Experimental evaluation on survival mechanism of the invader copepod Eurytemora americana in Bahía Blanca estuary, Argentina

BERASATEGUI, ANABELA A.; HOFFMEYER, MÓNICA S.; DUTTO, M. SOFÍA

Porto

Congreso; BIOLIEF- World Conference on Biological Invasions and Ecosystem Functioning; 2009

ICCE (International Centre for Coastal Ecohydrology) & CIIMAR (Centro Interdisciplinar Investigaçâo Marinha Ambintal)

Benthic resting eggs constitute a survival mechanism for Eurytemora americana which has a short pulse as planktonic phase. Its phylogenetic relationship with E. affinis seems to indicate that E. americana produces diapause eggs as a benthic phase. To study dormancy period, benthic eggs were incubated by simulating temperature and salinity in situ conditions all along the population pulse from June to November, 2007. It was observed that resting eggs began to appear in the sediment when population abundance was found highest. The number of eggs (frequently found in groups) in the sediment increased gradually as the declining population period advanced. The first nauplii appeared at 17 °C with 30-33 of salinity after a refractory warming period (19-21°C and hypersaline conditions of 33-35 during 5 months).The maximum number of hatchings was recorded at 15-17°C and 30-33.9 of salinity. A negative relationship trend between hatching success and temperature was observed. Taken together, our results indicate that E. americana produces diapausal eggs.