Search results for "WATER PEARL MUSSEL"
showing 6 items of 16 documents
The role of salmonid fishes in conservation of the endangered freshwater pearl mussel (Margaritifera margaritifera)
2016
The abundance of freshwater pearl mussels (Margaritifera margaritifera) has declined widely during the past century, and new conservation initiatives are needed. This thesis focused on the relationship between M. margaritifera and its salmonid host required for reproduction of this species. First, by exposing fish experimentally to glochidium larvae of M. margaritifera, different M. margaritifera populations were shown to demonstrate strong differences in their ability to parasitize different salmonid species. Atlantic salmon was clearly a better host for mussels in large river channels, whereas in small headwater tributaries brown trout was the best, or the only suitable, host. These findi…
Effect of substrate particle size on burrowing of the juvenile freshwater pearl mussel Margaritifera margaritifera
2021
AbstractJuveniles of the endangered freshwater pearl mussel (FPM,Margaritifera margaritifera) live burrowed in stream substrate for the first years of their life. Fine sediments block water exchange within substrate and may cause juvenile mortality and recruitment failure. To better understand the connection between success of juvenile FPM and substrate particle size, it would be important to understand behavioural responses of FPM to varying substrate sizes at this critical life stage. We placed newly detached FPM juveniles in a 7-mm layer of sieved sand sorted into five sizes (< 120, 120–200, 200–250, 250–500 and 500–650 µm) each with 10 replicate dishes, 10 juveniles per dish, with bu…
Electrofishing as a new method to search for unknown populations of the endangered freshwater pearl mussel Margaritifera margaritifera
2017
1. The freshwater pearl mussel Margaritifera margaritifera is threatened throughout its Holarctic range, but the occurrence of this species is insufficiently mapped. For the conservation of M. margaritifera, it is important to identify populations more comprehensively. 2. Traditionally mussels have been searched for visually using techniques such as diving and aquascope, both of which are potentially time-consuming and demanding survey methods. 3. In this study, a new search method is presented. As glochidia of M. margaritifera are larval parasites on gills of salmonid fish, electrofishing and non-destructive examination of salmonids with the naked eye may reveal the presence of glochidia a…
Interactions between two parasites of brown trout (Salmo trutta): Consequences of preinfection
2018
Preinfection by one parasitic species may facilitate or by contrast hamper the subsequent penetration and/or establishment of other parasites in a host. The biology of interacting species, timing of preinfection, and dosage of subsequent parasite exposure are likely important variables in this multiparasite dynamic infection process. The increased vulnerability to subsequent infection can be an important and often overlooked factor influencing parasite virulence. We investigated how the preinfection by freshwater pearl mussel Margaritifera margaritifera glochidia could influence the success of subsequent infection by the common trematode Diplostomum pseudospathaceum in brown trout Salmo tru…
Effect of low dissolved oxygen on the viability of juvenile Margaritifera margaritifera : Hypoxia tolerance ex situ
2022
The decline of endangered freshwater pearl mussel (FPM, Margaritifera margaritifera) has been attributed to juvenile mortality caused by low concentrations of dissolved oxygen in the stream substrate resulting from fine sediments (siltation) that impede water exchange in the interstitial microhabitat of juveniles. If low oxygen concentration causes recruitment failure of FPMs, knowledge on the oxygen tolerance of juvenile FPMs is essential for the conservation of the species, as it will justify conservation efforts improving water exchange in the bottom gravel. However, the tolerance of low oxygen of FPM juveniles has not been directly studied. Juvenile FPMs (9–11 months old) were exposed i…
Pulsed flow-through cultivation of Margaritifera margaritifera : effects of water source and food quantity on the survival and growth of juveniles
2020
AbstractConservation of the endangered freshwater pearl mussel (FPM) includes artificially rearing juveniles, but the pulsed flow-through (PFT) method, enabling the continuous renewal of water and food in culture containers, has not been applied to FPM. This study tested the PFT method in culture of FPM juveniles, and the effect of water source (tap vs well water) and food concentration (mixture of commercial phytoplankton products) on the survival and growth of juveniles. Beaker-specific survival rates varied from 0 to 100% (mean: 34%) and from 0 to 58% (mean: 16%) in the 1st (2-week) and 2nd (10-week) experiment, respectively. In the 1st experiment, juveniles attained statistically signif…