Growth and seasonal variations in distribution of Chauliodus sloani and C. danae (Pisces) from the mid North Atlantic

In the mid North Atlantic Chauliodus sloani is caught mainly between 55° and 29° N, while the majority is caught north of 35° N. The greatest density is found around 40° N. Chauliodus danae has the northern limit of its distribution at about 45° N. C. danae, in particular the smaller specimens, shows clear vertical migration and has food preference, while C. sloani does not show such migration and is most probably a random feeder. In both species there is a significant increase in length from south to north. From the analysis of growth features in the otoliths it is demonstrated that C. danae grows relatively faster than C. sloani, though it reaches a smaller maximum length. C. sloani attains a greater maximum length and a higher age. Together with some anatomical differences, these are indications that the relation between both species is less close than usually supposed.