Moorsel, G.W.N.M. van

Ecological status of Lac Bay, Bonaire

Client: Departement voor Ontwikkelingssamenwerking Nederlandse Antillen (DEPOS)

Project nr: 90.04

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Caribbean Christmas tree worms (Annelida: Polychaeta: Serpulidae: Spirobranchus) are considered host generalists in their associations with anthozoan (Scleractinia) and hydrozoan (Millepora) stony corals. As planktonic larvae, they settle on coral surfaces and start secreting a calcareous tube to be used as a dwelling. This tube usually becomes overgrown by the host coral (except for its opening) and may get encapsulated deep inside the coral skeleton. In this manner, the well-protected worms grow and survive predation and other hazards, allowing them to live for over four decades. When the host corals are overgrown by other organisms, such as octocorals and sponges, these may act as secondary hosts.

Previous surveys of the coral fauna of St. Eustatius were usually of short duration and part of a larger research that included all of the windward Netherlands Antilles (SSS = Saba, Saba Bank, St. Eustatius, and St. Martin). This may have caused an underestimation of its species richness. In an expedition to the Saba Bank in 1972, one sampling station (maximum depth 15 m) was added at the west coast of St. Eustatius, which resulted in a record 16 stony corals species from this island (Van der Land 1977). Bak (1975) visited all SSS islands from where he reported a total of 35 scleractinian species (< 35 m depth). Sybesma et al. (1993) listed 16 reef coral species. Klomp and Kooistra (2003) found 23 scleractinian species (partly specified), which they recorded from the windward islands, including 10 dive sites off St. Eustatius. Jongman et al. (2010) listed a total of 41 scleractinians but it is unclear how this information was obtained. The most recent inventory included 24 scleractinian species for St. Eustatius (Debrot et al. 2014). Since the coral faunas of Saba, Saba Bank, St. Eustatius, and St. Martin do not show a clear variation (Klomp and Kooistra 2003) the present results are compared with the previously published records (except for those in Jongman et al. 2010). In this way it may become clear if certain species have disappeared or became introduced (Hoeksema et al. 2011). 

This article was published in the following report:

MARINE BIODIVERSITY SURVEY OF ST. EUSTATIUS, DUTCH CARIBBEAN 2015 by Naturalis Biodiversity Center and the Netherlands ANEMOON Foundation