ALBERT

Description: Abstract Vinciguerria nimbaria larvae caught in August/September 1998 above the plateau and in the deep water area around the Great Meteor Seamount were analysed for nutritional condition and growth based on RNA/DNA ratios, size in length, dry weight, and otolith increment pattern. Data analysis was based on the following hypothesis: Due to its oceanographic features ("Taylor" column, retention area) the Great Meteor Seamount favours growth and nutritional condition for larval fish. Vinciguerria larvae caught above the plateau of the seamount showed significantly higher dry weights compared to the oceanic area, although the nutritional condition as measured by RNA/DNA ratios and dry-weight to larval-size relationships did not show any significant differences. Age-structure analysis based on otolith increments and growth rates indicated no significant differences between the sampling areas. Kurzfassung Beeinflusst die Große Meteorbank Wachstum und Ernahrungszustand von Fischlarven, insbesondere Vinciguerria nimbaria? Der Ernahrungszustand und das Wachstum von Vinciguerria-nimbaria-Larven, die im August/September 1998 iiber dem Plateau und im Tiefseebereich der Großen Meteorbank gefangen wurden, wurden mittels RNA/DNA-Analysen, Langen- und Gewichtsbestimmungen und anhand der Otolith-Tagesringstruktur analysiert. Folgende Hypothese wurde gepriift: Aufgrund ihrer hydrographischen Besonderheiten (Taylor-Säule, "Retention"-Bereich) ermöglicht die Meteorbank besseres Wachstum und eine bessere Ernahrungslage fur Fischlarven. Vinciguerria-Larven aus dem Bereich oberhalb des Seeberges hatten im Vergleich zum ozeanischen Bereich signifikant hi:ihere Trockengewichte, die RNA/DNA-Verhaltnisse und die Gewichts-Langen-Beziehungen zwischen den beiden Untersuchungsgebieten sowie die Altersverteilungen und Wachstumsraten zwischen beiden Gebieten ergaben keine signifikanten Unterschiede.

Description: Anchovy larvae (Engraulis anchoita) were sampled from an area of upwelling in the subtropical waters over the Brazilian shelf and from an area over the Argentinian shelf characterized by a tidal mixing front. They were analysed for their nutritional condition by measuring RNA/DNA ratios. The degree of starvation occurring in the two geographic areas was correlated to length distribution, developmental stage and position in the water column. It was shown that starving larvae (5 to 80 %) were mainly found in the smaller length classes (4 to 10 mm SL), but some larvae between 16 to 20 mm SL were also determined as starving (4 to 6 %). Larvae found in the stratified water column had higher RNA/DNA ratios reflecting a better nutritional condition than in the mixed water body. The degree of starvation at the same developmental stage was higher in Brazil than in the Argentinian area. RNA/DNA ratios of larvae from the Argentinian area showed a significant shift to higher values (indicating a better condition) than in Brazil. Results on the nutritional condition of the larvae based on RNA/DNA ratios were compared with zooplankton data and larval gut analyses determined on the same cruise. Speculations on the survival strategies of these two anchovy populations are given