Assimilation of freshwater salmonid aquaculture waste by native aquatic biotaThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 1965-1975 ◽  
Author(s):  
Marilynn A. Kullman ◽  
Karen A. Kidd ◽  
Cheryl L. Podemski ◽  
Michael J. Paterson ◽  
Paul J. Blanchfield
Keyword(s):  
Nitrogen Isotope ◽  
Fish Feed ◽  
Cage Culture ◽  
Experimental Lakes Area ◽  
Carbon And Nitrogen ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Northwestern Ontario ◽  
Littoral Invertebrates ◽  
Aquaculture Waste ◽  
Finfish Aquaculture

An experimental finfish aquaculture farm was operated in a small lake at the Experimental Lakes Area in northwestern Ontario, Canada. In this study, we used the distinct and enriched carbon and nitrogen isotope ratios (δ13C and δ15N) of rainbow trout ( Oncorhynchus mykiss ) feed and waste to determine whether the operation provided a novel source of energy for native biota. For 1 year prior to and for 3 years during the cage culture, we collected littoral, pelagic, and profundal invertebrates and minnows from the experimental and reference lakes. In both the second and third years of aquaculture, there was a significant increase in δ15N of all organisms sampled in the experimental lake; mean δ15N values of littoral, pelagic, and profundal invertebrates and minnows shifted towards the signature of the fish feed by up to 4.2‰. Significant increases in δ13C of up to 2.6‰ were observed in Mysis , profundal chironomids, and minnows but not in littoral invertebrates or zooplankton. Aquaculture waste became a progressively more important component of minnow diets over the course of this study. The dissolved and (or) particulate wastes of the cage operation became a novel source of energy for the native biota in this experimental lake.

Aquaculture impacts on the algal and bacterial communities in a small boreal forest lakeThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 1936-1948 ◽  
Author(s):  
David L. Findlay ◽  
Cheryl L. Podemski ◽  
Susan E.M. Kasian
Keyword(s):  
Water Quality ◽  
Nutrient Loading ◽  
Stocking Density ◽  
Freshwater Ecosystem ◽  
Experimental Lakes Area ◽  
Fish Food ◽  
Total N ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Northwestern Ontario ◽  
The Impact

A whole-lake experiment to examine the impacts of aquaculture on a freshwater ecosystem was conducted at the Experimental Lakes Area in northwestern Ontario, Canada. From 2003 to 2006, a 10 tonne fish capacity aquaculture cage stocked with rainbow trout ( Oncorhynchus mykiss ) was operated in Lake 375 and the impact of excess nutrients on the algal and bacteria communities was examined. The experiment was designed as a nutrient loading experiment with fish food and fish excretion the source of nutrients. Total N and P concentrations increased over the 4 years (15× and 4×, respectively). Phytoplankton biomass increased 4× annually following the start of aquaculture operation in 2003. The most dramatic responses occurred during spring and fall mixing, with blooms of chrysophytes and dinoflagellates increasing biomass by up to 12×. Bacteria biomass and densities were unaffected except for increases in late fall. Periphyton biomass was relatively unaffected except for an increase in biomass in the fourth year. The combination of a long water residence time in the lake coupled with an extremely high fish stocking density in Lake 375 resulted in an immediate impact on water quality. The results suggest that the impacts of aquaculture are accumulative and continual stocking will further impact water quality.

Phosphorus budget and productivity of an experimental lake during the initial three years of cage aquaculture

2008 ◽  
Vol 65 (11) ◽  
pp. 2485-2495 ◽  
Author(s):  
Corben E. Bristow ◽  
Antoine Morin ◽  
Ray H. Hesslein ◽  
Cheryl L. Podemski
Keyword(s):  
Steady State ◽  
Dissolved Oxygen ◽  
Total Phosphorus ◽  
Fish Farming ◽  
Experimental Lakes Area ◽  
Phosphorus Budget ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Cage Aquaculture ◽  
Aquaculture Waste ◽  
Oxygen Concentrations

An experiment was conducted at the Experimental Lakes Area (ELA; Ontario, Canada) to investigate the effect of rainbow trout ( Oncorhynchus mykiss ) cage aquaculture on the phosphorus budget and productivity of a small Precambrian Shield lake during the first three years of fish farming. Annual inputs of phosphorus to the experimental lake from aquaculture waste (67–100 kg) exceeded combined annual inputs from inflows and direct atmospheric deposition (4–18 kg). Compared with a reference lake, hypolimnetic dissolved oxygen concentrations in the aquaculture lake decreased by 36% and hypolimnetic ammonium and total phosphorus increased by 120% and 35%, respectively. However, compared with an epilimnion-fertilized lake, hypolimnetic dissolved oxygen in the aquaculture lake was 255% greater and epilimnetic suspended carbon and chlorophyll a was lower by 64% and 85%, respectively. Epilimnetic suspended carbon and hypolimnetic dissolved oxygen concentrations during aquaculture were more similar to concentrations measured in a hypolimnion-fertilized lake. Although the experimental lake remained oligotrophic during the initial three years of aquaculture, hypolimnetic dissolved oxygen decreased each year and hypolimnetic ammonium and total phosphorus increased each year, which suggests that the lake did not reach a steady state.

Effects of an experimental rainbow trout (Oncorhynchus mykiss) farm on invertebrate community compositionThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 1949-1964 ◽  
Author(s):  
Rebecca C. Rooney ◽  
Cheryl L. Podemski
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Rank Correlation ◽  
Organic Loading ◽  
Experimental Lakes Area ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Northwestern Ontario ◽  
Freshwater Aquaculture ◽  
Invertebrate Abundance ◽  
Production Cycles

We examined the development of changes in the zoobenthos along a transect from an experimental rainbow trout ( Oncorhynchus mykiss ) farm in Lake 375, Experimental Lakes Area, northwestern Ontario, Canada. After 2 months, invertebrate abundance was reduced under the fish cage (2542 ± 569 individuals·m–2) compared with samples collected 45 m away (16 137 ± 2624 individuals·m–2). Taxa richness was also depressed, but changes in biomass were variable. Reductions in abundance and richness at high organic loading levels are consistent with earlier models developed for the marine environment of responses to organic loading in marine systems. After two production cycles, the significant principal components axis explaining 76% of total variance in abundance was correlated with distance from the cage (Spearman rank correlation, r = –0.775, p = 0.014) and with chemical variables recommended for freshwater aquaculture monitoring (Pearson’s correlation coefficient, r = 0.78, 0.76, and 0.75 with p = 0.013, 0.018, and 0.020 for pore-water ammonia and sediment Cu and Zn, respectively). The effects of farming were localized, dissipating within 15 m of the cage edge. Invertebrate abundance demonstrated the most potential for incorporation into monitoring schemes at new farms. At established farms, richness may be a valuable monitoring metric.

Phytoplankton Community Responses to Nutrient Addition in Lake 226, Experimental Lakes Area, Northwestern Ontario

1987 ◽  
Vol 44 (S1) ◽  
pp. s35-s46 ◽  
Author(s):  
D. L. Findlay ◽  
S. E. M. Kasian
Keyword(s):  
Species Composition ◽  
Water Exchange ◽  
Phytoplankton Community ◽  
Late Summer ◽  
Nitrogen And Phosphorus ◽  
Experimental Lakes Area ◽  
Carbon And Nitrogen ◽  
Northwestern Ontario ◽  
Average Biomass ◽  
Reference Lakes

Inclusion of phosphorus in fertilizer added to one of two basins of a small lake, between which water exchange was greatly reduced by a vinyl sea-curtain, significantly increased epilimnetic phytoplankton biomass, and altered species composition. Over an 8-yr period, the average biomass of phytoplankton in the basin receiving carbon, nitrogen, and phosphorus (in ratios of 10:5:1) increased 4 to 8 times and the biomass in the basin receiving only carbon and nitrogen (in ratios of 10:5) increased 2 to 4 times over non-fertilized years. The basin receiving all three nutrients consistently had blooms in late summer which were dominated by nitrogen fixing species of cyanophytes. In comparison with unfertilized reference lakes, the proportion of phytoplankton in fertilized basins which was available to zooplankton as food was 10 times greater in the basin receiving all three nutrients, and two times greater in the basin receiving only nitrogen and carbon. When fertilization of both basins was stopped, species composition and levels of biomass reverted within a year to the composition and biomass levels of phytoplankton observed in the reference lakes and remained at those levels for 2 further years of study.

Carbon and Nitrogen Isotope Composition of the Wood of Pinus sylvestris, Betula pendula and Populus tremula

2020 ◽  
Vol 54 (8) ◽  
pp. 819-824
Author(s):  
P. Yu. Voronin ◽  
V. A. Mukhin ◽  
T. A. Velivetskaya ◽  
A. V. Ignatiev ◽  
Vl. V. Kuznetsov
Keyword(s):  
Pinus Sylvestris ◽  
Betula Pendula ◽  
Isotope Composition ◽  
Nitrogen Isotope ◽  
Populus Tremula ◽  
Carbon And Nitrogen ◽  
Nitrogen Isotope Composition

scholarly journals Apparent Digestibility of Macronutrients and Fatty Acids from Microalgae (Schizochytrium sp.) Fed to Rainbow Trout (Oncorhynchus mykiss): A Potential Candidate for Fish Oil Substitution

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 456
Author(s):  
Amélie Bélanger ◽  
Pallab K. Sarker ◽  
Dominique P. Bureau ◽  
Yvan Chouinard ◽  
Grant W. Vandenberg
Keyword(s):  
Fatty Acids ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Fish Oil ◽  
Nutrient Digestibility ◽  
Fish Feed ◽  
Potential Candidate ◽  
Apparent Digestibility ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Aquaculture Feed

Aquaculture feed formulation has recently turned its focus to reduce the reliance on marine-derived resources and utilise alternative feedstuffs, as an approach to improve the environmental sustainability of the aquaculture sector. The fish oil market is highly volatile, and availability of this commodity is continuously decreasing for use in aquaculture. Currently, a growing number of commercial efforts producing microalgae are providing omega 3-rich oil for sustainable aquaculture feed. This study was focused to determine the nutrient digestibility of a marine microalga, Schizochytrium spp., which is rich in docosahexaenoic acid (DHA) and long-chain polyunsaturated fatty acids (LC-PUFA), as a novel dietary lipid source that could be utilized effectively by rainbow trout (Oncorhynchus mykiss). A whole-cell Schizochytrium spp. biomass was used in the digestibility experiment at two different temperatures, 8 °C and 15 °C. No significant differences were detected between the two temperatures for the apparent digestibility coefficients (ADCs) of the dry matter (94.3 ± 4.9%), total lipids (85.8 ± 0.0%), crude proteins (89.5 ± 1.8%), energy (83.1 ± 1.7%) and fatty acids (85.8 ± 7.5%). The ADCs of the nutrients, energy, DHA and other fatty acids showed that Schizochytrium spp. is a high-quality candidate for fish oil substitution and supplement of LC-PUFA in fish feed with vegetable oils.

Land water linkages: influences of riparian deforestation on lake thermocline depth and possible consequences for cold stenotherms

1997 ◽  
Vol 54 (6) ◽  
pp. 1299-1305 ◽  
Author(s):  
Robert France
Keyword(s):  
Thermal Stratification ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Thermocline Depth ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Riparian Trees ◽  
Tree Removal ◽  
Riparian Tree ◽  
Land Water

The purpose of the present study was to determine if riparian deforestation would expose lake surfaces to stronger winds and therefore bring about deepening of thermoclines and resulting habitat losses for cold stenotherms such as lake trout (Salvelinus namaycush). Removal of protective riparian trees through wind blowdown and two wildfires was found to triple the overwater windspeeds and produce thermocline deepening in two lakes at the Experimental Lakes Area. A survey of thermal stratification patterns in 63 northwestern Ontario lakes showed that lakes around which riparian trees had been removed a decade before through either clearcutting or by a wildfire were found to have thermocline depths over 2 m deeper per unit fetch length compared with lakes surrounded by mature forests. Riparian tree removal will therefore exacerbate hypolimnion habitat losses for cold stenotherms that have already been documented to be occurring as a result of lake acidification, eutrophication, and climate warming.

A carbon and nitrogen isotope perspective on ancient human diet in the British Isles

2022 ◽  
Vol 137 ◽  
pp. 105516
Author(s):  
Michael I. Bird ◽  
Jordahna Haig ◽  
Sean Ulm ◽  
Christopher Wurster
Keyword(s):  
Nitrogen Isotope ◽  
British Isles ◽  
Human Diet ◽  
Carbon And Nitrogen

Phosphorus Budgets and Stoichiometry during the Open-Water Season in Two Unmanipulated Lakes in the Experimental Lakes Area, Northwestern Ontario

1994 ◽  
Vol 51 (12) ◽  
pp. 2739-2755 ◽  
Author(s):  
P. Campbell
Keyword(s):  
Water Column ◽  
Bottom Sediments ◽  
Open Water ◽  
Short Term ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Phosphorus Budgets ◽  
Mass Balance Approach ◽  
Primary And Secondary Producers ◽  
Column Total

A comparative mass-balance approach is used to describe and quantify phosphorus (P) cycles during the open-water season in two unmanipulated Experimental Lakes Area (ELA) lakes. A bimodal cycle generally prevailed, in which water-column total phosphorus (TP = total dissolved P plus sestonic particulate P) peaked just after ice-out and again late in the summer. Changes in mass of water-column TP were often much larger than corresponding net external inputs. Shifts of P to and from either zooplankton or fish in the water column do not explain the P residuals. Rather, the bottom sediments must have been adding P to the water column. Short-term regeneration of P from the bottom sediments also probably occurs in artificially eutrophied ELA lakes. The mechanism of regeneration is probably biological. Other aspects of P cycling and P stoichiometry are discussed, particularly in relation to nutrient control of population structure and the function of primary and secondary producers.

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