Western Brook Lamprey Research Articles

An experimental study to evaluate predation threats on two native larval lampreys in the Columbia River Basin, USA

AbstractExperimental predation studies were conducted to evaluate and compare the predation threats of 10 species of native and non‐native fishes on larvae of Pacific Lamprey, Entosphenus tridentatus, and Western Brook Lamprey, Lampetra richardsoni. The relative predatory threats were examined over four sets of binary factors, including the following: (a) short (2‐day) or long (7‐day) duration, (b) presence/absence of fine sediment, (c) live or dead larvae and (d) species of lampreys. Our short‐term results showed a positive correlation with the sizes of predator fishes and consumed lamprey larvae. Also, most predator fishes had a significantly higher propensity to prey on lamprey larvae when sediment was absent. Conversely, this demonstrated the importance of sediment in protecting lamprey larvae from predation. Based on the predatory behaviour for live and dead larvae, predator fishes were classified into four groups using principal component analysis. Predation rates of larvae in sediment by piscivorous predators including Northern Pikeminnow Ptychocheilus oregonensis and Smallmouth Bass Micropterus dolomieu were lower and showed no differences even when the study duration was extended. In contrast, predation rates by benthic predators including White Sturgeon Acipenser transmontanus and Common Carp Cyprinus carpio, increased when we extended the study duration. This suggests that when given longer duration, benthic predators are more adept at consuming larvae within the sediment. These results provide important context for assessing the potential threat of predation on lampreys in streams, which is a key knowledge gap for lampreys.

Contemporary and historical river connectivity influence population structure in western brook lamprey in the Columbia River Basin

The western brook lamprey Lampetra richardsoni (WBL) is a small non-parasitic lamprey that inhabits rivers and streams from southern Alaska to northern California. WBL remain in fresh water throughout their entire life and show limited dispersal. Although adults may migrate short distances upstream to spawn, most movement likely occurs through passive drifting of larvae downstream. Genetic differentiation among populations is thus expected to be high, even within a single basin, but WBL population structure has received little attention. The present study examined population connectivity of WBL from 23 sites throughout the Columbia River Basin and coastal Washington, using eight microsatellite loci and cytochrome b sequence data. Although population structure generally corresponded to contemporary river connectivity, there were some cases where genetic patterns were better explained by historical connections. Microsatellite genetic differentiation among populations separated by < 570 km was moderate to high; FST values ranged from − 0.0026 to 0.7117 and averaged 0.2929. Tributary distance was the best predictor of FST, suggesting that most gene flow takes place in tributaries rather than through the mainstem of the Columbia River. As predicted, gene flow occurred primarily in a downstream direction, resulting in lower genetic diversity in upstream sites. WBL populations in these areas may be particularly vulnerable to local extinction. Therefore, whereas anadromous lamprey management efforts are focused on improving passage at mainstem dams, conservation of WBL will require protection of individual watersheds with particular emphasis on headwater areas.

Bioenergetics Models to Estimate Numbers of Larval Lampreys Consumed by Smallmouth Bass in Elk Creek, Oregon

AbstractNonnative fishes have been increasingly implicated in the decline of native fishes in the Pacific Northwest. Smallmouth Bass Micropterus dolomieu were introduced into the Umpqua River in southwest Oregon in the early 1960s. The spread of Smallmouth Bass throughout the basin coincided with a decline in counts of upstream‐migrating Pacific Lampreys Entosphenus tridentatus. This suggested the potential for ecological interactions between Smallmouth Bass and Pacific Lampreys, as well as freshwater‐resident Western Brook Lampreys Lampetra richardsoni. To evaluate the potential effects of Smallmouth Bass on lampreys, we sampled diets of Smallmouth Bass and used bioenergetics models to estimate consumption of larval lampreys in a segment of Elk Creek, a tributary to the lower Umpqua River. We captured 303 unique Smallmouth Bass (mean: 197 mm and 136 g) via angling in July and September. We combined information on Smallmouth Bass diet and energy density with other variables (temperature, body size, growth, prey energy density) in a bioenergetics model to estimate consumption of larval lampreys. Larval lampreys were found in 6.2% of diet samples, and model estimates indicated that the Smallmouth Bass we captured consumed 925 larval lampreys in this 2‐month study period. When extrapolated to a population estimate of Smallmouth Bass in this segment, we estimated 1,911 larval lampreys were consumed between July and September. Although the precision of these estimates was low, this magnitude of consumption suggests that Smallmouth Bass may negatively affect larval lamprey populations.Received September 20, 2016; accepted March 31, 2017Published online June 6, 2017

Growth and annual survival estimates to examine the ecology of larval lamprey and the implications of ageing error in fitting models.

This study used existing western brook lamprey Lampetra richardsoni age information to fit three different growth models (i.e. von Bertalanffy, Gompertz and logistic) with and without error in age estimates. Among these growth models, there was greater support for the logistic and Gompertz models than the von Bertalanffy model, regardless of ageing error assumptions. The von Bertalanffy model, however, appeared to fit the data well enough to permit survival estimates; using length-based estimators, annual survival varied between 0·64 (95% credibility interval: 0·44-0·79) and 0·81 (0·79-0·83) depending on ageing and growth process error structure. These estimates are applicable to conservation and management of L. richardsoni and other western lampreys (e.g. Pacific lamprey Entosphenus tridentatus) and can potentially be used in the development of life-cycle models for these species. These results also suggest that estimators derived from von Bertalanffy growth models should be interpreted with caution if there is high uncertainty in age estimates.

Evaluation of Methods to Measure Condition in Pacific Northwest Larval Lampreys

Pacific lamprey (Entosphenus tridentatus) populations are declining and western brook lamprey (Lampetra richardsoni) status is unknown in the Pacific Northwest. Accurate measures of fish condition are a basic requirement to monitor health and status of fish populations. Fulton's condition factor has traditionally been used to assess condition of larval lamprey but alternative field-based and laboratory-based measures have not been assessed. We compared condition factor, body density, and lipid content of sympatric larval Pacific lamprey and western brook lamprey in 2010 and 2011 from two rivers of the Pacific Northwest. Condition factor was higher for Pacific lamprey than it was for western brook lamprey. All measures were variable and correlations among condition indices were weak. Body density and lipid content were higher in western brook lamprey in one year suggesting the possibility of increased energy requirements of metamorphosis to a nontrophic adult stage. The body density technique was onerous and likely has little field-based practicality. Body density and lipid content had a negative relationship as increased lipids leads to a more buoyant and less dense fish. Condition factor did not appear to be a good predictor of lipid content in our study and a suite of complex factors, including lipid dynamics prior to metamorphosis and nutritional resources, may underlie these results. This study provides one of the few empirical datasets on sympatric lampreys with different life history strategies.

Distribution of Pacific LampreyEntosphenus tridentatusin Watersheds of Puget Sound Based on Smolt Monitoring Data

Abstract Lamprey populations are in decline worldwide and the status of Pacific lamprey (Entosphenus tridentatus) is a topic of current interest. They and other lamprey species cycle nutrients and serve as prey in riverine ecosystems. To determine the current distribution of Pacific lamprey in major watersheds flowing into Puget Sound, Washington, we sampled lamprey captured during salmonid smolt monitoring that occurred from late winter to mid-summer. We found Pacific lamprey in 12 of 18 watersheds and they were most common in southern Puget Sound watersheds and in watersheds draining western Puget Sound (Hood Canal). Two additional species, western brook lamprey (Lampetra richardsoni) and river lamprey (L. ayresii) were more common in eastern Puget Sound watersheds. Few Pacific lamprey macrophthalmia were found, suggesting that the majority of juveniles migrated seaward during other time periods. In addition, “dwarf” adult Pacific lamprey (< 300 mm) were observed in several watersheds and may represent ...

Genetic diversity, endemism and phylogeny of lampreys within the genus Lampetra sensu stricto (Petromyzontiformes: Petromyzontidae) in western North America

Phylogenetic structure of four Lampetra species from the Pacific drainage of North America (western brook lamprey Lampetra richardsoni, Pacific brook lamprey Lampetra pacifica, river lamprey Lampetra ayresii and Kern brook lamprey Lampetra hubbsi) and unidentified Lampetra specimens (referred to as Lampetra sp.) from 36 locations was estimated using the mitochondrial cytochrome b gene. Maximum parsimony and Bayesian inferences did not correspond with any taxonomic scheme proposed to date. Rather, although L. richardsoni (from Alaska to California) and L. ayresii (from British Columbia to California) together constituted a well-supported clade distinct from several genetically divergent Lampetra populations in Oregon and California, these two species were not reciprocally monophyletic. The genetically divergent populations included L. pacifica (from the Columbia River basin) and L. hubbsi (from the Kern River basin) and four Lampetra sp. populations in Oregon (Siuslaw River and Fourmile Creek) and California (Kelsey and Mark West Creeks). These four Lampetra sp. populations showed genetic divergence between 2.3 and 5.7% from any known species (and up to 8.0% from each other), and may represent morphologically cryptic and thus previously undescribed species. A fifth population (from Paynes Creek, California) may represent a range extension of L. hubbsi into the Upper Sacramento River.

Laboratory Testing of a Modified Electroshocking System Designed for Deepwater Juvenile Lamprey Sampling

AbstractA submersible sled with the ability to electroshock and detect larval lampreys via an optical camera was developed to sample deepwater rearing habitats (&gt;1 m). Three trials, each with 10 juvenile western brook lampreys Lampetra richardsoni (70–150 mm), were conducted in a laboratory setting to determine the effective shocking area and detection efficiency of the device. Electroshock was delivered for 30 s, and lamprey responses were observed. The detection efficiency ranged from 40% to 70% for the three trials (mean detection efficiency = 60%). Mean postshock emergence time was 4.4 s, and the maximum was 13 s. The device detected juvenile western brook lampreys without the need to transport them to the surface, thereby increasing sampling volume per unit time and reducing the potential for injury caused by handling. The system was developed to determine juvenile lamprey presence in regions where backpack electrofishers are unable to survey due to water depth.

Short Communication Characterization of 12 microsatellite loci for the Pacific lamprey, Entosphenus tridentatus (Petromyzontidae), and cross-amplification in five other lamprey species

The Pacific lamprey (Entosphenus tridentatus) is an anadromous fish that is of conservation concern in North America and Asia. Data on Pacific lamprey population structure are scarce and conflicting, impeding conservation efforts. We optimized 12 polymorphic microsatellite loci for the Pacific lamprey. Three to 13 alleles per locus were observed in a sample of 51 fish collected from the West Fork Illinois River, Oregon. Observed heterozygosity ranged from 0.235 to 0.902 and expected heterozygosity ranged from 0.214 to 0.750. Cross-species amplification produced 8 to 12 polymorphic loci in four other Entosphenus species and in the western brook lamprey (Lampetra richardsoni). Two loci appear to be diagnostic for distinguishing Entosphenus from Lampetra. These markers will be valuable for evaluating population structure and making conservation decisions for E. tridentatus and other lamprey species.

Characterization of ten microsatellite loci for western brook lamprey Lampetra richardsoni

We describe the isolation and development of ten polymorphic microsatellite loci for western brook lamprey (Lampetra richardsoni). Two to nine alleles were observed per locus in a sample of 35 fish. Gene diversity ranged from 0.000 to 0.792 in six populations. Cross-species amplification was successful as nine, seven and eight loci were polymorphic in Lampetra pacifica, Entosphenus hubbsi, and Entosphenus tridentatus, respectively. These markers will aid in evaluating the population structure of lamprey that are native to western North America.

Rare species of cyclostomata and fish in the Upper Oka basin and within Kaluga oblast

The species list of fish of the Upper Oka basin is verified. Data on biology of rare species are presented (western brook lamprey Lampetra planeri, sterlet Acipenser ruthenus, bystryanka Alburnoides bipunctatus rossicus, asp Aspius aspius, undermouth Chondrostoma variabile, bitterling Rhodeus sericeus, and fresh-water sculpin Cottus gobio koshewnikowi). Their morphological characters, distribution in the Upper Oka basin relative abundances of these species, and its changes during recent decades are also commented.

OBSERVATIONS ON NEST CHARACTERISTICS, SPAWNING HABITAT, AND SPAWNING BEHAVIOR OF PACIFIC AND WESTERN BROOK LAMPREY IN A WASHINGTON STREAM

Abstract Spawning surveys of Pacific lamprey (Lampetra tridentata) and western brook lamprey (L. richardsoni) were conducted in the Cedar Creek drainage, a tributary within the Columbia River basin in Washington State. Twenty-seven surveys were conducted in 2001, 50 in 2002, and 53 in 2003. A total of 237 Pacific lamprey nests and 58 western brook lamprey nests were examined to describe nest characteristics (area, excavation depth, and longevity) and their associated habitat (water depth, water velocity, substrate size, and gradient). Spawning behaviors (timing, adult visibility, and courtship rituals) were evaluated to determine if spawning surveys could be used as an indicator of adult abundance. Pacific lamprey nests were larger in area and were excavated deeper than western brook lamprey nests; on rare occasions the 2 types of nests were found superimposed. Although western brook and Pacific lamprey nests displayed overlap in all habitat parameters, each species primarily exploited resources not readi...

Morphology and Aging Precision of Statoliths from Larvae of Columbia River Basin Lampreys

AbstractThe general morphology and precision associated with age determination of statoliths from larval Pacific lampreys Lampetra tridentata and western brook lampreys L. richardsoni found within the Columbia River basin were examined. Significant positive correlations were observed between the size of left and right statoliths from individuals. Principal components analysis indicated an allometric relationship between lamprey length and statolith size as well as a potential species grouping based on these measurements. Discriminant analysis was able to correctly classify more than 94% of Pacific lampreys and 92% of western brook lampreys based on lamprey length and statolith size, and Pacific lamprey statoliths tended to be larger than western brook lamprey statoliths for lampreys of a given size. Reader bias in age estimates of statoliths was greater for older lampreys. Multiple independent age readings of both statoliths from individual lampreys indicated that the overall average percent error was 16.7% for Pacific lampreys and 33.0% for western brook lampreys. Within‐individual average percent error ranged from 5.1% to 20.1% among species and readers. Within‐reader average percent error ranged from 6.4% to 17.8% among species and readers. The average percent error observed in this study was greater than that observed in studies of other species of lampreys; however, statoliths that were ambiguous or difficult to read were not excluded from this study. In general, the modal separation of age‐groups observed in length‐frequency distributions for lampreys is poor, as seen in this study; therefore, statolith‐based ages may verify or provide better estimates of population age structure. These data demonstrate that estimates of precision are necessary before management actions founded on statolith‐based age structure determination are implemented.

Effects of Temperature on Survival and Development of Early Life Stage Pacific and Western Brook Lampreys

AbstractWe examined the effects of temperature (10, 14, 18, and 22°C) on survival and development of Pacific lampreys Lampetra tridentata and western brook lampreys L. richardsoni during embryological and early larval stages. The temperature for zero development was estimated for each species, and the response to temperature was measured as the proportion of individuals surviving to hatch, surviving to the larval stage, and exhibiting abnormalities at the larval stage (i.e., malformations of the body). The estimated temperature for zero development was 4.85°C for Pacific lampreys and 4.97°C for western brook lampreys. Survival was greatest at 18°C, followed by 14, 10, and 22°C, significant differences being observed between 22°C and the other temperatures. Overall survival was significantly greater for western brook lampreys than for Pacific lampreys; however, the overall difference in proportion of individuals surviving was only 0.02. Overall survival significantly decreased from the time of hatch (proportion surviving = 0.85) to the larval stage (0.82; i.e., during the free‐embryo stage). The proportion of individuals exhibiting abnormalities at the larval stage was greatest at 22°C, followed by 18, 10, and 14°C, significant differences being observed between 22°C and the other temperatures. These data provide baseline information on the thermal requirements of early life stage Pacific and western brook lampreys and will aid in assessment and prediction of suitable spawning and rearing habitats for these species.

HPLC and ELISA analyses of larval bile acids from Pacific and western brook lampreys

Comparative studies were performed on two native lamprey species, Pacific lamprey ( Lampetra tridentata) and western brook lamprey ( Lampetra richardsoni) from the Pacific coast along with sea lamprey ( Petromyzon marinus) from the Great Lakes, to investigate their bile acid production and release. HPLC and ELISA analyses of the gall bladders and liver extract revealed that the major bile acid compound from Pacific and western brook larval lampreys was petromyzonol sulfate (PZS), previously identified as a migratory pheromone in larval sea lamprey. An ELISA for PZS has been developed in a working range of 20 pg–10 ng per well. The tissue concentrations of PZS in gall bladder were 127.40, 145.86, and 276.96 μg/g body mass in sea lamprey, Pacific lamprey, and western brook lamprey, respectively. Releasing rates for PZS in the three species were measured using ELISA to find that western brook and sea lamprey released PZS 20 times higher than Pacific lamprey did. Further studies are required to determine whether PZS is a chemical cue in Pacific and western brook lampreys.

Ophioxenos lampetrae sp. nov. (Digenea: Paramphistomidae) from ammocoetes of the western brook lamprey (Lampetra richardsoni Vladykov and Follett) in British Columbia, with comments on lamprey host–parasite relationships

Ophioxenos lampetrae sp. nov. (Digenea: Paramphistomidae) from the intestine of ammocoetes of the western brook lamprey (Lampetra richardsoni) in British Columbia, Canada, is described. It is distinguished from other members of the genus, O. dienteros and O. singularis (parasites of reptiles, primarily garter snakes, and amphibians in North America), by having relatively few vitelline folicles of limited anterior extent and a voluminous uterus filling most available intercaecal space. This appears to be the first record of a digenean utilizing a petromyzontid as a definitive host. Some aspects of lamprey host–parasite relationships are discussed.

Immunocytochemical studies of luteinizing hormone-releasing hormone in brains of agnathan fishes: II. Patterns of immunoreactivity in larval and maturing Western brook lamprey ( Lampetra richardsoni)

An immunocytochemical unlabeled antibody enzyme technique has been applied to localize mammalian-like immunoreactive luteinizing hormone-releasing hormone (ir-LH-RH) in central nervous tissues of Western brook lamprey ( Lampetra richardsoni). In larval animals faint specific immunocytochemical staining was found over perikarya in the posterior preoptic nucleus (PON), in fiber tracts passing ventro-posteriorly into the infundibulum, and in nerve endings in the neurohypophysis (NH). In brains of nonreproductive adults, faint staining of cell bodies was observed throughout the PON; staining of NH was intense. In reproductive adults, heavy staining was noted in PON perikarya, in beaded axons containing Herring body-like dilatations, and in NH. Perikarya with ir-LH-RH were distinct from those, presumably vasotocinergic ones, which stained with aldehyde fuchsin; specific immunocytochemical staining was absent in other brain regions and in control preparations. A change in number of cells stained, and in quality of staining was coincident with metamorphosis and sexual maturation; mechanisms by which ir-LH-RH might be transported from the preoptico-neurohypophysial system to the pars distalis to exert any physiological actions have not been established.

The neurohypophysial principles of the western brook lamprey, Lampetra richardsoni: Studies in the adult

Pharmacological and purification studies were carried out on lyophilised neurohypophysial tissues from Lampetra richardsoni and on control brain tissues. Crude neurohypophysial extracts contained 5.45 (4.41–6.73) mU/mg dry tissue of oxytocic activity; 3.27 mU/mg dry tissue appeared to be due to a neurohypophysial peptide which showed frog-bladder and other activities typical of arginine vasotocin (AVT). The use of trichloroacetic acid (TCA) and a carboxymethyl cellulose column resulted in a 190-fold purification of the peptide. Assay of the purified principle directly against synthetic AVT by different methods of assay suggested that it was AVT. Partition chromatography supported this finding. Control spinal cord tissues contained only low oxytocic activity (0.27 mU/mg dry tissue), but hindbrain materials showed the surprisingly high potency of 1.39 (1.19–1.62) mU/mg dry tissue. Purification of the hindbrain extract with TCA and carboxymethyl cellulose resolved an oxytocic agent with the thioglycollate lability and chromatographic and pharmacological properties of AVT. It amounted to approximately 0.18 mU/mg dry tissue, or only 12% of the total oxytocic activity present. The purification resolved small amounts of a number of oxytocic agents other than AVT. Some showed chromatographic similarities to oxytocin. However, none was destroyed by sodium thioglycollate. Any true neutral neurohypophysial principle could not have amounted to more than 1% of the AVT present (in terms of oxytocic activity), and there was no positive evidence for its existence in the neurohypophysis. The results suggest that AVT is the only neurohypophysial principle of L. richardsoni.

Lampetra richardsoni, a New Nonparasitic Species of Lamprey (Petromyzonidae) from Western North America

A new nonparasitic species of Petromyzonidae, Lampetra richardsoni, the western brook lamprey, from streams of British Columbia, Washington, Oregon, and possibly Alaska, is described and illustrated. This species is distinguished from Lampetra planeri (Bloch), the European brook lamprey (with which it has long been regarded as identical), by dentition, body proportions, pigmentation of the head and tail, and geographical distribution. The description is based on an examination of 275 specimens (69 transformed individuals and 206 ammocoetes).