Water Quality Reduces Sports Fish Edibility
A COMMON PERCEPTION FROM ang anglers is that sports fish caught in rivers and lakes that are su suffering from water quality p problems are going to be poor eating. Is this a myth or f fact? I believe this is a myth based on recent r research conducted on a stream in Southland t that suffers from poor water quality and many o other observations around the country. First, t trout are a good indicator of water quality; if t they continue to live in the waterway or lake th then the water is not heavily polluted and it is u unlikely eating the fish will be a health hazard. Y Yes, they could contain slightly elevated levels of chemicals, but unless you consume huge quantities it will not be an issue. Infact, fish from the sea are likely to carry higher levels. M Most of our trout fishery water quality issues are from agriculture runoff that reduces water clarity and biodiversity. This reduces the prey available to trout, especially mayflies, that has two observed consequences on sports fish edibility. One is a diet mostly made of the more pollutant tolerant mayflies, like the Deleatidium species that graze on the alga and pass on the flavour during the summer months into trout flesh (perch and salmon are not affected). This gives that muddy flavour that anglers complain about, but only during the warmer months. The other is the opposite in that trout and perch become better eating as they consume fewer mayflies and stoneflies, which are reducing by increased levels of nitrate, and more snails, mollusc, shrimp, crayfish, baitfish, and caddis, which can tolerate elevated levels of nutrients in the water. All these species are rich in carotene, which gives that rich red-coloured flesh in trout and fattens perch. Do not let this myth stop you going fishing on your local lowland waters and enjoying a meal of freshly caught fish.