Smooth Skate (Funk Island Deep Population)

Malacoraja senta

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

Smooth Skate (Malacoraja senta) belongs to the Class Chondrichthyes, which includes all shark and skate species. This species is one of the smallest skates in the Northwest Atlantic Ocean, growing up to 66 cm in length and weighing up to 1.2 kg. This species is distinguished from other skates in Canadian waters primarily by the combination of its long tail (equal in length to its body length) and 2 “triangles” of thin, opaque cartilage on its snout. Smooth Skate less than 1 year old (Young-of-the-Year or YOY skates) can be distinguished from other young Northwest Atlantic skates by 1–4 irregular pale “crossbars” or “half-bars” on its tail.

Habitat

Smooth Skate distribution

Approximate boundary of Funk Island Deep population, as adapted from COSEWIC 2012.

Map depicting approximate boundaries of the Funk Island Deep population of Smooth Skate around the northeast part of Newfoundland and Labrador on the Northeast Newfoundland Shelf and off southern Labrador. This map was adapted from the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) 2012 assessment and status report on the Smooth Skate (Malacoraja senta) in Canada.

Smooth Skate is native to the continental shelf off of North America — the only location in the world where this species lives. It is found from southern Georges Bank (south of Cape Cod) north to the Labrador Shelf (Hopedale Channel). Smooth Skate are not continuously distributed throughout their range and are considered to form four populations that are geographically isolated based on water temperature, depth, and other factors that are not yet understood. The Funk Island Deep population is found around the northeast part of Newfoundland and Labrador on the Northeast Newfoundland Shelf and off southern Labrador.

Smooth Skate usually live at depths between 70 and 480 m and in water temperatures of 2.7–10 °C. Densest concentrations of Smooth Skate occur in troughs surrounding shallower banks, where seawater is warmer. They are found mostly on soft mud (silt and clay), but also on sand, broken shells, gravel, and pebbles. This species is very selective in its diet, eating primarily small bottom-dwelling invertebrates (shrimp, euphausiids, mysids, amphipods, or “sea lice”) throughout most of its life; though, larger Smooth Skate also eat small groundfish.

Threats

COSEWIC identified the following main threats to the Funk Island Deep population of Smooth Skate in Canada:

  • Temperature – The Funk Island Deep population is most likely at the coldest thermal fringe of its distribution, and as a result, survival could be affected when temperature is lower than normal.
  • Fishery bycatch – There are no directed fisheries for any Smooth Skate population, but Smooth Skate are taken as bycatch in fisheries targeting other groundfish species. Even though bycatches have been declining since the early 1980s, the population has continued to decline even in areas with low trawling intensity.

Further Information

The minimum abundance estimate for the Funk Island Deep population of Smooth Skate (average 2008–2010) for all sizes is 1.1 million, 29% (0.3 million) of which are considered mature. This represents only 20% of past numbers; the average abundance estimate for mature and immature individuals at the peak in 1978–1980 was 5.3 million fish.

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

Smooth Skate (Funk Island Deep Population)

Smooth Skate

Illustration of a Smooth Skate viewed from its side. It is a flattened fish with a disc-shaped body. This species is distinguished from other skates in Canadian waters primarily by the combination of its long tail (equal in length to its body length) and 2 “triangles” of thin, opaque cartilage on its snout. Smooth Skate less than 1 year old can be distinguished from other young Northwest Atlantic skates by 1–4 irregular pale “crossbars” or “half-bars” on its tail. There is a group of 3–15 small orbital thorns in front of and around each eye, 2–4 shoulder thorns (except 1 per shoulder on skates <1 year old), and a single midline row of 22–32 small thorns that decrease in size from the neck area to the base of its tail (where midline thorns become “invisible” in size among numerous tail spines).

Scientific name: Malacoraja senta
SARA Status: No Status
COSEWIC Status: Endangered (May 2012)
Region: Newfoundland and Labrador

Did You Know?

Smooth Skate reproduce by laying an embryo in a hard-shelled egg case (“Mermaid's purse”) on the bottom of the ocean and each female produces 40–100 large egg cases per year. The skate embryo develops for 1–2 years inside the egg case and hatches as a fully formed juvenile of 7–10 cm in length. Little is known about predators of Smooth Skate, but the embryo developing inside an egg case has sometimes been found eaten by a shell-drilling gastropod, while juveniles and adults may be eaten by marine mammals, other skates, and larger fish. Smooth Skate live at least 15–25 years.

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