(DRAFT) - Taxonomy
Species dogfish, spiny
Species Id M010700
Date 27 AUG 96
TAXONOMY
NAME - dogfish, spiny
OTHER COMMON NAMES - spiny dogfish, dogfish, grayfish, piked dogfish, spurdog and Fr. aiguillat commun.
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - Chordata, Vertebrata
CLASS AND SUBCLASS - Elasmobranchiomorphi,
ORDER AND SUBORDER - Squaliformes,
FAMILY AND SUBFAMILY - Squalidae,
GENUS AND SUBGENUS - Squalus,
SPECIES AND SSP - acanthias,
SCIENTIFIC NAME - Squalus acanthias
AUTHORITY - Linnaeus, 1758
TAXONOMY REFERENCES - 258 and 1717
COMMENTS ON TAXONOMY -
A large family of small to very large, mostly bottom-living sharks occurring
literally in all the world's oceans from the Arctic to the Antarctic. They
occur from shallows to depths of 3675 m; shallower in cool temperate waters
but well offshore in the tropics.*258*
Taxonomy - 1 (DRAFT) - Status
Species dogfish, spiny
Species Id M010700
Date 27 AUG 96
STATUS
Coded Status
Commercial
Commercial/consumption
Commercial/industrial
See Comments
REFERENCES FOR STATUS - 258
COMMENTS ON STATUS -
The spiny dogfish has always been regarded by commercial fishermen as a
nuisance rather than an asset. When abundant they cause loss of gear and
loss of fishing time for other species. They destroy both fish and nets set
for herring, Atlantic salmon and mackerel; and have caused cessation of
longline fishing for cod and haddock by taking baits and rendering gear
useless for other species. However, in Europe they are widely used as food,
being headed, gutted, and skinned and sold as rock cod or rock salmon
(England). The dogfish was also widely used in the English fish-and-chip
market. In the eastern Atlantic they are fished commercially by otter trawl
and by longlines.
Periodic attempts have been made in eastern North America to promote
domestic consumption of dogfish with limited success. Elsewhere in the
world it is used fresh, frozen, smoked, and salted, and processed for liver,
oil, fish meal, pet food, fertilizer, and leather.
The dogfish is regularly used as a preserved specimen for laboratory
dissection in universities throughout North America. Because of this use,
its abundance, and its negative effect on commercial fisheries, an abundant
literature exists. It is probably the most written-about shark in the
world.
Limited commercial exploitation of dogfish for export seems probable at
some future date. Because of its slow growth, relatively low reproductive
capacity, long gestation period, and ease of capture, a management plan
would be essential to avoid overfishing and loss of stocks. There is
growing concern among fishermen and biologists alike that the recent
increase in abundance and maximum size of dogfish will result in increased
predation on commercial species.*258*
Status - 1 (DRAFT) - Distribution
Species dogfish, spiny
Species Id M010700
Date 27 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
Habitat Associations - 1 (DRAFT) - Food Habits
Species dogfish, spiny
Species Id M010700
Date 27 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
OTHER
REFERENCES FOR TROPHIC LEVEL - 258
LIFESTAGE FOOD FOOD PART
General Algae Not Specified
General Scyphozoans Not Specified
General Fish Not Specified
Food Habits - 1 (DRAFT) - Environment Associations
Species dogfish, spiny
Species Id M010700
Date 27 AUG 96
ENVIRONMENTAL ASSOCIATIONS
Environment Associations - 1 (DRAFT) - Life History
Species dogfish, spiny
Species Id M010700
Date 27 AUG 96
LIFE HISTORY
Description: Body slender, elongate, lateral keels on caudal peduncle,
upper precaudal pit present. Head slightly flattened; snout long, pointed;
mouth moderate; teeth small, similar in both jaws, cusps directed outwards
producing an almost continuous upper and lower cutting edge; eye oval, about
midway between tip of snout and first gill slits; gill slits small. Fins:
well developed; dorsals, 2, each preceded by a short, sharp heavy spine,
first dorsal spine one-half or less length of dorsal base, second dorsal
smaller than first but spine larger, origin or fin behind pelvics; caudal
asymmetrical, upper lobe large, no subterminal notch, ventral lobe well
developed; anal absent; pelvics moderate, bases closer to second dorsal than
first; pectorals narrow, rather long, posterior margins slightly concave.
The skin is covered with fine dermal denticles, giving a sandpaper effect.
Vertebrae 107-116. Size small, average about 70-100 cm TL. Color slaty
gray to white below; irregularly arranged small white spots on back and
sides from above pectorals to beginning of second dorsal.*258*
Reproduction: An ovoviviparous species and, as for all sharks, fertilization
is internal. The egg is large, up to 45 mm in diameter, and contains much
yolk. After fertilization and the descent of the eggs down the oviduct, the
eggs are enclosed in a capsule, 1-6 per capsule. The capsule persists for a
few months before breaking down to leave the embryos free to continue
development in the oviduct. The embryos have no placental attachment to the
female. The gestation period is long, about 22 mo, one the longest for any
vertebrate animal. The number of living young born by a female varies with
the size of the female, larger females having more young. Litter sizes
ranged from 2 to 15 embryos, with an average of 6.6 every 2 yr. The young
are born during cool winter months in the offshore waters of the
northeastern United States. Mating and fertilization occur following the
birth of the young.*258*
Growth: The spiny dogfish is slow-growing and long-lived. The young are
born when about 25-30 cm long. Males are sometimes said to mature at a
length of 78 cm and at age 11 yr, females at 92 cm and an age of 18-21 yr.
However, in a study of 1685 individuals taken off northeastern United
States, median lengths and ages at maturity for males was 59.5 cm and 6 yr,
and for females 79.9 cm and 12.1 yr. Growth rate probably decreases after
sexual maturity is attained. Males attain a maximum length of 120 cm and a
weight of 7 kg. Dogfish smaller than 60 cm are uncommon in Canadian
Atlantic waters.
Variability in age and growth may occur over time. Recent studies suggest
an increase in the number of large females over 100 cm, when compared with
another study, an increase in the average fecundity and thus an increase in
the amount of juveniles, and an overall increase in population abundance.
Ages can be determined by counting growth lines on the second dorsal spine
or by sectioning the spine.*258*
REFERENCES FOR LIFE HISTORY- 258
Life History - 1 (DRAFT) - Management Practices
Species dogfish, spiny
Species Id M010700
Date 27 AUG 96
MANAGEMENT PRACTICES
Management Practices - 1 (DRAFT) - References
Species dogfish, spiny
Species Id M010700
Date 27 AUG 96
References
258 * Scott, W.B., M.G. Scott. 1988. Atlantic Fishes of Canada.
Canadian Bulletin of Fisheries and Aquatic Sciences (219) (ed.).
University of Toronto Press Toronto, Canada:731.
References - 1