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Geology topics

Jennifer L. Nielsen

Publications and source records attributed to Jennifer L. Nielsen.

35 records · Page 2Linked to original sources

Seasonal marine growth of Bristol Bay sockeye salmon ( Oncorhynchus nerka ) in relation to competition with Asian pink salmon ( O. gorbuscho ) and the 1977 ocean regime shift

Recent research demonstrated significantly lower growth and survival of Bristol Bay sockeye salmon ( Oncorhynchus nerka ) during odd-numbered years of their second or third years at sea (1975, 1977, etc.), a trend that was opposite that of Asian pink salmon ( O. gorbuscha ) abundance. Here we evaluated seasonal growth trends of Kvichak and Egegik river sockeye salmon (Bristol Bay stocks) during even- and odd-numbered years at sea by measuring scale circuli increments within each growth zone of each major salmon age group between 1955 and 2000. First year scale growth was not significantly different between odd- and even-numbered years, but peak growth of age-2. smolts was significantly higher than age-1 smolts. Total second and third year scale growth of salmon was significantly lower during odd- than during even-numbered years. However, reduced scale growth in odd-numbered years began after peak growth in spring and continued through summer and fall even though most pink salmon had left the high seas by late July (10-18% growth reduction in odd vs. even years). The alternating odd and even year growth pattern was consistent before and after the 1977 ocean regime shift. During 1977-2000, when salmon abundance was relatively great, sockeye salmon growth was high during specific seasons compared with that during 1955-1976, that is to say, immediately after entry to Bristol Bay, after peak growth in the first year, during the middle of the second growing season, and during spring of the third season. Growth after the spring peak in the third year at sea was relatively low during 1977-2000. We hypothesize that high consumption rates of prey by pink salmon during spring through mid-July of odd-numbered years, coupled with declining zooplankton biomass during summer and potentially cyclic abundances of squid and other prey, contributed to reduced prey availability and therefore reduced growth of Bristol Bay sockeye salmon during late spring through fall of odd-numbered years.

Alaska↗

Aniakchak sockeye salmon investigations

Aniakchak National Monument and Preserve provides unusual and dramatic landscapes shaped by numerous volcanic eruptions, a massive flood, enormous landslides, and ongoing geological change. The focal point of the monument is Aniakchak Caldera, a restless volcano that embodies the instability of the Alaska Peninsula. This geological instability creates a dynamic and challenging environment for the biological occupants of Aniakchak and unparalleled opportunities for scientists to measure the adaptability of organisms and ecosystems to change. The sockeye salmon (Oncorhynchus nerka) is one member of the Aniakchak ecosystem that has managed to adapt to geologic upheaval and is now thriving in the park. Aside from just surviving in the harsh environment, these salmon are also noteworthy for providing essential marinederived nutrients to plants and animals and as a source of food for historic and present day people in the region.

Alaska↗

Linkages between climate, growth, competition at sea and production of sockeye salmon populations in Bristol Bay, 1955-2000

Bristol Bay, Alaska, supports one of the largest and most valuable salmon fisheries in the world. Salmon abundance in Bristol Bay and other northern areas more than doubled after the 1976–77 marine climate shift. However, in 1997–98, a major El Niño event led to unusual oceanographic conditions and Bristol Bay sockeye salmon production was unexpectedly low. Nevertheless, the effect of climate on biological mechanisms leading to greater salmon survival and production are poorly understood. In order to test several hypotheses linking climate to salmon growth, interspecific and intraspecific competition, and salmon production, we measured annual marine and freshwater scale growth of Bristol Bay sockeye salmon, 1955 to 2000.

Alaska↗

A comparison of genetic ariation between an anadromous steelhead, Oncorhynchus mykiss , population and seven derived populations sequestered in freshwater for 70 years

In 1926 cannery workers from the Wakefield Fisheries Plant at Little Port Walter in Southeast Alaska captured small trout, Oncorhynchus mykiss , from a portion of Sashin Creek populated with a wild steelhead (anadromous O. mykiss ) run. They planted them into Sashin Lake which had been fishless to that time and separated from the lower stream by two large waterfalls that prevented upstream migration of any fish. In 1996 we sampled adult steelhead from the lower creek and juvenile O. mykiss from an intermediate portion of the creek, Sashin Lake, and five lakes that had been stocked with fish from Sashin Lake in 1938. Tissue samples from these eight populations were compared for variation in: microsatellite DNA at 10 loci; D-loop sequences in mitochondrial DNA; and allozymes at 73 loci known to be variable in steelhead. Genetic variability was consistently less in the Sashin Lake population and all derived populations than in the source anadromous population. The cause of this reduction is unknown but it is likely that very few fish survived to reproduce from the initial transplant in 1926. Stockings of 50–85 fish into five other fishless lakes in 1938 from Sashin Lake did not result in a similar dramatic reduction in variability. We discuss potential explanations for the observed patterns of genetic diversity in relation to the maintenance of endangered anadromous O. mykiss populations in freshwater refugia.

Alaska↗

Sustaining salmonid populations: A caring understanding of naturalness of taxa

Species of the family of Salmonidae occur naturally in Northern Hemisphere waters that remain clear and cool to cold in summer. For purposes of reproduction, salmonids generally behaviorally respond to the currents of streams and lakes in recently glaciated areas. For feeding and maturation, many larger species migrate into existing systems of large lakes, seas, and oceans. The subfamilies include Salmoninae, Coregoninae, and Thymallinae. In many locales and regions of the hemisphere, numerous species of these subfamilies evolved and self-organized into species flocks or taxocenes of bewildering complexity. For example, any individual species may play different or unique ecological roles in different taxocenes. The northern Pacific and Atlantic Ocean ecosystems, with their seas and tributaries, each contained a metacomplex of such taxocenes that, in their natural state some centuries ago, resembled each other but differed in many ways. Humans have valued all species of this family for subsistence, ceremonial, naturalist, gustatory, angling, and commercial reasons for centuries. Modern progressive humans (MPHs), whose industrial and commercial enterprises have gradually spread over this hemisphere in recent time, now affect aquatic ecosystems at all scales from local to global. These human effects mingle in complex ways that together induce uniquely natural salmonid taxocenes to disintegrate with the loss of species, including those groups least tolerant to human manipulations, but extending more recently to those taxa more adapted to anthropogenic change. As we leave the modern era, dominated by MPHs, will we find ways to live sustainably with salmonid taxocenes that still exhibit self-organizational integrity, or will only individual, isolated populations of salmonid species, derived from those most tolerant of MPHs, survive? To achieve future sustainability of salmonids, we suggest implementation of a search for intuitive knowledge based on faith in the wisdom of nature and a caring-sharing, behavioral structure based on "survival of the wisest" for both humans and salmonids.

Conference Paper↗

Exploitation dynamics of small fish stocks like Arctic cisco

Potential impacts to the Arctic cisco population fall into both demographic and behavioral categories. Possible demographic impacts include stock recruitment effects, limited escapement into marine habitats, and variable age-class reproductive success. Potential behavioral impacts involve migratory patterns, variable life histories, and strategies for seasonal feeding. Arctic cisco stocks are highly susceptible to over-exploitation due to our limited basic knowledge of the highly variable Arctic environment and the role they play in this dynamic ecosystem. Our knowledge of potential demographic changes is very limited, and it is necessary to determine the abundance and recruitment of the hypothesized Mackenzie River source population, the extent of the coastal migratory corridor, growth patterns, and coastal upwelling and mixing effects on population dynamics for this species. Information needed to answer some of the demographic questions includes basic evolutionary history and molecular genetics of Arctic cisco (for instance, are there contributions to the Arctic cisco stock from the Yukon?), what is the effective population size (i.e., breeding population size), and potential links to changes in climate. The basic behavioral questions include migratory and variable life history questions. For instance, the extent of movement back and forth between freshwater and the sea, age-specific differences in food web dynamics, and nearshore brackish and high salinity habitats are topics that should be studied. Life history data should be gathered to understand the variation in age at reproduction, salinity tolerance, scale and duration of the freshwater stage, survival, and adult migration. Both molecular and ecological tools should be integrated to manage the Arctic cisco stock(s), such as understanding global climate changes on patterns of harvest and recruitment, and the genetics of population structure and colonization. Perhaps other populations are contributing to the population within the Colville River other than only the Mackenzie River population. This needs further exploration. By examining otolith microchemistry, unique transitions from freshwater to sea can be identified for these stocks. This may shed light on why some fish arrive at the mouth of the Colville River, while others don’t.

Conference Paper↗

Testing archival tag technology in coho salmon

Archive tags with temperature and light-geolocation sensors will be monitored for post-smolt coho salmon in Cook Inlet. Light/location relationships specific to the Gulf of Alaska developed under Project 00478 will be applied in this study of movement and migration paths for coho salmon during maturation in ocean environments in Cook Inlet. Salmon for this study will be reared in captivity (at the Alaska Department of Fish and Game hatchery at Fort Richardson) to 1+ year of age (200-250mm) and released in Cook Inlet as part of the department's Ship Creek sport-fishing hatchery release. FY 01 includes pilot studies of tag retention, behavior, and growth for coho in captivity. Ship Creek coho will be tagged mid-May. A spring release experiment in the first year will be contingent on the successful implementation and retention of these tags. Surveys for early jack recoveries will be done at the Ship Creek weir and among sport fishers. Monitoring for adult tag recoveries will be done in the coho commercial fishery in Cook Inlet and the derby sport fishery on Ship Creek. Archive tagged fish will be used to document coho salmon use of marine habitats, migration routes, contribution to the sport fishery, and hatchery/wild interactions for salmon in Cook Inlet.

Alaska↗

History and effects of hatchery salmon in the Pacific

There has been a long history of production of hatchery salmon along the Pacific coast - from California’s first efforts in the 1870s using eggs from chinook and rainbow trout to the recent large-scale production hatcheries for pink salmon in Japan and the Russian Far East. The rationale for this production has also varied from replacement of fish lost in commercial ocean harvests to mitigation and restoration of salmon in areas where extensive habitat alteration has reduced salmonid viability and abundance. Over the years, we have become very successful in producing a certain type of product from salmon hatcheries, but until recently we seldom questioned the impacts the production and release of hatchery fish may have on freshwater and marine aquatic ecosystems and on the sustainability of sympatric wild salmon populations. This paper addresses the history of hatcheries around the Pacific Rim and considers potential negative implications of hatchery-produced salmon through discussions of biological impacts and biodiversity, ecological impacts and competitive displacement, fish and ecosystem health, and genetic impacts of hatchery fish as threats to wild populations of Pacific salmon.

Speaking for the Salmon↗

Pop-up archival transmitting (PAT) tags: A method to investigate the migration and behavior of Pacific halibut ( Hippoglossus stenolepis ) in the Gulf of Alaska

Pop-up archival transmitting (PAT) tags provide a fisheries-independent method of collecting environmental preference data (depth and ambient water temperature) and migration distance. In this study, we evaluate the use of pop-up archival transmitting tags as a method to investigate demersal fish. We report the results from eight pop-up archival transmitting tagged Pacific halibut Hippoglossus stenolepis (from 107 to 165 cm FL) that were released in and around Resurrection Bay, Alaska. Commercial fishermen recovered three tags, while five tags transmitted data to Argos satellites. Horizontal migration was not consistent among fish as four Pacific halibut remained in the vicinity of release while the other four traveled up to 358 km from the release site. Vertical movement was not consistent among fish or over time; however, they spent most of their time at depths of 150 to 350 m. The minimum and maximum depths reached by any of the Pacific halibut were 2 m and 502 m, respectively. The fish preferred water temperatures of approximately 6°C, but experienced temperatures between 4.3 and 12.2°C. Light attenuation with depth prevented geolocation software and light sensing hardware from accurately estimating geoposition for the majority of days. The methods, adapted from investigations on large pelagic fish, proved to be effective for studying Pacific halibut in the northern Gulf of Alaska. PAT tags allowed us to obtain high accuracy locations of the fish at the end of the tag deployments as well as preliminary data to identify approximate seasonal locations and to characterize their depth and temperature characteristics. By using PAT tags, we will be able to ensure tag returns during the winter season (which is closed to fishing) and gain valuable biological information even if fish migrate large distances or to unexpected locations.

Alaska Fishery Research Bulletin↗

Population genetic structure of Santa Ynez rainbow trout – 2001 based on microsatellite and mtDNA analyses

Microsatellite allelic and mitochondrial DNA (mtDNA) haplotype diversity are analyzed in eight rainbow trout ( Oncorhynchus mykiss ) collections: two from tributaries flowing into the upper Santa Ynez River watershed at Gibraltar Reservoir (Camuesa and Gidney creeks); three from tributaries between Gibraltar and Jameson reservoirs (Fox, Blue Canyon, and Alder creeks); one from a tributary above Jameson Reservoir (Juncal Creek); Jameson Reservoir; and one from the mainstem Santa Ynez River above the Jameson Reservoir. Both analyses reveal a high degree of population structure. Thirteen microsatellite loci are amplified from 376 fish. Population pairwise comparisons show significant differences in allelic frequency among all populations with the exception of Juncal Creek and Jameson Reservoir (p = 0.4). Pairwise F st values range from 0.001 (Juncal Creek and Jameson Reservoir) to 0.17 (Camuesa and Juncal creeks) with an overall value of 0.021. Regression analyses (Slatkin 1993) supports an isolation-bydistance model in the five populations below Jameson Reservoir (intercept = 1.187, slope = -0.41, r2 = 0.67). A neighbor-joining bootstrap value of 100% (based on 2000 replicate trees) separates the populations sampled above and below Juncal Dam. Composite haplotypes from 321 fish generated using mtDNA sequence data (Dloop) reveal four previously described haplotypes (MYS1, MYS3, MYS5 and MYS8; Nielsen et al. 1994a), and one (MYS5) was found in all populations. Mean haplotype diversity is 0.48. Pairwise F st values from mtDNA range from -0.019 to 0.530 (0.177 over all populations) and are larger than those for microsatellites in 26 of 28 pairwise comparisons. In addition, the mtDNA and microsatellites provide contrasting evidence of the relationship of Fox and Alder creeks to the other six populations. Discrepancies between the two markers are likely due to the unique properties of the two marker types and their value in revealing historic (mtDNA) versus contemporary (microsatellites) genetic relationships. The contrasting results may indicate how relationships among the upper Santa Ynez River populations have changed since the installation of Juncal Dam. Comparisons of mtDNA haplotype frequencies from fish collected for this study with samples analyzed previously in JLN’s laboratory (1993) reveal significant differences in mtDNA haplotypes for Fox and Alder creeks. In the 2001 samples from this study, there is a loss of three haplotypes despite larger sample sizes. AMOVA analysis of what we term “upper” (Alder, Fox, Blue Canyon, Camuesa, Gidney creeks and the upper Santa Ynez mainstem) and “lower” (Hilton, Salsipuedes and the lower mainstem Santa Ynez River) Santa Ynez River populations (1993-2001) reveal that 11% of the variance in haplotypes is found between the upper and lower drainage. A comparison of the mtDNA data from this study with those available for southern California coastal and California hatchery O. mykiss populations yields F st values of 0.15 and 0.47, respectively. Differentiation of mtDNA haplotypes for population pairs of Santa Ynez River and hatchery fish show no significant differentiation between wild and at least one hatchery strain in Cachuma Reservoir, Hilton Creek, and the Lower Santa Ynez River.

California↗

Population genetic structure in Lahontan cutthroat trout

We used 10 microsatellite loci to examine the genetic population structure of cutthroat trout Oncorhynchus clarki within the Lahontan Basin complex. Genetic diversity was analyzed for trout from Nevada, California, and Utah representing three putative subspecies: Lahontan O. c. henshawi , Paiute O. c. seleniris , and Humboldt (an unnamed subspecies) cutthroat trout. We found significant differences in microsatellite diversity among the three putative subspecies found in this area. Analysis of molecular variance partitioned microsatellite variation as 9.8% among subspecies, 27.7% among populations, and 62.5% within populations of Lahontan Basin cutthroat trout. Genetic distance analyses (Cavalli-Sforza-Edwards and F st ) supported unique population structure in cutthroat trout from the Humboldt and Pilot Peak drainages. Pairwise F st values for Lahontan cutthroat trout were not significantly correlated with geographic distance between population pairs ( r 2 = 0.008; P < 0.0001), suggesting that they are extremely isolated populations with small effective sizes that are vulnerable to extinction. Two extant hatchery strains of Lahontan cutthroat trout showed genetic associations with different geographic source populations. The Pyramid Lake hatchery strain was most closely associated genetically with fish from Summit Lake. The Pilot Peak hatchery strain was associated genetically with Pilot Peak wild trout (Utah) and Macklin Creek trout (California). The phylogeographic diversity depicted in this study supports unique population structure and suggests important evolutionary relationships needed to evaluate transplanted populations and hatchery supplementation within the basin.

California, Idaho, Nevada, Oregon↗

Testing pop-up satellite tags as a tool for identifying critical habitat for Pacific halibut ( Hippoglossus stenolepis ) in the Gulf of Alaska

To maintain healthy commercial and sport fisheries for Pacific halibut ( Hippoglossus stenolepis ), critical habitat must be defined by determining life history patterns on a daily and seasonal basis. Pop-up satellite archival transmitting (PSAT) tags provide a fisheries-independent method of collecting environmental preference data (depth and ambient water temperature) as well as daily geolocation estimates based on ambient light conditions. In this study, 14 adult halibut (107-165 cm FL) were tagged and released with PSAT tags in and around Resurrection Bay, Alaska. Commercial fishermen recovered two tags, while five tags transmitted data to ARGOS satellites. Horizontal migration was not consistent among fish as three halibut remained in the vicinity of release while four traveled up to 358 km from the release site. Vertical migration was not consistent among fish and over time, but they spent most their time between 150-350 m. The minimum and maximum depths reached by any of the halibut were 2m and 502m, respectively. The fish preferred water temperatures of roughly 6 °C while experiencing ambient temperatures between 4.3 °C and 12.2 °C. Light attenuation with depth prevented existing geolocation software and light sensing hardware from accurately estimating geoposition, however, information from temperature, depth, ocean bathymetry, and pop-off locations provided inference on fish movement in the study area. PSAT tags were a viable tool for determining daily and seasonal behavior and identifying critical halibut habitat, which will aid fisheries managers in future decisions regarding commercial and sport fishing regulations.

Alaska↗

The role of hybridization in the distribution, conservation and management of aquatic species: Symposium review

This issue of Reviews in Fish Biology and Fisheries contains six papers addressing several critical aspects of hybridization in fishes and aquatic organisms. Hybridization is a phenomenon long recognized in fishes (Hubbs, 1920, 1955; Schwarz, 1981), as well as in other plant and vertebrate taxa, despite some rather dogmatic proclamations to the contrary, e.g., comments made by David Starr Jordan at the beginning of the 20th century that the species “line” is rarely crossed in fishes (Clark Hubbs, personal communication). Since that time, interspecific genetic introgression has been well documented in many fish genera and species: Barbus (Berrebi and CattaneoBerrebi, 1993); Cyprinodon (Echelle and Connor, 1989; Dowling and DeMarais, 1993); Gambusia (Hubbs, 1959; Scribner and Avise, 1994); Esox (Wahl and Stein, 1993); Lepomis (Avise et al., 1984); Luxilus (Duvernell and Aspinwall, 1995); Morone (Harrell et al., 1993); Notropis (Dowling et al., 1989; Dowling and Hoeh, 1991); Oncorhynchus (Busack and Gall, 1981; Campton and Utter, 1985; Loudenslager et al., 1986; Leary et al., 1987; Forbes and Allendorf, 1991; Dowling and Childs, 1992); Salmo (Nyman, 1970; Wilkins et al., 1993; Giuffra et al., 1996; Hartley, 1996; Perez et al., 1999); Salvalinus (Hammar et al., 1991; Bernatchez et al., 1995; Baxter et al., 1997; Glemet et al., 1998; Wilson and Bernatchez, 1998); Sebastes (Seeb, 1988); Stizostedion (Billington et al., 1988). See also reviews in Campton (1987), Verspoor and Hammar (1991), Smith (1992), and Scribner et al. (2000). More recently, a number of investigations have documented not only first generation hybrids, but also subsequent generation introgressant hybrids (Bartley et al., 1990; Verspoor and Hammar, 1991). As a result, our views about species typology and hybrids continue to change.

Reviews in Fish Biology and Fisheries↗

Microsatellite analyses of San Franciscuito Creek rainbow trout

Microsatellite genetic diversity found in San Francisquito Creek rainbow trout support a close genetic relationship with rainbow trout ( Oncorhynchus mykiss ) from another tributary of San Francisco Bay, Alameda Creek, and coastal trout found in Lagunitas Creek, Marin County, California. Fish collected for this study from San Francisquito Creek showed a closer genetic relationship to fish from the north-central California steelhead ESU than for any other listed group of O. mykiss . No significant genotypic or allelic frequency associations could be drawn between San Francisquito Creek trout and fish collected from the four primary rainbow trout hatchery strains in use in California, i.e. Whitney, Mount Shasta, Coleman, and Hot Creek hatchery fish. Indeed, genetic distance analyses ( δµ 2 ) supported separation between San Francisquito Creek trout and all hatchery trout with 68% bootstrap values in 1000 replicate neighbor-joining trees. Not surprisingly, California hatchery rainbow trout showed their closest evolutionary relationships with contemporary stocks derived from the Sacramento River. Wild collections of rainbow trout from the Sacramento-San Joaquin basin in the Central Valley were also clearly separable from San Francisquito Creek fish supporting separate, independent ESUs for two groups of O. mykiss (one coastal and one Central Valley) with potentially overlapping life histories in San Francisco Bay. These data support the implementation of management and conservation programs for rainbow trout in the San Francisquito Creek drainage as part of the central California coastal steelhead ESU.

California↗

Microsatellite analyses of Alameda Creek Rainbow/Steelhead trout

Microsatellite genetic diversity found in Alameda Creek rainbow trout support a close genetic relationship with coastal trout found in Lagunitas Creek, Marin County, California. No significant genotypic or allelic frequencies associations could be drawn among Alameda Creek trout and fish collected from the four primary rainbow trout hatchery strains in use in California, Whitney, Mount Shasta, Coleman, and Hot Creek strains, indeed, genetic distance analyses (δμ 2 ) supported genetic separation among Alameda Creek trout and hatchery trout with greater than 50% bootstrap values in 1000 replicate neighbor-joining trees. Fish collected for this study from Palo Seco and Sheppard Creeks shared allelic frequencies with both the fish in Alameda Creek and those found in Scott Creek in Santa Cruz County. Fish collected in Horseshoe Creek or San Lorenzo Creek (Alameda County) did not share this unique genetic relationship between Alameda Creek fish and putative wild coastal trout. These two streams had allelic frequencies similar to some hatchery trout strains and to wild trout captured in the Central Valley. These data suggest that there are two possible steelhead ESUs using the tributaries of San Francisco Bay (one coastal and one Central Valley) or that hatchery trout supplementation has impacted some, but not all streams with a subsequent loss of locally adapted genetic characteristics. These data support the implementation of conservation management of rainbow trout in the Alameda Creek drainage as part of the central California coastal steelhead ESU.

California↗

Uncertainty and instream flow standards

Several years ago, Science published an important essay (Ludwig et al. 1993) on the need to confront the scientific uncertainty associated with managing natural resources. The essay did not discuss instream flow standards explicitly, but its arguments apply. At an April 1995 workshop in Davis, California, all 12 participants agreed that currently no scientifically defensible method exists for defining the instream flows needed to protect particular species of fish or aquatic ecosystems (Williams, in press). We also agreed that acknowledging this fact is an essential step in dealing rationally and effectively with the problem. Practical necessity and the protection of fishery resources require that new instream flow standards be established and that existing standards be revised. However, if standards cannot be defined scientifically, how can this be done? We join others in recommending the approach of adaptive management. Applied to instream flow standards, this approach involves at least three elements.

Fisheries↗