Scientific name.......Squalus Acanthias
Common names..........Piked dogfish or Spiny dogfish
The Piked dogfish is also known as the Spiny dogfish. It is
identified by a large spiracle behind each large eye, the presence
of mildly poisonous spines on the two dorsal fins, and the lack of
an anal fin. They have a narrow head, relatively a long, pointed
snout and no medial barbel on anterior nasal flaps. Pectoral fins
with shallowly concave posterior margins and narrowly rounded rear
tips. First dorsal fin low, origin usually behind or sometimes over
pectoral free rear tips, first dorsal spine slender and very short
with origin well behind pectoral free rear tips.
The average size of the piked dogfish is 4 to 5.2 feet. Size at
birth is approximately 7.2 to 12 inches. Males mature at 3.2 feet
and females at 3.9 feet.
The upper and lower teeth are small, and similar in shape with
oblique points bent toward the outer corners of the mouth. The cusps
are deeply notched outward with a single sharp point. These form a
nearly continuous cutting edge from one corner of the mouth to the
other. There are 28 upper teeth and 22-24 lower teeth in the jaws of
the piked dogfish.
Their body is gray to a bluish-gray above, lighter to white below,
often with white spots on sides; pectoral fins with light posterior
margins in adults. dorsal fin tips and edges dusky or plain in
adults, with black apices and white posterior margins and free rear
tips in young; no conspicuous black blotches on fins.
Their diet includes small fishes, such as cod, herring, menhaden,
and haddock, as well as invertebrates such as krill, squid,
scallops, and crustaceans.
Mainly demersal ( occurring or living near or on the bottom of the
ocean ), apparently also epipelagic, sometimes solitary or schooling
with other small sharks, often forming immense dense feeding
aggregation on rich feeding grounds. Segregates by size and sex into
packs or schools of small juveniles ( both sexes ), mature males,
larger immature females, or large mature females (often pregnant).
Mixed adult schools occasionally reported.
Almost world-wide, except tropics and near poles. Little or no
mixing between northern and southern hemisphere populations and
limited genetic mixing between some stocks with overlapping range
and feeding grounds but different migration patterns. Boreal to
warm-temperate continental and insular shelves, occasionally slopes
from surface to 1,968 feet and possibly as deep as 4,744 feet.
Epipelagic from surface to 565 feet in cold water. Usually near
bottom on continental shelf, near surface in oceanic waters. Often
on soft sediments in enclosed and open bays and estuaries, where
most nursery grounds occur.
This species is extremely slow growing and can live for up to 70 -
100 years, varies between populations.
Females reach sexual maturity when 21 to 25 years old. They are
ovoviviparous, with a litter size from ( 1 to 30 ) varies regionally
and larger females have more and larger pups. Gestation period
varies regionally, from 18 to 24 months, to only 12 months in the
Black Sea ( where largest females pups and litters occur ).This
species is thought to have the longest gestation period of the
elasmobranches. The young are born head-first with cartilaginous
sheaths on the spines to protect the mother from injury.
Slow swimmers but undertakes long distances.
Harmless, not dangerous to man except through lacerations from the
mildly toxic dorsal spines.
Common, but stocks are nearly depleted in many areas. Near
threatened globally ( endangered northeast Atlantic, Vulnerable
northwest Atlantic ). Extremely well-studied. Possibly once the most
abundant shark and the most important commercial species, utilised
for meat ( high value in Europe ), liver oil and fins and supporting
large target trawl and line fisheries comparable to those for bony
fishes. Its slow growth, late maturity, longevity and low
reproductive capacity make it highly vulnerable to overfishing,
particularly since aggregations of large pregnant females are
usually targeted. Few fisheries are managed, some stocks are now
very seriously depleted or collapsed and catches declining steeply.
Also of commercial fisheries significance because large numbers may
damage fishing gear and affect catches of other species. Targeted by
sports anglers in some regions, displayed in public aquaria, and
important for scientific research and teaching.