Showing posts from October, 2022

Report to GBRMPA (1986)

  The attack of the triton elicits an escape response by the starfish which, if successful, results in rapid prey dispersion with the loss of only a few arms. The escape response varies in its successfulness and is heavily dependent on (1) size and hunger of predator, (2) prey size and degree of cumulative prey injury and (3) physical composition and relief of substrate. If the escape response is unsuccessful then the predator feeds on the starfish until the prey is either consumed (large predator-small prey) or discarded (small predator-large prey). Charonia tritonis will follow the scent of an injured starfish and resume the attack and subsequent feeding if hungry. When not in the process of prey hunting, capture or feeding, Charonia tritonis can appear inert. Under turbulent water-current conditions, the sensitive olfactory organ of Charonia tritonis can be disabled temporarily giving the appearance of random searching behavior. The distance over which Charonia tritonis can locate a

Coral Reef Starfish

Ormond et al. (1973) discussed the consequences of spawning aggregations of Acanthaster and suggested that the increased proximity of adult starfish may enhance the chances of fertilisation, especially if synchronous spawning takes place. It was suggested by Lucas (1984) that a conspecific stimulus would induce synchronous spawning in Acanthaster planci and a delayed spawning activity in dispersed individuals of Acanthaster planci was observed by Okaji (1991). It was suggested that this delay reflected less frequent stimulus from conspecifics in dispersed populations compared with aggregated populations and that synchronous spawning induced by such stimulus would lead to higher rates of fertilisation when the animals formed an aggregation. Evidence of the existence of sexual pheromones in starfish was presented by Miller (1989). The effect of sperm dilution, adult aggregation and synchronous spawning upon the fertilisation of sea-urchin eggs was reported by Pennington (1985). Penningto

List the Giant Triton on CITES

List the Giant Triton in Appendix 2 of the Convention on International Trade in Endangered Species (CITES) . The Giant Triton ( Charonia tritonis )  is a beautiful shell and a well-known predator of the crown-of-thorns starfish ( Acanthaster planci ). In many parts of the third world, it is still being collected in large numbers and sold to tourists as ornaments. As you admire the beautiful shell, spare a thought for the hungry mollusk that died. And don’t forget, they live on starfish. Many species of starfish are known to outbreak in different parts of the world. Prior to human collection, the giant triton might have controlled starfish numbers not by eating the many, but by preventing the aggregation that precedes the outbreak. At present, little is known of any aspect of the triton’s ecology despite its obvious importance in controlling starfish numbers. Petition to List the Giant Triton on CITES .

Starfish – Predator or Prey

The Giant Triton may affect aggregation and fertilization success of the Crown of Thorns Starfish. 1. General Background Outbreaks of the crown of thorns starfish (Acanthaster planci) have been studied for many years throughout the Indo-West Pacific region (Moran, 1986) and although many explanatory hypotheses have been proposed we do not understand why outbreaks of this starfish occur on some reefs while, on other nearby reefs, this starfish maintains a stable, low population density. On the Great Barrier Reef and elsewhere, most starfish research has centered on establishing the scale of Acanthaster outbreaks and the effect of Acanthaster predation on the coral reef community. The giant triton (Charonia tritonis) and other members of the genus Charonia are known predators of many species of starfish (Chesher, 1969; Endean, 1969; Laxton, 1971; Noguchi et al., 1982; Percharde, 1972) but there are few examples of other species predominantly preying on starfish (Harrold and Pearse, 1987)

Summary of the principal findings

  A summary of the principal findings  and some propositions regarding starfish outbreaks, including ChatGPT questions Dr Peter James and Dr Robert Endean at Green Island.  Increased sub-tidal abundance of blue linckia could precede COTS outbreaks . Most starfish are rare, cryptic, toxic and in one case even venomous .   The preferred prey is the species attacked preferentially by the predator .  Heron Reef (23° 27′ S, 151° 57′ E) Capricorn Group at southern end of GBR .  The attack of the triton elicits an escape response by the starfish .  Coral reef starfish species may trigger larval settlement in the giant triton .  “ a complex twist to more typical asteroid life-history strategies .”  Many eggs may never be fertilised when adult populations exist at low densities .  Cryptic species have been recognized by Byrne and Walker (2007) .  Giant triton attacks and consumes crown-of-thorns starfish.  (Beaver Reef, 2002).  Starfish Series – #CharoniaResearch This is ChatGPT at work. It&#