Capture and collection of lampreys: the state of the science

Abstract

The need for native lamprey conservation, improved lamprey fishery management, and better assessment of non-indigenous lamprey control measures has resulted in increased effort to survey lamprey populations and assess their status. Depending on the study objectives and target species/life stage, collection methods vary dramatically. We therefore provide a comprehensive review of sampling considerations and techniques used to capture, collect, handle, and enumerate both juvenile and adult lamprey life stages. Surveys for lamprey are often constrained by the lack of basic biological information, such as reliable characters for field identification of larvae (ammocoetes), migratory timing of anadromous forms, and spawning/nest building behavior of adults. However, there are a number of studies that have documented habitat preferences of the relatively sedentary ammocoetes. Consequently, existing sampling protocols have focused on the development of stratified sampling that targets optimal ammocoete habitat. In addition to this approach, we discuss methods and gear that can be used to survey migratory life stages, lamprey nests, and difficult-to-sample, deepwater ammocoete habitats.

Variability in migration timing of adult Pacific lamprey (Lampetra tridentata) in the Columbia River, U.S.A.

“…The ensuing review concluded that there were insufficient data on Pacific lamprey abundance (historic and current), population trends, stock structure, and basic biology to support federal protection for the species (USFWS 2004). The findings reflected the historically low priority of native lamprey management (Renaud 1997;Close et al 2002;Moser et al 2007).…”

Restoring River Connectivity: Prioritizing Passage Improvements for Diadromous Fishes and Lampreys

“…As such, populations in many areas are likely to have been underestimated. Specific surveys may therefore be required to quantify the status of target populations before passage improvements are undertaken (Cowx et al 2009;Moser et al 2007), and surveys of passage efficiency and habitat quality will also reduce the subjectivity of the assessment (Kemp and O'Hanley 2010;Raven et al 1998). Indeed, the greatest sources of between-assessor differences in B were generally the estimates of F and P. It may also be possible to incorporate confidence rankings for estimates based upon expert judgement, as is being developed for risk assessment of non-native species (e.g.…”

A new sampling technique for larval lamprey population assessment in small river catchments

“…Most protocols developed for lamprey assessments are based on ammocoete surveys (Moser et al, 2007). Early developments in this field emerged largely in North America during the effort to control invasive sea lamprey in the Great Lakes region (e.g.…”

“…In Europe, Harvey and Cowx (2003) and Nunn et al (2008) have recently proposed a sampling protocol for the condition assessment of lamprey population in the framework of the EC Habitat Directive. Sampling designs generally involve the use of electric fishing which is thought to be the best way to collect lamprey larvae (Weisser and Klar, 1990;Pajos and Weise, 1994;Moser et al, 2007).…”

“…The development of other techniques could help to encourage data collection. Alternatives to electrofishing for ammocoetes sampling (see Moser et al, 2007 for review), such as the suction dredge (Beamish andYouson, 1987, Bergstedt andGenovese, 1994;Steeves et al, 2003), the shovel and Ekman-Birge grab (Kainua and Valtonen, 1980) (Surber, 1937). This method allows sampling of a constant surface area and thus, data standardization.…”