Hands down, without a question, THE topic across Nebraska is the hot dry summer we are having. I was listening to KVSH radio in north-central Nebraska a couple weeks ago and one afternoon they had no hourly weather report from Wood Lake because “their temperature thingy was broken”. Now that’s hot! This week I have been hearing more and more questions about how this hot weather will affect our fish, so let me say some things about that and make some comments about catching fish in the middle of the summer.
We naturally think of water as being cool, cooler than the atmosphere, and we assume that fish need that cool environment in order to survive. That is true for some species of fish; species we refer to as cool-water or cold-water species. A cold-water fish like rainbow trout simply cannot survive above a certain temperature; that species biochemistry simply ceases to function once the water gets too warm. There are some temperature limitations in the habitats, water bodies, in which a given species of fish can survive. Stocked rainbow trout cannot survive the summer in a small urban lake in southeast Nebraska, and even northern pike, a cool-water species, have a distribution limited by temperature.
One of the unique things about Nebraska is that we have a diversity of fish species ranging from cold-water trout to cool-water pike and walleye to warm-water bass and catfish. Warm-water species not only tolerate warm water temperatures, they thrive in them. For warm-water species, the hot summer weather does not necessarily pose any danger at all; as long as those fish have sufficient water and good water quality they will survive just fine. Unfortunately, in Nebraska having enough water just to keep fish alive can be an issue. As of right now, a large stretch of the Platte River in central and east-central Nebraska does not have water and obviously our fish cannot survive those conditions. Fish need water! Without delving into the topics of Nebraska water law and water use, subjects that surely would get me in trouble, let me say that during periods of drought, some stretches of some rivers can dry up, and to a certain extent, that is a “natural” event on the Great Plains. Obviously, when it happens those river stretches that dry up lose all fish. When the water comes back, the fish will come back. Prairie rivers tend to be dominated by species of fish that are successful in harsh environments; species that may migrate or perish during droughts, but quickly re-colonize and repopulate when the water comes back. Great Plains rivers tend to be dominated by minnow species and perhaps green sunfish, orangespotted sunfish, and black bullheads; fish that can survive harsh conditions and quickly colonize when there is water.
Liquids can hold less of a dissolved gas at higher temperatures. It is a fact that warm water has less dissolved oxygen capacity than cool or cold water, and there usually is less dissolved oxygen in water during the middle of the summer. Again, I would tell you that is usually not a problem, during summer there is still enough oxygen to keep fish alive and thriving as long as there is enough good quality water. However, low oxygen levels can be a problem and can cause fish die-offs during the summer in waters that have water quality problems. Let me give you another example: Excessive nutrient loads in some waters can fuel algae blooms during the hottest parts of the summer. Now algae are nothing more than microscopic plants and all plants produce oxygen via photosynthesis. But, when the sun ain’t shining, plants, algae, respire and when they are doing that they consume oxygen. In a small body of water, a Nebraska farm pond for example, severe algae blooms during mid-summer can actually result in more than enough dissolved oxygen in the water during the day, but after dark, towards morning or after a few days of cloudy, calm weather, that algae can use so much oxygen that it causes a fish kill. In summary, there is less oxygen in the water during the heat of the summer, but that typically is not a problem unless there are other water quality issues.
Every angler will tell you that fishing success tends to lag during the “dog days” of summer. There have been 963,412 excuses made for fish being harder to catch during July and August. One of the most popular excuses is that fish become lethargic during the heat, “it is hot and uncomfortable and they just do not feel like feeding”. That is not at all true; fish are not humans; they do not “feel” or respond to their environment in the same way we do. On a hot, humid July evening all I feel like doing is sipping a lemonaide while sitting in some air conditioning, but that does not mean fish “feel” the same way.
Hang on, I am going to throw out a big, pointy-headed fish biologist word here, you have been warned. Fish are poikilotherms. That big word means that the body temperature of fish is the same as their environment. Most people just say that fish are “cold-blooded”, but that does not make any sense when the water temperature is 82 degrees F! Regardless, the temperature of the fish is the same as their environment and for the most part that means the metabolism rate of fish increases as the water temperature increases.
Fish DO NOT feed less during the summer because they are uncomfortably hot. In fact their metabolism rates increase with the warmer water temperatures and they actually feed as much or more during the summer than they do in any other season of the year! In fact even species that are nearing their upper lethal temperature will continue to feed right up to the point where they die.
So, if they are feeding more during the dog days of summer than they do at any other time, why are they so hard to catch? Which one of those other 963,411 excuses explains slower fishing during the summer months?
Fishing gets tough during the middle of the summer because of the abundance of natural prey that is available to the fish. With warm water temperatures, the entire aquatic food chain is operating at maximum capacity and zooplankton, aquatic insects, small fish and a host of other fish food organisms are at their peak abundance during the middle of the summer. It is almost so easy to get a meal that all a hungry fish has to do is swim around with their mouth open! On many Nebraska waters there are millions of young-of-the-year (YOY) baitfish available for predator fish to eat right now.
Fortunately, in this time of abundance, there are some strategies that can be used to increase your chances of catching fish during the summer. Specific strategies will vary from species to species and perhaps from one water body to the next, but there are some general strategies that will help. With an abundance of natural prey, feeding periods may be short; they can be intense, but typically do not last long. Try to identify prime areas where the fish will feed and make sure you are fishing those areas during prime times. Dawn and dusk are prime feeding times for most species of fish and are times when you should do everything possible to be on the water, on one of your best spots ready to take advantage of a feeding frenzy. Another prime feeding window may be just prior to the arrival of a summer thunderstorm (just make sure you are safe, watch the lightning and wind!).
Lastly, let me finish my rambling with a word about fish-handling during mid-summer. Have a plan for what you are going to do with fish before you ever catch them. The warm water temperatures and lower dissolved oxygen levels do mean that fish will stress more easily when being caught. If you are going to release fish, it is imperative to land them as quickly as possible, keep them in the water and handle them as little as possible and release them back into the water from which they were caught as soon as possible. Some anglers even will shift their fishing strategies from cool- and cold-water species during the hottest periods because just catching those species during peak temperatures can stress them enough to kill them. This is especially true for large, cool-water predator fish like wipers and muskies as well as the cold-water trout, so if you target those species during the summer, those fish in particular need to be landed absolutely as quickly as possible and released with as little handling as possible. Or, shift your summer fishing strategies to panfish, largemouth bass, white bass, or catfish, species that also are usually easier to catch during mid-summer. If you choose to harvest a few fish for a meal of fresh fish, there is no question the best way to handle those fish during the heat is to put them on ice immediately after they are caught. Take a cooler full of ice with you and put any fish you want to harvest in that cooler instead of in a livewell or on a stringer.