Life cycles and seasonal distributions of Calanus finmarchicus on the central Scotian Shelf

The life cycle of Calanus finmarchicus on and around Western Bank, 1991-199 2, was essentially annual; the overwintered generation (G(0)) produced G(1) that developed at temperature-dependent rates and then largely disappeared after June to winter as late copepodids at depth. However, a small fractio n of G(1) matured to spawn a less rapidly developing G(2) that outnumbered G(1) in the depths of Emerald Basin in autumn 1990. Estimated mortality on the central Scotian Shelf for G(1) from egg to copepodid stage 5 in June wa s similar to4%.day(-1) but subsequently for G(1) and G(2) was nearly consta nt at similar to1%.day(-1). Populations on Western Bank mostly derived from reproduction by overwintered G(2) on the Scotian Shelf. Larger populations in Emerald Basin in 1987-1988 were augmented from advected animals enabled to diapause there at depth and on Emerald Bank by inputs from beyond the s helf break, ultimately from farther north. Our observations and analyses ma tch the physical circulation in the region.