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Conservation aquaculture provides a means for promoting environmental stewardship, useful both in the context of restoring native species and limiting the production of invasive species. Aquaculture of lampreys is a relatively recent endeavor aimed primarily at producing animals to support the restoration of declining native populations. However, in the Laurentian Great Lakes, where sea lamprey Petromyzon marinus are invasive, the ability to acquire a reliable source of certain life stages would be a significant benefit to those controlling their populations and studying the species. Here, we apply methodologies developed for Pacific lamprey Entosphenus tridentatus restoration to investigate the feasibility of rearing larval sea lamprey under laboratory conditions. In two experiments lasting 3 and 9 months, we tested the effects of different dietary sources and water temperature (ambient and controlled) on the survival and growth of wild-caught larvae. Rearing conditions had no effect on mortality, as larval survival was 100% in both experiments. Growth was significantly affected by water temperature, with the highest average daily growth rates observed at 22 and 15°C (0.14 mm day−1) and lowest at 8°C (0.06 mm day−1). Diets of yeast alone (0.19 and 0.21 g L−1) performed better than those comprising a mixture of yeast and other material when fed 3 times weekly (rice flour, wheat flour, fish meal; 0.19 and 0.32 g L−1). Averaged across the three constant temperatures (8, 15, and 22°C), larvae fed on yeast grew 0.13 mm day−1 and 0.01 g day−1, whereas on yeast + fish meal, they grew 0.09 mm day−1 and 0.01 g day−1. At ambient temperature (4–20°C), larvae fed on yeast grew 0.15 mm day−1 and 0.01 g day−1, whereas those fed on yeast + wheat flour grew 0.13 mm day−1 and 0.008 g day−1 and those fed on yeast + rice flour grew 0.12 mm day−1 and 0.009 g day−1. An experimental duration of 90 days was sufficient to detect significant changes to larval sea lamprey growth stemming from temperature variation. Overall, rearing of sea lamprey in captivity appears feasible at low density (31–32 g m−2 and 17–25 larvae m−2), but uncertainties remain regarding the most appropriate means of providing adequate feed for these fish in high-density conditions. [ABSTRACT FROM AUTHOR]

The sea lamprey Petromyzon marinus is an invasive pest in the Laurentian Great Lakes basin, threatening the persistence of important commercial and recreational fisheries. There is substantial interest in developing effective trapping practices via the application of behavior-modifying semiochemicals (odors). Here we report on the effectiveness of utilizing repellent and attractant odors in a push-pull configuration, commonly employed to tackle invertebrate pests, to improve trapping efficacy at permanent barriers to sea lamprey migration. When a half-stream channel was activated by a naturally derived repellent odor (a putative alarm cue), we found that sea lamprey located a trap entrance significantly faster than when no odor was present as a result of their redistribution within the stream. The presence of a partial sex pheromone, acting as an attractant within the trap, was not found to further decrease the time to when sea lamprey located a trap entrance relative to when the alarm cue alone was applied. Neither the application of alarm cue singly nor alarm cue and partial sex pheromone in combination was found to improve the numbers of sea lamprey captured in the trap versus when no odor was present--likely because nominal capture rate during control trials was unusually high during the study period. Behavioural guidance using these odors has the potential to both improve control of invasive non-native sea lamprey in the Great Lakes as well as improving the efficiency of fish passage devices used in the restoration of threatened lamprey species elsewhere. La lamproie marine Petromyzon marinus est une espece nuisible envahissante dans le bassin des Grands Lacs laurentiens, menacant la persistance d'importantes peches commerciales et sportives. L'elaboration de pratiques de piegeage efficaces par l'application de substances semiochimiques (odeurs) qui modifient le comportement suscite un interet considerable. Nous faisons etat de l'efficacite de l'utilisation d'odeurs repulsives et attractives dans une configuration de detournement stimulodissuasif (<< push-pull >>), communement employee dans la lutte contre les especes nuisibles invertebrees, pour ameliorer l'efficacite du piegeage a l'emplacement de barrieres permanentes a la migration des lamproies marines. Quand la moitie du chenal d'un cours d'eau est activee par une odeur repulsive d'origine naturelle (un signal d'alarme putatif), nous constatons que les lamproies marines se placent a l'entree du piege significativement plus vite que quand il n'y a pas d'odeur, en raison de leur redistribution rapide dans le cours d'eau. La presence d'une pheromone sexuelle partielle agissant comme substance attractive dans le piege ne reduit pas le temps requis pour que les lamproies se placent a l'entree du piege par rapport a la situation oU seul le signal d'alarme est applique. Il n'est pas observe que l'application du signal d'alarme seul, ni d'une combinaison du signal d'alarme et de la pheromone sexuelle partielle augmente le nombre de lamproies marines capturees dans le piege par rapport a la situation oU aucune odeur n'est presente, vraisemblablement en raison du fait que le taux de capture nominal durant les essais controles etait inhabituellement eleve durant la periode d'etude. L'orientation du comportement a l'aide de ces odeurs pourrait ameliorer la lutte contre la lamproie marine, une espece envahissante non indigene dans les Grands Lacs, ainsi que l'efficacite des passes a poissons utilisees pour le retablissement d'especes de lamproies menacees dans d'autres endroits. [Traduit par la Redaction], Introduction The Laurentian Great Lakes are highly susceptible to the establishment of invasive species, and of the approximately 180 nonnative species currently recognized in this region, the sea lamprey Petromyzon [...]

Understanding the population structure of invasive sea lamprey (Petromyzon marinus) in the Great Lakes basin is essential for an effective control program. We review knowledge of lake connectivity, dispersal during the parasitic stage, and results from phenotypic, demographic, and genetic studies to evaluate how sea lamprey populations are structured. There is no evidence for contemporary movement between Lake Ontario and the Atlantic population, although it appears possible. Dispersal between Lake Ontario and the Finger Lakes is more likely, as is contemporary movement between Lakes Ontario and Erie via the Welland Canal, although neither has been directly observed. Downstream movement from Lake Erie to Lake Ontario via the Niagara River has been reported. Bidirectional movement between Lakes Erie and Huron has been observed, and movement of sea lamprey among the upper Great Lakes (especially between Lakes Huron and Michigan) is relatively common, although complete mixing likely does not occur. The maximum straight-line dispersal distance reported for a tagged sea lamprey was 628 km between the St. Marys River and western Lake Erie. Genetic population studies using a variety of molecular markers generally found weak but significant broad-scale population structure (e.g., between freshwater and anadromous populations, and among Lake Ontario, Lake Erie, and the upper Great Lakes), but finer-scale structure was rarely detected. Nevertheless, some within-basin structure is suggested by regional differences in phenotypic and demographic traits (e.g., sex ratio, body size). Further study will be important because management is most efficiently targeted when the geography of demographically independent populations is well-characterized. [ABSTRACT FROM AUTHOR]

The Laurentian Great Lakes of North America support a large and profitable freshwater fishery, but one continuously beset by parasitism from the invasive sea lamprey (Petromyzon marinus). Despite being the life stage that inflicts damage to the fishery, therefore necessitating a bi-national control program, our knowledge of juvenile sea lamprey ecology is poor and their response to control efforts are not assessed. Incidental capture of juvenile sea lamprey by commercial fishers is one means to collect data on this enigmatic life stage, and in Lake Huron such data have been collated since 1967. Here, we explore incidental captures of juvenile sea lamprey and their hosts from northern Lake Huron between 1987 and 2017 (n = 33,246 observations) to address four objectives. Firstly, we document collection efforts by fishers to provide historical context to the dataset. Secondly, we pose and test a series of questions related to fishery encounter, host selection, growth, distribution, and sex ratio to highlight how these types of data can be informative regarding juvenile sea lamprey ecology. Results presented here could be used to develop biological hypotheses to be addressed in future work. Thirdly, we directly assessed whether juvenile sea lamprey capture data could be useful in corroborating trends observed in adult sea lamprey abundance and wounding, as well as in identifying abundance and wounding hotspots. Lastly, we summarize research and outreach efforts that have benefited from the capture of juvenile sea lamprey in recent years. [ABSTRACT FROM AUTHOR]

Sea lamprey (Petromyzon marinus) is a species of conservation concern in their native range of the Atlantic coasts of Europe (Near Threatened to Critically Endangered) and North America (Secure to Critically Imperiled), and an invasive species of great economic and ecological concern in the Laurentian Great Lakes. Despite differences in life history strategy (anadromous natives vs adfluvial non-natives), the biology of sea lamprey is sufficiently similar to expect comparable responses to large-scale environmental change. We take a prospective look at the future (50 to 100 years) of sea lamprey management in an era of considerable environmental disturbance, and consider biological responses, management actions, and the future status of populations across the native and non-native ranges. Based on facilitated discussion by a diverse group of international experts, two major but poorly characterized classes of threats to sea lamprey were identified: climate change and socio-political issues. We discuss how climate induced changes affect growth, bioenergetics, and phenology of sea lamprey, and associated effects on control tactics (pesticides and barriers) and conservation. We consider tensions surrounding improving connectivity in the Great Lakes while controlling invasive sea lamprey, and discuss supplements and alternatives to pesticides and their wider effect, as well as the effects of new invasive species. To prevent the extirpation of native sea lamprey populations, or the re-expansion of non-native populations, we conclude with a call for new and ongoing dialogue and collaboration among all sea lamprey biologists and managers across the native and non-native range. [ABSTRACT FROM AUTHOR]

Lampreys (Petromyzontiformes) are a key component of freshwater ecosystems throughout temperate parts of the world. Of the 44 described species of lamprey, the sea lamprey (Petromyzon marinus) is certainly the most commonly recognized. This species has expanded its range from the Atlantic Ocean basin where it is of conservation concern in North America and Europe into the Laurentian Great Lakes where it is subject to a large-scale international control program. Many other species of lamprey are imperiled and require management intervention to ensure their persistence. These management efforts range from routine assessment and monitoring to active or proposed restoration plans where they have been extirpated. Regardless of whether the goal is to control or conserve a given lamprey population, an understanding of their basic biology is paramount when generating and executing management plans. Here, we take a broad look across core aspects of biology (survival, foraging, and reproduction) that encompass challenges and opportunities in regard to future science-based management of lampreys. We attempt to synergize basic and applied research to highlight where these findings are most applicable to solving management problems and reveal knowledge gaps. We conclude by suggesting future research avenues and questions aimed to stimulate progress in both basic and applied lamprey research. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Effects of temperature on development of Raja microocellata was tested by maintaining embryos in controlled conditions representative of those predicted under current climate scenarios. There was a positive relationship between size of neonates & developmental rate: temperatures 14.5–16.5°C produced skates 3.5–7%, respectively, smaller than those raised at 12.5°C. Developmental rates were also 12–23% faster, with neonates hatching 3–7 weeks earlier. [ABSTRACT FROM AUTHOR]

Adaptive divergence with gene flow often results in complex patterns of variation within taxa exhibiting substantial ecological differences among populations. One example where this may have occurred is the parallel evolution of freshwater‐resident nonparasitic lampreys from anadromous‐parasitic ancestors. Previous studies have focused on transitions between these two phenotypic extremes, but here, we considered more complex evolutionary scenarios where an intermediate freshwater form that remains parasitic is found sympatrically with the other two ecotypes. Using population genomic analysis (restriction‐associated DNA sequencing), we found that a freshwater‐parasitic ecotype was highly distinct from an anadromous‐parasitic form (Qlake‐P = 96.8%, Fst = 0.154), but that a freshwater‐nonparasitic form was almost completely admixed in Loch Lomond, Scotland. Demographic reconstructions indicated that both freshwater populations likely derived from a common freshwater ancestor. However, while the nonparasitic ecotype has experienced high levels of introgression from the anadromous‐parasitic ecotype (Qanad‐P = 37.7%), there is no evidence of introgression into the freshwater‐parasitic ecotype. Paradoxically, mate choice experiments predicted high potential for gene flow: Males from all ecotypes were stimulated to spawn with freshwater‐parasitic females, which released gametes in response to all ecotypes. Differentially fixed single nucleotide polymorphisms identified genes associated with growth and development, which could possibly influence the timing of metamorphosis, resulting in significant ecological differences between forms. This suggests that multiple lamprey ecotypes can persist in sympatry following shifts in adaptive peaks, due to environmental change during their repeated colonization of post‐glacial regions, followed by periods of extensive gene flow among such diverging populations. [ABSTRACT FROM AUTHOR]

Abstract: Alarm signals released after predator attack function as reliable public information revealing areas of high risk. The utility of this information can extend beyond species boundaries, benefiting heterospecifics capable of recognizing and responding appropriately to the signal. Nonmutually exclusive hypotheses explaining the acquisition of heterospecific reactivity to cues suggest it could be conserved phylogenetically following its evolution in a common ancestor (a species‐level effect) and/or learned during periods of shared risk (a population‐level effect; e.g., shared predators). Using a laboratory‐based space‐use behavioral assay, we tested the response of sea lamprey (Petromyzon marinus) to the damage‐released alarm cues of five confamilial (sympatric and allopatric) species and two distantly related out‐groups: a sympatric teleost (white sucker Catostomus commersonii) and an allopatric agnathan (Atlantic hagfish Myxine glutinosa). We found that sea lamprey differed in their response to conspecific and heterospecific odors; exhibiting progressively weaker avoidance of cues derived from more phylogenetically distant confamilials regardless of current overlap in distribution. Odors from out‐groups elicited no response. These findings suggest that a damage‐released alarm cue is at least partially conserved within the Petromyzontidae and that sea lamprey perceives predator attacks directed to closely related taxa. These findings are consistent with similar observations from gastropod, amphibian and bony fish taxa, and we discuss this in an eco‐evo context to provide a plausible explanation for the acquisition and maintenance of the response in sea lamprey. [ABSTRACT FROM AUTHOR]

Instream barriers affect anadromous lampreys worldwide by preventing access to spawning habitat, resulting in the decline of several species. Because lampreys rely heavily on olfactory cues to choose movement paths during upstream migration in rivers, the manipulation of these cues may be used to guide individuals into the vicinity of fish passage devices and thereby mitigate the impacts of barriers during migration. However, because experimentation with imperiled species presents significant legal and ethical challenges, use of a surrogate species that exhibits similar responses may prove very useful. Our laboratory study established that (1) the odor derived from dead Pacific LampreyEntosphenus tridentatuselicits an avoidance response from invasive Sea LampreyPetromyzon marinusfrom the Laurentian Great Lakes, and (2) the magnitude of this response does not differ from the conspecific alarm cue present in Sea Lamprey. By presenting the odor on the side of a river channel opposite a lamprey fish passage device, migrating lampreys of conservation concern may be guided to fishways, if the behavioral response to the cue has evolved in these taxa. Due to their availability and well-studied chemical communication system, Sea Lamprey may prove to be a useful surrogate for identifying and producing chemosensory cues for use in guiding Pacific Lampreys towards fish passage devices and away from intakes and screens. Received December 10, 2015; accepted May 6, 2016 Published online August 31, 2016 [ABSTRACT FROM AUTHOR]

The tendency of many species to abandon migration remains a poorly understood aspect of evolutionary biology that may play an important role in promoting species radiation by both allopatric and sympatric mechanisms. Anadromy inherently offers an opportunity for the colonization of freshwater environments, and the shift from an anadromous to a wholly freshwater life history has occurred in many families of fishes. Freshwater-resident forms have arisen repeatedly among lampreys (within the Petromyzontidae and Mordaciidae), and there has been much debate as to whether anadromous lampreys, and their derived freshwater-resident analogues, constitute distinct species or are divergent ecotypes of polymorphic species. Samples of 543 European river lamprey Lampetra fluviatilis (mostly from anadromous populations) and freshwater European brook lamprey Lampetra planeri from across 18 sites, primarily in the British Isles, were investigated for 13 polymorphic microsatellite DNA loci, and 108 samples from six of these sites were sequenced for 829 bp of mitochondrial DNA (mtDNA). We found contrasting patterns of population structure for mtDNA and microsatellite DNA markers, such that low diversity and little structure were seen for all populations for mtDNA (consistent with a recent founder expansion event), while finescale structuring was evident for nuclear markers. Strong differentiation for microsatellite DNA loci was seen among freshwater-resident L. planeri populations and between L. fluviatilis and L. planeri in most cases, but little structure was evident among anadromous L. fluviatilis populations. We conclude that postglacial colonization founded multiple freshwater-resident populations with strong habitat fidelity and limited dispersal tendencies that became highly differentiated, a pattern that was likely intensified by anthropogenic barriers. [ABSTRACT FROM AUTHOR]

Ecological speciation mechanisms are widely assumed to play an important role in the early stages of divergence between incipient species, and this especially true of fishes. In the present study, we tested explicitly for post-zygotic barriers to gene flow between a sympatric, recently diverged lamprey species pair that likely arose through ecological divergence. Experimental in vitro hybridization between anadromous parasitic Lampetra fluviatilis and resident nonparasitic Lampetra planeri resulted in a high proportion of embryos capable of attaining the burrowing pro-larval stage, strongly indicating no post-zygotic barriers to gene flow between these species. A sympatric, locally-adapted resident parasitic form of L. fluviatilis was also found to successfully hybridize with both members of this species pair. The consequences of these findings are discussed in the context of lamprey speciation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 108, 378-383. [ABSTRACT FROM AUTHOR]