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

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.

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Growth of rainbow trout (oncorhynchus mykiss) in the conditions of Tashkent province, Uzbekistan

E3S Web of Conferences ◽

10.1051/e3sconf/202125804040 ◽

2021 ◽

Vol 258 ◽

pp. 04040

Author(s):

SH Sulaymonov ◽

G Abdullaev ◽

S Saidumarov

Keyword(s):

Water Quality ◽

Rainbow Trout ◽

Dissolved Oxygen ◽

Oncorhynchus Mykiss ◽

Water Temperature ◽

Fish Farming ◽

Local Conditions ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Fish Productivity ◽

Feed Coefficient

Rainbow trout is a new fish farming object for Uzbekistan, the adaptability of which (first of all, growth) to local conditions should be carefully studied. We analyzed the growth of rainbow trout in the conditions of flowing pools and cages in the foothill zone of Tashkent province of Uzbekistan. From March to October, the water temperature in the Khojikent reservoir varied from 4.9 to 13.1 °C, the amount of dissolved oxygen was 8.4 to 11.5 mg/l, and the pH was 7.40 to 7.67. In the flowing basin, the temperature was 15-18 °C, pH 7.2-7.5, the amount of dissolved oxygen 6.1-11.2 mg/l. The conditions of the foothill zones of Uzbekistan in terms of water quality are favorable for the development of trout breeding. During the season, fish in cages increased from 250 g to 623 g, in pools from 25 g to 390 g on average. The waste was 1.7%. The actual fish productivity of the basin is 39 kg/m3, the cage is 30 kg/m3 and the feed coefficient in the basin is 1.2, in the cages - 1.09.

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Relationship between water flow volume and in-lake total phosphorus concentrations via dissolved oxygen concentrations and temperature in a warm temperate reservoir: Implications by path analysis

Lakes & Reservoirs Research & Management ◽

10.1111/j.1440-1770.2006.00298.x ◽

2006 ◽

Vol 11 (2) ◽

pp. 83-96 ◽

Cited By ~ 2

Author(s):

Ilhami Tuzun ◽

Ozlem Ince

Keyword(s):

Dissolved Oxygen ◽

Path Analysis ◽

Water Flow ◽

Total Phosphorus ◽

Flow Volume ◽

Warm Temperate ◽

Oxygen Concentrations

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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”.

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f09-128 ◽

2009 ◽

Vol 66 (11) ◽

pp. 1965-1975 ◽

Cited By ~ 19

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.

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Survival and behaviour of rainbow trout (Oncorhynchus mykiss) released from an experimental aquaculture operationThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f09-127 ◽

2009 ◽

Vol 66 (11) ◽

pp. 1976-1988 ◽

Cited By ~ 22

Author(s):

Paul J. Blanchfield ◽

Lori S. Tate ◽

Cheryl L. Podemski

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

High Growth ◽

High Growth Rate ◽

Normal Operation ◽

Farmed Fish ◽

Experimental Lakes Area ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Study Lake ◽

Cage Aquaculture

The potential for farmed fish that have escaped from open-cage aquaculture operations to affect native populations will depend on their survival and behaviour in the wild. We used standard commercial practices to rear 10 tonnes of rainbow trout ( Oncorhynchus mykiss ) in a 23 ha lake at the Experimental Lakes Area (Ontario, Canada). Each fall (2003–2005), we released farmed rainbow trout (escapees) into the study lake and monitored their movements using automated positioning telemetry. Rainbow trout experienced high annual mortality (~50%), with none surviving beyond 3 years. Farmed fish had narrowly defined pelagic distributions that comprised the upper few metres of the water column, even when at the cage site. Although released rainbow trout dispersed throughout the study lake, most spent significant portions of time at the cage site, especially during normal operation when commercial feed was available. Core use areas (50% Kernel) included the farm for half of the released fish. Surviving rainbow trout showed continued reliance upon the cage site in their second year. However, wide dispersal, high growth rate, and lack of reliance on the cage site by some escaped fish warrant further research to assess potential effects of open-cage aquaculture in the water bodies where the industry occurs.

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