Turnover SUCKS, but you can learn from it.
|How Spring Lake Turnover Impacts Fly Fishing
Spring is a time of renewal and rebirth, and for many fly anglers, it marks the start of another exciting season on the water. However, before rushing out to your favorite lake, it’s crucial to understand a critical phenomenon that occurs in many water bodies during this time of year: lake turnover. This natural process can significantly impact water quality, fish behavior, and ultimately, your fly fishing success.
This article goes deep into the science behind lake turnover, exploring its causes, effects, and implications for fly anglers. We’ll examine how it influences insect life and fish feeding patterns, providing valuable insights and strategies for successful spring fly fishing.
The Science Behind Lake Turnover
Lakes are dynamic ecosystems, constantly responding to changes in their environment, particularly temperature fluctuations. Lake turnover is a prime example of this dynamism, driven by the unique relationship between water temperature and density.
1. Water Density and Stratification:
Unlike most substances, water reaches its maximum density at 4°C (39.2°F). As water cools below this temperature, it becomes less dense, explaining why ice floats. This unique property leads to a fascinating phenomenon called stratification, where lakes form distinct layers based on temperature and density:
- Epilimnion: The uppermost layer, warmest in the summer and coldest in the winter. It’s rich in oxygen due to contact with the atmosphere and sunlight penetration, supporting a diverse ecosystem.
- Thermocline: A transition zone between the epilimnion and hypolimnion, characterized by a rapid temperature change.
- Hypolimnion: The deepest and densest layer, remaining relatively cold and stable throughout the year. Oxygen levels are often lower due to limited mixing and decomposition of organic matter.
2. The Turnover Process:
Lake turnover occurs twice a year, in spring and fall, driven by changes in water temperature and density:
- Spring Turnover: As winter’s grip loosens, ice melts, and the surface water warms, approaching 4°C. This denser water sinks, displacing the deeper, less dense water and initiating a mixing process. Wind action further enhances this mixing, leading to a complete circulation of the water column.
- Fall Turnover: As summer ends and temperatures drop, the surface water cools, becoming denser and sinking. This again triggers mixing, resulting in a uniform temperature and oxygen distribution throughout the lake.
Impacts on the Lake Ecosystem
Lake turnover is a crucial event for lake health, but it can temporarily disrupt the delicate balance of the ecosystem, affecting both fish and insects:
1. Oxygen Depletion:
While turnover ultimately replenishes oxygen in the deeper layers, the initial mixing can distribute oxygen-poor water throughout the lake. This can stress fish, particularly those species that require high oxygen levels, making them less active and less likely to feed.
2. Nutrient Mixing:
Turnover brings nutrients trapped in the hypolimnion to the surface, stimulating algal growth and kick-starting the food chain. However, excessive nutrient loading can lead to algal blooms, which can further deplete oxygen levels and negatively impact water quality.
3. Water Clarity:
The mixing process often stirs up sediment and decaying organic matter, reducing water clarity. This can make it difficult for fish to see your flies, and it can also hinder their ability to hunt effectively.
Lake Turnover and Fly Fishing: Challenges and Opportunities
Lake turnover presents both challenges and opportunities for fly anglers. Understanding these dynamics is key to success on the water:
1. Challenges:
- Reduced Fish Activity: Low oxygen levels and poor water clarity can make fish sluggish and less inclined to feed.
- Difficulty Finding Fish: Fish may move to different areas of the lake in search of more favorable conditions, making them harder to locate.
- Fly Selection and Presentation: Reduced visibility may require using larger, brighter flies and adjusting your retrieval techniques to attract attention.
2. Opportunities:
- Pre-Turnover Fishing: The period just after ice-out, before turnover begins, can be incredibly productive. Fish are often concentrated in shallow areas, eager to feed after a long winter.
- Post-Turnover Fishing: Once turnover is complete and the water stabilizes, fishing can improve dramatically. The influx of nutrients leads to increased insect activity and a resurgence in fish feeding.
- Targeting Specific Areas: Focus on areas with better oxygen levels, such as inlets, outlets, and windward shores where wave action increases oxygenation.
Strategies for Fly Fishing During Turnover
Here are some tips to improve your chances of success during lake turnover:
- Monitor Water Conditions: Pay VERY close attention to water temperature, clarity, and weather patterns. Look for signs of turnover, such as murky water and debris on the surface.
- Fish Shallow: Early in the season, focus on shallow areas where water warms faster and oxygen levels are higher.
- Use Bright Flies: Larger, brightly colored flies can be more visible in murky water. Consider using attractor patterns or streamers to entice strikes. (this does get impacted by lighting conditions as well)
- Adjust Your Retrieval: Experiment with different retrieval speeds and techniques to find what works best. A slow, steady retrieve can be effective when fish are less active.
- Target Inlets and Outlets: These areas often have higher oxygen levels and can attract fish during turnover.
- Be Patient and Persistent: Fishing during turnover can be challenging, but with patience and persistence, you can still enjoy success on the water.
Conclusion
Lake turnover is a fascinating natural process that plays a crucial role in the health of lake ecosystems. While it can temporarily disrupt fishing conditions, understanding its dynamics can help you adapt your strategies and continue to enjoy fly fishing throughout the spring season. By monitoring water conditions, adjusting your fly selection and presentation, and targeting specific areas, you can increase your chances of success and make the most of this unique time of year.