Starfish Series – #CharoniaResearch

A summary of the principal findings and some propositions regarding starfish outbreaks.

Increased sub-tidal abundance of blue linckia could precede outbreaks of COTS.Similar_Larval&PredatorsReducedMost species of starfish are rare, cryptic, toxic and in one case even venomous.MostStarfishAreRareReduced

Preferred prey is the species hunted and attacked preferentially by the predator.FavoriteNotCapturedReduced

Heron Reef (23° 27′ S, 151° 57′ E) in Capricorn Group at southern end of Great Barrier ReefHeronWistariReduced

The attack of the triton elicits an escape response by the starfishCharoniaTritonis1ReducedSpecies of coral reef starfish may trigger larval settlement in the giant triton.GiantTritonLarvaSettlementReduced

“a complex twist to more typical asteroid life-history strategies.” – Knott at al (2003)LarvalCloningReduced

Many eggs may never be fertilised when adult populations exist at low densitiesDifferentLarvalDevelopmentReduced

The fertilization reaction in the sea-urchin. Rothschild and Swann (1952)EggFertilizationReduced

Sea-urchins and starfish both belong to Phylum Echinodermata and while early research on the fertilization reaction was conducted by Rothschild and Swann (1949) on sea-urchins, the conclusions regarding egg fertilization and proximity of spawning individuals were just as applicable to starfish.

Human collection of the Giant Triton and other predators was suggested by Endean (1969) as a causative factor in starfish outbreaks but this Predator Control Hypothesis was generally disregarded due to the enormous potential numbers of starfish. Recent research demonstrating the strong avoidance reaction of the starfish to the triton together with an understanding of the importance of starfish aggregation to reproductive success may be slowly changing this opinion.

The existence of crown-of-thorns starfish outbreaks influenced many important world economic decisions of the 1960s, including the rejection on ecological grounds of a new sea-level Panama Canal. Starfish radial nerve extract (1-methyladenine) has been used to experimentally induce starfish spawning since Noumura and Kanatani (1962), but any possible causal connection with the starfish outbreaks has never been investigated.