Analyses of Western Gulf Coast Mottled Duck Harvest Data

摘要

This report contains a summary of the recent analyses of data from mottled ducks harvested in Texas and Louisiana. These analyses were performed solely to allow biologists and managers to engage in more informed and productive discussions of mottled duck harvest management. Our goal was to determine what types of harvest restrictions would be necessary to achieve various levels of harvest reduction should restrictions be deemed necessary in the near future, given that no formal assessment framework currently exists to evaluate the harvest potential of Western Gulf Coast mottled ducks. Analyses by the Central Flyway and FWS suggest that the Hunters Choice option that is currently being used in Texas may decrease harvest of mottled ducks by 18%. Analyses of harvest data in Louisiana presented at a workshop in April 2006 suggested that reducing the daily bag limit of mottled ducks from 3 .. 2 birds/day would decrease the total harvest by 3%. Reducing from 3..1 birds/day was estimated to decrease mottled duck harvest in Louisiana by 19%. Recently, the FWS has examined the distribution of mottled duck harvest data from 1997/98-2005/06 to estimate how shortened seasons can be used to achieve harvest reductions. We estimated that current seasons would need to be shortened by 14 days in Texas and 15 days in Louisiana order to reduce harvest by an additional 10% in each state in addition to bag limit reductions in Louisiana and Hunters Choice in Texas. If only reductions in season length were used to decrease harvest, we estimated that the hunting season would need to be decreased by 34 days in both Louisiana and Texas to decrease mottled duck harvest by 30%. This method likely overestimates the number of days that need to be cut from the season, because it assumes that hunter effort will not change during shorter seasons. However, we note that shorter seasons within longer seasons are highly undesirable by hunters, managers, and law enforcement, particularly in the case of mottled ducks, which look very similar to mallards. A season-within-a-season on mottled ducks would make it difficult for hunters to remain legal and law enforcement to enforce.