Cephalaspidomorphi (lampreys) > Petromyzontiformes
(Lampreys) > Geotriidae
Etymology: Geotria: Greek, gea = the earth, dealing with earth (Ref. 45335). More on author: Gray.
Neira et al. (1988) showed that ammocoetes of an Argentinian population were morphologically distinct from ammocoetes of both Chilean and Australasian (mainland Australia, Tasmania, and New Zealand) populations of the species. Additionally, they stated that adults from Argentina and from South Georgia Island had the cloaca positioned well posterior to the origin of the second dorsal fin rather than aligned immediately under its origin as in Chilean and Australasian populations. Perhaps, therefore, the Argentinian and South Georgian Island population represents a distinct species and this question merits closer scrutiny.
Environment / Climate / Range
Marine; freshwater; brackish; demersal; anadromous (Ref. 51243). Temperate; 34°S - 55°S, 114°E - 31°W (Ref. 89241)
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 62.0 cm TL male/unsexed; (Ref. 39873)
South America, South Australia, South New Zealand. Southwestern Atlantic, southwestern and soustheastern Pacific.
Coasts of South America: Chile, southern Argentina.
Chile: Andalién, Biobío, Carampangue, Malleco, Picoiquén, Huequén, Purén, Claro, Mehuín, Calle-Calle, Valdivia, Toma Galeones, Santo Domingo, Maullín, Curilelfu, and Donguil rivers, and Lake Risopatron;
Argentina: Limay River;
Falkland and South Georgia islands.
Occurs in mud burrows in upper reaches of coastal streams for the first four years of life until metamorphosis and subsequent downstream migration to the sea (Ref. 44894). Adults inhabit the sea for an undetermined period and are parasitic on other fishes. Migrate upstream which may last for 16 months and spawn in freshwater (Ref. 5154). Adults are often found below weirs and dams during their spawning migration which may take them 60 km or more upstream of the coast (Ref. 44894). Migration mostly takes place in rainy nights when water levels are rising, with temperatures between 12-14.5°C and when there is extensive cloud cover or during the dark phase of the moon (Ref. 5154). Sometimes they exit the water by wriggling up the bank to bypass obstacles to migration (Ref. 44894). Adults stop feeding while in freshwater and die shortly after spawning. Maximum length reported to reach 62 cm TL (Ref. 5154). Common length is 45-50 cm. Status of abundance decreased due to proliferation of obstacles such as dams and weirs to upstream spawning runs (Ref. 44894).
In New Zealand, the Maori use the Pouched Lamprey at the beginning of their upstream migration for human consumption and ceremonial purposes (McDowall, 1990). These are caught using weirs built along river edges or collected by hand as they are making their way up the rocky face of falls. They are then dried for human consumption (Ref. 89241).
Renaud, C.B., 2011. Lampreys of the world. An annotated and illustrated catalogue of lamprey species known to date. FAO Species Catalogue for Fishery Purposes. No. 5. Rome, FAO. 109 pp.
IUCN Red List Status (Ref. 90363)
Threat to humans
Fisheries: subsistence fisheries
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
CollaboratorsPicturesStamps, CoinsSoundsCiguateraSpeedSwim. typeGill areaOtolithsBrainsVision
Estimates of some properties based on empirical models
Phylogenetic diversity index (Ref. 82805
= 1.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00102 (-0.17398 - 0.17602), b=3.06 (2.97 - 3.15), based on all LWR estimates for this BS (Ref. 93245
Trophic Level (Ref. 69278
): 4.5 ±0.80 se; Based on food items.
Resilience (Ref. 69278
): Very Low, minimum population doubling time more than 14 years (Preliminary K or Fecundity.).
Vulnerability (Ref. 59153
): High to very high vulnerability (69 of 100) .