Ctenophores are one of the least known invertebrate phyla in Mexico, especially the benthic forms in which studies are incomplete and infrequent, lacking information about their ecology and diversity. As part of the environmental monitoring project ‘Biodiversidad Marina de Yucatán’ conducted in the southern Gulf of Mexico and Mexican Caribbean Sea, the benthic ctenophore Vallicula multiformis (Coeloplanidae) was identified in association with green algae in the southern Gulf of Mexico, and on an autonomous reef monitoring structure in the Mexican Caribbean Sea. This finding represents the first record of the occurrence of a benthic ctenophore species in Mexican waters. We provide morphological characteristics of V. multiformis in both reef areas. Recording this species increases the known number of Mexican ctenophore fauna from 33 to 34 taxa and represents baseline information for the continuous study of the ecology and diversity of benthic ctenophores in Mexico.

Bunodeopsis pelagica is one of the few species of sea anemones known to be found in the floating algae of Sargassum spp. It has been reported in the North Atlantic, particularly in the Canary Islands and the coast of Jamaica. The present study is the first to report the occurrence of B. pelagica in the Mexican Atlantic, found as epiphyte on Sargassum natans off Alacranes reef (southern Gulf of Mexico) and in Puerto Morelos reef (Mexican Caribbean), revealing that this species is much more widespread than has been reported. Bunodeopsis pelagica is mainly distinguished from other species of Bunodeopsis by having simple minute protuberances on its column, while its congeners have larger and much more developed vesicular projections. With the record of B. pelagica, the number of known species of actiniarian sea anemones from the Mexican Atlantic increases to 23.

Secondary clay minerals observed in the two uppermost basalt lava flows at ODP Site 1001, in the Caribbean Sea, drilled from the large igneous province of Cretaceous age, result from low-temperature alteration processes. Alteration mainly proceeds by circulation and diffusion of sea water. Six different types of clay mineral assemblage were recognized. Initial alteration with oxygenated sea water involves Fe and K fixation, creating visible oxidation halos parallel to the sides of cracks and fissures. A saponite/ beidellite mixture, interstratified smectite-glauconite, interstratified glauconite-nontronite and Fe oxyhydroxides are obtained depending on the distance from fluid conduits. The presence of beidellite may be due to enhanced Al mobilization resulting from high fluid flux. These early minerals are cross-cut by thin veins of pure celadonite or glauconite with further vesicle infill. Late-stage alteration is typified by the formation of saponite and takes place under closed reducing conditions resulting from deposition of the sedimentary overburden.

We report the first evidence of Hg content in marine sediments changing in connection with the climate-driven changes in ocean stratification during the Quaternary Period based on core samples from ODP Hole 1006A off Great Bahama Bank in the Caribbean Sea. The Hg content ranged from 5.9 to 60.7 ng/g with an average value of 33.1 ng/g during 350 and 1330 ka and changed inversely with δ18Oplanktonic values. The change in Hg content was positively correlated with total organic carbon (TOC) content, indicating connections between the δ15Norg and δ13Corg values of organic matter and the absolute abundance of a deep-dwelling calcareous nannoplankton (Florisphaera profunda). The marine Hg is thought to have been incorporated into the organic matter produced by deep-dwelling phytoplankton. Based on these results, we propose a mechanism by which marine Hg can collect in a thermocline formed in the stratified lower photic zone. Mercury content and nannoplankton assemblage in marine sediment provide information about the extent of stratification of the oceanic photic zone and the role of surface- and deep-dwelling phytoplankton in producing marine organic matter and changing its δ15Norg and δ13Corg values.

Cliona delitrix is one of the most abundant and destructive coral-excavating sponges on Caribbean reefs. However, basic aspects of its reproductive biology, which largely determine the species propagation potential, remain unknown. A 2-year study (October 2009 to September 2011) was conducted to determine the reproductive cycle and gametogenesis of a C. delitrix population located in a shallow reef in Florida, USA. Mesohyl tissue collected from randomly chosen and tagged sponge individuals was sampled one to several times a month, and analysed by light and transmission electron microscopy (TEM). Cliona delitrix is oviparous and gonochoric, except for a few simultaneous hermaphroditic individuals. The C. delitrix reproductive cycle in Florida is from April to December, and is triggered by an increase in seawater temperature to 25°C. Oogenesis and spermatogenesis were asynchronous among individuals; with different cohorts of oocytes co-occurring in females, and spermatic cysts in males. Granulose cells acted as nurse cells, contributing to the growth and maturation of both female and male gametes. Spawning of gametes was not always synchronized with full moon phase. Unlike most other oviparous sponges, the reproductive cycle of C. delitrix is versatile and includes multiple spawning events during the summer of each year. This characteristic maximizes sponge propagation on coral reefs during the warmer months of the year, particularly when thermal stress induces coral mortality. This aspect, combined with its success on polluted areas, make C. delitrix a suitable bioindicator of coral reef health.

Multiple tagging devices have been developed for long-term studies and estimating demographic parameters in sea urchins. In this study, we evaluated the use of passive integrated transponders (PIT-tag), and two types of nylon tags (T-bar and S-tag) in the sea urchin Diadema antillarum by measuring retention rate and apparent survival. The PIT-tags exhibited the highest retention, followed by T-bars, and lastly the S-tags. Differences in recapture were detected among the three types of tags (H = 6.99, P = 0.030). An a posteriori pairwise comparison test found significant differences between PIT-tags and each of the other two types (P < 0.05), whereas T-bar and S-tag did not exhibit significant differences between them (P > 0.05). The semi-captivity experiment exhibited similar results to the field experiment in terms of retention. This experiment also found higher mortality with T-bars. Differences between previous studies conducted under controlled conditions and experiments carried out in the field reflect high variability and the necessity of testing tagging procedures under both settings. The S-tag induced high spine autotomy and low retention; whereas the T-bar demonstrated low retention and low survival. Although the retention rate of PIT-tags was significantly higher than the other two, retention rates were still too low for practical utility in long-term field experiments. In conclusion, the present study does not support the use of any of these tags for long-term studies in D. antillarum.

Zoobotryon verticillatum, a widely dispersed stoloniferous fouling bryozoan, has been recently recorded from specimens collected from the hulls of vessels berthed in an Israeli marina. Though conspicuous and distinctive, it has been rarely recorded in surveys of the bryozoan fauna along the Levant coastline conducted over the past half century. It is suggested the species is native to the Caribbean Sea, and an invasive alien elsewhere, including the Mediterranean Sea.

Aruba is one of the most densely populated islands in the Caribbean. However, very little is known about its cetaceans. In 2010 and 2011, a total of 19721 km (1686 h) boat-based surveys over nearshore transects resulted in 117 positively-identified sightings comprising eight species. New records are also added for one of three previously-documented species. Five additional species were documented from strandings or reports by others. This brings the total number of cetacean species identified in Aruban waters to 16, of which nine are authenticated here for the first time. Atlantic spotted dolphin (Stenella frontalis (N = 59) and bottlenose dolphin (Tursiops truncatus) (N = 33) were the most frequently observed species, with sightings of both year-round, followed by spinner dolphin (S. longirostris) and false killer whale (Pseudorca crassidens). Additional species recorded are pantropical spotted dolphin (S. attenuata), striped dolphin (S. coeruleoalba), common dolphin (Delphinus capensis), rough-toothed dolphin (Steno bredanensis), short-finned pilot whale (Globicephala macrorhynchus), killer whale (Orcinus orca), Risso's dolphin (Grampus griseus), humpback whale (Megaptera novaeangliae), Bryde's/Eden's whale (Balaenoptera brydei/edeni), sperm whale (Physeter macrocephalus) and an unidentified beaked whale (Mesoplodon sp.). All cetaceans were sighted within 22 km of the coast in relatively shallow waters. Sighting rate was low (0.69 cetacean sightings per 100 km). Sightings of calves and neonates indicate that Aruba may be a nursing or breeding area for some species. The presence of several species of cetaceans in Aruba's coastal waters year-round indicates that status and threat assessments are needed to protect them.

Changes in total lipids and fatty acid profiles (FAPs) of gonad, digestive gland, mantle and muscle of the tropical scallop Nodipecten nodosus were examined during coastal upwelling and upwelling relaxation periods. Total lipids were most abundant in digestive gland, and intermediate in female gonad. Multidimensional scaling analysis of similarities (MDS-ANOSIM) and similarity percentage analyses (SIMPER) revealed significant changes of FAPs of the four tissues during the upwelling and upwelling relaxation periods. During both periods, SIMPER analysis revealed an internal similarity index greater than 90% for FAP of each tissue. However, during upwelling the gonad-FAP showed a lower dissimilarity index with the digestive gland-FAP (10), than with muscle-FAP (11) or mantle-FAP (13). In general, during upwelling, the fatty acids 16:0, 18:0, 16:1 n-7, 20:5n-3, 22:6n-3 and total PUFAn-3 explained 42 to 63% of variance between tissues; during upwelling relaxation, these fatty acids together with 14:0 and 18:1 n-7, explained 46 to 64% of variance. During upwelling period, MDS-ANOSIM showed a close association between FAP of digestive gland and gonad, suggesting a rapid transfer of fatty acids between these tissues, and consequently, that N. nodosus follows an opportunistic strategy during this period. In contrast, during upwelling relaxation, the slow and continuous fall in total lipid contents of digestive gland (September to November) and the progressive reduction of MDS distances between FAPs of digestive gland and gonad (August until November), suggest a gradual transfer of lipids from digestive gland to gonad to support the gonad development observed during this period. This suggests that N. nodosus switches to a conservative strategy during the upwelling relaxation period.

The occurrence of the tropical seagrass Halophila stipulacea (Hydrocharitaceae) is recorded for the first time on the Caribbean coast of Martinique (French West Indies, Caribbean Sea). Specimens were observed, since a large survey in 2006, on sandy substrates between 3 m and 32 m depths in this area. The species was found in mono-specific patches or mixed with other macrophytes as Syringodium filiforme (seagrass) and/or Ulva intestinalis (green alga). Halophila stipulacea was previously identified on the coasts of Dominica and St Lucia, two islands nearby our study area. While its presence was presumed to be in Martinique, it was never officially recorded. These findings off the coast of Martinique further define the distribution and widespread occurrence of this alien species within the Caribbean Sea.

Moored FADs (MFADs) have been a key area for development in Guadeloupe (Lesser Antilles) since the late 1980’s. The main objectives underpinning the development of MFADs were to (i) reduce fishing pressure on coastal fishing resources; (ii) boost fishermen’s incomes; and (iii) increase local consumption of locally generated fishery products as a proportion of overall consumption. This paper gives an overview of the current structure of Guadeloupe’s fishing fleet and fisheries, with a specific focus on MFAD fleets in a relatively unstructured environment with regard to regulation, and so how these fleets operate in a context of unrestricted development of private MFADs. In addressing the following key issues, this paper aims to: assess the economic performance of fleets operating on MFADs, understand why the MFAD fishing activity has not developed more than it has, and suggest how better MFAD management could improve the situation. Socio-economic information on a trip and fleet level basis were collected and stored on a fisheries information system to analyse the relative attractiveness of MFAD fishing and assess the overall economic performance of MFAD fleets as compared to other non-MFAD fleets. Non-monetary variables were also tested to explain the degree of dependence on MFADs. In 2008, economic returns from FADs were relatively low, both in terms of wages for the crews and in terms of profit for vessel owners. Earnings were higher than coastal fishing activities, but seem to have been very sensitive to the indicators used in our analysis. MFADs are expected to become much more attractive as a result of MFAD regulation, especially through the establishment of collective MFADs.

Mooreonuphis bidentata, a new species of onuphid polychaete, is newly described from the Mexican Caribbean. It was found in dead coral rocks at depths of 2.2 m and can be distinguished from its congeners by having simple filaments branchiae from chaetigers 19–24, as well as bi- and tridentate pseudocompound falcigers and large median simple tridentate hooded hooks in the first four chaetigers. Including M. bidentata sp. nov., the genus Mooreonuphis includes 19 species, which have been exclusively collected on the American coasts, mainly in tropical and temperate waters. From the Caribbean Sea, six species have been recorded. Of these, M. bidentata sp. nov, M. cirrata, M. dangrigae and M. intermedia are the only species having their locus typicus in this tropical region. A taxonomic key is presented for all the species of Mooreonuphis recorded from both sides of the American seas.

The western Atlantic pontoniine shrimp Ascidonia miserabilis is reported for the first time from Atol das Rocas, off Rio Grande do Norte, representing the first record of this species and the genus Ascidonia for Brazil and the south-western Atlantic. In addition, its geographical range in the Caribbean Sea is extended to Honduras and Panama. All specimens of A. miserabilis were collected from inside cryptic ascidians, Acidia spp., in very shallow water (1–2 m). Illustrations of the previously unknown colour pattern of A. miserabilis are provided for the first time.

Several species of bivalves belonging to families which are typically associated with reducing conditions, like those observed at methane seep sites, have been obtained in recent explorations of the Caribbean Sea margin off the coast of Colombia. The material has been collected at depths of around 500 m west of the Magdalena and Sinú deltas, located in the Sinú–San Jacinto fold belt. These bivalves correspond to the families Vesicomyidae (Calyptogena ponderosa, Vesicomya caribbea and Ectenagena modioliforma), Lucinidae (Graecina colombiensis and three unidentified species of Lucinoma), Solemyidae (Acharax caribbaea) and Thyasiridae (Conchocele bisecta). In addition, for the first time off Colombia empty tubes of vestimentiferan polychaetes, belonging to the family Siboglinidae, were collected. At some of these sites the presence of authigenic carbonates has been observed together with the biological material. Although the obligate seep fauna generally contains relatively few and endemic species, a large suite of accompanying heterotrophic species (here we report only the molluscs) has been found at the seep sites. The occurrence of carbonates, the geological characteristics of the area and the new biological evidence confirms the presence of methane seep ecosystems in the Caribbean Sea off Colombia.

A new family, of apseudomorphan Tanaidacea, Sphaeromapseudidae, is discovered and described from the Caribbean Sea. Sphaeromapseudidae is tentatively placed between the Metapseudidae and Tanzanapseudidae. A new genus Sphaeromapseudes and species, S. plumosetosa, associated with intertidal coral rubble, are described.

The new species Batea aldebaranae from the coast of Belize is described and distinguished from the similar species Batea cuspidata (Shoemaker, 1926) and Batea carinata (Shoemaker, 1926). Characteristic for the new species are: additional set of dorsolateral teeth on pleonites 1–2; pereopod 1 second article small, scale-like; propodus of pereopod 7 elongate, dactylus shortened and telson shallowly cleft.

A new thecideide brachiopod species, Thecidellina meyeri, is described from the southern Lesser Antilles (Aruba, Bonaire, Curaçao), Caribbean Sea, with unique morphological characters which clearly separate it from all other described species of Thecidellina in the region. A virtually complete series of ontogenetic stages is recorded, providing insight into the plasticity of shell development during growth in thecideide brachiopods and offering a well-defined standard for comparison with fossil material. Study of the soft tissue suggests that T. meyeri is dioecious, which contradicts the idea of Thecidellina to be hermaphroditic. The limited distribution and the unexpectedly high species diversity within the genus Thecidellina in the Caribbean region support the idea of allopatric speciation due to limited dispersal ability.

In a series of studies on eunicids, there were explicit or implicit indications that Eunice riojai described from the north-western Caribbean Sea, and Eunice sebastiani described from south-east Brazil, were synonyms. This was based upon a then recent monograph on the genus, and on the fact that some specimens were found in drifting wood which would explain the large geographical range. The study of some large specimens of E. sebastiani, collected at the type locality, shows that there are several relevant morphological differences between the two species and thus both species names must be regarded as distinct. In fact, E. sebastiani is unique in the genus because their maxillae V are bidentate. Furthermore, herein we re-describe these two species and re-evaluate some morphological features described in previous studies.