A new study has found that actively enriching aquaculture through habitat stimulation can result in significantly greater survival rates of fish stocks.
The study, published in the Journal of Applied Ecology under the title ‘Rearing background and exposure environment together explain higher survival of aquaculture fish during a bacterial outbreak’, was conducted by scientists at the University of Jyväskylä and Natural Resources Institute Finland. Researchers analysed the effects of enriching aquaculture on the disease resistance levels of Atlantic salmon and sea migrating brown trout.
The classic rearing environment for farmed fish is low in stimuli and can provide ideal conditions for bacteria and parasites to multiply and spread. The researchers therefore experimented with enriching aquaculture conditions by providing more complex rearing tanks equipped with a variety of structures, in order to better replicate the conditions the fish would experience in the wild; and found that fish exposed to common bacteria were substantially more likely to survive if they had experienced the enriched environment. Researchers suggest this may be due to a heightened tolerance for stress.
Ville Räihä, a PhD student at the University of Jyväskylä and researcher on the study, said: “Adding enrichments to rearing tanks significantly improved the survival of fish during natural disease outburst. However, there were minor differences between fish species and populations. The controlled exposure revealed that fish exposed to the disease in enriched environment had higher survival regardless of the rearing background in standard or enriched conditions. This emphasises the importance of the environment of exposure for severity of the disease.”
The global aquaculture industry is simultaneously becoming increasingly important as a source of food provision and subject to growing pressure due to the dual threats of overfishing and climate change. By reducing rates of disease and stock death, sustainable options such as enriching aquaculture could provide solutions both to food production rates and boosting stock levels of endangered fish species which are vulnerable to overfishing.
