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Proposed Recovery Strategy for Vancouver Lamprey

Species information

Common Names: Vancouver lamprey, Cowichan Lake lamprey, Lake lamprey

Scientific Name: Lampetra macrostoma

Canadian Occurrence: British Columbia

COSEWIC Status: Threatened, November 2000

SARA Status: Threatened, June 2003

COSEWIC Reason for Designation: This landlocked parasitic species is endemic to British Columbia and occurs in a very restricted area. It is at risk due to intensive human activity.

Status History: Designated Special Concern in April 1986. Status re-examined and confirmed in April 1998. Status re-examined and designated Threatened in November 2000. Last assessment based on an existing status report (Beamish 1998).

1. Description of the Species

1.1  General Biology

Lampreys are members of the Superclass Agnatha, jawless fishes.  Lampreys are distinguished by a cylindrical, eel-like, scale-less body and a round suctorial mouth armed with a series of sharp, horny teeth.  They have a small caudal fin, and long dorsal fin, often with two distinct parts; they have no paired fins (Figure 1).  The skeleton is cartilaginous, a trait that has contributed to a poor fossil record.  Lampreys have seven pairs of gills in the form of gill pouches, each with an individual opening to the outside (Scott and Crossman 1973).  There are about 40-45 species of lamprey within 9 genera, depending on the current interpretations of experts (ITIS 2005). 

Lampreys are generally distributed in temperate marine and freshwaters; the worldwide distribution is predominantly in the Northern Hemisphere (Scott and Crossman 1973).  About 1/3 of lamprey species are anadromous. As adults, lamprey species are either externally parasitic of other fish species, or do not feed at all.  All lamprey are semelparous and die soon after spawning (Larson 1980).

Drawing of Vancouver lamprey

Figure 1.  Drawing of Vancouver lamprey (from McPhail and Carveth 1993).

Lampreys are difficult to age reliably (Beamish and Medland 1988; Kostow 2002). They have a distinct larval phase followed by metamorphosis (Scott and Crossman 1973), but time to metamorphosis (sometimes called transformation) varies among species.  Larvae, called ammocoetes (Figure 2), live in burrows in stream and lake sediments (Scott and Crossman 1973).  Ammocoetes have sightless eyes; teeth and oral disk are absent, and the mouth is covered with an oral hood.  Ammocoetes feed by filtering microscopic plant and animal material and organic detritus through the oral hood (e.g., Manion 1967; Moore 1973, 1980; Sutton et al. 1994; Mundahl et al. 2005).

In British Columbia there are four described species of lamprey [1] (Beamish 1985).  The Western brook lamprey, Lampetra richardsoni, is a non-anadromous, non-parasitic, freshwater-resident species commonly found in streams.  The Pacific lamprey, L. tridentata, is anadromous and parasitic; it is commonly found in coastal streams and marine coastal areas.  The river lamprey, L. ayresi, is anadromous and parasitic.  It can be very abundant in the Fraser River, and is common in the Strait of Georgia during its parasitic phase.  Little research has been done on this species outside the Georgia Basin.  L. macrostoma, originally described by Beamish (1982), is parasitic and assumed to be derived from L. tridentata. It has been reported only in Cowichan and Mesachie lakes on Vancouver Island (Beamish 1998).  Common names of L. macrostoma are Vancouver lamprey, Cowichan Lake lamprey, or lake lamprey.  In this recovery strategy we refer to the species as Vancouver lamprey, the name with which it was listed under SARA.

External features of lamprey ammocoete

Figure 2.  External features of lamprey ammocoete (from McDermott 2003).

L. macrostoma has been deemed a separate species based on its unique morphological and physiological traits.  There are numerous differences between L. tridentata and L. macrostoma, including some unreported characters (R. Beamish, unpublished data), but the biggest differences are the size of the oral disk and physiological adaptation to fresh and marine waters (Beamish 1982).  The oral disk is the key character used to define and differentiate species of parasitic lamprey (Vladykov and Kott 1979); the disk of a Vancouver lamprey has approximately two-thirds more surface area than that of a similar size L. tridentata and there are some differences in dentition (Beamish 1982).  Physiologically, Vancouver lamprey are better adapted to life in freshwater (although they can survive in salt water), whereas Pacific lamprey are better adapted to life in sea water (Beamish 1982).  In fact, there is no evidence that L. tridentata can survive in freshwater after metamorphosis, except as a returning spawner (Beamish 1982, Clarke and Beamish 1988).  L. macrostomaalso has a smaller total size, larger eye, longer prebranchial length, and possibly a shorter trunk length than L. tridentata (Beamish 1982). 

Beamish (1982) indicated that L. macrostoma warrants status as a distinct species, since the magnitude of trait difference is equivalent to or greater than other species derived from L. tridentata.  However, the taxonomic status of Vancouver lamprey remains somewhat uncertain. The only genetic study involving this species to date (Docker et al. 1999) found that L. macrostoma was genetically indistinguishable from L. tridentata (and from a second L. tridentata derivative, the Pit-Klamath brook lamprey, L. lethophaga, from California). These results suggest that both species are recent derivatives of L. tridentata, but more extensive genetic analysis is required to better resolve the phylogenetic relationships among these closely-related species.

Vancouver lamprey range in size from 18 to 27 cm, with females slightly smaller than males (Beamish 1985).  The average size of recently metamorphosed lamprey is 11.7 cm (Beamish 1985).  The considerable growth that occurs from recently metamorphosed individuals to adult size indicates that the species is an obligate parasite (Beamish 1985).  It is possible to collect ammocoetes from lake and stream sediments, but adults are easily captured only during the spawning period (Beamish 1998).  Thus, very little is known about the young adult phase.

Like all lampreys, the Vancouver lamprey spawns once and dies shortly thereafter (Beamish 1998).  The spawning season is May to August.  Duration of larval and adult life is not known, but Vancouver lamprey are thought to spend about six years as larvae and two years post-metamorphosis (Beamish 1998).  Metamorphosis occurs from July to October; young adults likely remain in the substrate until the following spring (Beamish 1998).  Active feeding in adults is thought to commence during the spring after metamorphosis and continue until just before spawning, the following spring or summer (Beamish 1982).  Feeding adults readily prey upon live fish (Beamish 1982), and many fish collected in Cowichan Lake show scarring and wounds from lamprey (Carl 1953 cited in Beamish 1982; Beamish 1982). 

1.2 Distribution

The Vancouver lamprey is an extreme endemic.  It has been reported only in Cowichan and Mesachie lakes, on southern Vancouver Island, British Columbia, and the lower part of tributaries to these lakes (Figure 3).  The two lakes are adjacent and connected via the Robertson River, Bear Lake and an unnamed watercourse, sometimes referred to as Mesachie Creek.  There are no complete barriers to fish downstream of Cowichan Lake, as evidenced yearly by anadromous salmonids that use the lake and its tributaries for spawning and rearing.  Pacific lamprey are common downstream of the lake outlet, but have not been observed upstream of this point (Beamish 1982).  Likewise, Vancouver lamprey have not been observed downstream of the lake outlet (Beamish 1982).

1.3  Abundance

There has been little or no research done on this species since the 1980s, and at no time have estimates been made of total population or habitat-specific abundance.  The incidence of lamprey-induced scarring and wounding on salmonids implies that abundance fluctuates (Beamish 1998), but the magnitude and frequency of fluctuations is unknown.  It is expected that lamprey populations fluctuate in response to prey availability (Beamish 1998).  There is no evidence that the species is especially rare or in decline; however, no firm conclusions can be drawn with the current data.  Beamish (1998) provides a guess at abundance of 1,000 to 2,000 adults throughout both lakes.

1.4  Importance to People

The special significance of the Vancouver lamprey is primarily its scientific value.  There is no commercial value to the species.  As a parasitic species feeding predominantly on salmonids (a set of highly-valued species), lamprey are generally not well-regarded.  The fact that introduced lamprey have caused considerable harm in other systems (Fuller et al. 2005) likely adds to the lamprey’s poor reputation.  Conversely, others view Vancouver lamprey as a member of the native fauna, with its own intrinsic value, ecological role and contribution to biodiversity, and its special value to education and science.  As a scientific subject, the Vancouver lamprey is of considerable interest for its extreme endemism and as a newly-evolved species.  It is the only reported example of a freshwater parasitic derivative of L. tridentata in Canada, and is valued scientifically because it is an example of the resiliency in life history strategy that is a key to the evolutionary success of lamprey.  There may also be cultural value of Vancouver lamprey to First Nations, though consultations with First Nations by Fisheries and Oceans Canada in May 2006 did not yield information on the species’ cultural value. It should be noted that Pacific lamprey has significant cultural value for First Nations people in some regions (Close et al. 2002).

Distribution of Vancouver lamprey

Figure 3.  Distribution of Vancouver lamprey.  (Map base obtained from Ministry of Energy, Mines and Petroleum Resources, http://www.em.gov.bc.ca/mining/Geolsurv/MapPlace/themeMaps.htm).

[1] A fifth distinct taxon occurs in Morrison Creek, Vancouver Island, but has not been formally designated as a distinct species.