Published online by Cambridge University Press: 05 March 2009
This is the first work describing some biological aspects of the arrowhead dogfish, Deania profundorum. The specimens were captured in two surveys (2004–2005) between 151 and 1200 m off the Madeira archipelago (north-east Atlantic Ocean). A total of 351 females (36–110 cm) and 169 males (27–94 cm) were sampled. The smallest (27 cm) and the biggest (110 cm) specimens ever caught were recorded. Females were most abundant in the overall depths, apart from the middle range of 451–1050 m where the sex-ratio was 1:1. A vertical stratification by size occurred, since all the juveniles less than 40 cm length were caught deeper than 950 m. This species was sexually dimorphic with females growing to larger sizes than males and being larger at first maturity. All stages of maturity were found during the sampling period. Nineteen gravid females with six to 11 embryos (9–18 cm length) were found. The data obtained indicate that the Madeira slopes are a nursery and reproductive area for D. profundorum.