Climate change is shrinking fish in Michigan lakes – Bridge Michigan

Report on the Impact of Climate Change on Michigan’s Freshwater Fish Populations

An Analysis in the Context of Sustainable Development Goals

A recent study published in the journal Global Change Biology reveals that rising water temperatures and extended summer seasons in Michigan are causing a measurable reduction in the size of freshwater fish. This report analyzes these findings, their methodology, and their profound implications for several United Nations Sustainable Development Goals (SDGs), particularly SDG 13 (Climate Action) and SDG 14 (Life Below Water).

Methodology and Collaborative Efforts (SDG 17)

The research represents a significant achievement in collaborative science, aligning with SDG 17 (Partnerships for the Goals). The study was made possible through a partnership between:

• The University of Michigan
• The Michigan Department of Natural Resources (DNR)
• Citizen scientists via the Zooniverse platform

This collaboration facilitated the digitization of decades of handwritten field notes from the Institute for Fisheries Research, creating a long-term dataset. By aligning this historical data with long-term temperature models, researchers could track changes in fish size across generations.

Key Findings: Threats to Life Below Water (SDG 14)

The study’s conclusions present a direct threat to the conservation and sustainable use of freshwater ecosystems, a core target of SDG 14. The primary impacts observed include:

1. Systematic Reduction in Fish Size: Successive generations of fish are growing smaller as a direct response to environmental stressors caused by climate change.
2. Species-Specific Impacts: Of the 13 species studied, Northern pike showed the most significant decline, shrinking at an average rate of 0.5 to 4 millimeters annually across all life stages.
3. Ecological Consequences: The reduction in fish size has cascading effects on the aquatic food web.
   • Smaller fish are more vulnerable to predation.
   • Smaller fish produce fewer offspring, threatening population stability.

Climate Change Impacts and Projections (SDG 13)

The shrinking of fish populations is a clear indicator of the tangible impacts of climate change, underscoring the urgency of SDG 13 (Climate Action). The research connects the phenomenon directly to anthropogenic warming.

Observed and Projected Environmental Changes:

• Warming Waters: The primary driver for the observed changes in fish physiology and growth.
• Loss of Coldwater Habitats: A 2022 study projects that by mid-century, Michigan will lose over half of its high-quality coldwater lakes and the majority of its coldwater rivers.
• Population Declines: Warming waters are already implicated in the decline of cisco populations and reduced walleye reproduction rates.

Socio-Economic and Broader Environmental Implications

The ecological crisis detailed in the report has significant socio-economic ramifications, affecting goals related to economic stability and food security.

Impacts on SDG 8 (Decent Work and Economic Growth) and SDG 2 (Zero Hunger):

• Recreational Fishing and Tourism: Smaller, less desirable fish threaten the vitality of Michigan’s recreational fishing industry, a key economic contributor.
• Food Systems: While not the primary focus, declining fish stocks can impact local food availability and the livelihoods dependent on fisheries.

Impacts on SDG 15 (Life on Land):

The report situates the shrinking of fish within a broader pattern of climate-induced environmental degradation, which also includes the shrinking of Michigan’s boreal forests, highlighting the interconnectedness of aquatic and terrestrial ecosystems.

Conclusion and Future Directives

The evidence strongly indicates that climate change is fundamentally altering Michigan’s freshwater ecosystems. The shrinking size of fish serves as a critical bio-indicator of this change. To mitigate these impacts and advance the SDGs, future efforts must focus on:

1. Aggressive Climate Action (SDG 13): Reducing greenhouse gas emissions to slow the rate of water temperature increase.
2. Ecosystem Restoration and Management (SDG 14): Implementing targeted management strategies to bolster the resilience of aquatic habitats against climate change. State and tribal agencies are initiating projects to improve water quality in northern Michigan lakes.
3. Continued Research and Monitoring: Further investigation is required to understand the precise mechanisms driving reduced fish growth to inform effective conservation strategies.

SDGs Addressed in the Article

SDG 13: Climate Action

• The article directly links the shrinking of fish in Michigan to climate change, mentioning “warmer water and longer summer seasons” as the cause. It explicitly states that these changes stem from “fossil fuel consumption and resulting greenhouse gas emissions,” which is the central theme of SDG 13.

SDG 14: Life Below Water

• This goal is relevant as the article’s main focus is on the health of aquatic ecosystems and the species within them. It discusses the adverse impacts on fish populations, such as shrinking sizes, increased vulnerability, and declining reproduction rates (“ongoing cisco population declines and faltering walleye reproduction rates”). While SDG 14 primarily targets marine environments, its principles of conserving and sustainably using aquatic life apply to the Great Lakes ecosystems discussed.

SDG 15: Life on Land

• SDG 15 is directly applicable as it includes the protection and restoration of inland freshwater ecosystems. The article details the degradation of Michigan’s lakes (“Michigan is expected to lose more than half of its coldwater lakes by midcentury”) and the negative effects on the biodiversity within them, which aligns with the objectives of SDG 15.

SDG 17: Partnerships for the Goals

• The research highlighted in the article is a collaborative effort. It involved the University of Michigan, the Michigan Department of Natural Resources (DNR), and a “massive crowdsourced effort” using the Zooniverse platform to digitize data. This multi-stakeholder partnership between academia, government, and civil society to generate scientific knowledge is a core component of SDG 17.

Specific SDG Targets Identified

1. SDG 13: Climate Action

   • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards. The article discusses the negative impacts of climate change as a hazard to the lake ecosystems. The initiative by “state and tribal environmental agencies to boost water quality and habitat on selected northern Michigan lakes in hopes of bolstering them against the coming changes” is a direct action to strengthen resilience.
   • Target 13.3: Improve education, awareness-raising and human and institutional capacity on climate change mitigation and adaptation. The research itself, its publication in the journal Global Change Biology, and the article’s reporting on it serve to raise awareness. The quote from researcher Peter Flood about people not thinking about how climate change “might impact their fishing trip” underscores the need for this increased awareness.

2. SDG 14: Life Below Water

   • Target 14.2: Sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts, including by strengthening their resilience. Applying this principle to freshwater, the article describes significant adverse impacts (shrinking fish, population decline) and actions to protect the ecosystem and strengthen its resilience against climate change.
   • Target 14.4: Implement science-based management plans… to restore fish stocks. The article concludes by stating that the research is crucial for “developing management strategies going forward,” which directly relates to the creation of science-based plans to manage and protect fish populations.

3. SDG 15: Life on Land

   • Target 15.1: Ensure the conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems. The entire article is about the threat to Michigan’s inland freshwater ecosystems and the fish that inhabit them, making this target highly relevant.
   • Target 15.5: Take urgent and significant action to reduce the degradation of natural habitats [and] halt the loss of biodiversity. The shrinking of fish species, faltering reproduction rates, and the projected loss of coldwater lakes are clear examples of habitat degradation and biodiversity loss that this target aims to prevent.

4. SDG 17: Partnerships for the Goals

   • Target 17.16 & 17.17: Enhance multi-stakeholder partnerships that mobilize and share knowledge and encourage effective public, public-private and civil society partnerships. The research project is a model of this, combining the expertise of university scientists (U-M), government bodies (DNR), and the public through a “crowdsourced effort to digitize decades’ worth of written observations” via the Zooniverse platform.

Indicators for Measuring Progress

1. Indicators for Climate Action (SDG 13)

   • Change in water temperature and season length: The article identifies “warmer water and longer summer seasons” as the primary drivers of the problem. Tracking these metrics over time would be a direct indicator of the climate-related stress on the ecosystem.
   • Number of high-quality coldwater lakes: The article provides a specific, measurable projection: “by mid-century, more than half of Michigan’s 300 high-quality coldwater lakes will no longer be categorized as such.” The number and percentage of lakes retaining this status serves as a key indicator of climate impact.

2. Indicators for Life Below Water (SDG 14) & Life on Land (SDG 15)

   • Change in average fish size by species and age: The study explicitly measured this, finding that Northern pike “shrank across every life stage at average rates of between half-a-millimeter and nearly 4 millimeters annually.” This provides a precise indicator of ecosystem health.
   • Fish population and reproduction rates: The article mentions “ongoing cisco population declines and faltering walleye reproduction rates” as consequences of warming waters. These metrics are direct indicators of the viability of fish stocks and biodiversity.

3. Indicators for Partnerships for the Goals (SDG 17)

   • Mobilization of data through partnerships: The success of the “crowdsourced effort to digitize decades’ worth of written observations” can be measured by the volume of historical records transcribed and made available for scientific analysis. This serves as an indicator of an effective scientific partnership involving civil society.

Summary of SDGs, Targets, and Indicators

Source: bridgemi.com