Auke-Florian Hiemstra

ABSTRACT  

A coral community was examined on a semi-submersible platform that was moored at the leeward side of Curaçao, in the southern Caribbean, from August 2016 until August 2017. This community included several non- native or cryptogenic species. Among them were two scleractinian corals (Tubastraea coccinea and T. tagusensis) and two octocorals (Chromonephthea sp. and an unidentified Nephtheidae sp.). This is the first reported presence of T. tagusensis in the southern Caribbean, and the genus Chromonephthea in the Caribbean region. An ascidian, Perophora cf. regina, is also reported from the southern Caribbean for the first time, as well as a coral-associated vermetid gastropod, Petaloconchus sp., first recorded in the Caribbean in 2014. Lack of biofouling management could potentially harm indigenous marine fauna through the introduction of non-native species. Therefore monitoring communities associated with semi-submersible platforms is essential to track the presence and dispersal of non-native, potentially invasive species.   

Abstract. In contrast with a general decline of Caribbean reef corals, a previously rare sun coral is
increasing in abundance within shallow coral communities on Curacao. This azooxanthellate scleractinian
was identified as Cladopsammia manuelensis, which has an amphi-Atlantic distribution. Over the last decade,
C. manuelensis has increased abundance along the leeward coast of Curacao (southern Caribbean)
between depths of 4 and 30 m. This species was initially not noticed because it resembles the invasive coral
Tubastraea coccinea, which was introduced to Curacao from the Indo-Pacific around 1940. However, in contrast
to T. coccinea, C. manuelensis was previously only present on deeper reef sections (>70 m) of Caribbean
reefs. Our observations illustrate how the sudden increase in abundance of a previously unnoticed, apparently
cryptogenic species could result from natural dynamics on present-day reefs, but also could easily be
mistaken for an invasive species. The finding that deep reef sections can harbor species capable of colonizing
shallower reef zones highlights the importance of thorough inventories of reef communities across
large depth ranges, which can help us to discriminate between range increases of native species and the
arrival of invasives.

Key words: bathymetric distribution; Cladopsammia; coral reefs; cryptogenic; deep water; Dendrophylliidae; invasive;
native; Rhizopsammia; Tubastraea;.