Effects of coastal development on sawfish movements and the need for marine animal crossing solutions.

Although human-made barriers to animal movement are ubiquitous across many types of ecosystems, the science behind these barriers and how to ameliorate their effects lags far behind in marine environments compared with terrestrial and freshwater realms. Using juvenile sawfish in an Australian nursery habitat as a model system, we aimed to assess the effects of a major anthropogenic development on the movement behavior of coastal species. We compared catch rates and movement behavior (via acoustic telemetry) of juvenile green sawfish (Pristis zijsron) before and after a major coastal structure was built in an important nursery habitat. Acoustic tracking and catch data showed that the development did not affect levels of sawfish recruitment in the nursery, but it did constrain movements of juveniles moving throughout the nursery, demonstrating the reluctance of shoreline-associated species to travel around large or unfamiliar coastal structures. Given the current lack of information on human-made movement barriers in the marine environment, these findings highlight the need for further research in this area, and we propose the development of and experimentation with marine animal crossings as an important area of emerging research.

Efectos del desarrollo costero sobre los movimientos del pez sierra y la necesidad de soluciones para el cruce de animales marinos Resumen Mientras que las barreras construidas por humanos que limitan el movimiento de animales son ubicuas en muchos tipos de ecosistemas, la ciencia que sustenta estas barreras y la reducción de sus impactos está muy retrasada en ambientes marinos en comparación con medios terrestres y dulceacuícolas. Utilizando peces sierra juveniles en un hábitat de vivero australiano como sistema modelo, intentamos evaluar los efectos de un importante desarrollo antropogénico sobre el comportamiento de especies costeras. Comparamos las tasas de captura y el comportamiento de movimiento (mediante telemetría acústica) de peces sierra verdes juveniles (Pristis zijsron) antes y después de que se construyera infraestructura costera en un importante hábitat de vivero. El seguimiento acústico y los datos de captura mostraron que el desarrollo no afectó los niveles de reclutamiento de pez sierra en el vivero, pero sí restringió los movimientos de los juveniles desplazándose por el vivero, lo cual demuestra la renuencia de las especies asociadas a la costa a viajar alrededor de estructuras costeras grandes o desconocidas. Dada la actual falta de información sobre las barreras de movimiento creadas por el hombre en el medio marino, estos hallazgos destacan la necesidad de realizar más investigaciones en esta campo, y proponemos el desarrollo y la experimentación con cruces para animales marinos como un área importante de investigación emergente.

Cambios en la comunidad de peces por efecto del desarrollo costero en el Parque Nacional Huatulco (México) / Changes in fish communities from the effect of coastal development in Huatulco National Park (Mexico)

Resumen El incremento del aporte de sedimentos desde tierra derivado del desarrollo costero y urbanización ha producido efectos adversos en la estructura y función de los arrecifes coralinos. El objetivo de este estudio fue conocer la magnitud de disturbios por aportes excesivos de sedimentos en la comunidad íctica de arrecifes coralinos de las bahías Maguey y Violín del Parque Nacional Huatulco (México). Los muestreos de peces se realizaron antes y después de disturbios ocasionados por aportes de sedimentos asociados a obras de desarrollo costero. Como indicadores de cambios en las comunidades de peces se utilizaron el número de especies, diversidad, equidad y dominancia antes y después de la perturbación. El análisis se realizó mediante pruebas de comparación de medias, análisis de similitud (ANOSIM) y análisis de porcentaje de similitud (SIMPER). En ambas localidades, se observó, que, excepto la dominancia, la diversidad, equidad, abundancia y número de especies fueron mayores previos a la perturbación. En Maguey se observaron diferencias significativas en la equidad y dominancia (U=28, p=0.0401; U=24, p=0.0472), así como en la composición de especies y la abundancia (ANOSIM=0.35, p=0.009). El análisis de porcentaje de similitud (SIMPER) indicó que posterior a la perturbación, el 46 % de especies presentaron una disminución en su abundancia, destacó la ausencia de Prionurus laticlavius, así como el decremento en la abundancia de: P. punctatus, Cirrhitichthys oxycephalus, Microspathodon dorsalis, Lutjanus novemfaciatus y Stegates acapulcoensis. La inadecuada planeación y ejecución de proyectos de desarrollo costero que propiciaron aporte excesivo de sedimentos al mar determinaron cambios negativos en las comunidades coralinas de Maguey y Violín, cuyo efecto fue observado en la composición de especies, abundancia, equidad y dominancia de la comunidad de peces de Maguey.(AU)

Abstract Coastal development and urbanization have increased the sediments that are washed from the land surface, producing adverse effects on the structure and functioning of coral reefs. The objective of this study was to identify the degree to which excessive sediments have disturbed the fish community in the coral reefs in the Maguey and Violin bays, located in the Huatulco National Park (Mexico). Fish samples were collected before and after disturbances produced by sediments associated with coastal development projects. Indicators of changes in the fish communities included the number and diversity of species as well as equity and dominance before and after the disturbances. The analysis was performed through means comparison tests, similarity analysis (ANOSIM) and similarity percentage analysis (SIMPER). In both locations, it was observed that the diversity, evenness, abundance and number of species were higher prior to the disturbance, but not for dominance, which shows an inverse pattern. In Maguey, significant differences in evenness and dominance were observed (U = 28, p = 0.0401; U = 24, p = 0.0472), as well as in species composition and abundance (ANOSIM = 0.35, p = 0.009). The similarity percentage analysis (SIMPER) indicated that after the disturbance, more than 46 % of the species showed decreases in average abundance, highlighting the absence of Prionurus laticlavius, as well as the decrease in abundance of: P. punctatus, Cirrhitichthys oxycephalus, Microspathodon dorsalis, Lutjanus novemfaciatus and Stegates acapulcoensis. Inadequate planning and implementation of coastal development projects that contribute to the discharge of excessive sediments into the sea were determinants of negative changes in the coral communities in Maguey and Violin, whose effects could be seen in the composition of the species and the abundance, equity, and dominance of the fish community in Maguey.(AU)

Effects of reduced water quality on coral reefs in and out of no-take marine reserves.

Near-shore marine environments are increasingly subjected to reduced water quality, and their ability to withstand it is critical to their persistence. The potential role marine reserves may play in mitigating the effects of reduced water quality has received little attention. We investigated the spatial and temporal variability in live coral and macro-algal cover and water quality during moderate and major flooding events of the Fitzroy River within the Keppel Bay region of the Great Barrier Reef Marine Park from 2007 to 2013. We used 7 years of remote sensing data on water quality and data from long-term monitoring of coral reefs to quantify exposure of coral reefs to flood plumes. We used a distance linear model to partition the contribution of abiotic and biotic factors, including zoning, as drivers of the observed changes in coral and macro-algae cover. Moderate flood plumes from 2007 to 2009 did not affect coral cover on reefs in the Keppel Islands, suggesting the reef has intrinsic resistance against short-term exposure to reduced water quality. However, from 2009 to 2013, live coral cover declined by ∼ 50% following several weeks of exposure to turbid, low salinity water from major flood plume events in 2011 and subsequent moderate events in 2012 and 2013. Although the flooding events in 2012 and 2013 were smaller than the flooding events between 2007 to 2009, the ability of the reefs to withstand these moderate floods was lost, as evidenced by a ∼ 20% decline in coral cover between 2011 to 2013. Although zoning (no-take reserve or fished) was identified a significant driver of coral cover, we recorded consistently lower coral cover on reserve reefs than on fished reefs throughout the study period and significantly lower cover in 2011. Our findings suggest that even reefs with an inherent resistance to reduced water quality are not able to withstand repeated disturbance events. The limitations of reserves in mitigating the effects of reduced water quality on near-shore coral reefs underscores the importance of integrated management approaches that combine effective land-based management with networks of no-take reserves.

Entre historias y culebras: más que una bahía (Bahía Culebra, Guanacaste, Costa Rica) / Among stories and snakes: more than a bay (Bahía Culebra, Guanacaste, Costa Rica)

Among stories and snakes: more than a bay (Bahía Culebra, Guanacaste, Costa Rica). Bahía Culebra (Culebra Bay) is a semi-closed and protected geomorphological unit, which has a wide diversity of natural resources, encouraging the settlement of human populations and consequent coastal development. Bahía Culebra has been an important place from the historical, political, cultural and economic perspective, according to the literature search which included documents dating from the mid nineteenth century until 2011, from the National Archive of Costa Rica, the National Library, the Historical Research Center in Central America and some private collections. Its beauty, road networks, and the proximity to an international airport has made easier for it to become an intensive tourism development center. Coastal development was accelerated by the creation of the Polo Turístico Golfo de Papagayo (Papagayo Gulf Tourist Destination project). It should strengthen the legal framework and implementation of actions to promote the welfare of local populations and the proper management of natural resources, taking into account all factors and actors involved.

Bahía Culebra (Golfo de Papagayo, Guanacaste, Costa Rica) es una unidad geomorfológica semicerrada y bastante protegida, que cuenta con una amplia diversidad de recursos naturales, favoreciendo el asentamiento de poblaciones humanas y su consecuente desarrollo marinocostero. La reseña histórica de Bahía Culebra indica que este ha sido un sitio muy importante desde la perspectiva histórica, política, cultural y económica. La consulta bibliográfica incluyó documentos que datan de mediados del siglo XIX hasta el año 2011, los cuales fueron recopilados del Archivo Nacional de Costa Rica, la Biblioteca Nacional, el Centro de Documentación del Centro de Investigaciones Históricas de América Central y algunas colecciones privadas. Su notoria belleza escénica, la disponibilidad de redes viales en buen estado y la cercanía a un aeropuerto internacional han facilitado que la bahía se convierta en un centro turístico intensivo, generando un acelerado desarrollo costero a raíz de la creación del proyecto Polo Turístico Golfo de Papagayo (PTGP). Se debe fortalecer el marco jurídico e implementar acciones que promuevan el bienestar de las poblaciones locales y la adecuada gestión de los recursos naturales, tomando en cuenta todos los factores y actores involucrados.