What happened to the rainbow trout?
This year has been a fairly good season for trout fishing the Bow River. Early spring and into July, the trout fishing on the lower Bow River (below Policeman’s Flats) had been great. At that time, we were experiencing great rainbow trout fishing with catch numbers around 20-40 fish on a 7 hour jet boat trip. My clients were doing well and were kept very happy with their day and night fishing adventures. As the summer progressed onward, the temperatures skyrocketed into the thirties and the fishing slowed considerably as a result! Mid July was scorching on the water, even the morning bite on the river was slow compared to the last few years previous. It seemed to me that the fish had almost stopped feeding in the day time and had predominantly resorted to feeding at night, where the temperatures were at least a little cooler. Late July the river slowed and the bite was tough during some of the peak times on the river. I started to wonder, what happened to the fish, specifically the rainbows?
One topic of major concern is the fact that the province of Alberta has an agreement with TransAlta, who control the hydro-electric dams above the city limits of Calgary, as well as the city itself and the irrigation districts downstream. There are several great articles on the internet to address these concerns with fluctuating water flow levels. A great article I found can be seen here https://bowrivertrout.org/2018/07/20/bow-river-flows-how-are-they-controlled/. The main concern contained within this article is as follows “The 2013 flood had an enormous impact on the City of Calgary and other communities in the Bow River Basin. The hydrology of the Bow River in and downstream of Calgary was changed by the extremely high flows and the subsequent flood mitigation measures. The fishery was devastated but in recent years fish populations appear to have increased somewhat. The Government of Alberta commissioned The Bow River Water Management Project to provide strategic advice on opportunities to reduce future flood damage, improve the reliability of water supply and protect the long-term health of the Bow River Basin.
A report, “Advice to Government on Water Management in the Bow River Basin” (2), gave recommendations for short-term remediation and long-term solutions for flood control and water supply but with limited consideration of the impact on the ecosystem and fishery”. So the question here has to be asked, why did the Government of Alberta “React” and not study the effects of controlling water flow rates on a world class fishing destination? Why did they not do proper research on the impacts (downstream) to fluctuating water levels, and the impact to the fishery? Why did they NOT look at other examples to build a safe and proper solution that would at the very least, have minimal impact on the trout populations of a world class “Blue Ribbon” trout fishery? The lack of planning and proper studies completely blows my mind. The government of Alberta “reacted” to the disaster of 2013 and did not “Act” accordingly in my opinion.
Here is what the Environment Minister and the mayor of Calgary had to say about the flood of 2013.
Building Alberta’s flood defenses will help protect families and businesses from a repeat of the devastation experienced in 2013, when more than $6 billion in damage was inflicted on our infrastructure and economy. Our government has carefully weighed the options and is moving forward with a plan that makes the most sense for families, businesses, and taxpayers. This investment will help safeguard our communities and economy against increasingly severe and frequent natural disasters.
Shannon Phillips, Minister of Environment and Parks, 26 October 2015
“The flood of 2013 had a devastating impact on the lives of thousands of Albertans. I am very pleased that the new provincial government has moved to protect downtown Calgary and our flood prone communities from a similar flood in the future. The Springbank Off-stream Reservoir and the $150 million in provincial funding for additional mitigation along our rivers is a significant step forward. Of course, much more work is required for flood mitigation and watershed management on both the Bow and Elbow rivers, and we look forward to working collaboratively with both the provincial and federal governments on this issue”.
Naheed Nenshi, Mayor of Calgary, 26 October 2016
Nowhere here do I see any mention of the impact on the ecosystem, birds, fish, aquatic life exedra. I fully understand that people’s lives are of most importance, and their property, but what about the ecosystem?
Most of the local Calgary and surrounding residents may remember the movement to stop the dam at Springbank. You can see the website here http://www.dontdamnspringbank.org/ if you have not heard of the movement to stop the dam at Springbank. What good is that going to do when contaminates get into the soil and surrounding areas after a flood?
In my opinion, what this boils down to is the Alberta Government paying off TransAlta to control water levels without properly studying impact to a world class fishery. Early on this year, they let too much water out of Bearspaw Damn to fast, therefore leaving the river far too low later on in the season. There was enough water in the dam from runoff this year to release the water slowly and control the water levels!
A letter that was sent to TransAlta recently by Peter Crowe-Swords states “German:
The rapid drops and increase in Bow River flows we have seen this week as illustrated in the attached weekly flows at Calgary has destroyed the fishing and may well have long term impact on the future of the Bow River as a world class fishery. There is also evidence to suggest that the survival of trout can be compromised by flow variations of the nature that we have seen this week. It appears that Bearspaw Reservoir water management protocol is unable to cushion the fluctuations in water discharge from power generation at Ghost Reservoir. There is need to correct this mismanagement of our water resource before we see further depletion to a very vulnerable trout population that has seen significant declines recently. We trust that TransAlta recognizes the urgency to make changes to the Bow River water management operation procedures as soon as possible to alleviate further damage to the fishery”.
The Alberta Fish and Wildlife department was just electro shocking the river to count the fish that are left in the river. I personally would love to see the results of that study very soon. After we see those numbers, we need to make every effort to contact both the Alberta Government, and TransAlta, to let our voices of concern be heard, LOUD and clear. Here is the contact information for the person in charge at TransAlta hydro_operations@transalta.com or call 1-877-967-2555. The Alberta Government contact information is found here http://aep.alberta.ca/default.aspx
Here is a fantastic study of the impact of water flow and the findings from a study that was done on the St Lawrence River in Quebec. This is only some of the article but I will include a link for those of you who are interested in reading the full content.
The link to the full article may be found here!
Abstract
“The impacts of hydrological variations on fish productivity in the St. Lawrence River are poorly understood, despite their prime importance for water level management. The objective of this study was to test the hypothesis that the abundance of fish species and fish functional groupings in the lower St. Lawrence River varied from year to year as a result of environmental conditions. This was done by testing the empirical relationship between the annual abundance of fish recorded at one site since 1975 and the environmental conditions prevailing in the years preceding the catch, assuming causality between hydrological variability and reproductive success. Between 1975 and 2002, 13 fish species decreased significantly in number while the abundance of eight species increased and 18 species exhibited no long-term trend in their abundance. Fish groupings, the sum of the abundance of all species with similar ecological or habitat characteristics, indicated a significant decline in the abundance of anadromous fishes, long-distance migrants, shallow-water residents and wetland spawners since 1975. On the other hand, the percentage of benthic fish increased significantly during this period. Best predictive models relating fish abundance to specific water level or water temperature attributes were developed for different fish species and functional groups. In a majority of cases, the spring high water level and the spring baseline water temperature were the two abiotic attributes that explained, to variable degrees, the between-year variation in the abundance of fish species and groupings. These variations in fish groupings are the result of the shift in the hydrological regime from high to low water level conditions that have occurred in the St. Lawrence River over the past 30 years. Significant changes in the fish assemblage have occurred since 1975, without showing signs of persistence or resilience. The results of this study suggest that high water levels and flows may favour higher productivity of fish from various trophic levels or from different habitat groups. Future water level management in the St. Lawrence River must aim to maintain a high level of inter-annual variability in the hydrological regime, driven by climate as much as possible, in order to maintain high fish productivity and fish diversity.
Introduction
Hydrological disturbances are considered the most serious threat to the ecological sustainability of large rivers and their associated wetlands (Ward et al. 1999; Bunn and Arthington 2002). Riverine fish are particularly susceptible to these large-scale anthropogenic disturbances. Fluctuations in the hydrological regime can have direct, short-term impacts on the distribution and abundance of fish species, and can also have long-term impacts on fish productivity (Schlosser 1998). In the short term, hydrological fluctuations will influence fish species distribution patterns by modifying their movement and timing of occurrence (Marchand and de Lafontaine 2003). Over the longer term, they can influence the reproductive success and recruitment of fish species, ultimately affecting population levels. The relationship between water levels and recruitment is, however, species-dependent and cannot necessarily be generalized. Regular, high flood pulses have been reported to enhance riverine fish productivity. The flood pulse concept (Junk et al.1989) states that high flood pulses, causing the inundation of wetlands, are the major driving force for maintaining diversity and fish productivity in rivers. The inundation of riverine wetlands is believed to promote fish productivity by providing suitable spawning habitats, food and refuge for juvenile fish. The impact of these floods, in terms of magnitude, timing and duration, on fish recruitment has been documented for many temperate rivers (Galat et al. 1998; Sparks et al. 1998). High fish recruitment and year-class strength, which translate into high fish productivity, are favoured when the rise in water level is coupled with the optimal temperature for spawning (Junk et al. 1989).
The evidence for strong correlations between flood intensity and riverine fish catches in subsequent years has been reviewed by Welcomme (1995). Long, intense flood pulses generally had a positive impact on fish productivity, with a time lag depending on the growth characteristics of the particular species. Changes in the relative abundance of different fish species in response to hydrological fluctuations may alter the relative proportion of these species in a fish assemblage. It has been well documented that permanent changes in the hydrological regime of rivers have resulted in radical changes of the fish community structure. The impact of scenarios implying a more gradual shift toward low water levels and successive years of low flood conditions remains, however, more difficult to assess. It is expected that the fish community would gradually loose its floodplain spawners and long-distance migrants, and that the number of benthic-feeding fish would increase (Welcomme 2000; Bunn and Arthington 2002). A shift in the structure of the fish community toward a greater abundance of larger species is also expected.
The St. Lawrence River was regulated in 1960 and has since been characterized by a variable spring flood regime, including a recent series of years with low flow and short flood duration. The empirical relationships linking fluctuations in the hydrological and thermal regimes with fish population dynamics have been documented for some commercially exploited fish species in the St. Lawrence River using data collected over a relatively short time period (Fortin et al. 1990; Nilo et al. 1997; Mingelbier et al. 2001). These relationships provided evidence of the effect of hydrology on the dynamics of riverine fish. The impact of long-term climate change or anthropogenic disturbances of fish productivity in the St. Lawrence River has yet to be determined.
The objective of the present study was to assess the response of fish species and fish groupings as a function of long-term changes in the hydrological and climatic regime of the lower St. Lawrence River in order to develop performance indicators for water level management. This was achieved by testing the empirical relationships between various hydrological variables and multi-species fish catch data recorded at a fixed station in the lower St. Lawrence River between 1975 and 2002. The St. Lawrence River is a large fluvial ecosystem supporting a rich diversity of freshwater fishes, many of which exhibit seasonal migratory patterns over a large section of the river (de Lafontaine et al., 2003). The majority of these species migrate to specific habitats in the St. Lawrence River or its basin to spawn. Our working hypothesis was that the annual abundance of fish species and fish groupings will vary in relation to the hydrological conditions prevailing in preceding years, resulting in variability in specific reproductive success and recruitment. The long term data series on daily and annual catches of the multi-species fish assemblage recorded at the Saint-Nicolas experimental trap fishery operated by the Aquarium du Québec since 1975 provided a unique opportunity for testing our hypothesis. To our knowledge, studies investigating a fish assemblage of more than 40 species over a long time scale (i.e. more than 10 years) in a river as large and complex as the St. Lawrence River are virtually nonexistent in the literature. The relatively long time series of fish species abundance and environmental conditions (i.e. water level and temperature) for the St. Lawrence River are extremely valuable for better establishing and describing the link between inter-annual variations in the hydrological and thermal regime, and fish productivity in large river ecosystems. This study is part of a larger project aimed at understanding the variability in the structure and functioning of fish communities in response to environmental disturbances in the St. Lawrence River”.
