Reisenbichler, K. R.. Monterey Bay Aquarium Research Institute, reki@mbari.org
, . R.. ,

 
THE ECOPHYSIOLOGY OF THE ANTARCTIC SILVERFISH, PLEURAGRAMMA ANTARCTICUM, (PISCES, NOTOTHENIIDAE)
 
Pleuragramma antarcticum is a shoaling, pelagic planktivore with a circum-antarctic distribution. Pleuragramma were collected with midwater trawls from two diverse Southern Ocean ecological zones, to study the physiological adaptations of this species to environmental differences within its normal geographic range. Specimens collected from McMurdo Sound and Croker Passage were compared for differences in: 1) age, growth and relative abundance; 2) chemical composition; 3) food quality (as determined by chemical composition of the stomach contents). McMurdo Sound and Croker Passage specimens ranged from 1- to 13+ and 1- to 11+ years of age, respectively, and differed in regard to age-frequency composition. The differences in chemical composition between the two groups were seen primarily in juvenile specimens, and diminished with age. Significant differences in food quality were observed in young juveniles from the two sites, as well. The data suggest that a permanent pack-ice zone like McMurdo Sound offers more suitable prey for Pleuragramma larvae and small juveniles, as well as, adults. Whereas, the seasonal ice at Croker Passage may only constitute a feeding habitat primarily utilized by sub-adults migrating in from a nearby area of permanent pack-ice.
 
Day: Wednesday, Feb. 3
Time: 02:30 - 02:45pm
Location: Hilton of Santa Fe
 
Code: SS20WE0230H