Warm temps make for tough fishing | SierraSun.com

Warm temps make for tough fishing

Bruce Ajari

Warming temperatures have driven the fish deeper in most lakes and reservoirs, and the Truckee River has warmed as well. With temperatures reaching the high 60s and even low 70s in the river, fishing has become an early morning and late evening proposition.

Most anglers have found the fishing much tougher the past couple weeks. Even regulars on the river have found the fishing to be hit or miss.

The best time to get out lately has been from sun-up to midmorning, around 10 or 11 a.m. It is this period during which the coolest temperatures of the day on the river are occurring and the fish appear to be the most active. The late evening has also been a fairly good period.

Anglers often wonder just where to fish during these hot days, often referred to as the “dog days of summer.” In lakes and reservoirs the fish tend to seek cooler water that is denser than the warm water. The water tends to layer into thermoclines. A thermocline is a layer in a large body of water, such as a lake, that sharply separates regions differing in temperature. As a result, the temperature gradient across the layer is abrupt.

Fish will seek out the cooler water that sinks. When water gets too warm it does not have a lot of oxygen in it. As a result, the fish will be in the cooler water that does support better oxygen levels.

If you have a fish finder on your boat, locating these thermoclines is pretty simple since the fish suspend within them. A thermometer that you can drop into the depths also gives you the answer to where the cooler water is layered.

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Once you know what depth the fish are holding in, you can fish at that depth and increase your chances for success. Because the fish are suspended, that does not always mean they are actively feeding. You still have to fish for them!

In streams, fish cannot always go deeper to find more comfort because such depths are not always available to them. They will need more oxygen as the water warms, so they will look for areas that give them what they need. In streams this is often faster water.

The churning water in faster areas of a stream, such as heads of runs, creates bubbles that put oxygen into the system. As a result, fish will gather in these areas as waters get too warm for them in the other sections of the river. Pocket water is another good example of a similar location that meets the requirements of increased oxygen.

If you can locate springs within a stream, the cooler water that they bring into the river supports more oxygen. Besides springs, cooler water can be located below dams. Streams that run into the river from such locations can also be comfortable areas for fish to hold during these warm periods.

While fish can still be caught, anglers should be aware of the warmer water and spend the extra time necessary to revive fish when practicing catch-and-release angling during the heat of the summer months. Because of reduced oxygen levels, they will be exhausted when you land them. Spend the extra time and insure that they are there for future years when you release them.

Bruce Ajari is a Truckee resident and regular fishing columnist for the Sierra Sun and other area newspapers.