The invasion of the Indo-Pacific lionfish Pterois volitans into the western Atlantic, Caribbean Sea, and Gulf of Mexico is the fastest ever documented for a marine fish. Few studies have addressed the establishment of lionfish populations within a location, and habitats other than reefs have been largely overlooked. The present study reconstructed the invasion around South Caicos, Turks and Caicos Islands (TCI), from multiple sources of data. Densities and size frequencies of lionfish were compared in deep reefs (10 to 30 m) and shallow habitats (seagrass, mangrove, sheltered reef, and exposed reef < 5 m deep) over a 4 yr period (2007 to 2010). By the end of 2010, lionfish had been observed in all 5 habitats. There was a lag of almost 7 mo between the first sightings in shallow habitats (December 2007) and in deep reefs. After 2 to 3 yr, the density of lionfish in deep reefs surpassed those in shallow habitats. In November 2010, mean density was over 10× higher on deep reefs (9.51 lionfish seen observer −1 h −1 ± 5.37 SD) than in seagrass (0.87 ± 0.41; p < 0.05), which was significantly higher than in other shallow habitats (sheltered reef: 0.52 ± 0.47; exposed reef: 0.12 ± 0.13; and mangrove: 0.06 ± 0.10; p < 0.05). Lionfish on deep reefs (TL = 22.7 ± 7.5 cm) had significantly larger total lengths (TL; mean ± SD) than those in seagrass (TL = 15.0 ± 4.3 cm; p < 0.05) or sheltered reefs (TL = 14.6 ± 6.8 cm; p < 0.05). Assuming one population with ontogenetic movement between habitats, density and age estimates suggest that lionfish may have moved to deep reefs from other habitats. The results suggest that lionfish may settle preferentially, but not exclusively, in shallow habitats before moving to deep reefs. Only 2 studies have explicitly compared lionfish between different habitats. Barbour et al. (2010) found that mangroves supported higher densities of smaller-sized individuals than nearby reef areas, which has since been interpreted as displaying the nursery function of mangroves (Barbour et al. 2011). Similarly, Biggs & Olden (2011) reported that lionfish in seagrass were smaller than those found on reefs and suggested that lionfish may use seagrass as nurseries. Although the global concern focuses on lionfish's impact on reefs (Sutherland et al. 2010), evidently the threat also extends to other habitats such as mangroves and seagrass, especially in the context of their nursery function for native species (Nagelkerken 2000, Nagelkerken et al. 2001, Mumby et al. 2004. Therefore, whether ontogenetic changes in habitat use are also displayed by P. volitans warrants further investigation (Barbour et al. 2010).Additionally, whilst the international effort to document the spread of lionfish throughout its invasive range has been considerable (Schofield 2009, 2010, Johnston & Purkis 2011, far less emphasis has been placed on how a population develops within a new location as it becomes colonized. Thus, quantitative assessments of densities and sizes of lionfish across habitats, depths, and time have n...

Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -.94) and the Multivariate ENSO Index (MEI) for all years (r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the importance of region-wide collaborations.

Somatic growth dynamics are an integrated response to environmental conditions. Hawksbill sea turtles (Eretmochelys imbricata) are long‐lived, major consumers in coral reef habitats that move over broad geographic areas (hundreds to thousands of kilometers). We evaluated spatio‐temporal effects on hawksbill growth dynamics over a 33‐yr period and 24 study sites throughout the West Atlantic and explored relationships between growth dynamics and climate indices. We compiled the largest ever data set on somatic growth rates for hawksbills – 3541 growth increments from 1980 to 2013. Using generalized additive mixed model analyses, we evaluated 10 covariates, including spatial and temporal variation, that could affect growth rates. Growth rates throughout the region responded similarly over space and time. The lack of a spatial effect or spatio‐temporal interaction and the very strong temporal effect reveal that growth rates in West Atlantic hawksbills are likely driven by region‐wide forces. Between 1997 and 2013, mean growth rates declined significantly and steadily by 18%. Regional climate indices have significant relationships with annual growth rates with 0‐ or 1‐yr lags: positive with the Multivariate El Niño Southern Oscillation Index (correlation = 0.99) and negative with Caribbean sea surface temperature (correlation = −0.85). Declines in growth rates between 1997 and 2013 throughout the West Atlantic most likely resulted from warming waters through indirect negative effects on foraging resources of hawksbills. These climatic influences are complex. With increasing temperatures, trajectories of decline of coral cover and availability in reef habitats of major prey species of hawksbills are not parallel. Knowledge of how choice of foraging habitats, prey selection, and prey abundance are affected by warming water temperatures is needed to understand how climate change will affect productivity of consumers that live in association with coral reefs.

To address patterns of genetic connectivity in a mass-aggregating marine fish, we analyzed genetic variation in mitochondrial DNA (mtDNA), microsatellites, and single nucleotide polymorphisms (SNPs) for Nassau grouper (Epinephelus striatus). We expected Nassau grouper to exhibit genetic differentiation among its subpopulations due to its reproductive behavior and retentive oceanographic conditions experienced across the Caribbean basin. All samples were genotyped for two mitochondrial markers and 9 microsatellite loci, and a subset of samples were genotyped for 4,234 SNPs. We found evidence of genetic differentiation in a Caribbean-wide study of this mass-aggregating marine fish using mtDNA (FST = 0.206, p<0.001), microsatellites (FST = 0.002, p = 0.004) and SNPs (FST = 0.002, p = 0.014), and identified three potential barriers to larval dispersal. Genetically isolated regions identified in our work mirror those seen for other invertebrate and fish species in the Caribbean basin. Oceanographic regimes in the Caribbean may largely explain patterns of genetic differentiation among Nassau grouper subpopulations. Regional patterns observed warrant standardization of fisheries management and conservation initiatives among countries within genetically isolated regions.

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