Recent studies from the University of Jyväskylä, Finland, have found that size-based selection, similar to practices in fishing, can influence how fish cope with stress, significantly affecting their well-being and ability to adapt in changing environments. The research highlighted that prolonged exposure to manganese sulphate (MnSO4), a common water pollutant linked to mining activities, negatively affects the growth and behavior of zebra fish.
Traditionally, fishing targets medium to large fish through size limitations and gear restrictions, which often benefits species with quicker life cycles. Researchers at JYU discovered that zebra fish exhibit varying reactions to chronic manganese sulphate exposure based on their life-history traits.
“In our study,” notes Academy Research Fellow Silva Uusi-Heikkilä from the University of Jyväskylä, “we focused on two distinct life-history categories: fast-growing fish known for quick juvenile development, early maturation, and smaller size, versus slow-growing fish that experience gradual juvenile growth, later maturation, and larger size.”
Incorporating fish life-history types in conservation efforts
The results indicate that exposure to MnSO4 hinders growth in zebra fish and diminishes their condition factor, a measure of health. Nonetheless, the effects differ among life-history types. The fish with a rapid life-history strategy were more vulnerable to manganese sulphate, displaying slower growth rates at higher concentrations. Moreover, they showed a lower condition factor and reduced food intake compared to their slow-growing counterparts.
“Our results suggest that manganese sulphate can negatively affect fish growth and their ability to cope with stress, highlighting the importance of considering life-history traits in assessing stress tolerance among individuals,” Uusi-Heikkilä explains. “This study emphasizes the need to incorporate population life-history characteristics in environmental risk assessments and conservation strategies, while also recognizing the interaction between fishing practices and environmental influences on fish populations.”
Further information regarding emissions and environmental impacts
This study offers important insights into how pollutants like manganese sulphate can impact aquatic organisms differently based on their life-history strategies.
“These results are crucial for understanding the sustainability and adaptability of fish populations in contaminated environments,” Uusi-Heikkilä asserts.
The research was supported by the Emil Aaltonen Foundation, which provided funding to Professor Anna Kuparinen and her research team.
