Hoeksema, B.W.

Host-dependent variation in density of corallivorous snails (Coralliophila spp.) at Curaçao, southern Caribbean.

Snails of the genus Coralliophila (Muricidae: Coralliophilinae) are common in the Caribbean as corallivores that feed on a large range of host species. The present study concerns the distribution of two Coralliophila snails, C. caribaeaand C. galea, at 5-m and 10-m depths at Curaçao (southern Caribbean), as associates of the common scleractinians Orbicella annularis and Pseudodiploria strigosa. Coralliophila galea was abundant on both host species, while C. caribaea was represented only by a single individual on a colony of P. strigosa. No significant differences in shell length were found between snails associated with O. annularis and P. strigosa. The distribution of C. galea on both host species deviated significantly from a random distribution. The snails were most abundant at 5-m depth, particularly on larger colonies of O. annularis, with > 60 % of large colonies colonized by snails, while snails were absent on small colonies. This distinction was not significant in P. strigosa at the same depth or in O. annularis at a depth of 10 m. The results suggest that host preference should be considered in assessments of reef health in connection to damage caused by Coralliophila spp.

Date
2017
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Curacao

Biodiversity of Dutch Caribbean Reefs

The coral reefs of the Dutch Caribbean have recently received much attention in the scientific journal Marine Biodiversity. The first issue of 2017 contained various articles about coral reef research carried out in the Caribbean and particularly St. Eustatius and Curaçao. The new findings suggest that much remains to be discovered regarding the marine fauna and flora of Caribbean coral reefs. 

This news item was published in BioNews 4-2017

BioNews is produced by the Dutch Caribbean Nature Alliance and funded by the Ministry of Economic Affairs.

Date
2017
Data type
Media

Wave-swept coralliths of Saba Bank, Dutch Caribbean

During a recent reef coral survey at the submarine Saba Bank (Eastern Caribbean), an uncommon and diverse assemblage of unattached scleractinian corals (coralliths) was encountered, which has not been reported from the Atlantic before. Four different types of these free-living (unattached) corals were distinguished. They were observed on a relatively flat seafloor (15–20 m deep) with poor coral cover and full exposure to oceanic swell. Much of the substratum was not consolidated and consisted mainly of sand and fragments of branching coralline algae. One of the four types is the (1) anthocyathus stage in the life history of the free-living species Manicina areolata and Meandrina danae. The other three are coralliths formed as ecophenotypic varieties: (2) spheroidal–amoeboidal (= globular and (sub)massive) in Porites astreoides, Siderastrea radians, S. siderea, and Stephanocoenia intersepta; (3) tumbleweed-like (= globular and ramose) in Porites divaricata and P. furcata; and (4) discoidal (flat and circular with short branches) in Madracis decactis and possibly in M. cf. auretenra. This assemblage of free-living corals is likely related to a combination of abiotic factors consisting of wave exposure (swell), depths that waves can reach, a horizontal sea floor with little relief, an unconsolidated substratum, and low coral cover.

Date
2017
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Saba bank

Host switch by the Caribbean anemone shrimp Periclimenes rathbunae in Curacao

The anemone shrimp Periclimenes rathbunae Schmitt, 1924 (family Palaemonidae), is a common associate of shallow- water anthozoans in the tropical western Atlantic. It has been reported from several sea anemone species, an octocoral, a corallimorpharian, and a scleractinian coral (Brinkmann and Fransen 2016).

During a coral reef survey in Curacao (1 April 2014), a previously unknown association was found between an individual of P. rathbunae and a lettuce slug, Elysia crispata Mo ̈rch, 1863 (Fig. 1). It occurred on the reef slope (6–8 m deep) of Playa Kalki on the island’s northwestern tip (12°22'30'N, 69°09'28'W), where this slug appeared to be abundant (ca. 40 observed individuals per 1-h dive). The shrimp’s blue coloration matched that of its host, but it is usually dark red-brown (see, e.g., Brinkmann and Fransen 2016; Horka ́ et al. 2016).

Elysia crispata is a polymorphic sacoglossan sea slug (infraclass Opisthobranchia) that eats algae in a wide range of habitats (Krug et al. 2016). In this case, the shrimp was positioned on top of its host between the dorsal frills, as if riding it (Fig. 1a, b).

Periclimenes rathbunae is the second shrimp species recorded as associate of an opisthobranch gastropod and the first one in the Atlantic. The other shrimp, Zenopontonia rex (Kemp, 1922), lives on Indo-Pacific reefs and is famous under its junior synonym, Periclimenes imperator Bruce, 1967. This species lives with echinoderm hosts as a juvenile but changes to nudibranch hosts as it matures (Horka ́ et al. 2016). Periclimenes rathbunae also lives with a range of hosts, but it is not clear whether the association with E. crispata also results from an ontogenetic host switch. 

Date
2017
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Curacao

Naturalis Marine Expedition: Results marine biodiversity of St. Eustatius

In September, a report on the preliminary results of the Statia Marine Biodiversity Expedition (from June 2015) was published. This expedition served as the rst extensive baseline study to explore the marine biota of St. Eustatius, a small island belonging to the Caribbean Netherlands on the boundary between the eastern Caribbean Sea and the West Atlantic. Various undescribed species were discovered during the expedition. In addition, already described species were reported that previously were not known to occur in the Caribbean or even in the Atlantic Ocean. 

This news article was published in BioNews 29

BioNews is produced by the Dutch Caribbean Nature Alliance and funded by the Ministry of Economic Affairs.

Date
2016
Data type
Media
Theme
Research and monitoring
Geographic location
St. Eustatius

Stony corals of St. Eustatius

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

Date
2016
Data type
Other resources
Theme
Research and monitoring
Geographic location
St. Eustatius

Beta diversity of macroalgal communities around St. Eustatius, Dutch Caribbean

This study provides a baseline of the marine algal flora composition around St. Eustatius, Dutch Caribbean, by describing algal community structure in terms of species richness and beta diversity, and by providing a taxonomically reliable DNA barcode collection. A total of 156 species was found, including 91 that represent new records for St. Eustatius. Subtidal assemblages (126 species) and intertidal assemblages (48 species) showed little overlap. Algae assemblages in seagrass beds differed from those on hard substrates in species composition. In addition, seagrass communities contained a relatively high number of associated green algae species. Artificial substrates (such as shipwrecks) mimicked natural hard substrates in terms of species richness and composition, but missed some key species that characterize natural reef floras. Species accumulation curves and asymptotic species richness estimators show that the expected species richness is higher than the observed number of species, indicating that additional sampling is needed to record rare species. The phylogenetic trees provided in this study identified the presence of cryptic species and fills knowledge gaps in our understanding of Caribbean macroalgae.

Date
2017
Data type
Scientific article
Theme
Research and monitoring
Tags
Geographic location
St. Eustatius

Statia Marine Expedition

In June 2015, Naturalis Biodiversity Center, in collaboration with “Anemoon Foundation”, launched a new initiative in the Dutch Caribbean with the organization of a marine expedition to St. Eustatius. The expedition was hosted by the Caribbean Netherlands Science Institute (CNSI), diving was kindly supplied by Scubaqua Dive Centre and STENAPA St Eustatius acted as a local counterpart. The expedition team consisted of a multidisciplinary team of national and international researchers, citizen scientists, as well as university students from St. Eustatius, the Netherlands, Italy, Japan, Russia and the USA, each focusing on a particular group of organsms including corals, fishes, sponges, seaweeds, etc. 

This news article was published in BioNews 19

BioNews is produced by the Dutch Caribbean Nature Alliance and funded by the Ministry of Economic Affairs.

Date
2015
Data type
Media
Theme
Research and monitoring
Geographic location
St. Eustatius

Helioseris cucullata as a host coral at St. Eustatius, Dutch Caribbean

In order to demonstrate how scleractinian corals contribute to marine biodiversity by their host function, information on associated fauna was gathered during a biological survey at St. Eustatius, eastern Caribbean. This knowledge is especially urgent for a host coral such as Helioseris cucullata (Agariciidae), which has undergone strong declines in abundance at various Caribbean localities and has a poor record of associated fauna. New records of H. cucullata as host are presented for the coral gall crab Opecarcinus hypostegus (Cryptochiridae), the Christmas tree worm Spirobranchus giganteus (Serpulidae) and an unidentified serpulid tube worm of the genus Vermiliopsis. A second association record is reported for the coral barnacle Megatrema madreporarum (Pyrgomatidae). Coral-associated copepods were not found on H. cucullata despite a search for these animals. The new records were compared with previous records of other host coral species that showed elements of the same associated fauna. The present findings indicate that new discoveries concerning Caribbean coral reef biodiversity can still be made during field expeditions by targeting the assemblages of associated fauna of specific benthic host species.

Date
2017
Data type
Scientific article
Theme
Research and monitoring
Geographic location
St. Eustatius