Emerging conservation initiatives for lampreys: research challenges and opportunities

Lampreys worldwide face multiple anthropogenic stressors. Several species are ‘at-risk’ listed, yet abundance data for most remain insufficient to adequately assess conservation status. Lamprey population declines are largely due to habitat degradation and fragmentation, pollution, and exploitation. Conservation priorities include: quantification of population trends and distribution; identification of Evolutionarily Significant Units; improved water quality and habitat; barrier removal or effective mitigation; ecologically-sensitive river flow management and hydropower planning; and mitigation of climate change impacts. There is urgent need for ecological and population demographics data for multiple species, particularly those in the Southern Hemisphere, Caspian Sea region, and Mexico. Irrigation and damming are already extensive, or rapidly expanding (e.g. Chile), while water-stressed regions (Mexico, California, Chile, Australia, Iberia) may be further impacted by climate change-induced flow alteration and increased temperatures. Barrier removal should benefit lampreys by increasing available habitat. However, fishways vary in effectiveness and are often inadequate, but present research opportunities encompassing ecohydraulics, biotelemetry and engineering. Environmental DNA permits rapid assessment of lamprey distribution within catchments, especially if improvements to distinguishing genetically similar groups are possible. Marine environments may play a critical role in population dynamics yet remain a “black box” in anadromous lamprey biology. Studying juvenile lamprey ecology is a substantial challenge but should be a priority. Some examples are monitoring of parasitic feeding-phase lamprey through trawl surveys and fisheries bycatch, telemetry of movements, or examining chemical tracers of marine habitat use. Knowledge transfer between the sea lamprey control programme and native-lamprey biologists worldwide remains crucial to developing effective lamprey management

Lamprey fisheries: history, trends and management

Three anadromous lamprey species support important commercial fisheries in the northern hemisphere, sea lamprey in the Iberian Peninsula and France, European river lamprey in the Baltic Sea countries and Russia, and Arctic lamprey in Russia. Pacific lamprey, Caspian lamprey, Korean lamprey and pouched lamprey are harvested for subsistence and local commerce on the Pacific coast of North America, and in Russia, China and Oceania, respectively. Habitat loss caused by human activities in rivers have reduced lamprey populations and collapsed most commercial fisheries worldwide. Overfishing is a concern because traditional fishing gears (e.g., pots, fyke nets) target lampreys during their upstream migration, usually in physical bottlenecks, which can result in exceedingly high fishing mortality. The reduction in catches has inflated lamprey prices and encouraged illegal fishing in certain countries (e.g., Portugal, Russia). The success of management actions for lamprey fisheries could be at risk due to knowledge gaps that still exist regarding stock structure, estimates of stage-specific mortality, distribution at sea, preferred hosts, and climate change impacts to the distribution and availability of adequate hosts. There is an urgent need for good-quality data from reported commercial landings and also from monitoring studies regarding the efficacy of mitigation and restoration efforts (e.g., habitat restoration, fishing regulations, artificial rearing and stocking). Involving the general public and stakeholders in the management and conservation of lampreys through outreach actions is crucial to promote the protection of the ecological and cultural values of lampreys and the understanding of their vulnerability