UNIQUE BIOLOGICAL CHARACTERISTICS OF SPRING-SPAWNING HERRING (CLUPEA-HARENGUS L) IN MINAS BASIN, NOVA-SCOTIA, A TIDALLY DYNAMIC ENVIRONMENT

The unusual occurrence of a spring-spawning (May-June) Atlantic herring population in a tidally dynamic environment (Minas Basin, Nova Scotia) is investigated. Adult growth and reproductive characters are similar to those of a geographically adjacent population that also spawns in a tidally energetic environment but during autumn (August-October), rather than to those of another May- to June-spawning population that reproduces in an environment with low tidal energy. Minas Basin herring are shown to feed intensively during gonad maturation up to and including spawning. This has not been previously documented for Atlantic herring. Condition factor analysis shows that somatic tissues lose weight during gonad maturation in spite of the feeding behaviour. It is concluded that the high fecundity of Minas Basin herring is accomplished by increased gonad production. This suggests that high fecundity is prerequisite to life-cycle closure in highly dispersive environments. Analysis of parasitic larval nematode infection suggests Minas Basin herring are distributed with other herring populations from the Bay of Fundy region that aggregate along the southwestern edge of the Scotian shelf during summer to feed.