Roundnose Grenadier

Coryphaenoides rupestris

SARA Status
No Status
NS
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

SARA Status

  • No Status NS
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX
COSEWIC Status
Not at Risk
NR
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

COSEWIC Status

  • Not at Risk NR
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX

Description

Roundnose Grenadier (Coryphaenoides rupestris) is a deepwater, marine fish. It belongs to the family Macrouridae, a family commonly referred to as “rattails”. It has the following characteristics:

  • Body is short and slightly compressed, with a long, tapering, pointed tail;
  • Broad, compressed head with a soft, rounded snout;
  • Small barbel on chin, and a button-shaped plate on the tip of its snout;
  • Medium brown to grey in colour, with brownish-grey to black fins and mouth;
  • Can grow to 110 cm in length and weigh 1.7 kg; and
  • Can live to at least 72 years of age.

Habitat

Roundnose Grenadier is found on the continental slopes and the mid-Atlantic ridge of the North Atlantic Ocean. In the west, its range extends northwards from Cape Hatteras to Baffin Island and Greenland. In the east, its range extends from North Africa to Norway. In Canadian waters, this species is most abundant from Davis Strait, on the continental slope off of Newfoundland and Labrador, and along the edge of the Grand Banks to Georges Bank. It is sometimes captured on the Scotian Shelf.

Roundnose Grenadier is a deepwater fish that forms large schools. It is most abundant at depths of 400–1,200 m and has been reported as deep as 2,600 m. It prefers habitat with little or no current and water temperatures of 3.5–4.5 °C. Owing to its preference for deep waters, life stages of the Roundnose Grenadier are not well understood. Exact timing of spawning is unknown and may occur throughout the year. The eggs are round, 2.4 mm in diameter, free-floating, and are fertilized externally during a spawning event (known as “batch” spawning). This species has a low fecundity, a slow growth rate, and is late to mature. Females mature at about 10 years of age. Despite being very slow swimmers, Roundnose Grenadiers undergo seasonal migrations (possibly following preferred water temperatures or prey), as well as daily vertical migrations of more than 1,000 m off of the ocean floor (to feed on shrimp, shrimp-like crustaceans, squids, and small fish).

Threats

Fishing is the principal threat to Roundnose Grenadier. In the late 1950s–1960s, Roundnose Grenadier was harvested commercially through a targeted fishery. Directed fishing of Roundnose Grenadier has been under moratorium in North Atlantic Fisheries Organization Subareas 0, 2, and 3 since 1997. However, Roundnose Grenadier can be a significant bycatch in deepwater fisheries such as those targeting Greenland Halibut (Reinhardtius hippoglossoides). Outside of Canadian waters, the Roundnose Grenadier fishery is not regulated, with the exception of net mesh size. To date, there are no signs of population recovery for Roundnose Grenadier in Canadian waters.

Roundnose Grenadier populations are very susceptible to mortality caused by humans, because of their life-history characteristics (long lifespan, slow growth rates, late maturity and low fecundity) that limit this species' recovery after a disturbance.

Further Information

For more information, visit the Species at Risk (SARA) Public Registry Profile.

Text Sources:

COSEWIC. 2008. COSEWIC assessment and status report on the Roundnose Grenadier
Coryphaenoides rupestris in Canada.
Committee on the Status of Endangered Wildlife in Canada.
Ottawa. vii + 42 pp.

Roundnose Grenadier

Illustration of a Roundnose Grenadier

Illustration of a Roundnose Grenadier viewed from the side.
(Illustration: Gary Taylor)

The Roundnose Grenadier is medium brown to grey in colour and its fins and mouth are brownish-grey to black. The body is short, slightly compressed and tapers evenly to a sharp pointed tail. It has a fairly short and compressed head (comprising approximately 15% of its body length) and has a soft, rounded snout. There is a small barbel (whisker-like appendage) on the chin.

Scientific name: Coryphaenoides rupestris
SARA status: No Status
COSEWIC status: Endangered
Regions: Newfoundland and Labrador, Nunavut, and Nova Scotia

Did You Know?

Common names for the Roundnose Grenadier include Rattail, Rock Grenadier, Blunt-snouted Grenadier, and Black Grenadier. It is distinguished from other grenadiers in the North Atlantic by its soft, rounded snout and short, compressed head. Like many deepwater species, young grenadiers feed mainly on small crustaceans (amphipods, copepods) and gradually switch to eating fish and shrimp as they grow in length. Female Roundnose Grenadiers grow larger and heavier than males, and this species can live to at least 72 years of age.

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