Damon H. Goodman

Neither philopatric nor panmictic: microsatellite and mtDNA evidence suggests lack of natal homing but limits to dispersal in Pacific lamprey

Most species with lengthy migrations display some degree of natal homing; some (e.g. migratory birds and anadromous salmonids) show spectacular feats of homing. However, studies of the sea lamprey (Petromyzon marinus) indicate that this anadromous species locates spawning habitat based on pheromonal cues from larvae rather than through philopatry. Previous genetic studies in the anadromous Pacific lamprey (Entosphenus tridentatus) have both supported and rejected the hypothesis of natal homing. To resolve this, we used nine microsatellite loci to examine the population structure in 965 Pacific lamprey from 20 locations from central British Columbia to southern California and supplemented this analysis with mitochondrial DNA restriction fragment length polymorphism analysis on a subset of 530 lamprey. Microsatellite analysis revealed (i) relatively low but often statistically significant genetic differentiation among locations (97% pairwise FST values were <0.04 but 73.7% were significant); and (ii) weak but significant isolation by distance (r2 = 0.0565, P = 0.0450) but no geographic clustering of samples. The few moderate FST values involved comparisons with sites that were geographically distant or far upstream. The mtDNA analysis—although providing less resolution among sites (only 4.7%FST values were significant)—was broadly consistent with the microsatellite results: (i) the southernmost site and some sites tributary to the Salish Sea were genetically distinct; and (ii) southern sites showed higher haplotype and private haplotype richness. These results are inconsistent with philopatry, suggesting that anadromous lampreys are unusual among species with long migrations, but suggest that limited dispersal at sea precludes panmixia in this species.

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.

Pacific Lamprey in Coastal Drainages of California: Occupancy Patterns and Contraction of the Southern Range

AbstractPacific Lamprey Entosphenus tridentatus have been overlooked historically in fish surveys using standard salmonid methods along the Pacific coast of North America. As a result, little is known of even their broader distribution patterns at the drainage level. Over the last 2 decades, the species has shown a northward range contraction of over 900 km, and at this time the southernmost population is the Big Sur River in California. This study evaluates the hypothesis that Pacific Lampreys do not typically utilize relatively small coastal drainages ( 100 km2, but in only 3 of 29 drainages 50 km2, and primarily fr...

Free-swimming speeds and behavior in adult Pacific Lamprey, Entosphenus tridentatus

Lampreys are extremely efficient anguilliform swimmers, well–designed for long–distance travel, although they are frequently characterized as poor swimmers when compared to salmonids. We examine free–swimming adult Pacific Lamprey, Entosphenus tridentatus, in a raceway environment to approximate swim speeds and behaviors that may occur in the natural environment. Lampreys (mean Body Length 59.2 ± 3.0 cm, range 50–66 cm BL) traveled upstream at a mean groundspeed of 0.34 ± 0.188 BL/s (n=126, range 0.01–0.79 BL/s). Swimming activity was strongly nocturnal. Observed speeds in the lower range may have been the result of swimming in midwater against faster currents, indirect paths or rest periods. Lampreys generally took advantage of lower near–bottom current velocities by swimming within 6 cm of the bottom, where currents were substantially lower. Equivalent swim speeds, without currents, would be 0.49 ± 0.190 BL/s (range 0.17–0.96 BL/s). These speeds are in the high range of daily travel rates encountered in tagging studies of both Pacific Lamprey and Atlantic Sea Lamprey, Petromyzon marinus, but compare well when migration is limited to hours of darkness or tracking was continuous. Such rates suggest that, travelling only at night, lampreys would cover 1,000 km upriver in under four months. It is crucial that managers and designers incorporate the swimming capability, near–bottom association, utilization of boundary flow conditions, and nocturnal behavior of lampreys into their activities if we are to effectively manage in-stream facilities and conserve these key anadromous species.

Screen Efficiency and Implications for Losses of Lamprey Macrophthalmia at California’s Largest Water Diversions

AbstractWe investigated the guidance efficiency of fish screens for the protection of emigrating Pacific Lamprey Entosphenus tridentatus and Western River Lamprey (also known as River Lamprey) Lampetra ayresii in a series of experimental trials. All trials were conducted at the Tracy Fish Collection Facility, located in the Sacramento–San Joaquin River Estuary at the entrance to one of the world’s largest surface water diversions. Using 1,200 lamprey macrophthalmia, we tested for the effect of screen type, time of day, and channel water velocity to guide their swimming behavior to avoid entrainment. We found overwhelming evidence for an effect of screen type on efficiency, whereby all lampreys were successfully guided to a holding tank when a vertical traveling screen was used. This was likely due to the small pore size of the screen relative to lamprey sizes. In contrast, the efficiency of louvers, a behavioral screen designed for salmonids, varied by the interaction of time of day and channel velocity. ...