Fisheries and Oceans Canada’s (DFO) National Biofouling Monitoring Program (BMP) has conducted annual field surveys to monitor the introduction, establishment, spread, species richness, and relative abundance of native and non-indigenous species (NIS) since 2006. Standardized monitoring protocols employed by DFO-Maritimes, -Gulf, and -Quebec Regions include biofouling collector plates deployed from May to October at intertidal and shallow subtidal, geo-referenced sites, including public and private docks, aquaculture lease sites, public and private marinas and yacht clubs.

Initially in the Maritimes Region (2006-2017) collectors consisted of 3, 10 cm by 10cm PVC plates deployed in a vertical array and spaced approximately 40-cm apart with the shallowest plate hung at least 1 m below the surface to sample shallow subtidal and intertidal species (Sephton et al. 2011, 2017). Two replicate arrays were deployed at least 5 m apart per site. Since 2018, collector arrays were modified to enhance statistical replication, including 10 individual collectors deployed per site at 1 m depth and at least 5 m apart (as above) from May to October. The percent cover of AIS on all collectors was determined by visual examination and scored as follows; (i) ‘0’ = absent, (ii) ‘1’ = ≤25 % cover, (iii) ‘2’ = 25 to ≤50 %, (iv) ‘3’ = 50–75% , and (v) ‘4’ = >75%. Average percent cover is provided for all NIS observed annually per site. Presence-absence indicates that an NIS was observed on at least one collector plate.

One additional rocky intertidal species (Asian shore crab; Hemigrapsus sanguineus) was assessed via beach surveys as permitted by time and resources following its initial siting in St Mary’s Bay (Nova Scotia) in April 2020. Rapid assessment surveys conducted in the Fall of 2020 and 2021 were employed to delineate H. sanguineus’ distribution and relative abundance. Areas deemed suitable and at high risk for spread were targeted, including exposed rocky intertidal habitat in southwest regions of Nova Scotia and New Brunswick. Each rapid assessment consisted of 30-minute beach surveys per site conducted by 2 or 3 people (modified from Stephenson et al. 2011). During each survey, crabs were collected under rocks and seaweed in preferred cobble/boulder habitat (Lohrer et al. 2000). Count data was standardized for each site as the number of crabs collected per 30-min search per person.

Cite as:

DFO-Maritimes Biofouling Monitoring Program. Published October 2018, Updated December 2023. Coastal Ecosystems Science Division, Fisheries and Oceans Canada, Dartmouth, NS

Citations:

Sephton D, B Vercaemer, JM Nicolas, J Keays (2011) Monitoring for invasive tunicates in Nova Scotia, Canada (2006-2009) Aquatic Invasions 6: 391-403.

Sephton D, B Vercaemer, A Silva, L Stiles, M Harris, K Godin (2017) Biofouling monitoring for aquatic invasive species (AIS) in DFO Maritimes Regions (Atlantic shore of Nova Scotia and southwest New Brunswick): May-November, 2012-2015. Canadian Technical Report of Fisheries and Aquatic Sciences 3158: 72 pp.

Stephenson EH, RS Steneck, RH Seeley (2009) Possible temperature limits to range expansion of non-native Asian shore crabs in Maine. Journal of Experimental Marine Biology and Ecology 375: 21–31. doi:10.1016/j.jembe.2009.04.020