Warmer water increases early body growth of northern pike (Esox lucius), but mortality has larger impact on decreasing body sizes

Sammanfattning

Large fish species often display truncated size distributions related to harvest. In addition, temperature, food availability and density dependence affect body growth and together with natural mortality influence population size structure. Here we study changes in body growth, size distributions and mortality in both harvested and nonharvested populations of northern pike (Esox Lucius) over 50 years along the Baltic Sea coast and in Lake Malaren, Sweden. For coastal pike, body growth has increased coincidentally with increasing water temperatures, yet in the last two decades there has been a decrease of larger individuals. In Lake Malaren, in contrast, size distributions and body growth were stationary despite similar increases in water temperature. A dominance of slow-growing individuals in older age classes was evident in all studied populations, also in the no-take zone, suggesting other factors than fishing contribute to the mortality pattern. We propose that increasing temperatures have favoured body growth in coastal areas, but this has been counteracted by increased mortality, causing pike sizes to decline. To regain larger coastal pike, managers need to consider multiple measures that reduce mortality.

Publicerad i

Canadian Journal of Fisheries and Aquatic Sciences
2021, volym: 79, nummer: 5, sidor: 771-781
Utgivare: CANADIAN SCIENCE PUBLISHING

SLU författare

• Berggren, Terese

  • Institutionen för akvatiska resurser (SLU Aqua), Sveriges lantbruksuniversitet
    

• Bergström, Ulf

  • Institutionen för akvatiska resurser (SLU Aqua), Sveriges lantbruksuniversitet
    

• Sundblad, Göran

  • Institutionen för akvatiska resurser (SLU Aqua), Sveriges lantbruksuniversitet
    

• Östman, Örjan

  • Institutionen för akvatiska resurser (SLU Aqua), Sveriges lantbruksuniversitet
    

Associerade SLU-program

Kust och hav
Sjöar och vattendrag

Globala målen (SDG)

SDG13 Bekämpa klimatförändringarna
SDG14 Hav och marina resurser

UKÄ forskningsämne

Fisk- och akvakulturforskning
Oceanografi, hydrologi, vattenresurser

Publikationens identifierare

• DOI: https://doi.org/10.1139/cjfas-2020-0386

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/117106