The settlement behaviour of planulae larvae of the hermatypic coral Favia fragum (Esper)

Understanding and predicting the connectivity of coral reef organisms linked by larval dispersal is a key goal of tropical coastal ecosystem science and management. As oceanographers make advances modelling transport processes between reefs, ecologists should be prepared to embrace the population dynamics of organisms at larger metapopulation scales. A metapopulation is den~ographically closed but contains multiple open local populations. hlIetapopulation models of coral dynamics would aid the identification of larval source and sink areas and help identify the boundaries of demographically closed populations. Metapopulatlon models would also aid the understanding of species extinctions and help formulate transboundary management strategies to conserve ecosystem functlon Existing metapopulation models are not spat~ally realistic or proven to represent physical and biological processes at appropriate spatial and temporal scales. Before more realistic alternatives can be established, further research is needed into (1) the larval transport between reefs (i.e. the coupllng of reef-scale and oceanic models of water circulation, the pre-settlement mortality rates of larvae, and larval mobility in the water column), (2) the influence of larval supply on coral population dynamics at local (10s of kilometres) scales (i.e. processes of settlement behaviour, post-settlement mortality, and the pre-emption of space by algae), and (3) processes affecting the net fecundity of local populations (i.e. interactions of colony size, partial mortality rate, competition with algae, and the influence of habitat, physical disturbance, herbivore pressure, nutrification and sedimentation).

Section: Larval Settlementmentioning

confidence: 99%

Section: Larval Settlementmentioning

confidence: 99%

Can Caribbean coral populations be modelled at metapopulation scales?

Mumby¹

1999

“…Surfaces previously used in coral recruitment experiments include artificial substrata not generally found in the reef environment such as glass (Stephenson 1931, Hamgan 1972, Lewis 1974, Goreau et al 1981, Coles 1985, terracotta or ceramic tiles (Vaughan 1959 [cited in Lewis 19741, Brock 1979, Baggett & Bright 1985, PVC surfaces or plastic Petri dishes (Birkeland 1977, Birkeland et al 1982, Wallace & Bull 1982, Harriott 1983a, concrete blocks (Fitzhardinge 1985); as well as other surfaces similar to those found naturally in the field, such as tridacnid clam shells (Babcock 1986), slices of coral block (Harriott 1983b, Sammarco 1983, Alino et al 1985, Babcock 1985, 1986, and the outer surface of pieces of dead coral (Hamgan 1972, Lewis 1974, Sammarco & Carleton 1982, Wallace & Bdl 1982, Rylaarsdam 1983, Wallace 1983, 1985a.…”

Section: Introductionmentioning

confidence: 99%

A comparison of settlement plate types for experiments on the recruitment of scleractinian corals

Harriott¹,

Fisk²

1987

109

Eight substratum types, covering the range normally used for experiments on recruitment of scleractinian corals, were compared for cost, convenience, ability to attract recruits, and taxonomic composition of recruits. Plates varied significantly in number and types of recruits, indicating that studies uhlizing different types of settlement surfaces cannot be compared directly to one another. Recruitment patterns also varied between forereef and backreef study sites, a d d~n g to the growing list of factors that contribute to variability in scleractinian recruitment.

“…Additional support for the idea of vertical migration comes from laboratory research on planula behavior. These studies have shown that the planulae of several species of coral respond to irradiance (Duerden 1902, Edmondson 1929, Abe 1937, Kawaguti 1941, Harrigan 1972, Lewis 1974, gravity and currents (Kawaguti 1941), and, because of their gregarious settling behavior, chemical and tactile stimuli (Duerden 1902, Edmondson 1929, Kawaguti 1941, Harrigan 1972, Lewis 1974. Planulae thus appear to have the ability to carry out a diurnal vertical migration.…”

Section: Potential Diurnal Vertical Migrationmentioning

confidence: 99%

“…Several studies of the settling behavior of planulae of several species of coral indicate that most planulae settle within a few days when provided a proper substrate (Vaughan 1908, Edmondson 1929, Abe 1937, Harrigan 1972, Lewis 1974. When deprived of a suitable settling site, e. g. improper substrate or insufficient irradiance, the majority of planulae tested survived several weeks without settling, and then successfully settled when an appropriate substrate was provided.…”

Section: Planktonic Lifespan Of Planulaementioning

confidence: 99%

Abundance and distribution of planktonic coral larvae in Kaneohe Bay, Oahu, Hawaii

Hodgson¹

1985

A plankton sampling program was designed for the capture of coral planulae. More than 250 surface tows were made with a small, fine-mesh net along 5 transects established near the southeast fringing reef of Coconut Island, Oahu, Hawaii. Time between collection and sorting was minimized, and low temperature storage was employed in lieu of chemical fixation to prevent decomposition of the planulae prior to identification. More than 20,000 cnidarian larvae were collected and sorted, of which 90 % were scleractinian planulae. Twelve different types of cnidarian larvae were recognized. Six were identified as the planulae of the corals Pocillopora damicornis, Porites compressa, Montipora verrucosa, M. dilitata, Cyphastrea ocellina and Fungia scutaria. Two appear to be the zoanthina larvae of the zoanthids Palythoa vestitus and Zoanthus pacificus. Peak recovery of planulae generally occurred 3 to 7 d after onset of spawning or planulation. Limited data indicate that some coral planulae may undertake diurnal migration, residing near the surface at night and moving to several meters depth during the day. The potential for the export of large numbers of coral planulae from Kaneohe Bay is considered high, but whether this export is significant to recruitment on reefs outside the bay remains to be determined.