Role of Temperature and Organic Degradation on the Persistence of ...

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The environmental impact <strong>and</strong> management studies on cage aquaculture <strong>of</strong> salmonids have been predominantly concentrated in marine coastal areas, where in contrast, literature regarding Canadian aquaculture, especially in freshwater, has been limited in the past ( Kullman et al., 2007; Blanchfield, 2009; Kullman et al., 2009; Johnston et al., 2010). In an effort to improve public confidence <strong>and</strong> global competitiveness in Canadian aquaculture a $75 million Program for Sustainable Aquaculture was launched by Fisheries <strong>and</strong> Oceans Canada in 2000 (DFO, 2003). The primary objective <strong>of</strong> the program was to ensure environmentally sustainable development <strong>of</strong> the aquaculture sector, achieved primarily through a scientific review <strong>of</strong> the potential environmental effects <strong>of</strong> aquaculture in marine <strong>and</strong> freshwater ecosystems. This review, referred to as the State-<strong>of</strong>-Knowledge (SOK) Initiative, described the current status <strong>of</strong> scientific knowledge <strong>and</strong> provided future research recommendations encompassing marine finfish <strong>and</strong> shellfish, <strong>and</strong> freshwater finfish in Canadian aquaculture under three main themes: impacts <strong>of</strong> waste (nutrient <strong>and</strong> organic matter), chemicals used by the industry (pesticides, drugs <strong>and</strong> antifoulants), <strong>and</strong> interactions between farmed fish <strong>and</strong> wild species (disease transfer, <strong>and</strong> genetic <strong>and</strong> ecological interactions) (DFO, 2006). It is important to note that environmental effects <strong>of</strong> cage aquaculture are site-specific, depending on the environmental conditions <strong>and</strong> operational details at each site location (DFO, 2006). The SOK initiative does not address these issues but instead summarizes available scientific knowledge on recognized measurable affects that when observed at the ecosystem level, can generally be categorized into three main broad-scale changes: 1) Eutrophication (nutrient <strong>and</strong> organic matter enrichment leading to increased dissolved inorganic nutrient concentrations <strong>and</strong> decreased dissolved oxygen (DO) 5
2) Sedimentation (direct settling <strong>of</strong> feed pellets, faeces, increased organic matter flocculation leading to higher deposition rates <strong>of</strong> small particles, changes in turbidity) 3) Food web structure <strong>and</strong> function (changes in planktonic, fish <strong>and</strong> benthic community composition, enhanced/decreased productivity, behavioral avoidance, stimulation <strong>of</strong> harmful algal blooms, intertidal/macro algal community effects). The effects outlined above are complex <strong>and</strong> directly related to the production <strong>and</strong> release <strong>of</strong> organic waste <strong>and</strong> the interactions between cultured <strong>and</strong> wild species. In order to reveal the potential environmental effects <strong>and</strong> fill knowledge gaps, a vast array <strong>of</strong> different studies have been conducted, from laboratory based computer modeling to direct infield sampling <strong>and</strong> observations. Some <strong>of</strong> the vital studies addressing environmental management will be summarized here. Key Studies Waste production or nutrient loading from a cage aquaculture facility is a function <strong>of</strong> fish size, species, water temperature, feed composition, ration, feeding methods <strong>and</strong> other factors. The nutritional components released as waste that are biologically limiting <strong>and</strong> responsible for the eutrophication in freshwater <strong>and</strong> marine water are phosphorous <strong>and</strong> nitrogen respectively (Tyrell, 1999; Hudson et al., 1999). Researchers have successfully used changes in levels <strong>of</strong> bacterial populations, chlorophyll, algal biomass <strong>and</strong> phytoplankton to demonstrate increased primary productivity as a result <strong>of</strong> aquaculture nutrient input in marine <strong>and</strong> fresh waters (Ruokolahti, 1988; Munro et al., 1985; Eloranta <strong>and</strong> Palomaki, 1986; Carr <strong>and</strong> Goulder, 1990; Kelly, 1993; Smith et al., 2001). 6
Page 1 and 2: Role of</s
Page 3 and 4: Acknowledgments This research proje
Page 5 and 6: Chapter 3: Long Term Monitoring <st
Page 7 and 8: List of Tables Tab
Page 9 and 10: Figure 16. Whisker box-plot <strong
Page 11 and 12: List of Appendices
Page 13 and 14: List of abbreviati
Page 15 and 16: aquaculture technology in the Great
Page 17: each applies numerous Acts regardin
Page 21 and 22: effluents (especially the solid fra
Page 23 and 24: attribute sediments collected 30 m
Page 25 and 26: natural seasonal community dynamics
Page 27 and 28: The MOM system uses sediment traps
Page 29 and 30: δX = [(R sample - R stand<
Page 31 and 32: Stable isotopes have originally bee
Page 33 and 34: sapidissima, Alosa pseudoharengus)
Page 35 and 36: Sources of organic
Page 37 and 38: determining waste dispersion <stron
Page 39 and 40: signatures measured. The results sh
Page 41 and 42: 2.2.2. Active site sediment samplin
Page 43 and 44: 2.2.3. Feed sample and</str
Page 45 and 46: No significant correlation was foun
Page 47 and 48: Figure 4. Signatures of</st
Page 49 and 50: Table 5. Sediment signatures δ 13
Page 51 and 52: some cases been shown to deplete th
Page 53 and 54: In addition, no data is available o
Page 55 and 56: nitrogenous organic waste compounds
Page 57 and 58: the most important factors affectin
Page 59 and 60: environment, and i
Page 61 and 62: Figure 6. Great Lakes Region showin
Page 63 and 64: Table 7. Site location and<
Page 65 and 66: Table 8. Initial data logging start
Page 67 and 68: Functions of the F
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Temperature (ºC)
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Temperature (C o )
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Temperature (C o )
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fluctuations between 2 o C
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3.4. Discussion The large amplitude
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etention and distr
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located between two island<
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excitation by intrusion and
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et al. (2005) found that Onchorynch
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Myxobolus cerebralis (cause <strong
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Chapter 4. Role <s
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The following methods were used to
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Each randomly assi
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The remaining samples were collecte
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Figure18. Wireframe plot of
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Figure 20. Plot of
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Table 12. Orthogonal contrasts <str
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4.4.2 Nitrogen Isotope Results The
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Figure 22. Plot of
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Table 14. Summary of</stron
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Table 16. Estimate of</stro
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than the minimum for active sites.
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enriched than mean of</stro
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water flow. It has been shown that
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turnover rate for nitrosomas) for n
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In addition the quadratic effect <s
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isotopes could potentially conclusi
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and inactive sites
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Open water sites show specific wast
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References Altabet, M.A. 1988. Vari
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Capone, D.G. and K
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Einen, O., Holmefjord, I., Asgard,
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Hobson, K.A., Clark, R.G. 1992. Ass
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Kurle C.M, Worthy G. 2001. Stable i
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McClelland, J.W.,
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Peterson, B.J. and
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Strain, P.M., D.J. Wildish, <strong
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APPENDIX I Wire frame charts from p
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Figure 27. Wireframe plot o
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Figure 29. Wire frame chart for Sit
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Site 3 Figure 31. Wire frame chart
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Figure 33. Wire frame chart for sit
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Figure 35. Wire frame plot for site
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Site 5 Figure 37. Wire frame chart
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Figure 39. Wire frame chart for sit
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Figure 41. Wire frame diagram for s
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Site 7 Figure 43. Wire frame diagra
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APPENDIX II Spectral density plots
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Spectral Density Estimate by Period
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