Standing Stock and Production of Fish in a Cascading Lake System on the Canadian Shield

Abstract

To examine factors influencing fish biomass and production, I carried out a multiple mark and recapture program in a cascading lake system on the Canadian Shield. Standing stock and production were determined for all "large" fish (vulnerable to the gear in use) in the system. Total fish biomass (range 5.2–24.8 kg∙ha⁻¹) decreased with progression downstream and with increasing depth. Production ranged from approximately 2.2 to 6.6 kg∙ha⁻¹∙yr⁻¹ and operated in a manner identical to standing stock. Salmonid flesh production, however, formed a greater proportion to overall fish production in the downstream, less productive lakes. Biomass was strongly influenced by lake depth in this watershed, and this was confirmed by examination of other published data for fish biomass and production in Shield lakes.