BC Conservation Data Centre: Species Summary
Entosphenus macrostomus
Cowichan Lake Lamprey
| Scientific Name: | Entosphenus macrostomus (Beamish, 1982) | ||||||||||
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| Scientific Name Synonyms: |
Lampetra macrostoma
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| English Name: | Cowichan Lake Lamprey | ||||||||||
| English Name Synonyms: |
Lake Lamprey
Vancouver Island Lake Lamprey Vancouver Lamprey |
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| Classification / Taxonomy | |||||||||||
| Scientific Name - Concept Reference: | Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp. | ||||||||||
| Classification Level: | Species | ||||||||||
| Taxonomy Comments: | April 11, 2013 - Changed from Lampetra macrostoma to Entosphenus macrostomus to align with NatureServe (DDW). There are a number of freshwater populations derived from L. TRIDENTATA along the south coast of British Columbia. At one time one occurred in Elsie Lake near Port Alberni, and a similar parasitic form exists today in Ruby, Hotel and Sakinaw lakes on the Sechelt Peninsula (P91MCP01BCCA, O91UBC01BCCA). There is also a landlocked predaceous lamprey in Village Lake on Quadra Island. In these cases, however, there is no contact with seagoing lamprey so there is no evidence of biological isolation separating them as species. We are tracking only those populations which are separated by biological, rather than physical barriers. |
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| Species Group: | Vertebrate Animal | ||||||||||
| Species Code: | F-ENMA | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G2 (Oct 2019) | ||||||||||
| Provincial Status: | S2 (May 2019) | ||||||||||
| BC List: | Red | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Threatened (Dec 2017) | ||||||||||
| SARA Schedule: | 1 - Threatened (Jun 2003) | ||||||||||
| General Status Canada: | 1 - At Risk (2005) | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Subspecies Comments: | This is a freshwater derivative of the anadromous Pacific lamprey, Lampetra tridentata, and thus belongs to the Lampetra species group that has been placed in the genus Entosphenus by other authors. | ||||||||||
| Identification Comments: | Differs from L. tridentata by its smaller size, larger oral disc, larger eyes, and longer prebranchial length (Beamish 1982). However, the primary differences are ecological and physiological. L. macrostoma spends its entire life within a lake and never enters salt water; L. tridentata, although it spends its larval life in fresh water, migrates to salt water to pass its adult life, re-entering fresh water only to breed. In laboratory studies, postlarval L. macrostoma survived in fresh water while all attempts to maintain L. tridentata were unsuccessful. There are no geographical barriers keeping the species separated, but their spawning seasons may be separated, L. tridentata spawning earlier than L. macrostoma. It is also possible that L. tridentata may spawn exclusively in streams while L. macrostoma spawns in lakes. More studies are needed to determine if this is so (Beamish 1982). | ||||||||||
| Global Reproduction Comments: | Reproductive males and females aggregate at spawning areas in the lake, generally at the mouths of creeks, from May to August. Spawning behavior as observed in the laboratory is similar to that reported for LAMPETRA RICHARDSONI and L. TRIDENTATA. Larval lamprey have been found in the gravel in the lake in the vicinity of creeks and occasionally in creeks, but always close to the lake. They probably remain in the larval stage for six years. They metamorphose into young adults from July to October but probably remain in the gravel until the spring of the following year. Spawning occurs the following year, that is, two years after metamorphosis. Like all lake lamprey, LAMPETRA MACROSTOMA breeds only once (Beamish 1984, 1987, 2001). | ||||||||||
| Provincial Reproduction Comments: | Spawning behaviour as observed in the laboratory is similar to that reported for Lampetra richardsoni and L. tridentata. Larval lamprey have been found in the gravel in the lake in the vicinity of creeks and occasionally in creeks, but always close to the lake. They probably remain in the larval stage for six years then undergo metamorphosis. Spawning occurs two years after metamorphosis. Like all lake lamprey, L. macrostoma breeds only once (Beamish 1987, 2001). | ||||||||||
| Global Ecology Comments: | Coexists well with a large, healthy population of salmonid hosts. No LAMPETRA TRIDENTATA adults or larvae have been found in the same areas as this species. LAMPETRA TRIDENTATA do occur in the river flowing out of Cowichan Lake, but it is not known if they occur in the lake. LAMPETRA MACROSTOMA readily survives and feeds as a young adult in freshwater whereas LAMPETRA TRIDENTATA cannot survive as a young adult in fresh water (Beamish 1984, 1987). | ||||||||||
| Provincial Ecology Comments: | Coexists well with a large, healthy population of salmonid hosts. Lampetra macrostoma is able to survive and feed as a young adult in freshwater (Beamish 1987, 2001). | ||||||||||
| Migration Characteristics: (Global / Provincial) | |||||||||||
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Nonmigrant: Local Migrant: Distant Migrant: Within Borders Migrant: |
Y / Y Y / N N / N na / N |
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| Global Migration Comments: | Migrates between lakes and spawning sites at the mouth of several creeks around the lakes. | ||||||||||
| Provincial Mobility & Migration Comments: | Moves to shallow gravel areas in the lake or to the deltas of tributary streams to spawn. No lamprey have been found in the stream connecting the two lakes, suggesting that they may not move between the lakes (Beamish 1987, 2001). | ||||||||||
| Habitats: (Type / Subtype / Dependence) |
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| Global Habitat Comments: |
This lamprey lives in two oligotrophic freshwater lakes: Cowichan Lake is the larger lake, 152 meters maximum depth, 50.1 meters average depth; Mesachie Lake is considerably smaller, 32 meters maximum depth. No Vancouver lampreys have been found more than a few hundred meters upstream of the lake in the few creeks that have been examined (Beamish 1984, 1987). Ammocoetes burrow in silt, mud, or sand in quiet water (Page and Burr 1991). Spawning has been observed at the mouth of several creeks, where the adults aggregate in shallow, gravel-bottomed areas. Spawning may also occur in deeper water that is not easily examined (Beamish 1984, 1987). |
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| Provincial Habitat Comments: | Lives in two oligotrophic freshwater lakes: one 34 km long with a mean depth of 51 m and a maximum depth of 150 m; the other 7 km long with a surface area of approximately 59 hectares. None have been found more than a few hundred metres upstream of the lake in the few creeks that have been examined (Beamish 1987, 2001). Aggregates and spawns in shallow gravely areas located in the lakes or at the mouths of tributaries. Potential spawning habitat ranged from 20 cm to more than 2 m in depth; however, the full range of depth utilized was not determined as areas more than 15 cm deep were not easily studied (Beamish 1987, 2001). | ||||||||||
| Food Habits: |
Carnivore: Adult, Immature
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| Global Food Habits Comments: | Parasitic on salmonid fishes (Beamish 2001); SALMO CLARKI and young ONCORHYNCHUS KISUTCH are preferred, but others such as SALVELINUS MALMA are also attacked. Up to 50% of the salmonids captured in Mesachie Lake had evidence of lamprey attacks, indicating that this species feeds without killing a high percentage of its hosts. Of 221 salmonids sampled, 15% had wounds penetrating deeply into the body that could cause mortality (Beamish 1984, 1987). | ||||||||||
| Provincial Food Habits Comments: | Parasitic on salmonid fishes (Beamish 1987, 2001); Oncorhynchus clarki and young O. kisutch are preferred, but others such as Salvelinus malma are also attacked. Up to 50% of the salmonids captured in Mesachie Lake had evidence of lamprey attacks, indicating that this species feeds without killing a high percentage of its hosts. Of 221 salmonids sampled, 15% had wounds penetrating deeply into the body that could cause mortality (Beamish 1987, 2001). | ||||||||||
| Global Phenology: | |||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
Jan: Active / Active
Feb: Active / Active Mar: Active / Active Apr: Active / Active May: Reproducing / Reproducing June: Reproducing / Reproducing July: Reproducing / Reproducing Aug: Active / Active Sept: Active / Active Oct: Active / Active Nov: Active / Active Dec: Active / Active |
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| Provincial Phenology Comments: | Spawning occurs from May to August. At the end of the larval stage, amnocoetes undergo metamorphosis from July to October; the young adults probably remain in the gravel until the spring of the following year when they emerge and begin feeding on salmonids; feeding continues into the winter months (Beamish 1987, 2001). | ||||||||||
| Colonial Breeder: | Y | ||||||||||
| Length(cm)/width(cm)/Weight(g): | 23/ / | ||||||||||
| Elevation (m) (min / max): |
Global:
Provincial: 164 / 168 |
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| Distribution | |||||||||||
| Endemic: | Y | ||||||||||
| Global Range Comment: | This species is endemic to Vancouver Island, within Cowichan, Bear and Mesachie Lakes and their tributaries in British Columbia. They have not been observed below the lake outlets even though there are no barriers (Beamish 1982, cited in COSEWIC 2017). The known distribution is approximately 176 km2 (COSEWIC 2017). | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | CANNINGS, S. G., AND G. HAMMERSON | ||||||||||
| Last Updated: | Oct 26, 1995 | ||||||||||
| Provincial Information Author: | Ptolemy, J. | ||||||||||
| Last Updated: | Aug 05, 2005 | ||||||||||
| References and Related Literature | |||||||||||
B.C. Ministry of Environment. Recovery Planning in BC. B.C. Minist. Environ. Victoria, BC. |
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Beamish, R. J. 2001. Updated status of the Vancouver Island lake lamprey, Lampetra macrostoma, in Canada. Canadian Field-Naturalist 115:127-130. |
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Beamish, R.J. 1982. Lampetra macrostoma, a new species of freshwater parasitic lamprey from the west coast of Canada. Can. J. Fish. Aquat. Sci. 39:736-747. |
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Beamish, R.J. 1984. Status report on the lake lamprey (Lampetra macrostoma) in Canada. Comm. on the Status of Endangered Wildl. in Can., Ottawa. |
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Beamish, R.J. 1987.Status of the lake lamprey, Lampetra macrostoma, in Canada. Can. Field-Nat.101:186-189. |
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Beamish, R.J. 1987.Status of the lake lamprey, Lampetra macrostoma, in Canada. Can. Field-Nat.101:186-189. |
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Beamish, R.J. 2001. Updated status of the Vancouver Island Lake Lamprey, Lampetra macrostoma, in Canada. Can. Field-Nat. 115(1):127-130. |
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Lake Lamprey. 1999. B.C. Fish Facts. Conserv. Sect., Fish. Manage. Branch, B.C. Minist. Fish. 2pp. |
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Page, L. M., and B. M. Burr. 1991. A field guide to freshwater fishes: North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts. 432 pp. |
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Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp. |
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Williams, J.E, J.E. Johnson, D.A. Hendrickson, S. Contreras-Balderas, J.D. Williams, M. Navarro-Mendoza, D.E. McAllister, and J.E. Deacon. 1989b. Fishes of North America endangered, threatened or of special concern: 1989. Fisheries 14(6):2-20. |
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Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.
Suggested Citation:
B.C. Conservation Data Centre. 1995. Species Summary: Entosphenus macrostomus. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Apr 26, 2025).