Distribution patterns of ichthyoplankton in El Rincón shelf region, Argentina

HOFFMEYER, M. S.; MENÉNDEZ, M. C.; TORRES, E. R; BIANCALANA, F.

Espinho, Portugal

Simposio; The Plankton Symposium and Methodologies, equipments & environmental research workshop; 2001

The plankton Symposium

DISTRIBUTION PATTERNS OF ICHTHYOPLANKTON IN EL RINCON SHELF REGION, ARGENTINA M. S. HOFFMEYER, F. BIANCALANA, M. C. MENENDEZ AND E. R. TORRES Instituto Argentino de Oceanografía, Con. La Carrindanga Km. 7.5, 8000 Bahía Blanca, Argentina Email: bmhoffme@criba.edu.ar Qualitative and quantitative ichthyoplankton and enviromental data from a cruise in El Rincón coastal region during the beginning of November, 1993, were analyzed in the attempt to define the ichthyoplankton distribution patterns and to find the environmental factors acting on them. Principal componet analysis (PCA) applied to eggs and larvae abundance data and Clusters analysis (CA) of samples using Euclid distance and complete linking, were performed. A multiple lineal, regression analysis (MLRA) of abundance of eggs and larvae and zooplankton abundance (ZOO), salinity (SALT), temperature (TEMP9, particulate organic carbon (COP), chlorophyll a (CLO) and phaeopigments was also out applying the stepwise method in the variables selection. Three first components from PCA accounted for 91.2 % of total data variance. According to the correlation between these three components and variables, the first component represented Scienidae eggs and larvae, P. signata eggs and E. anchoita larvae, while the second component represented B.aurea . eggs and larvae. B. aurea and P. signata larvae were the most correlated ones, although negatively, with the third component. MLRA selected models were: for eggs= -45.778 + 1.017 ZOO + 11.2752 SALT and for larvae: -44.7 – 0.001COP + 1.35 SALT + 0.7112 ZOO, with multiple determination coefficients (R2) of 0.482 and 0.601, respectively. Ditribution patterns determined for eggs and larvae of different particular taxa were similar to those obtained for total ichthyoplankton. Similar dependence relations with environmental variables were also abserved.