Cod Year-class Variations and Abundance of Other Commercial Fish in NAFO Divisions 3NO

Abstract

Possible biological relationships of cod (Gadus morhua) with other important commercial fishes are explored. Cod year-class variations are compared with variations of yellowtail flounder and American plaice spawning biomass, mackerel age 1+ group abundance, and redfish densities. The adult fish biomass of these species are considered as an index of their egg and larval abundances. Possible competitive and predator-prey relationships between the 0-age groups and young individuals of cod and these species are examined through correlation analyses. No significant relationships between cod and redfish and yellowtail flounder were found. It seems that mackerel is a predator on cod larvae. A positive high correlation between spawning American plaice biomass and cod year-class strength was found. High American plaice spawning biomass may promote high cod recruitment through a predator-prey interaction. Alternatively, both species may respond similarly to an environmental signal.