DOI: 10.5061/dryad.m905qfvdx
title: Unionid Monitoring and Biodiversity Observation (UMBO): Monitoring data for freshwater mussels (Bivalvia: Unionidae) in seven southwestern Ontario, Canada watersheds (1999-2024)

description: Fisheries and Oceans Canada, in partnership with Environment and Climate
 Change Canada and the Ausable Bayfield Conservation Authority, has
 established the Unionid Monitoring and Biodiversity Observation (UMBO)
 network to track species-specific mussel abundance and population
 trajectories across seven watersheds in southern Ontario: Ausable River,
 Bayfield River, Grand River, Maitland River, Saugeen River, Sydenham
 River, and Thames River. The dataset includes results from 51 monitoring
 sites: 8 sites in the Ausable River, 1 site in the Bayfield River, 7 sites
 in the Grand River, 6 sites in the Maitland River, 4 sites in the Saugeen
 River, 13 sites in the Sydenham River, and 12 sites in the Thames River.
 Each river was sampled on a 5-10 year cycle, with Ausable River and
 Sydenham River sites having been sampled 3 times, and sites in all other
 rivers sampled twice.
description: A systematic sampling approach with three random starts was
 employed by a minimum three person search crew. Generally, each site was
 divided into 25 3 m x 5 m (15 m<sup>2</sup>) blocks although
 occasionally additional blocks/quadrats were sampled. Within each block,
 three 1 m<sup>2</sup> quadrats were excavated. The quadrats
 were selected randomly before the survey began and the same three quadrats
 were excavated in each block at a site. Each quadrat was searched,
 beginning at the downstream end of the quadrat using three different
 techniques: (1) visual scan with the naked eye; (2) visual search with a
 viewing box; and, (3) excavation 10 to 15 cm into the substrate. After
 each method was used within a quadrat, all of the mussels found were
 identified, sexed visually (if sexually dimorphic), and measured (maximum
 length in millimeters) using Vernier calipers. When the quadrat was fully
 excavated, the removed substrate was replaced and the mussels were
 returned to the 1 m<sup>2</sup> area from which they were
 collected.  Data are available for 33 species representing 133 unique
 subpopulations (species x river).
description: # Unionid Monitoring and Biodiversity Observation (UMBO): Monitoring data
 for freshwater mussels (Bivalvia: Unionidae) in seven southwestern
 Ontario, Canada watersheds (1999-2024) Dataset DOI:
 [10.5061/dryad.m905qfvdx](10.5061/dryad.m905qfvdx) ## Description of the
 data and file structure ### Files and variables #### File:
 Fisheries_and_Oceans_Canada_UMBO_data_1999-2024.csv
 **Description:** 60,431 unique collections (species x quadrat x block x
 date x site) of freshwater mussels at 51 sites across 7 watersheds in
 southwestern Ontario, Canada.  ##### Variables * SiteCode: unique
 alpha-numeric identifier for each site  * Drainage: tertiary watershed
 identifier * Waterbody: local waterbody name * Date: date of record
 collection (day-month-year) * BlockNo: block number (range 1 - 42) *
 QuadratNo: quadrat number (range 1 - 19) * Genus: generic name following
 MolluscaBase eds. (2025). MolluscaBase. Accessed at
 [https://www.molluscabase.org](https://www.molluscabase.org) on
 2025-08-01. doi:10.14284/448. Blank if no mussel collected from the
 quadrat.  * Species: specific name following MolluscaBase eds. (2025).
 MolluscaBase. Accessed at
 [https://www.molluscabase.org](https://www.molluscabase.org) on
 2025-08-01. doi:10.14284/448. Blank if no mussel collected from the
 quadrat.  * Common Name: common name following Williams, J.D., Bogan,
 A.E., Butler, R.S., Cummings, K.S., Garner, J.T., Harris, J.L., Johnson,
 N.A., & Watters, G.T. (2017). A revised list of the freshwater mussels
 (Mollusca: Bivalvia: Unionida) of the United States and Canada. Freshwater
 Mollusk Biology and Conservation, 20(2), 33-58. Blank if no mussel
 collected from the quadrat.  * Size: maximum anterior - posterior length
 in millimeters. Blank if no mussel collected from the quadrat.  * Gender: 
 M = male; F = female; U = unknown. Blank if no mussel collected from the
 quadrat.