Modelling the effect of a slope-water intrusion on advection of fish larvae in May 1995 on Georges Bank

In the spring of 1995, an intrusion of warm/salty slope water occurred on t he southern flank of Georges Bank. As observed on several cross-bank hydrog raphic and acoustic Doppler current profiler sections. this intrusion resul ted in a narrow (10 km) but intense shelfbreak jet (30 cm s(-1) westward re sidual) in the near-surface waters. A satellite tracked drifter with a drog ue located in the core of this jet (15 m) travelled 120 km to the west in 5 .5 d. To examine this process and demonstrate the potential redistribution of fish larvae (collected with bongo net hauls) in the presence of a slope- water intrusion, a finite-element 3D circulation model has been initialized with the observed CTD density field. Moored velocity records are assimilat ed into the model to estimate the oceanic boundary elevations of a limited- area grid. The simulated particle tracks indicate enhanced along-bank flow relative to the long-term seasonal mean and a downwelling convergence zone in the vicinity of the shelf/slope front. The model resolves most of the su btidal flow and provides insight into the vertical advection of the animals and potential mechanisms of retention and loss.