Research needs for the management of water quality issues, particularly phosphorus and oxygen concentrations, related to salmonid cage aquaculture in Canadian freshwaters

2005 ◽  
Vol 13 (1) ◽  
pp. 1-19 ◽  
Author(s):  
N D Yan
Keyword(s):  
Water Quality ◽  
Supply And Demand ◽  
Research Needs ◽  
Cage Culture ◽  
Knowledge Gaps ◽  
Mass Balance Models ◽  
Regulatory Instruments ◽  
Cage Aquaculture ◽  
Quality Issues ◽  
The Difference

A growing awareness of the difference between the supply and demand for fish products is fueling rapid growth of an aquaculture industry in Canada, including a freshwater sector, based mainly on the cage farming of rainbow trout. Cage farms can release relatively large loads of organic matter and nutrients to the environment. In consequence, federal and provincial resource management agencies need to develop regulatory instruments that will foster the growth of the industry while ensuring minimal water quality impacts. Such instruments should be science based, but there are currently key gaps in our understanding of the water quality implications of the operations of freshwater cage aquaculture. Here I review the state of science of the water quality implications of cage aquaculture and identify 11 knowledge gaps that currently hamper the development of sound, science-based cage culture management instruments. Perhaps the most important finding of the review is the recognition that, while aquaculture has produced significant increases in lakewater total phosphorus (TP) levels in some situations, classic phosphorus mass balance models may substantially overestimate the contributions of cage farms to TP concentrations in some lakes. Research on this, and perhaps the other knowledge gaps identified in this review, should aid the development of sound management instruments for freshwater cage aquaculture in Canada and elsewhere. Key words: aquaculture, cage culture, water quality issues, phosphorus, BOD, review, research needs, freshwaters.

scholarly journals The Long-Term and Retention Impacts of the Intervention Policy for Cage Aquaculture on the Reservoir Water Qualities in Northern China

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3325
Author(s):  
Gelin Kang ◽  
Jingchen Yin ◽  
Naixin Cui ◽  
Han Ding ◽  
Shaoming Wang ◽  
...  
Keyword(s):  
Water Quality ◽  
Central Government ◽  
Point Sources ◽  
Additive Models ◽  
Cage Culture ◽  
Long Term Effects ◽  
Reservoir Water ◽  
Cage Aquaculture ◽  
The Impact

To ensure the safety of the water supply of the Panjiakou reservoir, in 2016, the Chinese central government comprehensively banned the fishing cage culture that had lasted for almost 30 years. However, the long-term effects and retention impacts of the government’s mandatory intervention on the reservoir water quality are unknown. To determine the reservoir water quality, we employed statistical methods along with the mathematical model to investigate the internal relationship since the construction of the reservoir. We applied seasonal trend decomposition using loess (STL) to explore the long-term and seasonality trend of monthly total nitrogen (TN) and total phosphorous (TP). To separate the impact of upstream water quality changes from cage culture on reservoir water quality, we employed generalized additive models (GAMs). We created a model, the LAKE2K model, to investigate the internal sources of the sediment that accumulated during the aquaculture period and its retardant effect. The results revealed that the concentration of upstream TN was more affected by non-point sources than by TP. The long-term policy of encouraging aquaculture has greatly contributed to the increase in the reservoir TP concentration rather than an increase in TN; the prohibition of cage aquaculture has resulted in a sharp drop in TP. After the ban, the sediment became the main source of TP. We suspect that the TP concentration of the reservoir and sediment will decrease gradually until a new equilibrium is reached within 10 years. This study offers lake managers an opportunity to increase their insight into the interaction of management measures with water quality and provides valuable information for the natural recovery of the eutrophic system.

The Difficulties and Promise of an Interagency Public Information Campaign for Water Quality Issues

1993 ◽  
Vol 28 (3-5) ◽  
pp. 65-68
Author(s):  
Michelle Miller
Keyword(s):  
Water Quality ◽  
Public Information ◽  
The United States ◽  
United States Department ◽  
Information Campaign ◽  
Department Of Agriculture ◽  
Voluntary Programs ◽  
University Of Wisconsin ◽  
Quality Issues ◽  
State And Local

The following case study addresses the difficulties and promise of developing a statewide interagency public information campaign to raise general awareness of water quality issues and governmental programs to address them. Due to only moderate success of voluntary programs to curb nonpoint source pollution, agencies are looking toward information and education programs to motivate the public toward conservation behavior. One of the biggest obstacles in developing an effective information/education program is institutional barriers to interagency cooperation, mirroring difficulties local conservationists encounter in their work to restore and maintain water quality at the watershed level. Cooperation between federal agencies, and resource commitment to public information is necessary at the federal level, as well as state and local levels. Agencies involved to date include the United States Department of Agriculture-Soil Conservation Service; Wisconsin State Departments of Natural Resources, and Agriculture, Trade and Consumer Protection and Administration; University of Wisconsin-Extension; Wisconsin Land Conservation Association.

scholarly journals Phosphorous Supply to a Eutrophic Artificial Lake: Sedimentary versus Groundwater Sources

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 563
Author(s):  
Wiebe Förster ◽  
Jan C. Scholten ◽  
Michael Schubert ◽  
Kay Knoeller ◽  
Nikolaus Classen ◽  
...  
Keyword(s):  
Water Quality ◽  
Stable Isotope ◽  
Pore Water ◽  
Lake Water ◽  
Sediment Cores ◽  
Eutrophic Lake ◽  
Stable Water Isotopes ◽  
Artificial Lake ◽  
Sediment Pore Water ◽  
Mass Balance Models

The eutrophic Lake Eichbaumsee, a ~1 km long and 280 m wide (maximum water depth 16 m) dredging lake southeast of Hamburg (Germany), has been treated for water quality improvements using various techniques (i.e., aeration plants, removal of dissolved phosphorous by aluminum phosphorous precipitation, and by Bentophos® (Phoslock Environmental Technologies, Sydney, Australia), adsorption) during the past ~15 years. Despite these treatments, no long-term improvement of the water quality has been observed and the lake water phosphorous content has continued to increase by e.g., ~670 kg phosphorous between autumn 2014 and autumn 2019. As no creeks or rivers drain into the lake and hydrological groundwater models do not suggest any major groundwater discharge into the lake, sources of phosphorous (and other nutrients) are unknown. We investigated the phosphorous fluxes from sediment pore water and from groundwater in the water body of the lake. Sediment pore water was extracted from sediment cores recovered by divers in August 2018 and February 2019. Diffusive phosphorous fluxes from pore water were calculated based on phosphorus gradients. Stable water isotopes (δ2H, δ18O) were measured in the lake water, in interstitial waters in the banks surrounding the lake, in the Elbe River, and in three groundwater wells close to the lake. Stable isotope (δ2H, δ18O) water mass balance models were used to compute water inflow/outflow to/from the lake. Our results revealed pore-water borne phosphorous fluxes between 0.2 mg/m2/d and 1.9 mg/m2/d. Assuming that the measured phosphorous fluxes are temporarily and spatially representative for the whole lake, about 11 kg/a to 110 kg/a of phosphorous is released from sediments. This amount is lower than the observed lake water phosphorous increase of ~344 kg between April 2018 and November 2018. Water stable isotope (δ2H, δ18O) compositions indicate a water exchange between an aquifer and the lake water. Based on stable isotope mass balances we estimated an inflow of phosphorous from the aquifer to the lake of between ~150 kg/a and ~390 kg/a. This result suggests that groundwater-borne phosphorous is a significant phosphorous source for the Eichbaumsee and highlights the importance of groundwater for lake water phosphorous balances.

scholarly journals Perceptions and determinants of households' participation in a randomized evaluation on water quality testing and information in southern Ghana

Water Policy ◽  
2017 ◽  
Vol 19 (6) ◽  
pp. 1206-1224 ◽  
Author(s):  
Charles Yaw Okyere ◽  
Felix Ankomah Asante
Keyword(s):  
Water Quality ◽  
Economic Benefits ◽  
Randomized Experiment ◽  
Subjective Analysis ◽  
Factors Affecting ◽  
Variable Approach ◽  
Quality Testing ◽  
Quality Issues ◽  
Household Heads ◽  
Southern Ghana

Abstract In this paper, we analyze perceptions and determinants of households' participation in a randomized experiment on water quality testing and information in southern Ghana. Beneficiary households assessed the components of the intervention including its relevance and adequacy in improving understanding of water quality issues. Motivating and constraining factors to participation in the randomized experiment are also assessed. We also estimate the correlates of participation in the intervention. Social and economic benefits derived from the intervention based on perceptions are compared with impacts of the intervention using an instrumental variable approach. We found evidence that subjective analysis estimates of the effects of the intervention are higher than the objective analysis estimates. Households generally perceived the intervention to be relevant in improving their understanding of water quality issues. However, there are differing opinions based on random assignment into either child or adult treatment groups on most- and least-liked attributes of the intervention, and also motivating and constraining factors affecting participation in the intervention. The factors that statistically and significantly influenced participation in the intervention include educational attainment, ethnicity, religious denomination and marital status of the household heads, in addition to the location of residence.

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