The status and management of the lionfish, Pterois sp. in Trinidad and Tobago.

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=0.0002L(2.5654). 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).

A study on the recovery of Tobago's coral reefs following the 2010 mass bleaching event.

In 2010, severe coral bleaching was observed across the southeastern Caribbean, including the island of Tobago, where coral reefs are subject to sedimentation and high nutrient levels from terrestrial runoff. Here we examine changes in corals' colony size distributions over time (2010-2013), juvenile abundances and sedimentation rates for sites across Tobago following the 2010 bleaching event. The results indicated that since pre-bleaching coral cover was already low due to local factors and past disturbance, the 2010 event affected only particular susceptible species' population size structure and increased the proportion of small sized colonies. The low density of juveniles (mean of 5.4±6.3 juveniles/m(-2)) suggests that Tobago's reefs already experienced limited recruitment, especially of large broadcasting species. The juvenile distribution and the response of individual species to the bleaching event support the notion that Caribbean reefs are becoming dominated by weedy non-framework building taxa which are more resilient to disturbances.

Fish assemblages on fringing reefs in the southern Caribbean: biodiversity, biomass and feeding types / Ensambles de peces en los arrecifes de franja en el Caribe sur: biodiversidad, biomada y tipos de alimentación

Reef fish assemblages in the Caribbean are under increasing pressure from human activities. Inadequate enforcement of legislation coupled with unreliable and data-poor landings in Tobago have led to the unregulated exploitation of reef fish for decades. This study addresses the lack of data on major reefs. Visual observations of fish fauna were conducted from November 2011-May 2013 at open access reef sites (Speyside, Charlotteville, Culloden, Arnos Vale, Mt. Irvine, La Guira, Kilgwyn, Plymouth and Black Rock) and one protected area (Buccoo Reef Marine Park). Belt transects surveys were used to determine fish density, species diversity and abundance at the 10-15m depth contour. Fish sizes were converted to biomass using the length-weight relationship of fish W=aLb. Most fish assemblages were dominated by small herbivores (<15cm), in particular Pomacentridae and Scaridae. Few large predators (>40cm) e.g. Serranidae, were noted, which is indicative of fishing pressure. MDS ordination identified three fish assemblages: i) northeastern, ii) southwestern and iii) intermediate. The northwestern cluster (Speyside and Charlotteville) were most representative of reef fish assemblages across the entire island, and exhibited the highest species richness, diversity and biomass. However, the southwestern cluster the highest numerical abundance. The marine protected area contained higher fish biomass, abundance, diversity and richness, but it was only representative of reef fish assemblages on the southwest of the island and not the entire Tobago. Research on the reef fishery, particularly spear fishing, is recommended to determine impact.

Los ensamblajes de peces de arrecife en el Caribe están bajo una creciente presión de las actividades humanas. La ejecución inadecuada de la legislación, junto con los desembarques poco fiables y con escasez de datos en Tobago han llevado a una explotación sin reglas durante décadas. Este estudio aborda la falta de datos sobre las comunidades de peces de arrecife en los principales arrecifes. Las observaciones visuales se llevaron a cabo desde noviembre 2011 hasta mayo 2013 en sitios de acceso a los arrecifes abiertos (Speyside, Charlotteville, Culloden, Arnos Vale, el monte Irvine, La Guira, Kilgwyn, Plymouth y Negro Rock) y un área protegida (El parque Buccoo Marine Reef). Se utilizaron encuestas para determinar la densidad de peces, la diversidad y abundancia de especies a 10-15m de profundidad del contorno. El tamaño de los peces se convirtió a biomasa utilizando la relación talla- peso de los peces W=aLb. La mayoría de las comunidades de peces son dominadas por pequeños herbívoros (<15cm), en particular Pomacentridae y Scaridae. Pocos depredadores grandes (>40cm), por ejemplo Serranidae, se observó, lo que es indicativo de la presión de pesca. El análisis de escala multidimensional identificó tres conjuntos distintos de peces indicados como i) del noreste, ii) al suroeste y iii) grupos intermedios. El grupo del noroeste (Speyside y Charlotteville ) es más representativo de comunidades de peces de arrecife en toda la isla, y mostró la mayor riqueza de especies, diversidad y biomasa. Sin embargo, se observó la abundancia más alta de peces en el grupo del suroeste. El área marina protegida contenia mayor biomasa, abundancia, diversidad y riqueza de peces, pero era el único representante de las asociaciones de peces arrecifales en el suroeste de la isla y no de todo Tobago. Se recomienda determinar los impactos de la pesca en los arrecifes, particularmente con el uso de arpón.

Prioritizing key resilience indicators to support coral reef management in a changing climate.

Managing coral reefs for resilience to climate change is a popular concept but has been difficult to implement because the empirical scientific evidence has either not been evaluated or is sometimes unsupportive of theory, which leads to uncertainty when considering methods and identifying priority reefs. We asked experts and reviewed the scientific literature for guidance on the multiple physical and biological factors that affect the ability of coral reefs to resist and recover from climate disturbance. Eleven key factors to inform decisions based on scaling scientific evidence and the achievability of quantifying the factors were identified. Factors important to resistance and recovery, which are important components of resilience, were not strongly related, and should be assessed independently. The abundance of resistant (heat-tolerant) coral species and past temperature variability were perceived to provide the greatest resistance to climate change, while coral recruitment rates, and macroalgae abundance were most influential in the recovery process. Based on the 11 key factors, we tested an evidence-based framework for climate change resilience in an Indonesian marine protected area. The results suggest our evidence-weighted framework improved upon existing un-weighted methods in terms of characterizing resilience and distinguishing priority sites. The evaluation supports the concept that, despite high ecological complexity, relatively few strong variables can be important in influencing ecosystem dynamics. This is the first rigorous assessment of factors promoting coral reef resilience based on their perceived importance, empirical evidence, and feasibility of measurement. There were few differences between scientists' perceptions of factor importance and the scientific evidence found in journal publications but more before and after impact studies will be required to fully test the validity of all the factors. The methods here will increase the feasibility and defensibility of including key resilience metrics in evaluations of coral reefs, as well as reduce costs. Adaptation, marine protected areas, priority setting, resistance, recovery.

Presence of the chytrid fungus Batrachochytrium dendrobatidis in populations of the critically endangered frog Mannophryne olmonae in Tobago, West Indies.

The emerging infectious disease chytridiomycosis is prevalent in Central and South America, and has caused catastrophic declines of amphibian populations in the Neotropics. The responsible organism, Batrachochytrium dendrobatidis, has been recorded on three West Indian islands, but the whole of the Caribbean region is predicted to offer a suitable environment for the disease. Monitoring the spread of chytridiomycosis is thus a priority in this region, which has exceptionally high levels of amphibian endemism. PCR analysis of 124 amphibian skin swabs in Tobago (Republic of Trinidad and Tobago) demonstrated the presence of B. dendrobatidis in three widely separated populations of the frog Mannophryne olmonae, which is listed as Critically Endangered on the basis of recent population declines. Chytridiomycosis is presently endemic in this species, with a prevalence of about 20% and no associated clinical disease. Increased susceptibility to chytridiomycosis from climate change is unlikely in amphibian populations in Tobago, as this island does not have high montane environments, but remains a possibility in the sister island of Trinidad. Preventing the spread of chytridiomycosis within and between these and other Caribbean islands should be a major goal of practical conservation measures for amphibians in the region.