High host densities dilute sea lice Lepeophtheirus salmonis loads on individual Atlantic salmon, but do not reduce lice infection success

The invasive Chinese pond mussel Sinanodonta woodiana (Lea, 1834) as a host for native symbionts in European waters

“…In our study, higher density of S. woodiana was noted in heated lakes (Kraszewski and Zdanowski, 2001;Spyra et al, 2012), but higher prevalence of mussels was observed in fish ponds. This result suggests that high host density can decrease the prevalence of inhabited individuals due to N o n -c o m m e r c i a l u s e o n l y the dilution effect as the probability of an individual host being infested by symbionts decreases with increasing host density (Mooring and Hart, 1992;Côté and Poulin, 1995;Samsing et al, 2014).…”

Toward a model-based prediction system for salmon lice infestation pressure

“…Our results indicate that this is a reasonable assumption and is also in accordance with results of Johnsen et al (2016). Although it has been shown that factors like the age of the lice, the water temperature, the current speed, the light conditions, turbulence, the water salinity, etc., influence the infestation process (Bricknell et al 2006, Samsing et al 2014), a complete understanding is still not established. It would also have been preferable to have an observational data set where high infestation levels occurred more frequently than in the present and with higher resolution in space to confirm the modeled patchiness in lice abundance.…”

Effect of exposure on salmon lice Lepeophtheirus salmonis population dynamics in Faroese salmon farms

“…Likewise, large hosts can carry a greater number of parasites (Lees et al 2008, Heuch et al 2009, Jansen et al 2012), increasing contact rates and exposure time (Jackson & Minchin 1992, Tucker et al 2002. The complexity of host density on sea lice population dynamics is further increased by 'the dilution effect', a negative relationship between host density and infection intensity (Samsing et al 2014). …”