The Crown-of-Thorns starfish Acanthaster planci (Linne') in Ceylon

The Crown-of-Thorns starfish Acanthaster planci is a predator of coral and has been responsible for the widespread destruction of coral reefs. In Sri Lanka this starfish was first reported by Clarke in 1915. Recently skin-divers reported that Acanthaster planci was present in very large numbers in the coastal waters off Trincomalee, especially on the coral formations around Pigeon Island. It is well known that the multiplication of the starfish to plague proportions is a serious threat to the coral reef formations round the Island. If it were allowed to continue its depredations the entire coral reef belt round the Island might be destroyed in a short time. The monsoon waves would then convert the dead coral to rubble. In the absence of a barrier against the advancing waves during the monsoon it would also lead to serious erosion of the shoreline. The coral reef fish would also disappear with the destruction of the coral formations. On account of these considerations it was decided to conduct a survey of the Crown-of-Thorns starfish in eastern coastal waters in order to estimate the magnitude of the population of the starfish in these waters.

The demonstration of chemosensory food detection in Hymenocera picta Dana (Decapoda, Caridea), a proposed predator of the crown-of-thorns starfish Acanthaster planci (L)

Hymenocera picta, the painted shrimp, is a possible predator of A canthaster planci. the crown-of-thorns starfish. H. picta detects food by chemical cues alone and visual cues play no part in the initial location of prey. The presence of food in the water causes the shrimp to become more active, and distance chemoreceptors are probably present in the antennules of the shrimp. Extract of A. planci has statistically similar attractive powers to an extract of Linckia multifora, the starfish supplied as food to the shrimps. The painted shrimp was not attracted to fish extract (Chaetodon sp.) and may respond only to starfish. It is suggested that although H. picta is able to kill and feed on small juvenile A. planci. it is probably an ineffective predator against larger adult Crown-of-thorns starfish.

"Rapid and dramatic changes in vegetation" of a small pond on Holy Island (Northumbria): Chaotic dynamics?

This note describes changes to the relative extent of four structurally dominant submerged macrophytes in a pond on Holy Island National Nature Reserve, Northumbria, between 1991 and 1998. The estimated extent of the four submerged macrophytes and bare substratum between 1991 and 1998 showed dramatic changes with no obvious pattern or periodicity, as well as no identifiable natural or anthropogenic causes. Chaotic variation may be an important character of submerged pond plant populations, so that surveys taken in a single year may give an unreliable picture of plant populations.

Management of broodstock and quality control of fish seed in Hungary

Common carp (Cyprinus carpio) breeding has a long tradition in Hungary. However, recent economic changes in Eastern Europe and new developments in aquaculture necessitated the need for ensuring quality of the brood stock used in hatcheries and the legal and institutional frameworks needed to implement the program. In addition to good research and development programs and gene banking, it became essential to establish an appropriate legal framework, organize, coordinate and control breeding activities, and provide financial support. It was a major breakthrough for carp breeding when C.carpio was recognized as one of the cultivated animals in the Animal Breeding Act in 1993. The Carp Breeding Section of the Hungarian Fish Producers Association plays an important role in carp breeding programs. Thirteen breeding farms of the Carp Breeding Section have 24 certified C.carpio varieties. In Hungary, about 80 % of the seed used as stocking for commercial production are from high quality certified breeders.