Atlantic Whitefish

Coregonus huntsmani

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

The Atlantic Whitefish (Coregonus huntsmani) belongs to the salmon and trout family (Salmonidae). It has the following external features:

  • silvery sides, a silvery-to-white belly and a dark blue-to-dark green back;
  • an elongated body and a mouth opening at the end of its snout;
  • dorsal fin and forked tail fin are dusky in colour;
  • adult fish range from 20-25 cm fork length (FL) for lake-residents and average 38 cm FL for anadromous fish; and
  • a small, fleshy fin between the dorsal and tail fins known as an adipose fin, which is typical of members of the salmon and trout family.

Atlantic Whitefish differ from the more common Lake Whitefish by the following features:

Characteristic Atlantic Whitefish Lake Whitefish
Number of lateral line scales 91-100 70-97
Mouth shape Near-terminal (mouth opening is at the end of its snout) Sub-terminal (mouth opening just below the snout).
Well-developed teeth Present Not present
Number of vertebrae 63-64 55-64
Length of pectoral fin ray Footnote 1 Relatively shorter Relatively longer
Size of scales Footnote 2 Relatively smaller Relatively larger

Genetically, the Atlantic Whitefish represents the most ancient representative of the Whitefish species in North America.

Habitat

Unique to Canada, Atlantic Whitefish have been reported only in the Tusket River and Petite Rivière watersheds in southern Nova Scotia. Sadly, the Tusket River population no longer exists. The Petite Rivière population therefore represents the last remaining wild population of Atlantic Whitefish in the world.

The Petite Rivière Atlantic Whitefish population is lake-resident, meaning it completes its lifecycle within freshwater. Its habitat is limited to 3 small interconnected freshwater lakes within the upper Petite Rivière watershed. The lakes are characterized by silt bottoms and rocky shorelines, and their average annual pH is greater than 5.6. The maximum depth in Hebb, Milipsigate and Minamkeak lakes is 17 m, 16 m and 13 m, respectively. Atlantic Whitefish prefer cool water and are rare or absent in surface waters during the summer. During the spring and fall adult Atlantic Whitefish feed on small fish and invertebrates. The habitat preferences of juvenile Atlantic Whitefish are not well understood, but juveniles have been observed in nearshore areas. Controlled laboratory experiments have shown that for all life history stages, low pH decreases the survival of Atlantic Whitefish; and, that Atlantic Whitefish juveniles exhibit growth in water temperatures between 11.7℃ and 24℃, with optimum growth occurring at 16.5℃.

The Tusket River Atlantic Whitefish population was anadromous (meaning it spawns in fresh water, but spends much of its life at sea). Despite the lack of recorded evidence, Atlantic Whitefish in the Petite Rivière also likely occurred as an anadromous population prior to the construction of dams with inadequate fish passage. Anadromous Atlantic Whitefish were believed to inhabit coastal waters during the summer and likely migrated into fresh water for the winter to spawn before returning to the sea in the spring. Spawning times in the wild are unknown, but in captivity, Atlantic Whitefish spawn from mid-November to early January. Anadromous Atlantic Whitefish likely fed on amphipods, small periwinkles and marine worms while at sea.

Threats

Several factors may have contributed to the species’ extirpation in the Tusket River system. The damming of the Tusket River in 1929 interfered with the migratory movement of the Atlantic Whitefish for many years and rising acidity in some portions of the river may have negatively affected their reproductive success. Incidental capture of Atlantic Whitefish in Gaspereau fisheries and poaching in the Tusket River fishways are also believed to have contributed to this decline.

In the Petite Rivière, the construction of dams with inadequate fish passage between the sea and the lakes may have caused the demise of the anadromous population in the area. Past fishing activities, including bycatch in Gaspereau fisheries and directed angling, may also have been contributing factors. Currently, interactions with illegally introduced invasive fish species, Smallmouth Bass and Chain Pickerel, pose a significant threat to the survival of this last remaining population of Atlantic Whitefish.

Further Information

Atlantic Whitefish were listed as Endangered under the federal Species at Risk Act (SARA) in 2003. Atlantic Whitefish are protected under SARA and the federal Fisheries Act. The Maritime Provinces Fishery Regulations under the federal Fisheries Act have prohibited the possession and retention of Atlantic Whitefish since 1993.

The Atlantic Whitefish and its habitat are also protected by provincial legislation, including the Nova Scotia Endangered Species Act and the Nova Scotia Environment Act. Minamkeak, Milipsigate and Hebb Lakes form the water supply for the town of Bridgewater and as such have received environmental protection as a designated Watershed Protected Water Area under the Environment Act since 2006.

Fisheries and Oceans Canada published a Recovery Strategy for Atlantic Whitefish in 2007. An amended Recovery Strategy and an Action Plan were posted as proposed to the Species at Risk Public Registry in 2016 and a Report on the progress of Recovery Strategy implementation for the period 2007-2012 was published in 2016. The goal of the Atlantic Whitefish Recovery Strategy is to achieve stability in the current population of Atlantic Whitefish in Nova Scotia, re-establish the anadromous form and expand the population beyond its current range.

DFO and its partners have undertaken a variety of recovery actions to date to support survival and recovery of Atlantic Whitefish. Management measures to restrict recreational angling targeting other species have been put in place on the Petite Rivière to avoid interactions with Atlantic Whitefish. As well, the 3 Petite Rivière lakes have been identified as critical habitat for Atlantic Whitefish in the Proposed Recovery Strategy. DFO developed and documented an Atlantic Whitefish culture methodology and captive-reared Atlantic Whitefish were released into Anderson Lake, Nova Scotia to evaluate the feasibility of using captive-reared fish to establish a new population outside of the Petite Rivière system. Since 2004, the Bluenose Coastal Action Foundation has collaborated with DFO on the Atlantic Whitefish Recovery Project to raise awareness about Atlantic Whitefish and to undertake various monitoring and stewardship activities. In 2011-2012, a fishway at Hebb Lake Dam was built by the Bridgewater Public Service Commission to facilitate fish passage and it is monitored by the Bluenose Coastal Action Foundation. In 2014, a 3-year boat-based electrofishing program in the Petite Rivière lakes was implemented in collaboration with the Nova Scotia Department of Fisheries and Aquaculture, Inland Fisheries Division to evaluate the potential to reduce the abundance of invasive species in Atlantic Whitefish habitat and to estimate the population size of invasive species.

For more information on Atlantic Whitefish and to view the recovery documents, visit the Species at Risk Public Registry.

Atlantic Whitefish

Atlantic Whitefish. Photo credit: Bob Semple

Atlantic Whitefish. Photo credit: Bob Semple

Scientific name: Coregonus huntsmani
Taxonomy: Fishes (freshwater)
SARA Status: Endangered (2003)
COSEWIC Status: Endangered (1984, 2000, 2006, 2010)
Region: Nova Scotia

Map showing the present and historical Canadian watershed distribution of Atlantic Whitefish.

Map showing the present and historical Canadian watershed distribution of Atlantic Whitefish.

Atlantic Whitefish. Photo credit: John Whitelaw, DFO

Atlantic Whitefish. Photo credit: John Whitelaw, DFO

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