(DRAFT) - Taxonomy
Species grenadier, rock
Species Id M010120
Date 27 AUG 96

TAXONOMY

NAME - grenadier, rock

OTHER COMMON NAMES - Roundnose grenadier, Rattail and Fr: grenadier de roche

ELEMENT CODE -

CATEGORY - Fish

PHYLUM AND SUBPHYLUM - ,

CLASS AND SUBCLASS - Osteichthyes,

ORDER AND SUBORDER - Gadiformes,

FAMILY AND SUBFAMILY - Macrouridae,

GENUS AND SUBGENUS - Coryphaenoides,

SPECIES AND SSP - rupestris,

SCIENTIFIC NAME - Coryphaenoides rupestris

AUTHORITY - Gunnerus, 1765

TAXONOMY REFERENCES - 258

COMMENTS ON TAXONOMY -
The rock grenadier is placed in the genus Macrurus by Andriashev (1954)
*258*.

Taxonomy - 1 (DRAFT) - Status
Species grenadier, rock
Species Id M010120
Date 27 AUG 96

STATUS

Coded Status
See Comments
Migrant

REFERENCES FOR STATUS - 258

COMMENTS ON STATUS -
The rock grenadier undertakes diurnal vertical feeding migrations, evidenced
by pelagic food organisms found in stomachs and by catches during midwater
trawling *258*.

When the grenadiers have reached 40-50 cm in length, they begin their return
migration *258*.

There is no directed fishery for rock grenadier by Canadian fleets. In the
northwest Atlantic off the Newfoundland coasts and in Davis Strait a
directed commercial fishery operated by foreign fleets (mainly the USSR) has
been in existence since 1967, when catches were first reported to ICNAF.
Catches fluctuated in NAFO (previously ICNAF) subareas 1-5 from 38,000 t in
1968 to an estimated 4000 t in 1982 (with the exception of the 1971 catch of
83,000 t). The steady decline has reduced the fishery to a by-catch level
in the Greenland halibut fishery. The population in Canadian waters was
recognized as one stock. The liver is said to be rich in fats and vitamins
*258*.

Status - 1 (DRAFT) - Distribution
Species grenadier, rock
Species Id M010120
Date 27 AUG 96

DISTRIBUTION

Distribution - 1 HABITAT ASSOCIATIONS

HABITAT - MARINE

REFERENCES FOR HABITAT - 258

LAND USE -
Water

REFERENCES FOR LAND USE - 258

COMMENTS ON HABITAT ASSOCIATIONS -
The rock grenadier is an inhabitant of deep waters mainly of continental
slopes and shelves in the North Atlantic; some live in great depths. In
the northwest Atlantic it is commonly found in depths of 400-1000 m; in
other regions of the North Atlantic it is reported from depths of 350-2500
m and possibly deeper. Off northern Newfoundland and Labrador greatest
concentrations were found at depths greater than 503 m, where bottom
temperature was in the range 3.5-4.5 oC. The rock grenadier undertakes
diurnal vertical feeding migrations, evidenced by pelagic food organisms
found in stomachs and by catches during midwater trawling. Horizontal
movements along the continental slope were assumed to be less than 161 km
*252*.

ANIMAL/PLANT SPECIES ASSOCIATIONS -
Whale
Halibut (Reinhardtius hippoglossoides)
Redfish
Myxosporidians - 5 sp.
Monogenean - 1 sp.
Cestodes - 3 sp.
Trematodes - 5 sp.
Nematodes - 3 sp.
Crustaceans - 2 sp.
Trematode (Dolichoenterum sp.)
Trematode (Conocerca crassa)

REFERENCES FOR SPECIES ASSOCIATIONS - 258

COMMENTS ON SPECIES ASSOCIATIONS -
Predation and Competiton: Considered a slow swimmer, the rock grenadier may
be prey of many other fishes. Rock grenadier have been found in the
stomachs of whales. At times Greenland halibut, Reinhardtius
hippoglossoides, feed heavily on them, and young fish are eaten by redfish
and other species *258*.

Parasites and disease: The rock grenadier is host to a wide variety of
parasites infesting pelagic and benthic animals, which are often
intermediate hosts in the cycle of development of the parasite. The
incidence of larval helminths in rock grenadier studied from Norwegian
waters also indicated that this fish acts as an intermediate host of
parasites infecting its predators *258*.

Eighteen species of parasites, including myxosporidians (5), monogenean (1),
cestodes (3), trematodes (5), nematodes (3), and crustaceans (2), were
recorded from the rock grenadier in the Davis Strait, Labrador and N Grand
Bank areas of the northwest Atlantic *258*.

Two additional trematodes, Dolichoenterum sp. and Gonocerca crassa, from the
species in Labrador waters were noted *258*.
Habitat Associations - 1 (DRAFT) - Food Habits
Species grenadier, rock
Species Id M010120
Date 27 AUG 96

FOOD HABITS

TROPHIC LEVEL -
CARNIVORE

REFERENCES FOR TROPHIC LEVEL - 258

LIFESTAGE FOOD FOOD PART
General Crustaceans Not Specified
General Squid, Octopus Not Specified
General Osteichthyes Not Specified
General Perciformes Not Specified
General Myctophiformes Not Specified
General Salmoniformes Not Specified

REFERENCES FOR GENERAL FOOD - 258

COMMENTS ON FOOD -
The rock grenadier feeds on a great variety of small crustaceans and
eupausiids, squid, and small fishes including myctophids, bathylagids, and
cottids. Composition of food organisms varied somewhat in different
localities; in the northwest Atlantic crustaceasn (mainly amphipods and
mysids) were eaten in northern areas; on the northeastern slope of the Grand
Bank myctophids were the main component in the stomachs of the few specimens
examined. The species is reported to make significant vertical migrations
from the bottom to feed as indicated by midwater trawl catches in the
commercial fishery. Capture of specimens (at average depth of 480 m off
bottom) during midwater trawling in Icelandic waters by the research vessel
Walther Herwig indicated that the species fed on pelagic animals and moved
off the bottom to feed. The incidence of various parasites infesting the
rock grenadier also suggested both pelagic and benthic feeding behavior
*258*..

Feeding is seasonal, the major consumption being during autumn-winter,
diminishing in intensity in summer months *258*.

Food Habits - 1 (DRAFT) - Environment Associations
Species grenadier, rock
Species Id M010120
Date 27 AUG 96

ENVIRONMENTAL ASSOCIATIONS

G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae

LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Water Depth Preference: 1000-1500 ft.
G Water Depth Preference: Greater than 1500 ft.
G Water Depth Preference: Specified in Comments
G Water Temperature: Below 15 degrees C
G Water Temperature: Specified in Comments
BA Water Depth Preference: Greater than 1500 ft.
BA Water Depth Preference: Specified in Comments

REFERENCES FOR ENVIRONMENTAL ASSOC_ - 258

REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 258

COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
The rock grenadier is an inhabitant of deep waters mainly of continental
slopes and shelves in the North Atlantic; some live in great depths. In
the northwest Atlantic it is commonly found in depths of 400-1000 m; in
other regions of the North Atlantic it is reported from depths of 350-2500
m and possibly deeper. Off northern Newfoundland and Labrador greatest
concentrations were found at depths greater than 503 m, where bottom
temperature was in the range 3.5-4.5 oC. The rock grenadier undertakes
diurnal vertical feeding migrations, evidenced by pelagic food organisms
found in stomachs and by catches during midwater trawling. Horizontal
movements along the continental slope were assumed to be less than 161 km
*252*.

COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
Main spawning grounds were assumed to be deeper than 850 m *258*.

Environment Associations - 1 (DRAFT) - Life History
Species grenadier, rock
Species Id M010120
Date 27 AUG 96

LIFE HISTORY

Reproduction: Spawning grounds have not been established. It has been
proposed by various authors that spawning occurs in Icelandic waters. The
eggs and larvae are carried passively by the Irminger Current to waters
south of Greenland, by the West Greenland Current to Baffin Island area, and
in the Polar and Labrador currents to waters off Labrador and eastern
Newfoundland. When the grenadiers have reached 40-50 cm in length, they
begin their return migration. Main spawning grounds were assumed to be
deeper than 850 m *258*.

Information on time of spawning is sparse. In northern seas of the USSR it
was suggested rock grenadiers spawned in late autumn. Spawning males and
postspawning females were taken in a trawl from depths of 580-850 m
northwest of Rockall Bank at the end of October 1968 and individuals off
Iceland were in prespawning condition in May and had completed spawning by
August. It was concluded that the species was a spring and autumn spawner.
A study felt that they spawned intermittently throughout the year in waters
off Iceland. It noted that juveniles, about 80 mm long, were encountered
along the continental slope of North America from the Grand Bank area to the
Cumberland Peninsula, and also off west Greenland and south of Iceland
*258*.

A study concluded the rock grenadier is not viviparous and that eggs are
fertilized at the time of spawning. Observations on incubated eggs revealed
that they are free-floating, spherical, 2.3-2.4 mm in diameter, with a
honeycomb pattern and celled membrane, and contain a single oil globule. A
female may produce up to 16,000 eggs *258*.

The study also noted that eggs of macrourids are 1-2 mm in diameter, and
that in ripe ovaries small, medium, and large eggs are found together *258*.

Growth: Little is known of development and rate of growth in the northwest
Atlantic. The commercial fishery off Newfoundland and Labrador captured
concentrations of the rock grenadier in 500-1000 m depths during feeding
migrations. The fish were 60-70 cm in length, 9-14 yr old, and weighed
0.4-0.8 kg. All were sexually immature. Exploratory fishing has shown that
the percentage of mature fish increases with depth. Young stages, 36-54 mm
in length, were reported off the Norwegian coast and south off Iceland. The
species is slow-growing, late in maturing, and long-lived. Females are
considered to be faster-growing and larger than males. Aging techniques
using scales or otoliths may be underestimating the age of rock grenadiers
*258*.

Description: Body elongate, rounded anteriorly, strongly compressed
posteriorly, tapering gradually from origin of first dorsal to tip of body.
Head large, compressed, ridges without scaly armature; snout very blunt,
projecting beyond mouth, upper profile convex; mouth inferior, almost
terminal, upper jaw longer than lower, small barbel on lower jaw; teeth
villiform in both jaws, outer series in upper jaw enlarged; eye large,
ovate. Gill rakers 9. Branchiostegals 6. Fins: dorsals, 2, first of 10-13
rays, second ray spine-like, leading edge serrated; second dorsal of 103-183
soft rays; caudal absent; anal 104-193 soft rays; pelvics 7 or 8, first ray
Life History - 1 (DRAFT) - Life History
Species grenadier, rock
Species Id M010120
Date 27 AUG 96

much produced; pectorals 16-19. Scales small, stenoid, with slender,
retrose spinules, covering body and head; small buttonshaped plate with
radiating ridges on point of snout. Lateral line indistinct. Vertebrae
63-79; abdominal vertebrae 11-13 (Coryphaenoides). Size to 100 cm long.
Color: body medium brown; fins deep brownish violet *258*.

Predation and Competiton: Considered a slow swimmer, the rock grenadier may
be prey of many other fishes. Rock grenadier have been found in the
stomachs of whales. At times Greenland halibut, Reinhardtius
hippoglossoides, feed heavily on them, and young fish are eaten by redfish
and other species *258*.

Two additional trematodes, Dolichoenterum sp. and Gonocerca crassa, from the
species in Labrador waters were noted *258*.

Feeding is seasonal, the major comsumption being during autumn-winter,
diminishing in intensity in summer months *258*.

LIFE HISTORY CODES -
Breeding/Spawning Season: June
Breeding/Spawning Season: July
Breeding/Spawning Season: August
Breeding/Spawning Season: September
Breeding/Spawning Season: October
Average Number of Offspring/Reproductive Effort: Grea
Periodicity: Most active in fall
Periodicity: Most active in winter

REFERENCES FOR LIFE HISTORY- 258

Life History - 2 (DRAFT) - Management Practices
Species grenadier, rock
Species Id M010120
Date 27 AUG 96

MANAGEMENT PRACTICES

Management Practices - 1 (DRAFT) - References
Species grenadier, rock
Species Id M010120
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