The continuous smooth hockey stick: a newly proposed spawner-recruitment model

Abstract

Spawner-recruit relationships are important components of fisheries management. The two most widely used models have been criticized for unsatisfactory fits and biologically unreasonable extrapolations. A simple hockey stick model has been shown to provide more robust predictions, however, this model is not widely used, possibly because the abrupt change from density-dependence to density-independence is unrealistic and the piecewise model is difficult to fit. Here I present a continuous two-parameter model that resembles a smoothed hockey stick and provides parameter estimates similar to the piecewise hockey stick. The new model is easily parameterized with regular curve-fitting routines.