Spatio-temporal distribution and abundance of <Emphasis Type="Italic">Euphausia crystallorophias</Emphasis> in Terra Nova Bay (Ross Sea,Antarctica) during austral summer

Average abundance values for Euphausia crystallorophias in the shelf region of Terra Nova Bay were generally high. Mean number of adults and juveniles were 20 and 87 ind/m², respectively, while larval concentrations were much higher, reaching a mean of 14,764 ind/m². Euphausia crystallorophias were very patchy in their distribution during all stages of their life cycle. The distribution patterns of E. crystallorophias in TNB seem to be strictly correlated both to hydrological features such as the presence of polynyas, pack-ice zone and certain temperatures values. According to our data, E. crystallorophias spawned from early October to early January. For the two age groups (0+ and 1+) an average growth rate of 0.074 and 0.076 mm/day was found, respectively. The mean biomass of larval E. crystallorophias (from Metanauplius to Furcilia I) in January was estimated as 84 mg WW/m². This article belongs to a special topic: Five articles on Sea-ice communities in Terra Nova Bay (Ross Sea), coordinated by L. Guglielmo and V. Saggiomo, appear in this issue of Polar Biology. The studies were conducted in the frame of the National Program of Research in Antarctica (PNRA) of Italy.