While haddock is an historically important New England groundfish, there is limited information about the fish’s reproductive biology. In this project, researchers are examining the daily sound patterns of female haddock to determine when haddock spawn. Preliminary indications suggest that spawning occurs just after sunset. A second focus is to improve the quantification of haddock fecundity estimates. This study will provide basic biological data necessary to pave the way for future studies to use passive acoustics to map haddock spawning areas and essential fish habitats.