With Virginia oyster stocks on the rise, so is poaching – and that has caught the attention of regulators. The public oyster season opens Tuesday and the Virginia Marine Police are taking aim at what they call an epidemic of poaching. Last month, for instance, the Virginia Marine Resources Commission revoked the fishing licenses of five commercial oyster harvesters who pleaded guilty to poaching by overharvesting. Marine Police will seek out oyster poachers by air, land and sea. The force has dedicated officers to seek out offenders as a top priority. One attraction for poachers is the tenfold increase in the state’s oyster harvest in the past decade, although oysters are still only a fraction of historic highs in the Chesapeake Bay and its tributaries.