Do bears facilitate transfer of salmon resources to aquatic macroinvertebrates?

2005 ◽  
Vol 62 (10) ◽  
pp. 2285-2293 ◽  
Author(s):  
Monika Winder ◽  
Daniel E Schindler ◽  
Jonathan W Moore ◽  
Susan P Johnson ◽  
Wendy J Palen
Keyword(s):  
Pacific Northwest ◽  
Life Histories ◽  
Pacific Salmon ◽  
Stream Invertebrates ◽  
The Pacific ◽  
Salmon Carcass ◽  
Isotope Analyses ◽  
Long Term Survey ◽  
Spawning Habitats

In coastal areas of the Pacific Northwest bears (Ursus spp.) prey heavily on spawning Pacific salmon (Oncorhynchus spp.) and selectively kill energy-rich individuals that are the most recent arrivals on spawning grounds. Pacific salmon eventually die in spawning habitats anyway, albeit with considerably lower energetic content. We investigated whether foraging activities of bears facilitate growth of stream invertebrates by increasing the duration of salmon carcass availability and the nutritional value of carcasses for scavengers. Our survey in southwest Alaska showed that carcasses are highly colonized by caddisfly (Trichoptera) larvae. Caddisflies show a strong preference for bear-killed over senescent carcasses, which may be a result of extended temporal availability, improved accessibility of consumable tissue, and higher energetic content of bear-killed fish. Isotope analyses further indicate uptake of marine-derived nutrients in caddisflies during the salmon run, which, however, does not extend into subsequent generations. Thus, species with life histories linked to the annual marine derived nutrient pulse gain the biggest advantage from the salmon resource subsidy. A long-term survey in several creeks in this region showed that bear predation intensity varied greatly among creeks and years, therefore indirect effects of bear predation on aquatic scavengers are likely highly patchy in time and space.

Propagated Fish in Resource Management

2004 ◽  
Keyword(s):  
Pacific Northwest ◽  
Natural Population ◽  
Pacific Salmon ◽  
Monitoring And Evaluation ◽  
Wild Fish ◽  
Large Numbers ◽  
The Pacific ◽  
In Captivity ◽  
National Marine Fisheries Service

<em>Abstract.</em>—A number of stocks of anadromous salmonids in the Pacific Northwest are currently listed by the National Marine Fisheries Service (NOAA Fisheries) as threatened or endangered under the U.S. Endangered Species Act (ESA). The ESA recognizes that conservation of listed species may be facilitated by artificial propagation, including captive broodstocks, while factors impeding population recovery are identified and corrected. Captive broodstock programs differ from conventional salmon culture in that fish of wild origin are maintained in captivity throughout their life to produce offspring for the purpose of supplementing wild populations. The relatively short generation time (2–7 years) and potential to produce large numbers of offspring (1,500–5,000 eggs per female average, depending on the species) make Pacific salmon ideal for captive broodstock rearing. However, the technology is not without potential complications and risks. The paper presents guidelines to ensure a sound basis for implementation of captive broodstocks. Considerations must be based on overall knowledge of survival, reproductive success, and offspring fitness to accurately determine levels of risk in implementing a salmonid captive broodstock program. In general, use of captive broodstocks should be restricted to situations where the natural population is dangerously close to extinction. Proper precautions should be taken to minimize genetic impacts during the collection, mating, and rearing of captive broodstocks, as any alteration to the original genetic composition of the population in captivity may reduce the efficacy of supplementation in rebuilding the natural population. Furthermore, liberation of fish from captive broodstocks should be consistent with the known behavior of existing wild fish and on whatever knowledge is available of the life history characteristics of the wild fish. Because the benefits and risks have not been established through long-term monitoring and evaluation, captive broodstock development should be considered an experimental approach and used with caution.

Long-term growth-increment chronologies reveal diverse influences of climate forcing on freshwater and forest biota in the Pacific Northwest

2014 ◽  
Vol 21 (2) ◽  
pp. 594-604 ◽  
Author(s):  
Bryan A. Black ◽  
Jason B. Dunham ◽  
Brett W. Blundon ◽  
Jayne Brim-Box ◽  
Alan J. Tepley
Keyword(s):  
Pacific Northwest ◽  
Growth Increment ◽  
Climate Forcing ◽  
The Pacific

Detecting persistent change in the habitat of salmon-bearing streams in the Pacific Northwest

2004 ◽  
Vol 61 (2) ◽  
pp. 283-291 ◽  
Author(s):  
David P Larsen ◽  
Philip R Kaufmann ◽  
Thomas M Kincaid ◽  
N Scott Urquhart
Keyword(s):  
Pacific Northwest ◽  
Pacific Salmon ◽  
Monitoring Network ◽  
Habitat Characteristics ◽  
Detection Sensitivity ◽  
Trend Detection ◽  
Spatial And Temporal Variation ◽  
The Pacific ◽  
Two Factors ◽  
Consistent Change

In the northwestern United States, there is considerable interest in the recovery of Pacific salmon (Oncorhynchus spp.) populations listed as threatened or endangered. A critical component of any salmon recovery effort is the improvement of stream habitat that supports various life stages. Two factors in concert control our ability to detect consistent change in habitat conditions that could result from significant expenditures on habitat improvement: the magnitude of spatial and temporal variation and the design of the monitoring network. We summarize the important components of variation that affect trend detection and explain how well-designed networks of 30–50 sites monitored consistently over years can detect underlying changes of 1–2% per year in a variety of key habitat characteristics within 10–20 years, or sooner, if such trends are present. We emphasize the importance of the duration of surveys for trend detection sensitivity because the power to detect trends improves substantially with the passage of years.

Low Mortality of Larval Lampreys from Electrofishing, Suction-pumping, Anesthesia, and Handling

2017 ◽  
Vol 8 (2) ◽  
pp. 640-647 ◽  
Author(s):  
Jeffrey C. Jolley ◽  
Christina T. Uh ◽  
Gregory S. Silver ◽  
Timothy A. Whitesel
Keyword(s):  
Pacific Northwest ◽  
Control Group ◽  
Long Term Effects ◽  
Negative Effects ◽  
Short Term ◽  
Important Species ◽  
Pacific Lamprey ◽  
The Pacific ◽  
Delayed Mortality

Abstract Native lamprey populations are declining worldwide. In the Pacific Northwest focus on conservation and management of these ecologically and culturally important species has increased. Concern has emerged regarding the effects of sampling and handling of lamprey, with little to no attention given to the larval lifestage. We monitored the survival of larval Pacific Lamprey Entosphenus tridentatus and Lampetra spp. after backpack electrofishing, deepwater electrofishing and suction-pumping, anesthesia, and handling. We performed survival trials on wild-caught lamprey (n = 15 larvae in each trial) collected from the Clackamas River drainage in Oregon, USA, coupled with control group trials from lamprey sourced from a hatchery (n = 10 larvae). Short-term (96 h) survival was &gt;98% with only one observed mortality. Delayed mortality (1 wk) was observed for four individuals that had fungus; two of those were positive for the bacteria Aeromonas hyrdrophila. We recorded blood hematocrit as a secondary measure of stress. The baseline, nonstressed larvae hematocrit levels did not differ from those of fish that had undergone stress through electrofishing, suction-pumping, and handling without anesthesia. Electrofishing, suction-pumping, and anesthesia showed no short-term negative effects on larval lamprey although potential long-term effects remain unstudied. These techniques appear to provide efficient and relatively safe methods for collecting and surveying larval lamprey.

Long-Term Effects of Tillage, Nitrogen, and Rainfall on Winter Wheat Yields in the Pacific Northwest

2003 ◽  
Vol 95 (4) ◽  
pp. 828-835 ◽  
Author(s):  
K. M. Camara ◽  
W. A. Payne ◽  
P. E. Rasmussen
Keyword(s):  
Winter Wheat ◽  
Pacific Northwest ◽  
Long Term Effects ◽  
The Pacific

scholarly journals Economic Costs of Different Riparian Management Regulations in the Pacific Northwest

2007 ◽  
Vol 22 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Kevin W. Zobrist ◽  
Bruce R. Lippke
Keyword(s):  
Pacific Northwest ◽  
Lower Cost ◽  
Riparian Habitat ◽  
Economic Costs ◽  
Wood Production ◽  
Riparian Management ◽  
The Pacific ◽  
Western Washington ◽  
Management Issues

Abstract Riparian management is an important consideration for sustainable wood production in the Pacific Northwest. Western Washington and Oregon have similar riparian management issues but different regulatory prescriptions. Application of these prescriptions to a sample of 10 small private ownerships illustrate some of the economic differences of each state's approach. Economic costs tend to be higher in Washington but can be significant in both states. Lower cost strategies through alternate plans may be important for protecting riparian habitat while ensuring the long-term economic viability of forestry in the region.

The Rationality of Mechanization in the Pacific Salmon-Canning Industry before the Second World War

1988 ◽  
Vol 62 (4) ◽  
pp. 626-655 ◽  
Author(s):  
Dianne Newell
Keyword(s):  
Pacific Northwest ◽  
Pacific Salmon ◽  
New Technology ◽  
Continuous Process ◽  
Second World War ◽  
Process Technology ◽  
The Pacific ◽  
Labor System ◽  
Canning Industry ◽  
Second World

An industry may fail to adopt or to extend new technology for many reasons other than lack of entrepreneurial vision. In the following article, Professor Newell considers the halting and incomplete diffusion of mechanization and continuous-process technology in the salmon-canning industry of the Pacific Northwest. She shows that the fragile and cyclical character of the natural resource, the labor system employed, and the remote and isolated locations of individual production units all affected cannery operators' decisions about technology adoption, and that the persistence of manual labor reflected rational, not reactionary, business choices.

scholarly journals Pathogens of Pacific Lamprey Detected Through Routine Fish Health Screenings

2019 ◽  
Vol 10 (2) ◽  
pp. 517-524 ◽  
Author(s):  
Jeffrey C. Jolley ◽  
Kenneth M. Lujan
Keyword(s):  
Pacific Northwest ◽  
Aeromonas Hydrophila ◽  
Vibrio Vulnificus ◽  
Conservation Management ◽  
Pacific Salmon ◽  
Specific Information ◽  
Fish Health ◽  
Fish Pathogens ◽  
Pacific Lamprey ◽  
The Pacific

Abstract Interest in conservation, management, and captive rearing of Pacific Lamprey Entosphenus tridentatus in the Pacific Northwest has risen in recent years. General and specific information regarding the occurrence of fish pathogens and the risk of Pacific Lamprey as a vector for pathogens to other species is not well understood. Specific efforts to captively rear or artificially propagate Pacific Lamprey at facilities that are used for Pacific salmon Oncorhynchus spp. have increased. We performed fish health surveys on wild-caught larval and adult Pacific Lamprey from locations that were used as lamprey sources for captive research to determine the occurrence of bacteria, viruses, and parasites that may be pathogens. A variety of potential pathogens was detected, most notably Aeromonas hydrophila and Vibrio vulnificus from larval Pacific Lamprey and A. salmonicida from adult lampreys. There was a general lack of pathogenic activity and absence of viral detections from all lampreys. The diversity of bacteria encountered from the larvae in our study could be indicative of the wide diversity of bacteria that is known to be associated with larval lamprey in general. Further efforts to understand pathogenic risk from Pacific Lamprey to salmonid propagation programs are warranted.

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