Enhancement of Sockeye Salmon (Oncorhynchus nerka) by Lake Fertilization in Great Central Lake: Summary Report

1978 ◽  
Vol 35 (12) ◽  
pp. 1580-1596 ◽  
Author(s):  
R. J. LeBrasseur ◽  
C. D. McAllister ◽  
W. E. Barraclough ◽  
O. D. Kennedy ◽  
J. Manzer ◽  
...  
Keyword(s):  
Primary Production ◽  
Food Chain ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Standing Stock ◽  
Ammonium Phosphate ◽  
Trophic Levels ◽  
Percentage Survival ◽  
Initial Hypothesis ◽  
Lake Fertilization

Great Central Lake was treated with ca. 1001 of commercial grade fertilizer (ammonium nitrate and ammonium phosphate) annually from 1970 through 1973. Limnological parameters and sockeye salmon (Oncorhynchus nerka) juveniles and adults were monitored from 1969 through 1976 to test the hypothesis that increasing the supply of inorganic nutrients in an ultraoligotrophic lake would increase production at succeeding trophic levels. Rates of change and linkages between different elements of the food chain leading to juvenile sockeye salmon were identified. During fertilized years mean summer primary production increased fivefold, zooplankton standing stock increased 9 times, the percentage survival from estimated potential egg deposition to juvenile sockeye increased 2.6 times, while mean stock size of adult sockeye increased from < 50 000 to > 360 000. Adult sockeye returning to an adjacent untreated lake also increased in abundance. The data for the 8-yr period support the initial hypothesis, but the dominant processes affecting production and interrelationships between different trophic levels in different years remain masked. Key words: food chain, limnology, sockeye salmon, primary production, zooplankton, eutrophication, lake fertilization, enhancement

Mortality Trend Among Young Sockeye Salmon (Oncorhynchus nerka) During Various Stages of Lake Residence

1938 ◽  
Vol 4a (3) ◽  
pp. 184-191 ◽  
Author(s):  
R. E. Foerster
Keyword(s):  
Linear Relationship ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Mortality Trend ◽  
Percentage Loss ◽  
Percentage Survival

Young sockeye salmon, marked and liberated into Cultus lake, B.C., at intervals during the year were counted as seaward migrants. A linear relationship between time in the lake and percentage survival was found for periods of from 9.5 to 3.5 months, and from this the trend in percentage loss is computed. Mortality is found to be heavy during the first few months—approximately 65.4 per cent in the first 2.5 months—decreasing, however, as the year advances and the young sockeye increase in size.

Sockeye salmon (Oncorhynchus nerka) nursery lake fertilization: Review and summary of results

2004 ◽  
Vol 12 (3) ◽  
pp. 133-162 ◽  
Author(s):  
K D Hyatt ◽  
D J McQueen ◽  
K S Shortreed ◽  
D P Rankin
Keyword(s):  
Food Web ◽  
Green Algae ◽  
Sockeye Salmon ◽  
Inorganic Nitrogen ◽  
Oncorhynchus Nerka ◽  
Adult Survival ◽  
Bottom Up ◽  
Blue Green Algae ◽  
Marine Survival ◽  
Lake Fertilization

We reviewed 24 sockeye salmon (Oncorhynchus nerka) nursery lake experiments that involved whole-lake fertilization with appropriate treatment and control years. We found that: 21 of 21 studies showed that fertilization was associated with increased chlorophyll a concentrations, 16 of 16 showed increased zooplankton biomasses, 16 of 16 demonstrated increased average smolt weights, and 11 of 13 showed increased smolt biomasses. Studies involving assessments of egg-to-smolt survival were rare, but all (4 of 4) showed increased survival rates. Studies involving increased smolt-to-adult survival (i.e., marine survival) were even rarer, but all (3 of 3) showed that lake fertilization and increased smolt size were associated with increased marine survival. Several fertilization studies reported problems, and some offered solutions. For instance, when whole-lake fertilization stimulated the growth of blue-green algae, fertilizer with higher nitrogen to phosphorus ratios was used to control the problem. Conversely, when high nitrogen to phosphorus ratios were associated with blooms of ungrazable diatoms, notably Rhizosolenia eriensis, reduced nitrate concentrations were recommended. To date, solutions designed to constrain the growth of both blue-green algae and Rhizosolenia blooms remain elusive. Some studies showed that when both mysids (large invertebrate planktivores) and juvenile sockeye inhabit the same lake, sockeye suffer from a competitive disadvantage and mysids consume 80–90% of the available zooplanktonic food production. Similarly, a small number of studies demonstrated that competition from sticklebacks (Gasterosteus aculeatus) adversely affected sockeye growth rates, and although the problem remains unresolved, ongoing work in lakes containing kokanee (O. nerka), suggests that stocked cutthroat trout (Salmo clarki) may be capable of controlling stickleback densities through predation. Despite all of these difficulties, in almost all cases, when lakes were fertilized with various mixtures of inorganic nitrogen and phosphorus, pelagic food web bottom-up control was strong enough and predictable enough to ensure that sockeye smolt biomass increased. We conclude that sockeye nursery lake fertilization is a technique that can contribute usefully to both the enhancement and conservation of sockeye salmon populations. Key words: sockeye salmon, lake fertilization, bottom-up, aquatic food web.

scholarly journals The impact of introduced Ponto-Caspian mysids (Paramysis lacustris) on the trophic position of perch (Perca fluviatilis) in European mesotrophic lakes

2019 ◽  
pp. 38
Author(s):  
Vytautas Rakauskas
Keyword(s):  
Primary Production ◽  
Chain Length ◽  
Food Chain ◽  
Trophic Position ◽  
Perca Fluviatilis ◽  
Trophic Levels ◽  
Gut Contents ◽  
Potential Predator ◽  
Food Chain Length ◽  
The Impact

Paramysis lacustris was introduced into Lithuanian lakes in the middle of the 20th century. It was assumed that P. lacustris will enhance efficiency of primary production utilization and channelling of primary production towards higher trophic levels, i.e. commercially important fish species. However, at the time of P. lacustris introduction, there were no reliable data about its trophic position in lakes. Thus, P. lacustris was considered to have no or little impact on native ecosystems. Until now, there is a gap in the knowledge of the trophic role and potential impacts of P. lacustris on local food webs in lakes. Here we investigated the impact of P. lacustris on the food chain length of its potential predator Perca fluviatilis in temperate lakes. In this study, gut contents and stable isotope analyses were performed to assess the diet and trophic position of P. lacustris and P. fluviatilis in lakes with and without invasive mysids. The results obtained revealed that P. lacustris consumes a significant amount of animal prey and occupies the third trophic level in lake littoral zones. Furthermore, our results showed that P. lacustris might enhance the food chain length for at least some zooplanktivorous fishes. Overall, the assumption that P. lacustris invasion has no whole-ecosystem consequences, as it was thought before its introduction, is not correct.

Responses of Sockeye Salmon (Oncorhynchus nerka) to Fertilization of British Columbia Coastal Lakes

1985 ◽  
Vol 42 (2) ◽  
pp. 320-331 ◽  
Author(s):  
Kim D. Hyatt ◽  
John G. Stockner
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Trophic Levels ◽  
Phosphorus Fertilizer ◽  
Nitrogen And Phosphorus ◽  
Coastal Lakes ◽  
Standing Stocks ◽  
Marine Survival ◽  
Heterotrophic Production

Addition of nitrogen and phosphorus fertilizer to several British Columbia coastal lakes has resulted in increased autotrophic and heterotrophic production and larger standing stocks of zooplankton. These changes at the primary and secondary trophic levels are reflected by increased in-lake growth of juvenile sockeye salmon (Oncorhynchus nerka) and larger outmigrant smolts. Evidence is presented that smolt size changes in fertilized lakes will lead to increases in the harvestable surplus of sockeye adults by promoting both increases in marine survival and an earlier age-at-return to the fishery.

Impact of fertilization and stocking on trophic interactions and growth of juvenile sockeye salmon (Oncorhynchus nerka)

2002 ◽  
Vol 59 (8) ◽  
pp. 1361-1373 ◽  
Author(s):  
Asit Mazumder ◽  
Jim A Edmundson
Keyword(s):  
Food Web ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Trophic Levels ◽  
Food Web Structure ◽  
Web Structure ◽  
Mean Size ◽  
Average Size ◽  
The Impact

Using 16 years of data on nutrients, plankton, and sockeye fry and smolts from Packers Lake, Alaska, we test the impact of nutrients and fry stocking on the growth and productivity of juvenile sockeye salmon (Oncorhynchus nerka). To enhance sockeye production, this lake was fertilized (1983–1996) and stocked annually (1987–1996) with sockeye fry. Before fertilization, the density of sockeye fry was low (<0.20 fry·m–2), the size and biomass of Daphnia were low, and sockeye smolts were relatively small. Before stocking, all trophic levels responded positively to fertilization. The biomass and mean size of Daphnia increased significantly. The average size of age-1 and age-2 smolts increased three- to four-fold. Fry stocking produced dramatic declines in both biomass and mean length of Daphnia and in size of smolts. When large-sized (>1 mm) Daphnia were significantly reduced in density under heavy predation by sockeye fry, the growth of juvenile sockeye declined, even under continued fertilization. We show that fry density and associated food web structure are major determinants of juvenile sockeye responses to fertilization and stocking. This study probably provides the first long-term experimental results linking limnological and nutrient – food web concepts to trophodynamics and productivity of juvenile sockeye salmon.

On the Relation of Adult Sockeye Salmon (Oncorhynchus nerka) Returns to Known Smolt Seaward Migrations

1954 ◽  
Vol 11 (4) ◽  
pp. 339-350 ◽  
Author(s):  
R. E. Foerster
Keyword(s):  
Multiple Regression ◽  
Negative Correlation ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Average Weight ◽  
Actual Number ◽  
Average Percentage ◽  
Residual Variability ◽  
Percentage Survival

Data were obtained from Cultus Lake giving (a) the number of seaward migrating smolts each year from 1927 to 1944, (b) their mean length and weight, and (c) the number of adults from each smolt migration which returned in the spawning escapement to the lake. These indicate a negative correlation –.5;24, (P < 0.05) between number of smolts and percentage return of adults. By multiple regression this is shown to be related almost wholly to the size of the smolts. With an increase in average weight of smolts from 4 to 10 grams, their average percentage survival is tripled.Smolt size and numbers together account for about 60 per cent of the variation in actual number of adult salmon which arrive at the lake. The residual variability could not be definitely related to available qualitative indices of fishing intensity or duration.

ENERGY TRANSFER EFFICIENCIES ON LOWER TROPHIC LEVELS WITH INTENSIVE OYSTER FARMING IN HIROSHIMA BAY, JAPAN

2017 ◽  
Author(s):  
Akira Umehara ◽  
Akira Umehara ◽  
Satoshi Asaoka ◽  
Satoshi Asaoka ◽  
Naoki Fujii ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Primary Production ◽  
Skeletonema Costatum ◽  
Warm Season ◽  
Nutrient Supply ◽  
Trophic Levels ◽  
Phytoplankton Primary Production ◽  
Mean Values ◽  
Hiroshima Prefecture ◽  
Study Species

In enclosed water areas, organic matters are actively produced by phytoplankton due to abundant nutrient supply from the rivers. In our study area of the semi-enclosed Hiroshima Bay, oyster farming consuming high primary production has been developed since the 1950s, and the oyster production of Hiroshima prefecture have had the largest market share (ca. 60%) in Japan. In this study, species composition of phytoplankton, primary production, and secondary production of net zooplanktons and oysters were determined seasonally at seven stations in the bay between November 2014 and August 2015. In the bay, diatoms including Skeletonema costatum dominated during the period of the study. The primary productions markedly increased during summer (August), and its mean values in the northern part of the bay (NB) and the southern part (SB) were 530 and 313 mgC/m2/d, respectively. The productions of net zooplankton and oyster increased during the warm season, and its mean values in the NB were 14 and 1.2 mgC/m2/d, and in SB were 28 and 0.9 mgC/m2/d, respectively. The energy transfer efficiencies from the primary producers to the secondary producers in the NB and SB were 2.8% and 9.1%, respectively. However, the transfer efficiency to the oysters was approximately 0.3% in the bay. This study clearly showed the spatial difference of the productions and transfer efficiencies, and the low contribution of the production of oysters in secondary productions in Hiroshima Bay.

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