The Pacific Lamprey Entosphenus tridentatus is an anadromous fish that has severely declined in the Snake River basin. In 2007, the Nez Perce Tribe initiated translocation of adults to this region from the main-stem Columbia River and has continued the translocations to this day. These actions are aimed at restoring larval abundance along with holistic habitat improvements. We performed parentage and sibship analyses with 260 single-nucleotide polymorphism loci to monitor productivity of translocated lamprey over a decade (2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018). These results provide the first direct evidence that translocations boosted larval abundance, increased juvenile production in the interior Columbia River (~3% in 2017 and 2018), and demonstrated successful migration to the Pacific Ocean. Per capita juvenile production from Snake River adult lamprey translocations out-performed that of their volitionally migrating counterparts in the interior Columbia River, demonstrating that translocating adults to suitable habitats increased overall productivity. We projected that the translocations may eventually return enough adult offspring to the Columbia River to replace the annual take of adults for translocations, despite many adults likely returning to other basins. These translocations are also restoring Pacific Lamprey to historical areas where they had been nearly extirpated, which has impactful benefits both culturally and ecologically. Further, this study provided an unprecedented volume of data that has redefined key biological attributes, including timing of life stage transformation (average of 6.7-year-old juveniles), larval growth rates (~22 mm/year for the first 4 years), ocean duration (average of 5.1 years), dispersal (~3% of Snake River-origin adults that return to the Columbia River will divert to the Willamette River), and life span (median age of postspawn adults was 12.9 years). We even quantified a new biological phenomenon of delayed spawning, which occurs at low rates (~9%) in nature. These data provide an opportunity to monitor ongoing translocation efforts and inform adaptive management to aid species recovery.

Fish migrations are energetically costly, especially when moving between freshwater and saltwater, but are a viable strategy for Pacific salmon and trout (Oncorhynchus spp.) due to the advantageous resources available at various life stages. Anadromous steelhead (O. mykiss) migrate vast distances and exhibit variation for adult migration phenotypes that have a genetic basis at candidate genes known as greb1L and rock1. We examined the distribution of genetic variation at 13 candidate markers spanning greb1L, intergenic, and rock1 regions versus 226 neutral markers for 113 populations (n = 9,471) of steelhead from inland and coastal lineages in the Columbia River. Patterns of population structure with neutral markers reflected genetic similarity by geographic region as demonstrated in previous studies, but candidate markers clustered populations by genetic variation associated with adult migration timing. Mature alleles for late migration had the highest frequency overall in steelhead populations throughout the Columbia River, with only 9 of 113 populations that had a higher frequency of premature alleles for early migration. While a single haplotype block was evident for the coastal lineage, we identified multiple haplotype blocks for the inland lineage. The inland lineage had one haplotype block that corresponded to candidate markers within the greb1L gene and immediately upstream in the intergenic region, and the second block only contained candidate markers from the intergenic region. Haplotype frequencies had similar patterns of geographic distribution as single markers, but there were distinct differences in frequency between the two haplotype blocks for the inland lineage. This may represent multiple recombination events that differed between lineages where phenotypic differences exist between freshwater entry versus arrival timing as indicated by Micheletti et al. (2018a). Redundancy analyses were used to model environmental effects on allelic frequencies of candidate markers, and significant variables were migration distance, temperature, isothermality, and annual precipitation. This study improves our understanding of the spatial distribution of genetic variation underlying adult migration timing in steelhead as well as associated environmental factors and has direct conservation and management implications.

Removal of two dams in the Elwha River basin, Washington, started one of the largest river restoration projects ever attempted in the Pacific Northwest. These dams had eliminated Pacific Lamprey Entosphenus tridentatus populations upstream. After the dam removals, larval production increased in the upper watershed, but the sources and numbers of new adult spawners were unknown. We applied genetic stock identification (GSI), parentage assignment (PA), and sibship assignment (SA) methods to (1) determine the origins of Pacific Lamprey larvae and juveniles, (2) quantify the increase in numbers of successful Elwha River spawners (i.e., effective number of breeders [Nb]) and assess whether the current numbers of spawners have reached levels equivalent to those of neighboring undammed basins, and (3) determine the relative productivity of streams within the Elwha River and how overall productivity originating from this system may be distributed across the broader surrounding region. We utilized a highly accurate set of 263 single‐nucleotide polymorphism (SNP) loci to perform PA and SA (>99% accuracy rate) and an additional set of 28 SNPs for GSI. Our results showed that a single stream (Indian Creek) was the source of 41% of larval and juvenile production in the Elwha River. Our Nb estimates for the Elwha River indicated a 12‐fold increase in Nb during the 3 years after dam removal, with recent Nb estimates matching those of neighboring Olympic Peninsula basins. These results indicate rapid recolonization potential for this highly dispersive species, and high productivity within the Elwha River suggests that restoring passage to adequate habitat is a highly effective approach for re‐establishing populations of Pacific Lamprey in coastal systems.

Results of crossing triploid females of ornamental koi, a variant of Common Carp Cyprinus carpio, with diploid koi males in two consecutive spawning seasons (2014 and 2015) are presented. A total of seven progenies from six triploid females (one female was spawned twice) were produced and analyzed. The same as normal diploid females, triploid females were highly fertile and produced hundreds of thousands of eggs (up to 400,000 per female). Processes of embryo incubation and hatching of larvae in progenies obtained from triploid females proceeded normally; however, mass mortality of hatched larvae occurred at the swim‐up stage. Nevertheless about 200,000 swim‐up larvae were obtained and stocked for further rearing. A total of about 1,000 juveniles (or 0.5% of the number of stocked larvae) was collected from outdoor tanks. As expected, all analyzed larvae and juveniles in control progenies obtained by crosses of diploid females with diploid males were diploid. About 95% of analyzed fish (larvae and juveniles) obtained by crossing triploid females with diploid males were aneuploids with ploidy ranging from 2.14n to 3.0n; mean values of fish ploidy in progenies obtained from different triploid females varied from 2.47n to 2.63n. Since aneuploid fish have in their genomes one haploid set from parental males, the data obtained indicate that triploid koi females produced aneuploid eggs with ploidy range from haploid to diploid level and a modal ploidy level around 1.5n, similar to the production of aneuploid spermatozoa observed earlier for triploid males in fish. About 5% of juveniles obtained from triploid females had ploidy range from 3.21n to 4.0n. Apparently these fish resulted from spontaneous suppression of the second meiotic division in aneuploid eggs.