Patterns of sexual recruitment of acroporid coral populations on the west fore reef at Discovery Bay, Jamaica.

Coral recruitment was examined on terracotta tiles deployed for four six-month periods between March 2001 and April 2003 on the West Fore Reef at Discovery Bay, Jamaica. During each sampling period, four tiles were deployed on each of two arrays at six depths ranging from 3 m to 33 m. Only three Acropora spat recruited to the tiles over the sampling period. The Acropora spat recruited during only one of the four six-month sampling periods and at only one depth, 3m. That represents a density of 8 spat m(-2) at 3 m depth for one six-month sampling period. Acropora recruitment represented <1 % of the total spat recruiting to the tiles deployed at 3 m during the four sampling periods. Density of acroporids on the West Fore Reef is low. Only one Acropora colony (an A. palmata) was recorded during Point-Quarter surveys of coral cover and density at depths of 3 m, 9 m, 14 m and 19 m. Considering the paucity of acroporid colonies and the infrequent settlement of acroporid spat on the West Fore Reef, it is unlikely that the historic abundance of A. palmata and A. cervicornis will return soon.

Caribbean corals in crisis: record thermal stress, bleaching, and mortality in 2005.

BACKGROUND: The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS: Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE: Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.

Evaluating the potential of natural reproduction and artificial techniques to increase Acropora cervicornis populations at Discovery Bay, Jamaica / Evaluación del potencial de la reproducción natural y técnicas artificiales para aumentar las poblaciones de Acropora cervicornis en Discovery Bay, Jamaica

Shallow water Acropora species have become uncommon on north coast Jamaican coral reefs owing to a number of factors. On many reefs, algae have taken their place. The result is loss of habitat for many species of fish and invertebrates and less attractive reefs with fewer fish. These reefs appear to be prime candidates for coral restoration. However, the potential for coral to naturally recover should be examined before efforts to restore reefs are undertaken. Reef restoration is unnecessary if the population has the capacity to recovery through natural means. We observed that the rate of settlement of Acropora spat in the Caribbean is much lower than the spat settlement rate of several other Caribbean coral families and much lower than Acropora spat settlement rates in the South Pacific. A very low percentage of apparently healthy colonies of A. cervicornis possessed developing gametes in July 2005, a month before spawning. It appears that the long-term survival of remnant A. cervicornis populations is threatened unless successful sexual reproduction is restored. Several techniques were used to test transplant methods for restoring A. cervicornis populations. The mean survivorship and growth rate of one technique was >75% and nearly 250% per annum, respectively. Working with hotel operators, environmental groups, and local fishers, we are attempting to reintroduce A. cervicornis to sites where it previously existed and increase coral biomass and complexity at these sites. Reefs with greater A. cervicornis biomass have larger edible fish populations. With localized protection of these restored reefs we anticipate an increase of larger edible fish not only on reefs within the restored protected areas but also on adjacent reefs. Furthermore, increased coral and fish biodiversity improves the attractiveness of the reef community for divers and snorkelers. Rev. Biol. Trop. 54 (Suppl. 3): 105-116. Epub 2007 Jan. 15.

Las especies someras de Acropora se han vuelto poco comunes en los arrecifes de la costa norte de Jamaica debido a numerosos factores. En muchos arrecifes, las algas han tomado su lugar y el resultado es la pérdida de hábitat para muchas especies de peces e invertebrados y la pérdida de atractivo de los arrecifes, que tienen mucho menos peces. Estos arrecifes parecen ser excelentes candidatos para restauración de corales. Sin embargo, antes de emprender un esfuerzo de restauración, debe examinarse el potencial de los corales para regenerarse naturalmente, ya que si la población tiene la capacidad de recobrarse por sus propios medios, la restauración de arrecifes se vuelve innecesaria. Nosotros observamos que la tasa de colonización por adherencia a un sustrato duro de Acropora en el Caribe, es más baja que la de muchas otras familias de corales del Caribe y mucho menor que la de Acropora en el Pacífico sur. Un muy bajo porcentaje de colonias de A. cervicornis poseía gametos en desarrollo y estaba saludable en julio de 2005, un mes antes del desove. Al parecer, la supervivencia a largo plazo de las poblaciones remanentes de A. cervicornis está amenazada a menos que se restaure una reproducción sexual exitosa. Se utilizaron varias técnicas para probar los métodos de transplante para restaurar las poblaciones de A. cervicornis. La supervivencia promedio y la tasa de crecimiento resultantes de una de las técnicas fue de >75% y de casi 250% por año, respectivamente. Al trabajar con agentes de hoteles, grupos ambientalistas y pescadores locales, estamos tratando de reintroducir A. cervicornis en lugares donde anteriormente existía e incrementar la biomasa del coral y la complejidad de estos sitios. Los arrecifes con mayores biomasas de A. cervicornis tienen también mayores poblaciones de peces comestibles. Si se protegen estos arrecifes en restauración, prevemos que habrá un incremento de peces comestibles, no sólo en los arrecifes restaurados, sino también en los adyacentes. Más aún, el aumento en la biodiversidad de corales y peces mejora el atractivo del arrecife para los buzos.