Evolution of Eurytemora americana population, a zooplanktonic copepod invader in Bahia Blanca estuary, Argentina

HOFFMEYER, M.S; BERASATEGUI, A. A; DUTTO, M.S

Portugal

Conferencia; BIOLIEF-World Conference on Biological Invasions and Ecosystem functioning; 2009

CIMAR

Eurytemora americana, a common low abundant copepod in some estuaries of the northern Hemisphere, develops a population pulse in Bahia Blanca Estuary, between June and November, which, in the last years, has become dominant. This study reports E. americana population   abundance variability during several years in relation to environmental conditions in the inner zone of this estuary. Data on abundance, salinity, temperature and chlorophyll-a, during pulses occurring in 1990, 1998, 2002, 2007 and 2008, were analyzed. Pulses varied in magnitude along the years analyzed. The highest abundance values with temperatures < 8 ºC and salinities >  28 were recorded in the period 2002-2007. An inverse relationship between abundante and temperature was evident. Although no relationships between abundance and salinity chlorophyll-a were found, it seems likely that the highest E. americana abundance pulses were due to the combined effect of temperature with other variables. After its introduction in the mid 1980s, E. americana population has shown an increase trend in this estuary.