Rough Sagre

or Great Lanternshark

Etmopterus princeps




The rough sagre is a slender and small deep water shark. Both dorsal fins have an associated spine at their origin. This shark is of uniform colour being black or brownish black. The teeth on the upper jaw have 5 smooth edged cusps while the lower teeth have a single oblique cusp. Early reports suggested that it possessed photophores (light producing organs), and thus referred to it as the lantern shark. However, later reports suggest that it is not luminescent.



The rough sagre occurs in both the western and eastern North Atlantic. In the western North Atlantic it is present off southern Nova Scotia to southern New England. It is common throughout this range.



This is a deep dwelling animal that is often found at depths between 570 and 2200 meters (1870 to 7300 feet). A report of a capture on the Scotian Shelf was at a depth of 950 meters (3100 feet).


Life History

It grows to a maximum size of approximately 75 cm (30 in). Average size is about 55 cm (22 in).



The diet of this shark is unknown.



Little is known about reproduction in this shark although development is assumed to be ovoviviparous. A 55 cm male specimen was reported as being mature.


Interaction with People

Since this is a deep dwelling species it usually has no interactions with humans except when accidentally caught while deep-sea fishing.


Distinguishing Characteristics

  • Uncertain if it has luminescent photophores
  • No anal fin
  • Dorsal fin spines
  • Thorn-like, nearly erect dermal denticles
  • Upper teeth with 5 cusps, lower teeth oblique with single cusp