Eventos de Mareas Rojas: Estrategias de manejo preventivas en Ecuador.

Abstract

Se realizó un análisis retrospectivo de la información existente sobre mareas rojas en el área marina costera e insular del Ecuador comprendidos entre 1968 y 2009, con el propósito de ubicar áreas y épocas de mayor ocurrencia, las especies causantes de estos eventos y los registros de mortalidad de organismos. Los resultados evidenciaron 131 eventos de marea roja. Los años de mayor ocurrencia fueron en 1985 (Estero Salado), 2001 (área central costera) y 2003 (Puná y costas de El Oro), posiblemente en respuesta a condiciones oceanográficas locales; no todas las mareas rojas necesariamente coincidieron con los eventos El Niño o La Niña. Los meses de mayor ocurrencia de mareas rojas fueron marzo abril, y mayo, aunque estos también se xx evidenciaron en todos los meses del año, coincidentes con la época cálida (mayor radiación solar) y mayo es un mes de transición estacional. La mayor ocurrencia se localizó en el Golfo de Guayaquil (80%), principalmente en los canales internos (Estero Salado y Río Guayas), sector de Puná y frente al borde costero de El Oro que se relacionan con áreas de mayor uso antrópico. Se identificaron treinta y siete especies causantes de mareas rojas, siendo la clase Dinophyceae la más relevante con veintiocho especies de dinoflagelados, seguidos por Cyanophyceae, Bacillariophyceae (tres especies), Raphidophyceae (dos especies) y un Ciliado. El Golfo de Guayaquil fue el sitio de mayor número de especies. Mesodinium rubrum fue el ciliado con mayor número de mareas rojas seguidos por Gymnodinium sp., Noctiluca scintillans y Cochlodinium catenatum. En abril y mayo se registró la mayor densidad celular. Solo veintiséis eventos se relacionaron con mortalidad de organismos (peces, camarón y larvas de camarón) estos ocurrieron principalmente en el Golfo y no han tenido una explicación científica que permita conocer cual fue la causa. Estos resultados establecen la necesidad de una propuesta de estrategias en el manejo integrado de la prevención, control y vigilancia a futuros eventos de mareas rojas y a sus impactos.

A retrospective analysis of the existing information was made on red tides, happened in understood the coastal and insular marine area of Ecuador between 1968 and 2009, in order to locate aerial geographic of main impact, times of the occurrence, species producing causes of these events and the registries of mortality of organisms. The results demonstrated 131 events of red tide in which 26 events of mortality of organisms were included. The years of greater occurrence were in 1985 (Estero Salado), 2001 (coastal central area) and 2003 (Puná island and coasts of El Oro), possibly in answer to local oceanographic conditions; all the red tides necessarily did not agree with the El Niño or La Niña events. The months of main occurrence were in March, April, xxi and May, although these also were demonstrated in every month of the year, coincident with the warm time (main solar radiation) and May is a seasonal transition month. The aerial geographic of the most occurrence was located in the Gulf of Guayaquil (80%), mainly in the internal channels (Estero Salado and Guayas River), near of Puná island and in front of the El Oro Province, sites that are related to areas of greatest anthropogenic use. Thirty and seven species were identified cause of red tides, being the Dinophyceae class with twenty-eight species of dinoflagellates, followed by Cyanophyceae, Bacillariophyceae (three species), Raphidophyceae (two species) and one Ciliate. The Gulf of Guayaquil it was the site that had of most number of species. Mesodinium rubrum was the dominant taxon with highest number of red tides, followed by Gymnodinium sp., Noctiluca scintillans and Cochlodinium catenatum. The months with greater cellular density were in April and May, only the twenty-six events were related to mortality of organisms (fish, shrimp and larvae of shrimp) and these happened in the Gulf mainly; this not had a scientific explication, because any environmental authority at the present as it was the cause. These results establish the necessity of actions anticipated by means of a strategies proposal in the integrated management of the prevention, control and monitoring to future events of red tides and their impacts.