Southeastern Caribbean Sea Research Articles

A new species of shrimp, genus Ambidexter Manning & Chace, 1971 (Decapoda: Processidae), from southeastern Caribbean Sea, Venezuela, with key to genus

A new species of processid shrimp, Ambidexter cochensis sp. nov. is described from Venezuela, on the basis of several specimens collected in seagrass beds at a depth less than 1 m. This new species is closely related to A. swifti Abele, 1972 from eastern Pacific, which mainly differs by the number of carpal articles of the second pereiopod, the setation pattern on the telson and the structure of the appendix masculina of the male second pleopod. A key to genus is presented.

Seasonal Factors Affecting Sea turtle nesting in the Southeastern Caribbean Sea (Gulf of Paria, Venezuela)

Seasonal Factors Affecting Sea turtle nesting in the Southeastern Caribbean Sea (Gulf of Paria, Venezuela)

Seasonal factors affecting sea turtle nesting in the Southeastern Caribbean Sea (Gulf of Paria, Venezuela)

The nesting characteristics (number of nests and eggs, time of year, nesting initiation, and nesting length) of leatherback (Dermochelys coriacea) and hawksbill (Eretmochelys imbricata) sea turtles of the southern Caribbean Sea (specifically in the Gulf of Paria in Venezuela), were examined in association with weekly precipitation averages and number of rainy days per week during the period between 2009 and 2018. We hypothesized about the influence of rainfall intensity and patterns as the main abiotic factor for sea turtle nesting. On average, leatherbacks preferred nesting during the drier season of each year (March, April, and May), while hawksbills nested during the rainy season (June to September). For both species, we found few significant correlations between the number of nests or clutch size (number of eggs per nest) and weekly averages of seasonal precipitation rates in the region. Average hawksbill clutch sizes were not correlated with average precipitation rates but were positively correlated with the number of rainy days per week (r=0.66, P≤0.05). Average hawksbill clutch sizes decreased each year on average (-3.3 eggs/year, r=-0.88, P≤0.001), which coincided with a negative long-term trend in the number of rainy days (-0.11 rainy days/week, r=-0.69, P≤0.05). During the study period, nesting activities for both leatherback and hawksbills started progressively later (0.9 and 0.6 weeks/year, respectively p≤0.05) and were shorter (-0.9 and -0.8 weeks /year, P≤0.1 and P≤0.05, respectively).

A 125-ka record of northern South American precipitation and the role of high-to-low latitude teleconnections

The occurrence of rapid last glacial temperature shifts in both Greenland ice and subpolar marine sediment cores, so-called Dansgaard-Oeschger (D-O) cycles, is evidence of a tight regional climate connectivity in these northern latitudes. By contrast, processes behind high-to-low-latitude teleconnections during the D-O cycles are less well understood, due to imprecisions in cross-dating marine and ice core records and a general lack of solid multi-proxy records from the tropical region. Here we aim to study the response of the tropical ocean-atmosphere system to D-O variability by using a sediment core from the southern Caribbean Sea, located under the direct influence of the Intertropical Convergence Zone (ITCZ) and the Atlantic meridional overturning circulation (AMOC). During D-O cycles, abrupt shifts in the deposition of fine-grained terrigenous material sourced from the Orinoco and Amazon rivers are recognized. These sedimentary changes were associated with fluctuations in both the ITCZ location and the AMOC strength through their respective influence on the hydroclimate of northern South America and strength of ocean currents delivering fluvial material to the study site. Stable oxygen isotope data further suggest increase in the upper ocean temperatures in the southeastern Caribbean Sea during stadial events. As these warming trends correlate with Antarctic temperatures, they seem to contain imprints of the bipolar seesaw and AMOC variability, demonstrating that our core location was influenced by processes prevalent in both hemispheres.

Reproductive biology and space–time modelling of spawning for sailfish Istiophorus platypterus in the western Atlantic Ocean

ABSTRACTThis study presents data and estimates reproductive parameters of the sailfish Istiophorus platypterus (Shaw, 1792) in the western Atlantic, useful for future stock assessments of the species in the Atlantic Ocean. During the period 2006–2011, a total of 1132 fish were sampled by scientific observers on board Venezuelan and Brazilian longline vessels and from artisanal fisheries based out of Cumaná, Puerto La Cruz and Playa Verde, Venezuela and Cabo Frio, Rio de Janeiro, Brazil. The ovaries of 543 females were classified into five ovarian development phases based on microscopic analysis of the most advanced group of oocytes. Generalized additive models were applied to the gonadal index and sex ratio data in order to assess spatio-temporal trends of the reproductive activity and identify the spawning areas. Space–time effect was a significant factor contributing to changes in sex ratio and reproductive activity. Spawning activity was observed in two distinct areas. On the south-east Brazilian coast spawning peaked during December–February, while in the south-eastern Caribbean Sea spawning occurred between March and September, with its peak in March and April. Using a Bayesian approach, size at 50% maturity was estimated to be 146.12 cm (credibility interval of 95%, 138.45–152.09 cm). Batch fecundity ranged from 436,800 to 2,492,500 hydrated oocytes per female. This study confirms multiple aggregation spawning for this species in the western Atlantic Ocean.

Reliability of first-hand accounts on the study of historical tsunamis in northeastern Venezuela (southeastern Caribbean Sea)

The occurrence of tsunami waves on the eastern Caribbean Venezuelan coasts during 5 Venezuelan (local) earthquakes (01-IX-1530, 15-VII-1853, 29-X-1900, 17-I-1929 and 9-VII-1997), have been confirmed through the search and evaluation of written accounts by primary sources (eye witnesses) of tsunami inundation during these events. Among the outcomes of this new assessment are: 1) the run-up heights of several of those tsunamis have been substantially reduced. In fact, maximum run-up heights for the 5 tsunamis are: 5-7 m at Cumaná for the 1530 event, 5 m at Barlovento and 3 m at the Neverí mouth for the 1900 tsunami, 3 m at western Cumaná for the 1853 and 1929 events and about 1 m for the 1997 earthquake. 2) These new estimates on wave heights for local earthquakes restrict the search for tsunamites by trenching and coring to mainly the first 500-m-wide strip from the coastline in low-lying flatlands. The source of these tsunami waves may be complex. Some are surely the result of coastal-submarine sliding (1929 AD, 1997 AD), tectonic slip on active strike-slip (or normal oblique slip) faults (1530 AD, 1900 AD) or combination of tectonic slip and sliding (1853 AD). Appropriate numerical modeling of tsunami wave generation, migration and inundation are urgently in need to understand these tsunami mechanics.

Spatial variability in factors that control the sinking flux of organic and inorganic particles in the Cariaco Basin: a vision from space

ABSTRACTThe Cariaco Basin, located on the continental margin of the south-eastern Caribbean Sea, has been a site of extensive oceanographic research since the early 1950s. Here we examined the seasonal and spatial variability in satellite wind, sea surface temperature (SST), surface chlorophyll (CHL), and primary production (PP) within the Cariaco Basin (1994–2009). This variability has implications in modulating the vertical flux of particulate material to the bottom of the basin. While cross-shore Ekman Transport was positive (upwelling inducing) year-round, it showed 20–60% higher values (stronger upwelling) in the eastern sub-basin, compared to the western sub-basin 1.35–2.77 m2 s−1 and 1.06–1.73 m2 s−1, respectively; p < 0.01). This translated into differences in CHL concentration and PP rates between the eastern and western Cariaco sub-basins. Long-term seasonal means of SST, CHL, and PP showed significant inter-basin differences (p < 0.01) between December and July; during that period the eastern basin was cooler (24.86 ± 1.03°C vs. 25.56 ± 0.80°C, p < 0.01), with higher CHL (0.50 mg m−3 vs. 0.35 mg m−3; p < 0.01) and PP (1763 ± 994 vs. 782 ± 129 mg C m−2 day−1, p < 0.01) than the western sub-basin. The eastern Cariaco sub-basin had larger seasonal amplitude and variability in oceanographic characteristics than the western sub-basin, while the western sub-basin had slightly higher and more variable seasonal riverine run-off inputs. These differences have implications for the interpretation of the paleoclimate sediment record stored in different sectors of the Cariaco Basin.

Spatial variability of Spanish sardine (Sardinella aurita) abundance as related to the upwelling cycle off the southeastern Caribbean Sea.

The Sardinella aurita fishery off northeastern Venezuela, region of seasonal wind-driven coastal-upwelling, accounts for 90% of the Caribbean Sea small pelagic catch. This law-protected artisanal fishery takes place up to ~10 km offshore. The spatial distribution, number of schools, and biomass of S. aurita were studied using eight hydro-acoustic surveys (1995–1998). The study included the analysis of satellite-derived sea surface temperature and chlorophyll-a. Surveys were grouped by strong, weak, and transitional upwelling seasons. Relationships between these observations were analyzed using Generalized Additive Models. Results show that during the primary upwelling season (January-May) sardines were widely distributed in upwelling plumes that extended up to 70 km offshore. In the other hand, during the weak upwelling season (September-October) higher sardine densities were found within 10 Km off the coastal upwelling foci. The number of small pelagic schools was directly correlated with small pelagic densities; however, regardless of the season, higher numbers of small pelagic schools were always closer to the shoreline, especially during warm conditions. These two behaviors increase the availability and catchability of sardines for the artisanal fishery during the warm season, regardless of the total stock size. Using this evidence, we pose the hypothesis that the collapse of the regional S. aurita fishery in 2005 was due to a combination of stressful habitat conditions sustained since 2004. These included bottom-up factors due to food scarcity caused by weak upwelling, combined with top-down stress due to overfishing, as sardines accumulated in narrow diminished upwelling plumes located close to the coast. The increased catchability within easily accessible upwelling foci led to the demise of this biological resource, which as of 2014 had not yet recovered. Environmental conditions affecting the sardine habitat needs to be taken into account for the management of this stock. For example, during years with weak upwelling, special measures should be taken during the warm season on the second half of the year to avoid further pressure on the stock.

Tropical precipitation anomalies and d -excess evolution during El Niño 2014-16

The last 2014-16 El Nino event was among the three strongest episodes on record. El Nino considerably changes annual and seasonal precipitation across the tropics. Here, we present a unique stable isotope data set of daily precipitation collected in Costa Rica prior to, during, and after El Nino 2014-16, in combination with Lagrangian moisture source and precipitation anomaly diagnostics. δ2H composition ranged from -129.4 to +18.1 (‰) while δ18O ranged from -17.3 to +1.0 (‰). No significant difference was observed among δ18O (P = 0.0186) and δ2H (P = 0.664) mean annual compositions. However, mean annual d-excess showed a significant decreasing trend (from +13.3 to +8.7 ‰) (P < 0.001) with values ranging from +26.6 to -13.9 ‰ prior to and during the El Nino evolution. The latter decrease in d-excess can be partly explained by an enhanced moisture flux convergence across the southeastern Caribbean Sea coupled with moisture transport from northern South America by means of an increased Caribbean Low Level Jet regime. During 2014-15, precipitation deficit across the Pacific domain averaged 46% resulting in a very severe drought; while a 94% precipitation surplus was observed in the Caribbean domain. Understanding these regional moisture transport mechanisms during a strong El Nino event may contribute to a) better understanding of precipitation anomalies in the tropics and b) re-evaluate past stable isotope interpretations of ENSO events in paleoclimatic archives within the Central America region. This article is protected by copyright. All rights reserved.

Population distribution, host-switching, and chemical sensing in the symbiotic shrimp Lysmata pederseni: implications for its mating system in a changing reef seascape

Lysmata pederseni, a protandric simultaneously hermaphroditic shrimp that inhabits the tube sponge Callyspongia vaginalis, is monogamous in the central and southeastern Caribbean Sea. We tested the null hypothesis of monogamy in a northern Caribbean population. In the Florida Keys, shrimps did not inhabit host individuals in pairs with a frequency greater than expected by chance alone. Hermaphrodites inhabited sponges solitarily and often brooded embryos. Hermaphrodites do not store sperm and need to be inseminated shortly after molting to fertilize a new batch of eggs. Thus, males and/or other hermaphrodites are likely switching among host individuals in search of sexual partners. Field experiments demonstrated low shrimp host fidelity. Host residence time was ~2 times shorter for males than for hermaphrodites. We inferred a polygynandrous mating system in L. pederseni from the Florida Keys, with male-role and young hermaphrodites often moving among sponges in search of older, more sedentary, female-role hermaphrodites. We expected shrimps to use water-borne chemical cues originating from conspecifics or sponges to locate sexual partners. Experiments demonstrated that shrimps were attracted to water-borne cues originating from sponges but not conspecifics. We have described the mating system of a reef-associated shrimp in a fast-pace shifting seascape increasingly dominated by sponges and vanishing stony corals. In the central and southeastern Caribbean Sea, with greater coral cover and lower sponge abundance than in the Florida Keys, the same species is monogamous. Whether or not similar shifts in the social organization of other coral reef-dwelling marine organisms are occurring due to contemporary changes in seascapes is a relevant topic that deserves further attention.

Decadal variability in the oxygen inventory of North Atlantic subtropical underwater captured by sustained, long‐term oceanographic time series observations

AbstractHistorical observations of potential temperature (θ), salinity (S), and dissolved oxygen concentrations (O2) in the tropical and subtropical North Atlantic (0–500 m; 0–40°N, 10–90°W) were examined to understand decadal‐scale changes in O2 in subtropical underwater (STUW). STUW is observed at four of the longest, sustained ocean biogeochemical and ecological time series stations, namely, the CArbon Retention In A Colored Ocean (CARIACO) Ocean Time Series Program (10.5°N, 64.7°W), the Bermuda Atlantic Time‐series Study (BATS; 31.7°N, 64.2°W), Hydrostation “S” (32.1°N, 64.4°W), and the European Station for Time‐series in the Ocean, Canary Islands (ESTOC; 29.2°N, 15.5°W). Observations over similar time periods at CARIACO (1996–2013), BATS (1988–2011), and Hydrostation S (1980–2013) show that STUW O2 has decreased approximately 0.71, 0.28, and 0.37 µmol kg−1 yr−1, respectively. No apparent change in STUW O2 was observed at ESTOC over the course of the time series (1994–2013). Ship observation data for the tropical and subtropical North Atlantic archived at NOAA National Oceanographic Data Center show that between 1980 and 2013, STUW O2 (upper ~300 m) declined 0.58 µmol kg−1 yr−1 in the southeastern Caribbean Sea (10–15°N, 60–70°W) and 0.68 µmol kg−1 yr−1 in the western subtropical North Atlantic (30–35°N, 60–65°W). A declining O2 trend was not observed in the eastern subtropical North Atlantic (25–30°N, 15–20°W) over the same period. Most of the observed O2 loss seems to result from shifts in ventilation associated with decreased wind‐driven mixing and a slowing down of STUW formation rates, rather than changes in diffusive air‐sea O2 gas exchange or changes in the biological oceanography of the North Atlantic. Variability of STUW O2 showed a significant relationship with the wintertime (January–March) Atlantic Multidecadal Oscillation index (AMO, R2 = 0.32). During negative wintertime AMO years trade winds are typically stronger between 10°N and 30°N. These conditions stimulate the formation and ventilation of STUW. The decreasing trend in STUW O2 in the three decades spanning 1980 through 2013 reflects the shift from a strongly negative wintertime AMO between the mid‐1980s and mid‐1990s to a positive wintertime AMO observed between the mid‐1990s and 2013. These changes in STUW O2 were captured by the CARIACO, BATS, and Hydrostation S time series stations. Sustained positive AMO conditions could lead to further deoxygenation in tropical and subtropical North Atlantic upper waters.

Is otolith microchemistry (Sr: Ca and Ba:Ca ratios) useful to identify Mugil curema populations in the southeastern Caribbean Sea?

The aim of the present study was to evaluate the potential use of otolith microchemistry (Sr:Ca and Ba:Ca ratios) to identify silver mullet, Mugil curema, populations in Southeastern Caribbean Sea. Fish samples were collected in 7 areas of Nueva Esparta State (Venezuela). The otolith Sr:Ca and Ba:Ca ratios and water Sr:Ca were determined (by ICP-OES and EDTA volumetric method). Otoliths Sr:Ca and Ba:Ca ratios and Sr:Ca partition coefficient of mullets in Cubagua island (south of the State) were significantly different from ratios in La Guardia (north of the State). A discriminant analysis of otolith Sr:Ca and Ba:Ca ratios separated Cubagua Island from La Guardia values. These results suggest the existence of different mullet groups in the Southeastern Caribbean Sea. For this, the simultaneous use of Sr:Ca and Ba:Ca ratios could be a potential tool to identify populations in the study area.

A climatological study of the effect of sea-surface temperature on North Atlantic hurricane intensification

The climatic influence of sea-surface temperature (SST) on intensification is examined for North Atlantic hurricanes by averaging hourly intensity increases from best-track data over the period 1986–2013 in 4° by 4° latitude–longitude grid cells. Independent monthly SST data over the same period are averaged in the same cells. After removing cells with cold water or fast moving hurricanes, the SST effect on intensification, at the climate scale, is quantified by regressing intensification onto SST while controlling for average intensity. The regression is performed using a generalized linear model from a gamma family and a logarithmic link function. The model shows a statistically significant relationship, with higher intensification values associated with higher SST values. On average, mean intensification increases by 16% [(9, 20)% uncertainty interval] for every 1 °C increase in mean SST. A clustered region where the model underpredicts intensification is noted over the southeastern Caribbean Sea, perhaps related to the fresh water plume from the Orinoco River.

Characterization of phytoplankton variability in the Cariaco Basin using spectral absorption, taxonomic and pigment data

The spectral absorption coefficient of marine phytoplankton provides information on phytoplankton community structure, biomass, and general physiological conditions. These variables are necessary for understanding and predicting ocean productivity, carbon fluxes, underwater light propagation, water quality, and for assessing marine photochemical processes. The Cariaco Basin, located on the continental shelf of Venezuela in the southeastern Caribbean Sea, is the site of the CARIACO Ocean Time-Series project. Since 1995, CARIACO has collected bio-optical (hyperspectral inherent and apparent optical properties — IOPs and AOPs, respectively), biogeochemical and ecological observations to characterize local ecosystem variations in response to regional and global changes in climate. We examine phytoplankton taxonomic and pigment time series data collected by this program between 2006 and 2012 to understand how seasonal changes in these parameters relate to bio-optical data (i.e., absorption spectra). TChla and accessory pigments varied seasonally in response to changes in the phytoplankton community composition, with higher concentrations of microphytoplankton (>20μm; 45%) during upwelling (December–April) than during the rainy season (16%; May/June–October/November). Picophytoplankton (<2μm) dominated during the rainy season (66%). The absorption properties also exhibited seasonal variations. Diagnostic pigments could not be identified in a quantitative way using derivative analysis of phytoplankton absorption, likely because of overlapping of absorption spectra among the pigments present. The POC:TChla ratio at CARIACO was variable and dependent on bulk carbon (not necessarily related to phytoplankton) and the functional groups present at any given time, underscoring the fact that using a fixed ratio of POC:Chla in biogeochemical models can lead to large uncertainties in carbon budgets from coastal zones. Low POC:TChla was associated with microphytoplankton size class (diatoms), while picophytoplankton (cyanobacteria) exhibited higher ratios. These results contribute to furthering our understanding of coastal phytoplankton dynamics and how they relate to optical signatures.

Deepwater marine litter densities and composition from submersible video-transects around the ABC-islands, Dutch Caribbean

Baseline data on anthropogenic seafloor debris contamination in the year 2000 is provided for 24 submersible video transects at depths of 80–900m, off the Dutch ABC-islands (Aruba, Bonaire, Curaçao), in the southeastern Caribbean Sea. In total, 202 objects were documented from a combined 21,184m of transect, ranging from sandy lower island-slope to rocky upper island-slope habitat. Debris densities differed significantly with depth. Highest debris accumulation (0.459 items 100m−2 or 4590 items per km2) occurred at depths of 300–600m on more shallow-sloping (20–30°) sand and silt bottoms. The overall average debris density was 0.27 objects per 100m2 (or 2700 items per km2), which is an order of magnitude higher than most other deepwater debris studies. What we describe may be representative for other small, populated, steep volcanic Caribbean islands. Food and beverage-related items were the single largest usage category identified (44% of objects; mostly glass beverage bottles).

Spatial and seasonal variability of dissolved organic matter in the Cariaco Basin

AbstractDissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) were measured monthly at the CARIACO Time Series station (10°30′N, 64°40′W) in the southeastern Caribbean Sea between 2005 and 2012. Marked seasonal variability in DOC concentrations was observed, with lower values (~66 µM) in the upper water column (&lt;75 m) during the upwelling season (December–April) due to the injection of cool, DOC‐impoverished Subtropical Underwater from the Caribbean Sea. During the rainy season (May–November) waters were stratified and upper layer DOC concentrations increased to ~71 µM. Interannual variability in surface (1 m) concentrations of DOC was also observed in response to the variable strength in upwelling and stratification that the Cariaco Basin experienced. DON and DOP showed no such seasonality. At depths &gt;350 m, DOC concentrations were 56 ± 4.7 µM, roughly 10 µM higher than those in the Caribbean Sea over the same depth range. DON and DOP showed similar vertical profiles to that of DOC, with higher concentrations (6.8 ± 1.2 µM N and 0.15 ±0.09 µM P) in the upper water column and invariant, lower concentrations at depth (4.8 ± 1.6 µM N and 0.10 ± 0.08 µM P). Wind‐driven advection of surface DOC out of the Cariaco Basin was estimated to support a net export ~15 Gmol C yr−1 into the Caribbean Sea; this rate is comparable to the flux of settling particulate organic carbon to depths &gt;275 m within the basin.

Monogamy does not last long in Pontonia mexicana, a symbiotic shrimp of the amber pen-shell Pinna carnea from the southeastern Caribbean Sea

Theory suggests that symbiotic species should be monogamous and form long-lasting heterosexual pairs in/on hosts when inhabiting scarce and small hosts in environments where predation risk away from hosts is high (e.g., tropical subtidal). This prediction was tested with Pontonia mexicana which inhabits the relatively small and scarce amber pen-shell Pinna carnea in the tropical Caribbean. In agreement with theory, P. mexicana were found dwelling as heterosexual pairs in the mantle cavity of pen-shell individuals with more frequency than expected by chance alone. However, additional observations suggested that male–female pairing of P. mexicana does not last long. First, males paired with females that were close to molt and become sexually receptive more frequently than expected by chance alone. In monogamous species in which pairing appears to be long lasting, males occur with females in the same host, independent of the reproductive condition of the female. Second, the body size of paired shrimps was poorly correlated and the relationship between host and shrimp body size was weak. If males and females of P. mexicana were staying within host individuals for long periods of time, a tight correlation between host and shrimp size and between males and females in a pair would have been found. Lastly, sexual dimorphism in terms of cheliped size was evident; males invested considerably more resources to this body structure compared to females. In monogamous species in which pairing appears to be long-term, sexual dimorphism is low or absent given that sexual selection is weak in this mating system. Overall, our data suggests that monogamy in P. mexicana does not last long and that males switch among host individuals in search of receptive females. Manipulative experiments are necessary to understand the conditions favoring short- and long-term monogamy in symbiotic crustaceans.

Population dynamics and reproductive output of the non-indigenous crab Charybdis hellerii in the south-eastern Caribbean Sea

Charybdis hellerii is one of several poorly known non-indigenous crabs in the Caribbean. In this study we report on the reproductive dynamic of a shallow subtidal population that invaded Isla Margarita, Venezuela, south-eastern Caribbean Sea &gt; 15 years ago and has persisted in the region up to date. Male and female crabs, both large and small, were found year-round at the study site. The size–frequency distribution indicated a lifespan of 2–3 years. Charybdis hellerii reproduces continuously but with very low intensity during the year. Small individuals (&lt;25 mm carapace length) were uncommon and intermittently found during the study period. Sex-ratio varied between 0.1 and 0.65 (mean ± SD = of 0.46 ± 0.14) and did not differ significantly from 1:1 ratio during most of the year. The size of the smallest brooding female was 36.81 mm carapace width (CW). Behavioural size at first maturity (movable abdomen) in males and females was estimated to be 22.39 mm CW (confidence limits: 18.35–24.72) and 37.43 mm CW (35.55–39.09), respectively. Reproductive output, estimated as the ratio of embryo to female body dry mass, varied between 0.052 and 0.084 (0.07 ± 0.008). Also, reproductive output was size-dependent with large females allocating proportionally less resources to egg production than small females. The reproductive schedule here reported for C. hellerii disagrees with the generalized idea of exotic populations ‘thriving’ in an environment free of natural enemies (e.g. predators, competitors and diseases).

Bio-optical characteristics of Cariaco Basin (Caribbean Sea) waters

Bio-optical properties of marine waters of the Cariaco Basin (southeastern Caribbean Sea) were assessed monthly between 1995 and 2005 as part of the CARIACO Ocean Time Series program. Temporal changes in light quality and penetration were caused by seasonal variation in the concentration of three major optical constituents, namely phytoplankton, detrital particles, and colored dissolved organic matter (CDOM). All constituents showed higher absorption coefficients during the upwelling season (January–May) compared to the rainy season (June–November). Both the absorption coefficient due to CDOM ( a g (440)) and due to phytoplankton ( a ph (440)) had similar contributions to total absorption of light during the upwelling season ( a ph (440)=0.062±0.042 m −1, a g (440)=0.065±0.047 m −1). In contrast, a g (440) dominated light absorption during the rainy season ( a ph (440)=0.017±0.011 m −1, a g (440)=0.057±0.031). This led to an overestimate in SeaWiFS-derived chlorophyll concentrations during the rainy season, of between 7% and 45%. The detrital component, a d (440), typically showed the smallest contribution ( a d (440)=0.021±0.014 m −1 during upwelling and 0.007±0.001 m −1 during the rainy season). There was no clear relationship between the various optically active components in time. During the upwelling season the chlorophyll-specific absorption coefficient, a p h ⁎ (440), was nearly half the value observed during the rainy season due to changes in the package effect (explaining ∼40% of the variability) and in accessory pigment composition as a result of species succession (explaining ∼60% of the variability). The euphotic zone depth (depth of the 1% photosynthetic active radiation (PAR) level) was typically shallower during the upwelling season (36.7±12.3 m) than during the rainy season (47.9±13.5 m) due to the onset of a shallower and stronger phytoplankton bloom. During upwelling, the highest chlorophyll- a concentrations (Chl>1 mg m −3) were observed in the upper 25 m with primary production rates exceeding 1800 mgC m −2 d −1. During the rainy season, a deep chlorophyll maximum (DCM, concentrations between 0.2 and 0.8 mg m −3) was observed between 35 and 55 m, with low (<0.2 mg m −3) Chl concentrations above this depth and primary production values of ∼990 mgC m −2 d −1. The DCM occurred immediately above the seasonal thermocline and around the 1% PAR light level. During the upwelling season, no DCM was observed.

Presence of the invasive red lionfish, Pterois volitans (Linnaeus, 1758), on the coast of Venezuela, southeastern Caribbean Sea

We report the presence of the invasive Indo-Pacific red lionfish (Pterois volitans) in 23 localities of the Venezuelan coast, southeastern Caribbean Sea. This finding is based on ten specimens collected at Parque Nacional Archipielago de Los Roques (PNAR, Dependencias Federales), Playa Cal, Caraballeda and Puerto Carayaca (Estado Vargas) and 30 specimens observed in 18 localities of PNAR, Parque Nacional Morrocoy (Estado Falcon), Bahia de Cata, Ensenada de Cepe (Estado Aragua), Puerto Cruz, Chichiriviche de La Costa, Mamo, Catia La Mar, La Guaira, Macuto, Caraballeda (Estado Vargas) and Farallon Centinela (Dependencias Federales). The specimens were collected and observed from November 2009 to June 2010. This is the first published report documenting their occurrence in Venezuela.