The Effects of DAM Removal on River Colonization by Sea Lamprey Petromyzon Marinus

Abstract

Habitat fragmentation is an important cause of biodiversity loss in freshwater systems, as worldwide rivers have been fragmented by dams and other hydraulic structures. To restore freshwater fish populations, some barriers have been removed, but the long‐term ecological effects of this removal have been rarely quantified. In the present study, we quantified the effects of barrier removal on river colonization by anadromous sea lamprey (Petromyzon marinus) by analyzing the spatial distribution and nest density in a small coastal river (France) from 1994 to 2011. Our results demonstrated the benefit of dam removal within few years after restoration. Indeed, the spatial distribution of nests shifted significantly upstream and was more uniform throughout the river after removal. Our results also suggest that the spatial patterns of habitat colonization were affected by the density of nests, river flow and connectivity. Finally, although the number of nests was significantly higher after removal, it was not possible to clearly identify the contribution of intrinsic versus external factors involved in this pattern. Further investigations are therefore needed to quantify the potential subsequent effects on juvenile recruitment and the overall population dynamics. Copyright © 2014 John Wiley & Sons, Ltd.

Pacific lamprey recolonization of a Pacific Northwest river following dam removal

“…There are also reports of Pacific lampreys present in Indian Creek of the Elwha River Basin following the removal of Elwha Dam in 2012 (Witze, ). Sea lampreys, Petromyzon marinus , have also been shown to rapidly recolonize portions of stream basins following dam removals when they were already present downstream of the dam (Hogg, Coghlan, & Zydlewski, ; Lasne, Sabatié, Jeannot, & Cucherousset, ).…”

Rapid visual assessment of spawning activity and associated habitat utilisation of sea lamprey (Petromyzon marinus Linnaeus, 1758) in a chalk stream: implications for conservation monitoring

“…More recently, however, Lasne et al. () demonstrated the efficacy of nest counts for evaluating the effects of dam removal on the P. marinus colonisation of a coastal river system in France.…”

“…Examples specific to P. marinus tend to be restricted mainly to 'grey' literature sources, but include extensive monitoring to evaluate the efficacy of a range of control treatments for invasive populations across 10 tributaries of Lake Champlain, USA (Parren and Hart, 2012), surveys which successfully confirmed the rivers supporting spawning activity in the Humber catchment rivers, UK (Bellflask Ecological Survey Team, 2009), and the use of nests to identify spawning grounds and the characterisation of spawning habitat in the River Mulkear, Ireland (Igoe et al, 2004). More recently, however, Lasne et al (2015) demonstrated the efficacy of nest counts for evaluating the effects of dam removal on the P. marinus colonisation of a coastal river system in France.…”

Sea LampreyPetromyzon marinusBiology and Management Across Their Native and Invasive Ranges: Promoting Conservation by Knowledge Transfer

“…Other studies have revealed technical fish-265 ways are also problematic for P. fluviatilis to utilize (Laine et al, 1998;Q4 Lucas et al, 2009;Foulds and Lucas, 2013), with Aronsuu et al (2015) suggesting that natural-like fish ramps might be a good solution to enhance their passage over low-head barriers. Nevertheless, 270 Lasne et al (2015) revealed that barrier removal can be the most effective mechanism to enable P. marinus passage, with higher numbers of nests that were more consistently distributed occurring several years after barrier removal in a French coastal stream. This con-275 trasts to Lucas et al (2009) who reported that in the River Derwent, England, only 2% of adult P. fluviatilis spawners were recorded in 98% of the river's total spawning habitat as this was located above a series of impassable low-head barriers.…”

“…For determining the size of the inward spawning migration run of adults then suggested techniques include redd (nest) counts and application of video monitoring on fish passes (e.g., Lasne et al, 2015;Pinder 855 et al, 2015). In the tidal River Garonne, France, the species is commercially exploited using drifting trammel nets and unbaited pots, and these provide catch returns from which statistics are produced to highlight patterns in their relative abundance and provide adults for bio-860 metric characteristics (Beaulaton et al, 2008).…”