Otter-trawl records and midwater-trawl catches suggested that some mesopelagic fishes are permanent members of the midwater fauna of the Gulf of Maine rather than strays.Benthosema glaciale,Ceratoscopelus maderensis,Myctophum punctatum, andMaurolicus muelleri, cold water or ubiquitous species, occur in the Gulf throughout the year, and warmwater species derived from adjacent Slope Water offshore were captured in the Gulf during the summer and fall. Nine species of mesopelagic fishes are here recorded from the Gulf for the first time.