A stochastic model of a fishery which recognizes a contagion effect in
the fishing process (i.e. the fact that the events of individual fish
being caught are not independent) is developed and is used to establi
sh how the probability distribution of the aggregated annual catch of
the fishery depends upon the aggregated annual fishing effort. From th
is relationship, and the assumption of deterministic, non-linear popul
ation dynamics, it is possible to determine analytically a likelihood
function of the various model parameters (catchability coefficient, tw
o parameters of the Ricker stock-dynamic model and a contagion paramet
er). Maximum likelihood estimates and likelihood ratio confidence inte
rvals for these model parameters can then be obtained numerically. The
method is applied to two sets of catch-effort data. The performance o
f the method is assessed by comparing predictions of catch and catch-p
er-unit-effort with observed values for reserved data which were not u
sed for model fitting. Also confidence estimates of the maximum sustai
nable yield are obtained and the credibility of such estimates discuss
ed.