Mussel populations diminished from freshwaters in Europe during the 20th century, both due to human harvest and hydropower constructions. Therefore, substantial efforts have been dedicated towards restoration and reintroduction operations. Nevertheless, few studies have assessed mussel behavior in response to substrate and within stream preferences, which makes reintroduction operations uncertain and short of scientific guidelines. The aim of this study was to evaluate the importance of environmental factors for pearl mussel habitat selection and thus, provide knowledge that may make mussel introduction more successful. I investigated the behavior of freshwater pearl mussels (Margaritifera margaritifera) following introduction in a stream (Gäddbäcken) in Northern Sweden. Here, I used short behavioral trials and stream surveys to assess pearl mussel habitat preference (substrate, stream depth and water velocity) when introduced in novel environments. When comparing juvenile and adult pearl mussel behavior in my laboratory trials, I found that juvenile pearl mussels are more active (faster to do their first move) than adult mussels. In the within stream experiment, I found that there was a high correlation between water velocity and remaining pearl mussels, where mussels were more common in water with a velocity of 0.5 m/s than at lower velocities. Also, there was a positive correlation between water depth and remaining pearl mussels, where pearl mussels increased in abundance at depth over 0.3 m. My results suggesting that within stream conditions (water depth and stream velocity) can to a large part explain the pearl mussel presence at different localities in the stream. In other words, to increase the likelihood of successful introduction of pear mussels, my study indicate that individuals should be introduced to stream velocities of around 0.5 m/s and a water depth of 0.3 - 0.45 m.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:umu-191705 |
| Date | January 2022 |
| Creators | Holmgren, Malin |
| Publisher | Umeå universitet, Institutionen för ekologi, miljö och geovetenskap |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Malin Holmgren |
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