Commercial fishery landings of the black scabbardfish, Aphanopus carbo, from the Madeira mid-water drifting longline fleet (northeastern Atlantic) were studied for 2 years within a Portuguese government programme for fishing management. The process noted that 20% of the total catch corresponded to the intermediate scabbardfish, Aphanopus intermedius. Length-frequency distribution, and age, growth and reproduction of both species were analysed and compared. The results revealed significant differences in age and growth in influencing the length-frequency distributions. Intermediate scabbardfish attained the largest size (148 cm TL) and age (15 years). However, the two species had similar reproductive strategies. According to data published on A. carbo in this region, it is thought to be very likely that previous studies unintentionally mixed both species together in their analyses.