The dog days of summer (July 3 to August 11) are well upon us and fishing, at least in many of our Southern Interior lakes, has taken a turn for the worst. Most fish, it would seem, have made a beeline for the bottom of the lake where water temperatures are a bit cooler and the water contains more oxygen. As water temperatures rise, the level of dissolved oxygen particles becomes depleted making it harder on fish to absorb oxygen through their gills – in effect, it makes it harder for them to breath.
Any of the fish I’ve encountered as of late were so lethargic that you could drop a fly, lure or just about anything else right on top of their heads and they wouldn’t have reacted. Having said that, fish usually will become more active in late evening when and if water temperatures have cooled off enough.
Another problem with extended warm temperatures is that in many lakes, any fish that you might catch and want to eat are, well, not really all that good to eat. They taste like mud.
Contrary to what some people seem to think, fish do not taste muddy because of the muddy lake bottom in which they are caught. The flavour is caused by a chemical compound called geosmin. The two primary producers of geosmin in freshwater lakes are the blue-green algae you see on the surface of some lakes and actinomyces bacteria which causes decomposition of organic material on the lake bottom. Algae and actinomyces bacteria release geosmin into the water (it is actually released when the living algae and bacteria die), which trout breathe in through their gills and then transfer, through the bloodstream, into their skin, flesh and muscle tissue.
Geosmin is only eliminated with time once the algae bloom clears and/or decomposition slows.
The rate of elimination is dependant on water temperature and the fat content of the fish, which is species and age/size specific. Ironically, both algae and decomposition increase in warmer water, while it takes longer for a fish to eliminate the geosmin compounds from their system in cooler water due to metabolism rates.
Although fish can still taste muddy in the fall, it is much more of a problem during the hot summer months when the algae is in full bloom. The problem diminishes as water temperatures cool down and are less likely to occur in lakes which are relatively deep and low in organic matter.
The problem can also exist in lakes with a high degree of suspended clay particles. The clay absorbs the geosmin, that subsequently passes through the gills of fish.
It can be hard to predict which lakes will have muddy tasting fish.
Two lakes of similar depth, with the same type of algae bloom, may not produce similar tasting fish. Sometimes it’s just a matter of what micro-habitat a fish frequents when eating.
If you do keep a fish that you suspect is going to taste muddy, you can usually distinguish a slight muddy smell when you’re cleaning it. You can try soaking the fish in vinegar to help remove the taste, but I’ve never really found vinegar all that successful – geosmin breaks down in acid. There are all sorts of so-called remedies for muddy-tasting fish, but, like I say, I’ve never found one that works.
Once I know the muddy taste is there I can always taste it, regardless of how it is prepared, how much spice might be used or what kind of sauce it’s covered with.
The best way to get rid of the muddy taste in trout is to practise catch and release. Simply return the fish back to the water and figure out something else to have for dinner.