Modeling protected species distributions and habitats to inform siting and management of pioneering ocean industries: A case study for Gulf of Mexico aquaculture.

Marine Spatial Planning (MSP) provides a process that uses spatial data and models to evaluate environmental, social, economic, cultural, and management trade-offs when siting (i.e., strategically locating) ocean industries. Aquaculture is the fastest-growing food sector in the world. The United States (U.S.) has substantial opportunity for offshore aquaculture development given the size of its exclusive economic zone, habitat diversity, and variety of candidate species for cultivation. However, promising aquaculture areas overlap many protected species habitats. Aquaculture siting surveys, construction, operations, and decommissioning can alter protected species habitat and behavior. Additionally, aquaculture-associated vessel activity, underwater noise, and physical interactions between protected species and farms can increase the risk of injury and mortality. In 2020, the U.S. Gulf of Mexico was identified as one of the first regions to be evaluated for offshore aquaculture opportunities as directed by a Presidential Executive Order. We developed a transparent and repeatable method to identify aquaculture opportunity areas (AOAs) with the least conflict with protected species. First, we developed a generalized scoring approach for protected species that captures their vulnerability to adverse effects from anthropogenic activities using conservation status and demographic information. Next, we applied this approach to data layers for eight species listed under the Endangered Species Act, including five species of sea turtles, Rice's whale, smalltooth sawfish, and giant manta ray. Next, we evaluated four methods for mathematically combining scores (i.e., Arithmetic mean, Geometric mean, Product, Lowest Scoring layer) to generate a combined protected species data layer. The Product approach provided the most logical ordering of, and the greatest contrast in, site suitability scores. Finally, we integrated the combined protected species data layer into a multi-criteria decision-making modeling framework for MSP. This process identified AOAs with reduced potential for protected species conflict. These modeling methods are transferable to other regions, to other sensitive or protected species, and for spatial planning for other ocean-uses.

Caribbean mesophotic coral ecosystems are unlikely climate change refugia.

Deeper coral reefs experience reduced temperatures and light and are often shielded from localized anthropogenic stressors such as pollution and fishing. The deep reef refugia hypothesis posits that light-dependent stony coral species at deeper depths are buffered from thermal stress and will avoid bleaching-related mass mortalities caused by increasing sea surface temperatures under climate change. This hypothesis has not been tested because data collection on deeper coral reefs is difficult. Here we show that deeper (mesophotic) reefs, 30-75 m depth, in the Caribbean are not refugia because they have lower bleaching threshold temperatures than shallow reefs. Over two thermal stress events, mesophotic reef bleaching was driven by a bleaching threshold that declines 0.26 °C every +10 m depth. Thus, the main premise of the deep reef refugia hypothesis that cooler environments are protective is incorrect; any increase in temperatures above the local mean warmest conditions can lead to thermal stress and bleaching. Thus, relatively cooler temperatures can no longer be considered a de facto refugium for corals and it is likely that many deeper coral reefs are as vulnerable to climate change as shallow water reefs.

Marine Protected Area monitoring in the nearshore waters of Grenada, Eastern Caribbean: benthic cover and fish populations / Monitoreo en aguas cercanas al área marina protegida en la costa de Granada, Caribe Oriental: cobertura bentónica y poblaciones de peces

Grenada is highly dependent on coral reefs as a source of food and to support tourism. Local and global environmental stressors threaten these reefs. Legislation was created for this MPA in 2001, permanent mooring buoys were deployed in 2009 and enforcement of fishing restrictions began in 2010. Initiatives to address point and nonpoint source pollution from the land have recently begun, aimed at reducing stress on reef area. This study documents benthic cover and fish populations associated with reefs in a Marine Protected Area (MPA) along Grenada’s southwest coast from 2008 through 2012. Both Point Line Intercept and Photo Quadrat methods were used to assess benthic cover along permanent 30m transects (8 in and 12 outside the area) annually. Fish and Diadema antillarum urchin relative abundance were determined based on 2m wide belt surveys along the same transects. The predominant substrate cover was algae, ranging from 41% in 2009 to 74.2% in 2011. A general trend of increasing algal cover was noted. Combined annual survey results prior (2008-2010) and after controls were implemented (2011-2012) showed a significant increase in algal cover. The predominant algal form was macroalgae comprising 65.4% - 90.8% of total algae. Live hard coral percent cover ranged from 8.7% to 21.1%. Little annual variation was observed in percent live coral cover. Branching corals (34.1% - 52.3% of total living hard coral) were the most common. Of the 19 living hard coral species identified, Porites porites (21%-23%) and Porites astreoides (20%) dominated percentage composition. Madracis mirabilis contributed 21% of total live hard coral outside the MPA but only 8.7% in the MPA. Of the 63 species of fish identified in the study areas Chromis spp. (71.5% - 46%) was the dominant group. Wrasse had a significant increase from 6.9% in 2008 to 21.5% in 2010 inside the MPA with a similar increase peaking in 2011 outside the MPA. There was a noticeable (though not statistically significant) increase in piscivorous fishes in the MPA in 2012. This is a promising indication that fishing restrictions in the MPA may be having an effect. Diadema antillarum density was low, ranging from 4.58 to 0.21 urchins/100m² outside and 0.28 to 0.10 urchins/100m² inside despite a stocking attempt in the area in 2011.

Granada es muy dependiente de los arrecifes coralinos como fuente de alimento y apoyo al turismo. Factores estresantes locales y globales amenazan con estos arrecifes. La legislación fue creada para esta área protegida en el 2001, boyas de amarre fueron colocadas en 2009 y las restricciones a la pesca comenzaron a implementarse a partir del 2010. Iniciativas para reducir el estrés por contaminación terrestre, de fuentes puntuales y no-puntuales, en la zona comenzaron recientemente. Este estudio documenta la cobertura bentónica y poblaciones de peces asociados a los arrecifes del área marina Protegida (MPA) a lo larfo de la costa suroeste de Granada del 2008 al 2012. Se utilizaron los métodos de Punto Línea Intercepción (PLI) y Cuadrantes Fotográficos (PQ) para evaluar anualmente la cobertura bentónica a lo largo de transectos permanentes de 30m (ocho dentro y 12 fuera del MPA). La abundancia relativa de peces y del erizo negro Diadema antillarum a través de censos visuales de 2m de ancho a lo largo de los mismos transectos lineales. La cobertura de sustrato estuvo dominada por algas con 41% en 2009 y 74.2% en 2011. Se notó una tendencia general de aumento en la cobertura algal. La combinación de los resultados antes de las encuestas (2008-2010) y después de la implementación de los controles del MPA (2011-2012) mostró un aumento significativo en la cobertura algal. La forma algal predominante fue macroalgas que consta el 65.4% y el 90.8% del total de algas. El porcentaje de cobertura de coral durovarió entre un 8.7% y un 21.1%. Se observó una pequeña variación anual en el porcentaje de cobertura de coral vivo. Los corales ramificados (34.1%-52.3% del total de corales duros) fueron la forma de coral más común encontrada durante el estudio. De las 19 especies de corales duros identificados, Porites porites (21% - 23%) y Porites astreoides (20%) dominaron el porcentaje de composición. Madracis mirabilis contribuyó en un 21% del total de corales duros fuera del MPA pero solo un 8.7% en el MPA. De las 63 especies de peces identificadas en el área de estudio Chromis spp. (71.5% - 46%) fue el grupo dominante. Los lábridos (Labridae) mostraron un aumento significativo de su abundancia de un 6.9% en 2008 a un 21.5% en 2010 dentro del MPA con un pico de incremento similar en el 2011 fuera de la MPA. Hubo un aumento notable (aunque no significativo estadísticamente) en los peces piscívoros dentro del MPA en 2012. Esto es una indicación prometedora de que las restricciones de pesca en la MPA pueden estar dando efecto. La densidad de Diadema antillarum fue baja, osciló entre 4.58 y 0.21 erizos/100m² fuera del MPA y entre 0.28 y 0.10 erizos/100m² dentro del MPA a pesar de la existencia de un programa de repoblación de la especie llevado a cabo en el 2011.

Benthic and fish population monitoring associated with a marine protected area in the nearshore waters of Grenada, Eastern Caribbean / Monitoreo de la población bentónica y de peces asociada con un área marina protegida en las aguas cercanas a la costa de Granada, Caribe Oriental

Annual benthic and fish population surveys were completed at five locations in the nearshore waters along Grenada´s southwest coast during 2008-2010. Two survey sites are located in a newly launched Marine Protected Area (MPA). Photo Quadrat (PQ) and Point Line Intercept (PLI) surveys were used to determine substrate cover. Algae was the primary live cover increasing significantly from 45.9% in 2008 to 52.7% in 2010 (PLI). Algae was also predominant (61.0%-59.3%) in the PQ surveys although annual variation was not significant. Hard coral cover ranged from 16.5% to 15.4% (PLI) and 11.4% to12.0% (PQ) with no significant differences between years. Branching and encrusting corals occurred more frequently than massive corals. In the three annual surveys neither algal cover nor hard coral varied significantly between MPA and non-protected areas (PLI). Relative abundance of fishes along 30x2m belt transects did not vary significantly among years however density of fishes decreased significantly across years for most major groups. Chromis spp. dominated the survey sites at 65.2% in 2008 and 49.8% in 2010, followed by territorial damselfish,11.1% and 15.5%, wrasse increased from 7.3% to 15.5%. Both the substrate cover and fish survey data analyses indicated a stable but degraded community. Annual surveys are planned at these sites for the foreseeable future. Existing and future data from this project will be valuable in determining the efficacy of MPA management, guiding resource management decisions and monitoring the health status of Grenada’s valuable reef systems.

Un estudio sobre poblaciones bentónicas y de peces fue realizado en cinco localidades en la zona costera en el suroeste de Grenada entre 2008 y 2010. Dos sitios se ubicaron en una Área Marina Portegida (AMP) recientemente creada. Para determinar la cobertura se utilizaron foto-cuadrantes (FQ) y transectos de intersección de puntos (TIP). Las algas fueron el principal componente del bentos, aumentando significativamente de 45,9% en 2008 a 52,7% en 2010 (TIP). Las algas también fueron predominantes (61,9%-59,3) en los FQ, aunque las diferencias anuales no fueron significativas. La cobertura de corales pétreos tenía un ámbito de 16,5% a 15,4% (TIP) y de 11,4% a 12,0% (FQ), sin diferencias significativas entre años. Los corales ramificados e incrustantes fueron más frecuentes que los corales masivos. En los tres años no hubo diferencias significativas entre las AMPs y las áreas no protegidas. La abundancia relativa de peces a lo largo de un transecto de 30x2m no varió significativamente entre los años, sin embargo, la densidad de peces decreció significativamente a través de los años, para los grupos principales. Chromis spp. predominó con 65,2% en 2008 y 49,8% en 2012, seguido por damiselas territoriales, 11,1% y 15,5%, y los lábridos aumentaron de 7,3% a 15,5%. Tanto la coberura del sustrato como los datos de peces indican una comunidad estable pero degradada. Sondeos anuales están planeados para el futuro. Los datos existentes y futuros de este proyecto serán muy útiles para determinar la eficacia de la gestión de las AMPs y el estado de salud de los sistemas arrecifales de Grenada.