also examined in relation to adult biology contexts.
Habitat Selectivity and Reliance on Live Corals for Indo-Pacific Hawkfishes (Family: Cirrhitidae)
PLOS ONE, 2015
Hawkfishes (family: Cirrhitidae) are small conspicuous reef predators that commonly perch on, or shelter within, the branches of coral colonies. This study examined habitat associations of hawkfishes, and explicitly tested whether hawkfishes associate with specific types of live coral. Live coral use and habitat selectivity of hawkfishes was explored at six locations from Chagos in the central Indian Ocean extending east to Fiji in the Pacific Ocean. A total of 529 hawkfishes from seven species were recorded across all locations with 63% of individuals observed perching on, or sheltering within, live coral colonies. Five species (all except Cirrhitus pinnulatus and Cirrhitichthys oxycephalus) associated with live coral habitats. Cirrhitichthys falco selected for species of Pocillopora while Paracirrhites arcatus and P. forsteri selected for both Pocillopora and Acropora, revealing that these habitats are used disproportionately more than expected based on the local cover of these coral genera. Habitat selection was consistent across geographic locations, and species of Pocillopora were the most frequently used and most consistently selected even though this coral genus never comprised more than 6% of the total coral cover at any of the locations. Across locations, Paracirrhites arcatus and P. forsteri were the most abundant species and variation in their abundance corresponded with local patterns of live coral cover and abundance of Pocilloporid corals, respectively. These findings demonstrate the link between small predatory fishes and live coral habitats adding to the growing body of literature highlighting that live corals (especially erect branching corals) are critically important for sustaining high abundance and diversity of fishes on coral reefs.
2020
The rarely occurred Hawkfish Cirrhitichthys bleekeri Day, 1874 is described based on the single specimen caught during demersal trawling survey conducted at 45 m depth of south west coast of India (9° 02.1'N; 76° 18.2'E at 40-45 m). An analysis of the morphometric, meristic characters and radiographic of the sample are compared with those of existing records of same and sibling species of the genus Cirrhitichthys (C.calliurus, C.aureus) and probability for putative hybrid of hawkfish species is discussed.
Bigeye scad Selar crumenophthalmus and round scad Decapturus macarellus were sampled from commercial fishery catches in Hawaii. Size at maturity of bigeye scad is ::;200 mm standard length. Spawning season is from April through September or October. Round scad mature at about 245 mm SL, and spawning occurs from April through August. Both species appear to spawn sometime between dawn and dusk. For bigeye scad, the frequency of post-ovulatory follicles indicates that females spawn every three days; batch costs average about 3% of body weight. Postovulatory follicles were found very infrequently in round scad. Mean batch fecundities of bigeye scad and round scad were 92,000 and 136,000, respectively; relative fecundity of bigeye scad averaged about twice that of round scad. Fecundities of bigeye scad and round scad are similar to those reported for other tropical carangids. Annual reproductive output appears to be higher in bigeye scad and round scad than in the temperate Trachurus spp., but spawning frequency of the latter may have been underestimated by most previous studies. Pelagic mackerel-like species of the family Carangidae are important components of coastal pelagic ecosystems in both temperate and tropical regions. In temperate areas, particularly in eastern boundary upwelling systems, jack or horse mackerels, (Trachurus spp.), are typically second in importance only to clupei-forms in abundance and fishery yield. The counterparts of Trachurus spp. in most tropical and subtropical areas are species of the genera Selar and Decapturus. These genera make up important fractions of fishery yields throughout the lndo-Pacific. In Hawaii, catches of the bigeye scad or akule, S. crumenophthalmus, and the round scad or opelu, D. macarellus, were almost 500 tons in fiscal year 1990-91, and as a group were exceeded in value only by the scombroids, deep bottom-fishes (lutjanids and serranids), and coryphaenids (Hawaii Division of Aquatic Resources statistics). Carangids, particularly tropical species, are poorly studied compared to clu-peiforms or scombroids. Studies in Hawaii by Yamaguchi (1953) and Kawamoto (1973) represent the best sources of data on the biology of round scad and bigeye scad, respectively, but neither investigated any aspect rigorously or with modern methodology. Spawning frequency has not been investigated in either genus. In this paper we present results of an investigation of reproductive biology of both species based on samples taken from fishery catches in Hawaii. Our objectives were to determine as precisely as possible the above and other reproductive variables for eventual use in management of the fisheries and for comparison with available data on other carangids-particularly the temperate Trachurus spp. MATERIALS AND METHODS Fish Samples.-We attempted to purchase samples at approximately monthly intervals from commercial fishery catches. All bigeye scad and most round scad were caught off the leeward (SW) side of the island of Oahu. All results given here are based on fish taken between 1-2 h after sunset and 1-2 h before dawn by surface handline used in conjunction with a night light. Fish were placed on ice immediately after capture and held iced until laboratory analyses after landing the next morning. 33