Cheating about the cod

The Northeast Arctic cod is managed by a total quota shared evenly between Norway and Russia. It appears that Russia has been overfishing its quota by substantial amounts for a number of years, due to insufficient monitoring of fishing vessels. This paper considers what would be the best reply by Norway to given levels of Russian overfishing. It is found that in most cases the best Norwegian reply would be also to overfish its quota. An aggregate biomass model with stochastic growth and recruitment is used to analyze this question, with parameters estimated from 1946-2005 data. Recruitment is serially correlated but apparently independent of the spawning stock. A model using the estimated serial correlation in recruitment and a random disturbance is capable of reproducing recruitment patterns similar to the irregular pattern observed since 1946.