Spectaclecase (Margaritifera monodonta) is a federally endangered freshwater mussel species that has experienced a 55% reduction in range (USFWS 2014) and is currently concentrated in three rivers in the Midwest of the United States (Gasconade, Meramec Rivers, MO, and St. Croix River, WI). Its preference for living under large rocks and boulders has limited detection of new populations by traditional survey methods. Environmental DNA technology has been used to detect invasive and rare species, but its use for detection of rare, benthic-dwelling species in large flowing systems has been limited. Here, we propose using environmental DNA to identify presumable sites for discovery of M. monodonta. We designed a M. monodonta-specific qPCR assay and tested it using M. monodonta-housed tank water and water samples from two known mussel beds on the St. Croix River and three known mussel beds on the Mississippi River. We observed higher overall detection rate on the St. Croix River (30.2%) compared to the Upper Mississippi River (0.60%). We also observed higher eDNA detection rates (73.3-93.1%) in 2018 for samples collected during the larval release period in May compared to samples collected in August after reproduction stopped (55.6-70.8%) on the St. Croix River. We tested samples collected at three distances downstream of the two mussel beds found in the St. Croix River, but we did not observe a significant effect of distance on our detection rates. However, we did observe greater detection rates for samples collected near the bottom compared to at the surface. Our results indicate that this novel qPCR assay can successfully detect M. monodonta eDNA and could be utilized to rapidly screen locations to guide intensive physical searches for populations in riverine systems.

This data release includes the data associated with the manuscript "Freshwater mussel distribution and catchment prioritization for mussel conservation in the Northeastern United States." It describes native freshwater mussel distribution data for Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut as well as catchment priority scores for different conservation activities. The data release also includes some data to enable better understanding of the models used in the associated manuscript such as model standard deviations and model parameter permutation importance values.

Positive and negative dreissenid mussel DNA quantitiative PCR results from environmental DNA water samples collected in Montana, Wisconsin and Minnesota to assess if environmental DNA can extend the seasonal window for dreissenid mussel early detection.

Positive and negative dreissenid mussel DNA quantitiative PCR results from environmental DNA water samples collected in Montana, Wisconsin and Minnesota to assess if environmental DNA can extend the seasonal window for dreissenid mussel early detection.

Data is included for two types of field surveys conducted for freshwater mussels in the mainstem of the middle and upper Delaware River in the Mid-Atlantic region of the United States from 2000-2002. Timed search (qualitative) surveys were conducted during 2000-2001 from a point at the confluence of the East and West Branches of the Delaware River near Hancock, NY continuously downstream to a point at the mouth of the Paulins Kill River near Columbia, NJ. In this qualitative survey, mussel species and counts were collected in the field catch-per-unit-effort (CPUE) data was determined for all mussel species within each of 1,095 consecutive stream sections ~200 m in length. Subsequent quantitative surveys were conducted in select 200-m sections of river using quadrats during 2002 in order to estimate abundance and density of mussel present in these sections. One Excel file contains data from qualitative surveys, and a second excel file contains data from quantitative quadrat surveys.

Data is included for two types of field surveys conducted for freshwater mussels in the mainstem of the middle and upper Delaware River in the Mid-Atlantic region of the United States from 2000-2002. Timed search (qualitative) surveys were conducted during 2000-2001 from a point at the confluence of the East and West Branches of the Delaware River near Hancock, NY continuously downstream to a point at the mouth of the Paulins Kill River near Columbia, NJ. In this qualitative survey, mussel species and counts were collected in the field catch-per-unit-effort (CPUE) data was determined for all mussel species within each of 1,095 consecutive stream sections ~200 m in length. Subsequent quantitative surveys were conducted in select 200-m sections of river using quadrats during 2002 in order to estimate abundance and density of mussel present in these sections. One Excel file contains data from qualitative surveys, and a second excel file contains data from quantitative quadrat surveys.

A systematic sampling design was developed to sample mussels in Upper Mississippi River navigation Pools 3, 5, 6, 8, 13 and 18. Hydrologically-enforced buffers were created at a hierarchy of scales to better determine the extent of influence on mussel population assemblages. Buffers were generated using a radii of 1000 meters from the quadrat site point. Several landcape metrics related to the buffer shape, underlying water depth at several modeled river discharges, aquatic vegetation presence, river training structure presence, topographic position, aquatic area classification, adjacent land use types, and wind fetch magnitude were then calculated to help assess which of these metrics/indices are predictive of the distribution, abundance, diversity, and recruitment of native mussels across these six pools in the Upper Mississippi River.

A systematic sampling design was developed to sample mussels in Upper Mississippi River navigation Pools 3, 5, 6, 8, 13 and 18. Hydrologically-enforced buffers were created at a hierarchy of scales to better determine the extent of influence on mussel population assemblages. Buffers were generated using a radii of 10 meters from the quadrat site point. Several landscape metrics related to the buffer shape, underlying water depth at several modeled river discharges, aquatic vegetation presence, river training structure presence, topographic position, aquatic area classification, adjacent land use types, and wind fetch magnitude were then calculated to help assess which of these metrics/indices are predictive of the distribution, abundance, diversity, and recruitment of native mussels across these six pools in the Upper Mississippi River.

A systematic sampling design was developed to sample mussels in Upper Mississippi River navigation Pools 3, 5, 6, 8, 13 and 18. Hydrologically-enforced buffers were created at a hierarchy of scales to better determine the extent of influence on mussel population assemblages. Buffers were generated using a radii of 100 meters from the quadrat site point. Several landcape metrics related to the buffer shape, underlying water depth at several modeled river discharges, aquatic vegetation presence, river training structure presence, topographic position, aquatic area classification, adjacent land use types, and wind fetch magnitude were then calculated to help assess which of these metrics/indices are predictive of the distribution, abundance, diversity, and recruitment of native mussels across these six pools in the Upper Mississippi River.