115 research outputs found
Bumphead Parrotfish: Bolbometopon muricatum
No full textBolbometopon muricatum (Valenciennes 1839), the largest of the scarine labrids (Choat et al. 2006), is an excavating parrotfish (Scaridae). The genus is monotypic comprises a distinct lineage within the group and is notable for its massive jaws and associated musculature (Bellwood 1994). The evolutionary history of the scarine labrids identifies them as a geographically widespread but relatively recent group, confined mainly to coral reefs. The lineage containing Bolbometopon diverged approximately 13 my bp (Alfaro et al. 2009). Although the parrotfishes have a number of distinctive morphological and nutritional traits recent phylogenetic analyses place them within the broader grouping of the Family Labridae (Westneat and Alfaro 2004). We now know that large wrasses such as Cheilinus undulatus (Chap. 12.13) are more closely related to large parrotfishes such as Bolbometopon than they are to any of the smaller wrasses that inhabit coral reefs. B. muricatum is widespread on Indo-Pacific coral reefs with a distribution covering 37.6 × 10 6 km 2 and extending from the Red Sea through the Indian Ocean and Indo- Australian archipelago to the central and southern Pacific excluding the Hawaiian Islands and the Marquesas. There is also some doubt as to whether this species occurs in the Society Islands (Rob Myers, personal communication in 2009)
Sexual Dimorphism in the Labrid Fish Pseudolabrus celidotus (Bloch and Schneider) 1801
No full textDuring a systematic study of New Zealand
fishes belonging to the genus Pseudolabrus
Bleeker 1861, it was observed that one of
the commonest species, P. celidotus, occurred
in two distinct colour phases. This was first
noted by Richardson (1848) who described
the two colour variants as separate species. The
subsequent literature did not recognise these as
species, but merely as varieties, although the
true relationship was not clarified. A study of
populations of this species, both in the field
and in the laboratory, revealed that the colour
differences were due to sexual rather than environmental
or geographic factors, and represented
a moderately developed degree of sexual
dimorphism. An attempt has been made here
to examine the relative proportions of each
colour phase in selected populations, the sequence
of transition from one colour phase to
the other, and the sizes at which transition
occurs
High population connectivity across the Indo-Pacific: congruent lack of phylogeographic structure in three reef fish congeners
No full textWe used the mitochondrial control region and a comparative approach to study the genetic population structure of two surgeonfishes, Naso brevirostris and Naso unicornis, across their Indo-central Pacific ranges. Our purpose was to compare our results with those of a previous study of Naso vlamingii [Klanten, S.O., van Herwerden, L., Choat J.H., 2007. Extreme genetic diversity and temporal rather than spatial partitioning in a widely distributed coral reef fish. Mar. Biol. 150, 659–670] another widely distributed Indo-central Pacific Naso species. We found no evidence of a barrier to gene flow between the Indian and Pacific Oceans for either species, consistent with what was shown for N. vlamingii. Overall, both target species lacked spatial population partitions and probably have complex patterns of gene flow on several spatial scales. Despite the lack of geographic population structure distinct clades were observed in N. brevirostris, similar to those found in N. vlamingii. Coalescence times for intraspecific clades of N. brevirostris and N. vlamingii approximate each other, suggesting parallel evolutionary histories. A bimodal mismatch distribution in N. brevirostris indicates that a biogeographic barrier separated N. brevirostris populations sometime during its species history. Naso unicornis, in contrast, lacked genetic structure of any kind, although it has what could represent a single surviving clade. Congruent lack of spatial population structure among all three species suggest that such patterns are not due to stochastic processes of DNA mutation and are most likely driven by ecological and environmental factors
Review of data on fishes of commerical and recreational fishing interest in the Great Barrier Reef Vol. 2
No full textThis document lists 1132 references directly relevant to reef fisheries in general and reef fisheries on the Great Barrier Reef in particular. It was prepared for the Great Barrier Reef Marine Park Authority as part of a review of data on fishes of commercial and recreational fishing interest on the Great Barrier Reef. The companion volume (Volume I, Williams and Russ, 1994) provides a review of the data specifically relating to the Great Barrier Reef and includes its own reference section which is partially, but not completely, a subset of the references provided here.This is Vol 2 of 2. Volume 1 can be found at http://hdl.handle.net/11017/23
Comparative demography of commercially important parrotfish species from Micronesia
No full textFishery-independent sampling was used to determine growth patterns, life span, mortality rates and timing of maturation and sex change in 12 common parrotfishes (Labridae: tribe Scarinae) from five genera (Calotomus, Cetoscarus, Chlorurus, Hipposcarus and Scarus) in Micronesia. Interspecific variation in life-history traits was explored using multivariate analysis. All species displayed strong sex-specific patterns of length-at-age among which males reached larger asymptotic lengths. There was a high level of correlation among life-history traits across species. Relationships between length-based and age-based variables were weakest, with a tenuous link between maximum body size and life span. Cluster analysis based on similarities among life-history traits demonstrated that species were significantly grouped at two major levels. The first grouping was driven by length-based variables (lengths at maturity and sex change and maximum length) and separated the small- and large-bodied species. Within these, species were grouped by age-based variables (age at maturity, mortality and life span). Groupings based on demographic and life-history features were independent of phylogenetic relationships at the given taxonomic level. The results reiterate that body size is an important characteristic differentiating species, but interspecific variation in age-based traits complicates its use as a life-history proxy. Detailed life-history metrics should facilitate future quantitative assessments of vulnerability to overexploitation in multispecies fisheries
Abundance patterns of reef sharks and predatory fishes on differently zoned reefs in the offshore Townsville region final report to the Great Barrier Reef Marine Park Authority
No full textSharks were counted in six 500 x 20 m transects on the slope of each reef during late
March 2008. Densities of whitetip reef sharks (Triaenodon obesus) were twice as high on
green reefs as on blue reefs but were twice as high on pink reefs as on green reefs.
Similarly, grey reef sharks (Carcharhinus amblyrhynchos) were four times as abundant
on green reefs as on blue reefs, but twice as abundant on pink reefs as on green reefs.
We also recorded the abundance of large teleost reef fishes during all counts. There
were similar patterns in the density of the common coral trout (Plectropomus leopardus),
with 1.5 times as many coral trout on green reefs as on blue reefs but 2.5 times as many
on pink reefs compared with green reefs
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