Assertion: mackerel | /r/CapableOf | vary in abundance
Facets:
value: so widely
type: DEGREE
value: over periods of years
type: TEMPORAL
Source sentences:
text: It follows from this, and from the fact that mackerel vary so widely in abundance over periods of years that the precise localities of greatest egg production may be expected to vary from year to year, depending on the local concentrations of the fish.