Bottlenecks to Fishery Yield for American Lobster in a Portion of the Gulf of St. Lawrence

Abstract

Egg production, larval survival, and migration of large benthic stages are considered to be possible bottlenecks to fishery yields for the American lobster Homarus americanus in the eastern Northumberland Strait, southern Gulf of St. Lawrence. Egg production, measured as eggs per trap haul and stage I larval production, was high compared with that of surrounding areas with greater fishery yield. The only area that could have supplied larvae by drift supported average egg production. Low levels of postlarvae developed from this average to high egg production, implicating low larval survival as the proximal cause of low fishery yield. A scarcity of small lobsters in the catch over several decades also indicated that recruitment was low and that the fishable stock was supported by immigration. Because of this spatially variable relationship between egg production and fishery yield, we recommend setting management targets specific to an area.