Freshwater Mussels of the SOSMART Area

Todd J. Morris1 and Scott Reid2

1GLLFAS, Fisheries and Oceans Canada, Burlington, ON2ARDS, OMNR, Peterborough, ON

Overview

• Biology/Ecology• Distribution• Species at Risk• Sampling and Monitoring

Mussel Ecology

Unionids cycle nutrients, transfer energy within ecosystems, provide habitat and clarify water bodies (Dillon 2001, Vaughn et al. 2008)

Algae

Detritus

Bacteria

Haag and Rypel 2010

Long Life-spans

Rep

rodu

ctio

n

©M. C. Barnhart

http://www.nature.ca/rideau/j/images/img0065.jpg

K. McNichols University of Guelph

Complex Life Cycle

Reproductive TacticsBroadcast Release

Lures pre-glochidial releasepost-glochidial release

Host Capture

many glochidia, low cost,low success, host generalists

few glochidia, high cost,high success, specialists

Mussel Lures

• 842 recognized species world-wide (Order: Unionoida)

• 302 in North America (2 Families)

• 55 in Canada (2 families)

• 41 in Ontario (1 Family)

Global Diversity

Graf and Cummings 2009

Mussel Hot-SpotsD

istri

butio

n

Mussel Hot-SpotsD

istri

butio

n

Species at Risk

Nationally at Risk

65% of Canadian mussel species are in need of conservation

Source: Wild Species 2000; National General Status Assessment for Freshwater Mussels (2004)

Spe

cies

at R

isk

Nationally at Risk

• 55 species in Canada• 18 COSEWIC listed species

• 1 Extirpated • 13 Endangered • 1 Threatened• 3 Special Concern

• 15 Candidate species awaiting assessment

Spe

cies

at R

isk

SAR Distribution within SOSMART

Rainbow Habitat• Small to medium-sized rivers

and inland lakes• Historically: shallow nearshore

areas of the lower Great Lakes• In or near riffles• emergent vegetation moderate

to strong current• cobble, gravel, sand • clean, well-oxygenated• Depths < 1 mRainbow – END (SARA)

TH (ESA)

D. McGoldrick, NWRI

Rainbow

http:// www.conservation.state.mo.us /conmag/2003/08/10.htm

D. Mc Goldrick, NWRI, ECRainbow

Eastern Pondmussel• Habitat

– Sheltered areas of lakes, slack-water areas of rivers and canals

– Prefer fine substrates and mud

– Depths (03-4.5m)– L. St. Clair >95% sand– Lower reaches of rivers

Eastern Pondmussel – END

S Staton (NWRI)

Eastern Pondmussel

MapleleafHabitat:• medium to large rivers • firmly packed coarse gravel

and sand to a substrate of firmly packed clay/mud (broad range)

• historically from larger lakes, but recent data indicate it has largely been lost from these habitats Mapleleaf – THR

Mapleleaf

LilliputHabitat:• Low gradient streams/rivers,

coastal wetlands • Soft substrates – mud and silt• Highly turbid systems• Previously thought restricted to

L. Erie watershed but no known from L. Ontario.

Lilliput – COSEWIC Candidate

Sampling/Monitoring

Sampling Methods• Wadable/accessible sites

– Inventory– Life history

• Non-wadable/accessible sites

Timed-searches

Ideal for first time surveysRiver bottom visually searched for a set amount of time – 4.5 person-hours

Data:

Species presence/absenceRelative abundance (CPUE)Distribution patterns (within watershed)Size class distributionsSex ratios

Wadable - Inventory

Advantages:• Cheap and requires little planning• Easy to execute in the field

Limitations:• Easily biased• Small species & juveniles often

overlooked• Not great at estimating population

size• No statistical rigor

# species found related to effort!

Wadable - Inventory

Systematic sampling with excavation

Ideal for determining population size and trend through time

Can easily be adapted for a wide range of applicationsData:

DensityDistribution patterns (within site)Micro-habitat preferencesSize class distributionsSex ratios

Wadable – Life History

Upstream

Acr

oss

Wadable – Life History

Advantages:• Gives precise estimates for

patchily distributed populations• Spreads sampling effort throughout

the survey site• Can calculate variance for

statistical analyses

Limitations:• Labour intensive• Requires a minimum of 3 people

(4 ideal)

Wadable – Life History

Non-wadable, high visibility

65 m2

Data:

Species presence/absenceDensitySize class distributionsSex ratios

Snorkelling/Diving

Non-wadable, low visibility

Non-wadable, low visibility

Non-wadable, low visibility

Non-wadable, low visibility

Additional InformationOntario Freshwater Mussel Recovery Team