Czech Lake Lipno
- The two main drivers of warm-water fish are temperature and food quantity
- New methods for calculating Eurasian perch was developed
- Carp in central Europe is still in suboptimal conditions. It does not reproduce naturally, and biomass loss exceeds the production
- IBM forecasting the biomass and yield of pikeperch was developed for the Lipno reservoir.
Effects of climate change
Temperature, invasive species, eutrophication, and fishing are main threats to the coldwater species in central Europe, such as brown trout and whitefish. In some water systems they are already extinct. Oligotrophication (decrease in nutrients) improves water quality but decreases production of commercial species. The emerging top predator, the wels catfish, thrives with increasing water temperatures, but is a threat to many species, especially percid fish, which also experiences suboptimal temperature conditions as temperatures increase.
Risks and opportunities
Risks: Complete loss of cold-water species, overfishing of commercial species, economic losses from intensive carp fishery. In the distant future, overbreeding of carp or some allochthonous warm water fish.
Opportunities: Increased production of emerging warm water fish (catfish, pikeperch, carp, other cyprinid fish, centrarchids). Predatory species can be exploited as new biomanipulation tools.
Maximum protection of cold-water fish (fishing ban and preventing invasive fish). Fishery regulations and focusing of fishermen’s attention on utilisation of emerging species. Biomeliorative measures: water level manipulation during spawning, stocking of predatory species, biomeliorative catches.
Salmonid fish will be considered luxury goods as salmonid fishery decreases in importance. This may not mean the decrease of its economic importance if people are willing to pay for luxury goods.
Also, warm water fishery has to be changed. Finding the right balance of the developing food web may be a challenge as even emerging species can be overfished. However, future challenges may lead to improving fisheries management as a whole.