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

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: McLaren, Ian A, Head, Erica, Sameoto, D D
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2001
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Emerald Basin; Calanus finmarchicus
• Online Access: http://dx.doi.org/10.1139/f01-007; http://www.nrcresearchpress.com/doi/pdf/10.1139/f01-007

The life cycle of Calanus finmarchicus on and around Western Bank, 1991–1992, 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 fraction 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 was ~4%·day –1 but subsequently for G 1 and G 2 was nearly constant at ~1%·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 shelf break, ultimately from farther north. Our observations and analyses match the physical circulation in the region.