Abstract:
Daily commercial albacore catches made by U. S. trollers fishing
off central California and Oregon are correlated with daily upwelling
indices and predictive catch models are developed.
Models predicting total catch/day and catch/boat/day are
formulated for the region off central California in 1961 to 1963 and
off Oregon in 1967 to 1969. These models explain 28 to 91% of the
variances in expected catches one day in advance for the years
studied. The total catch/day models are better predictors than the
catch/boat/day models, indicating that the behavior of albacore
fishermen is important in developing predictive catch models when
catch records are used.
The statistically significant terms of catches lagged to upwelling
indices in the models recur at one to three, six to nine and 13 to
14 days off Oregon, and at less than five days off central California.
The reason for the long lags off Oregon may be due to active and
relaxed cyclical upwelling events. The lags of less than five days
in both locations may be associated with the delay of upwelling after
the onset of northerly or northwesterly winds. The relationships
between daily catches and daily upwelling indices off Oregon and
central California indicate that albacore catches and fishing
success are affected by pulses of upwelling.
Catches as functions of catches, when present in the models,
are positive and significant at lags of one day and either positive
or negative at lags of two days or more. These values suggest
that albacore catches probably remain high for one day after the
start of good fishing.
