A1 Journal article (refereed)
The endangered freshwater pearl mussel Margaritifera margaritifera shows adaptation to a local salmonid host in Finland (2022)

Taskinen, J., & Salonen, J. K. (2022). The endangered freshwater pearl mussel Margaritifera margaritifera shows adaptation to a local salmonid host in Finland. Freshwater Biology, 67(5), 801-811. https://doi.org/10.1111/fwb.13882

JYU authors or editors

Publication details

All authors or editors: Taskinen, Jouni; Salonen, Jouni K.

Journal or series: Freshwater Biology

ISSN: 0046-5070

eISSN: 1365-2427

Publication year: 2022

Publication date: 15/02/2022

Volume: 67

Issue number: 5

Pages range: 801-811

Publisher: Wiley-Blackwell

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1111/fwb.13882

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/79893


1. The freshwater pearl mussel Margaritifera margaritifera (FPM) is an endangered unionid which has a glochidium larva that attaches to the gills of Atlantic salmon Salmo salar or brown trout S. trutta, although some FPM populations have been shown to exclusively attach to only one of these species. The origin of host fish populations may be crucial for conservation actions for this mussel species, but the relative suitability of local (sympatric) and non- local (allopatric) salmonid populations as the hosts for FPM has been studied only rarely. We hypothesised that FPM glochidia would show adaptation to local salmonid strains and, there-fore, that they would be more successful (abundant, larger) attached to sympat-ric than to allopatric fish.
2. Here, we investigated the infection success (abundance and growth of encysted larvae in fish) of FPM in local versus non- local fish by caging different strains of brown trout and Atlantic salmon in rivers where FPM populations are present.
3. Higher abundances of glochidia in local fish were observed in three brown trout streams, and larger glochidia were found in sympatric hosts in one brown trout stream and in one salmon river. Furthermore, non- local allopatric fish were not better hosts than local fish in any of the FPM populations tested, neither in brown trout or salmon rivers and neither in abundance nor size of larvae. Therefore, the results supported the hypothesis that glochidia show local adap-tation by being more successful when attached to local fish strains.
4. Thus, the local, sympatric fish strain should be preferred in FPM conservation programmes that involve captive breeding of juvenile mussels and introduction of host fish, but the regional assessment of local host dependency of FPM also would be important outside the current study area.
5. The results also indicate the importance of restoration of original salmonid pop-ulations in FPM rivers to enable the natural, effective reproduction cycle of FPM in their original, sympatric hosts, and thus to promote the recovery of endan-gered FPM populations.

Keywords: species protection; Margaritana margaritifera; adaptation (change); larvae; parasitism; host species; Salmoniformes

Free keywords: conservation; glochidia; host-parasite co-evolution; local adaptation; Unionoida

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Ministry reporting: Yes

Reporting Year: 2022

Preliminary JUFO rating: 2

Last updated on 2022-14-09 at 12:16