Pollution damages ecosystems around the globe and some forms of pollution, like oil pollution, can be either man-made or derived from natural sources. Despite the pervasiveness of oil pollution, certain organisms are able to colonise polluted or toxic environments, yet we only have a limited understanding of how they are affected by it. Here, we analysed phenotypic responses to oil pollution in guppies (Poecilia reticulata) living in oil-polluted habitats across southern Trinidad. We analysed body-shape and life-history traits for 352 individuals from 11 independent populations, six living in oil-polluted environments (including the naturally oil-polluted Pitch Lake), and five stemming from non-polluted habitats. Based on theory of, and previous studies on, responses to environmental stressors, we predicted guppies from oil-polluted waters to have larger heads and shallower bodies, to be smaller, to invest more into reproduction, and to produce more but smaller offspring compared to guppies from non-polluted habitats. Contrary to most of our predictions, we uncovered strong population-specific variation regardless of the presence of oil pollution. Moreover, guppies from oil-polluted habitats were characterised by increased body size; rounder, deeper bodies with increased head size; and increased offspring size, when compared to their counterparts from non-polluted sites. This suggests that guppies in oil-polluted environments are not only subject to the direct negative effects of oil pollution, but might gain some (indirect) benefits from other concomitant environmental factors, such as reduced predation and reduced parasite load. Our results extend our knowledge of organismal responses to oil pollution and highlight the importance of anthropogenic pollution as a source of environmental variation. They also emphasise the understudied ecological heterogeneity of extreme environments.

This body of work demonstrated the levels of selected contaminants (as well as their potential sources), in mussels (Mytella guyanensis) - a known bio-indicator of pollution, along the west coast (Gulf-of-Paria) of Trinidad. The findings demonstrated that polyaromatic hydrocarbons levels in the mussels investigated were moderate to high (201.80–1200.08 μg/kg). Notably, benzo(a)pyrene levels (1.15–9.32 μg/kg) exceeded the European Union guidelines at various sites. The distribution of PAHs and trace elements in the Gulf of Paria are impacted by tidal currents and local source discharge. Significant risks were identified from toxic carcinogenic equivalent levels (3.01 to 22.37 μg/kg) and mutagenic equivalent levels (3.98 to 38.61 μg/kg). The concentration of trace elements, Zn (46.05–56.36 mg/kg) and Cd (0.46–1.17 mg/kg), exceeded both local and international guidelines at certain sites investigated. The analysis revealed a high bioavailability of the identified pollutants in the Gulf of Paria from industrial, urban and marine activities.

Sharks are long-lived apex predators which can accumulate toxic metals such as mercury and arsenic. Samples of Sphyrna lewini and Carcharinus porosus were collected from two commercial fish landing sites in Trinidad. Heavy metal concentrations were determined in the muscle, dorsal fin, vertebrae and liver using atomic absorption spectrometric. The provisional tolerable weekly intake (PTWI) and target hazard quotient (THQ) were determined to assess the potential health risks to consumers. Mercury levels ranged between 74–1899μg/kg in S. lewini and 67–3268μg/kg in C. porosus. Arsenic levels ranged between 144–2309μg/kg in S. lewini and 762–6155μg/kg in C. porosus. Cadmium levels generally ranged between 0.27–27.29mg/kg in S. lewini and 0.6–29.89mg/kg in C. porosus. Lead levels generally ranged between 0.14 and 208.81mg/kg in S. lewini while C. porosus levels ranged between 0.30 and 459.94mg/kg. The PTWI and THQ values suggest that consumption of these shark species can therefore be a major source of exposure to lead, cadmium, arsenic and mercury in humans and is likely to have potential health risk over long term exposure.

Trinidad and Tobago was the last Caribbean island to be invaded by the lionfish and since its invasion in 2012 they have spread to most coral reef and hard bottom environments. Standard reef fish surveys were used to assess lionfish population densities and size distributions from 2013–2015. Total lengths ranged between 6.2–40.4cm and 2.2–950g in weight. The length-weight relationship was described by W=0.0002L2.5654. Fish densities were highest in the northeast Tobago at 326lionfish/ha and the lowest in the southwest Tobago at 10.5lionfish/ha. In order to curtail the spread of this invasive species, a culling programme was initiated at selected reefs to regularly remove lionfish at monthly intervals. On the selected reefs 26–30% reduction in mean lionfish biomass and 25–27% reduction in abundance was noted compared to control sites (p<0.05).

In this study, quantitative polymerase chain reaction targeting the atrazine catabolism gene, atzA, was used to detect the presence of atrazine degrading bacteria as an indicator of atrazine contamination in 11 sites in Georgia, nine coastal sites in Puerto Rico and 11 coastal sites in Trinidad. The atzA gene was detected in five stations in Georgia (Oak Grove Island entrance, Blythe Island Recreation Park, Jekyll Island., Village Creek Landing and Dunbar Creek Sea Island Rd Bridge). In Puerto Rico gene was detected in five sites (Boquilla, Oro Creek, Fishers Association, Ceiba Creek and Sabalos Creek) while seven sites in Trinidad (Carli Bay, Las Cuevas Bay, Quinam Bay, Salybia River, Salybia Bay, Maracas River and Maracas Bay) showed the presence of atzA.

Concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in nearshore marine surficial sediments from three locations in Trinidad. Sediments were sampled at Sea Lots on the west coast, in south Port-of-Spain Harbor, south of Sea Lots at Caroni Lagoon National Park, and on Trinidad’s east coast at Manzanilla. Total PCB concentrations in Sea Lots sediments ranged from 62 to 601ng/g (dry weight {dw}), which was higher than at Caroni and Manzanilla, 13 and 8ng/g dw, respectively. Total OCP concentrations at Sea Lots were ranged from 44.5 to 145ng/g dw, compared with 13.1 and 23.8n/g (dw), for Caroni and Manzanilla respectively. The concentrations of PCBs and of some OCPs in sediments from Sea Lots were above the Canadian interim sediment quality guidelines. To date, this data is the first report on the levels of PCBs and other organochlorine compounds from Trinidad and Tobago.

Sequential extraction was used to determine the geochemical distribution of trace metals in coastal sediments from Trinidad and Tobago. The results showed that there was considerable variation in the bioavailability, mobility and ecological risk of the metals determined. Cadmium had very high ecological risk: 57–88% of cadmium was associated with the exchangeable and carbonate bound metal fraction (F1). Ecological risk decreased in the order manganese> nickel> lead> zinc. Copper had the lowest ecological risk: lowest percentages of copper were associated with F1 (1–15%) and F2 (3–15%), while considerable percentages (48–55%) were associated with the residual fraction. Management of the risks posed by these metals in the marine environment requires a holistic approach including reduction in trace metal inputs from point and non-point sources of pollution, particularly off the west coast of Trinidad, and public education on the impacts of trace metals in the environment and on human health.

Fecal pollution in the coastal marine environments was assessed at eleven sampling locations along the Georgia coast and Trinidad, and nine sites from Puerto-Rico. Membrane filtration (EPA method 1604 and method 1600) was utilized for Escherichia coli and enterococci enumeration at each location. Quantitative polymerase chain reaction (qPCR) amplification of the 16S ribosomal RNA gene was used to determine the presence of the Helicobacter pylori in marine samples. There was no significant correlation between the levels of E. coli, enterococci and H. pylori in these water samples. H. pylori was detected at four of the 31 locations sampled; Oak Grove Island and Village Creek Landing in Georgia, Maracas river in Trinidad, and Ceiba Creek in Puerto Rico. The study confirms the potential public health risk to humans due to the widespread distribution of H. pylori in subtropical and tropical costal marine waters.

The goal of this study was to determine the potential for Enterohemorrhagic Escherichia coli O157:H7 (EHEC) contamination in tropical marine waters. Samples were collected from urban, suburban, and rural sites around the islands of Puerto Rico and The Republic of Trinidad and Tobago. Quantification of E. coli and EHEC was evaluated using MI plates and qPCR. EHEC was detected in six sites in Puerto Rico: West of La Parguera Town, Boquilla, Oro Creek, Fishers Association, Joyuda Lagoon, and Boqueron Wetland Creek and in two rural sites in Trinidad: Balandra Bay and Quinam Bay. Plate count enumeration of E. coli was not a reliable indicator for the presence of EHEC. The sites where EHEC was detected on both islands are used for recreational bathing, water sports and recreational/commercial fisheries and therefore pose a public potential health risk.

Concentrations of heavy metals were determined in nearshore marine sediments and fish tissue from Sea Lots area on the west coast, at Caroni Lagoon National Park, and in the Point Lisas harbor, Trinidad. The most dominant metals found in sediments were Al, Fe and Zn with mean concentrations highest at Sea Lots (Al-39420μg/g; Fe-45640μg/g; Zn-245μg/g), when compared to sediments from Point Lisas (Al-11936μg/g; Fe-30171μg/g; Zn-69μg/g) and Caroni (Al-0400μg/g; Fe-19000μg/g; Zn-32μg/g), High concentration of Cu, Al, Fe and Zn were also detected in fish tissue from Point Lisas and Caroni. Metal concentrations in fish tissue showed significant correlation with sediment metals concentration, which suggests that tissue levels are influenced by sediment concentration. Of the metals, only Zn, Hg and Cu had a bioaccumulation factor (BAF) greater than one, which suggests a high bioaccumulation potential for these metals.