Use of Spotter Pilot Reports for Creation of an Adult Abundance Index for Atlantic Menhaden

The industrial fishery for Atlantic menhaden is concentrated in lower Chesapeake Bay and contiguous ocean waters.  Spotter aircraft locate fish schools and direct the setting of the purse-seine nets. Prior to fishing on Mondays, several spotter pilots fly routine “Sunday patrols” to locate concentrations of fish schools.  Spotter pilot reports are relayed to vessels captains who make appropriate decisions on where to fish on Monday mornings.  Reviews of recent menhaden stock assessments recommended exploring the utility of spotter pilot reports to estimate relative abundance of adult menhaden.  The extant menhaden company, Omega Protein Inc., made spotter pilot reports available from five of the previous six fishing seasons.  The company’s chief pilot translated industry jargon and school biomass estimates on the spotter reports onto a gridded chart of Chesapeake Bay and adjacent waters.  We developed areal indexes of apparent abundance (IAA) based on pooled counts of school biomass intervals divided by number of flights.  IAAs were paired with areal removals of menhaden by the fleet using vessel logbook information.  The IAA for Virginia ocean waters warrants further investigation as a coastal index of adult menhaden abundance.