1,721,278 research outputs found
Feeding preferences and dietary specialisation among obligate coral-feeding butterflyfishes
No full text[Extract] Coral reef fishes have long been known to exhibit highly specialised patterns of habitat use (e.g., Fautin, 1985; Munday et al., 1997; Gardiner and Jones, 2005), but are generally considered to be highly versatile in their feeding (Ross, 1986; Bellwood et al., 2006c), opportunistically consuming a wide range of different prey. One striking example of this is the range of fishes (including algal farming damselfishes) that abandon their normal feeding habitats to take advantage of ephemeral, lipid-rich prey, feeding on corals eggs during annual mass spawning by scleractinian corals (Pratchett et al., 2001; McCormick, 2003). There is however, increasing realisation that coral reef fishes can be extremely specialised when it comes to diet. The broad trophic groups once used to categorise reef fishes (e.g., planktivores, herbivores, carnivores and omnivores) are increasingly being sub-divided to capture important differences in ecosystem function (Graham et al., 2006; Hoey and Bellwood, 2011), while some studies simply recognise that individual species have unique and important functional roles (e.g., Bellwood et al., 2003, 2006b). Many species have extremely specialised diets or feeding habits, such as Holacanthus angelfishes that feed almost exclusively on sponges, and mainly on just one species (Randall and Hartman, 1968) or tube-lip wrasses (Labroides and Labrichthys) that consume coral mucous from small wounds that they inflict on specific coral types (Cole et al., 2008)
Diversity in diet and feeding behaviour of butterflyfishes: reliance on reef corals versus reef habitats
No full text[Extract] Considerable research attention has focused on the feeding habits of coral reef butterflyfishes, especially Chaetodon butterflyfishes (reviewed by Cole et al., 2008), largely due to their propensity to feed on corals (more specifically, reef-building scleractinian corals). Coral feeding infers a very high dependence upon living corals, which has led to suggestions that changes in the-abundance (or behaviour) of butterflyfishes may provide an effective indicator for declines in coral cover (e.g., Khalaf and Crosby, 2005; Gochfeld, 2006), or even declining condition of entire coral reef ecosystems (Reese, 1977; Hourigan et al., 1988; Crosby and Reese, 1996, 2005). Butterflyfishes, especially highly specialised coral-feeding species, are certainly sensitive to changes in the availability of scleractinian corals (e.g., Crosby and Reese, 2005; Samways, 2005; Pratchett et al.,2006; Graham, 2007; Wilson et al., Chapter 14). However, responses of butterflyfishes to coral loss are very complex, highly species-specific, and often delayed, which greatly reduces their effectiveness as indicators of coral health (Crosby et al., Chapter 10). Variation in dietary breadth and composition among butterflyfishes, which determines coral-dependence, is nonetheless very important in understanding inherent vulnerabilities of butterflyfishes to sustained and ongoing coral loss associated with the worldwide degradation of coral reef ecosystems (Pratchett et al., 2008a, Pratchett, Chapter 6)
The origins and diversification of coral reef butterflyfishes
No full text[Extract] The Chaetodontidae is a diverse family of percomorph fishes represented by 122 extant species, characterised by deep compressed bodies, small protruded mouths and bristle-like teeth (Allen et al., 1998). The family is dominated by fishes of the genus Chaetodon, which are among the most conspicuous inhabitants of coral reef environments. Two thirds of all butterflyfishes are found living within coral reef habitats, and many of these species feed mainly, if not exclusively, on reef-building corals (Cole et al., 2008; Cole and Pratchett, Chapter 5). Because of their reliance on corals for food, Chaetodon butterfly fishes are regarded among the most specialised and highly evolved coral reef fishes (e.g., Gosline, 1985). These fishes are inextricably linked to the corals on which they feed (Reese, 1977, 1981), but did the family originate within coral reef environments
Susceptibility of butterflyfish to habitat disturbance: do 'chaets' ever prosper?
No full text[Extract] Disturbance is an integral component of ecology, responsible for re-setting successional clocks and preventing the dominance of climax communities (Grime, 1973; Connell, 1978). However, ecologists, environmentalists and resource managers are concerned that the diversity, frequency, intensity, and spatial extent of disturbances is increasing (Hoegh-Guldberg, 1999; Wooldridge et al., 2005), and communities are perpetually in the early stages of succession, or have 'flipped' to alternate stable states (Scheffer et al., 2001)
Harvesting of butterflyfishes for aquarium and artisanal fisheries
No full text[Extract] Direct harvesting of fishes and other coral reef organisms represents the most significant and pervasive anthropogenic impact on coral reef ecosystems (e.g., Roberts, 1995; Jackson et al., 2001; Myers and Worm, 2003), causing a range of direct and indirect effects on populations, communities, and ecosystems. Extensive harvesting of very large and previously abundant reef-associated organisms has caused massive changes in coral reef ecosystems-throughout the last two centuries (Jackson et al.,2001), and contemporary fisheries continue to overexploit many reef species (e.g., Morris et al., 2000). Coral reef fisheries account for a relatively small proportion of global fisheries yield (<1%), but are fundamental in providing food and livelihoods in many tropical nations (e.g., Bell et al., 2009). Also, coral reef fishes are probably more vulnerable to exploitation compared to many other fisheries stocks (Russ, 1991), and overfishing of reef fishes with critical functional roles, such as herbivorous fishes, has contributed to extensive and accelerating degradation of coral reef habitats (e.g., Hughes, 1994, 1996) and greatly increases vulnerability to subsequent disturbances (Bellwood et al., 2003; Hughes et al., 2007)
Butterflyfishes as a model group for reef fish ecology: important and emerging research topics
No full text[Extract] In his preface to a special issue (and dedicated workshop) on the biology of butterflyfishes, Motta (1989) suggested that butterflyfishes have received disproportionate scientific attention compared to other common and conspicuous families of coral reef fishes. In support of this assertion, the number of scientific publications that consider butterflyfishes (151 Web of Knowledge; 382 publications since 1927) is far greater than for many other families of nominal reef fishes (e.g., angelfishes, surgeonfishes, and rabbitfishes); the only families that have been more intensively studied are the Pomacentridae (damselfishes), Serranidae (groupers) and Labridae (parrot fishes and wrasses), which probably reflects their high diversity, commercial and functional importance, respectively. In this respect, research on butterflyfishes has contributed greatly to genera l understanding of the biology and ecology of coral reef fishes (e.g., Almany et al., 2007; Lawton et al., 2011). The fields of research in which butterflyfishes have played essential roles also extends well beyond the notion that butterflyfishes are "indicators" of overall reef health, which is the usual justification for studying this relatively unique group of reef fishes (e.g., Ohman et al., 1998; Bozec et al., 2005; Shokri et al., 2005)
Hybridisation among butterflyfishes
No full text[Extract] Hybridisation is defined as the interbreeding of individuals from two distinct populations (sensu stricto species), which are distinguishable on the basis of one or more heritable characters, following Harrison (1993). Hybrids have been recognised, based on intergrading of characteristic features from parent species, since at least the 1700's and have been documented among plants, corals, gastropods, crustaceans, insects, amphibians, reptiles, birds, mammals and fish (Barton and Hewitt, 1985; Schwenk, 1993; Bieme et al., 2003; van Oppen and Gates, 2006). At least 10% of animals and 25% of plant species are known to hybridise, although the true proportion is probably higher because hybridisation often goes unnoticed (Mallet, 2005, 2007). The fact that hybridisation is not a rare phenomenon but occurs in a considerable proportion of species, presents a significant challenge to the fundamental biological definition of a species (Barton and Hewitt, 1985; Mallet, 2005)
Reproductive investment and fecundity of Pacific crown-of-thorns starfish (Acanthaster cf. solaris) on the Great Barrier Reef
Get PDFCrown-of-thorns starfish (Acanthaster spp.) is reported to have exceptional reproductive capacity, but this has been largely inferred based on the overall weight of gonads (and mostly for females), and there are limited estimates of the concentration of gametes within gametogenic tissues. This study quantified gamete concentrations for both male and female Pacific crown-of-thorns starfish (Acanthaster cf. solaris), collected on Australia’s Great Barrier Reef in 2014–2019. Gamete concentrations varied greatly among female starfish (12,338–133,810 oocytes g−1), such that the estimated reproductive capacity ranged from \u3c 1000 oocytes for the smallest (141 mm) individual up to 106 million oocytes for a 480-mm diameter female. Gamete concentrations were much more conserved for male starfish, and did not vary with size. Nonetheless, the total mass of gametogenic tissue increased with size, and fecundity of large males \u3e 400-mm diameter approached 53 billion sperm. This study reaffirms that crown-of-thorns starfish have exceptional reproductive capacity, which is strongly size-dependent, but also varies greatly among individuals. Importantly, individual variation in reproductive output may be important in understanding for population irruptions of Acanthaster spp., and their concomitant effects on reef ecosystems
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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