# Dock Spider — Spider Squad

## Common Name
Dock spider, fishing spider, wharf spider

## Scientific Name
Dolomedes (genus — several species in Ontario, most commonly Dolomedes triton and Dolomedes tenebrosus)

## Size
Ontario's largest spider. Female body: 17 to 25 mm. Leg span: up to 75 to 90 mm. Males are smaller (roughly half the size of females). Dock spiders are visually striking at full size.

## Appearance
Dark brown to grey with cream or yellow markings along the sides of the body. Legs are long and thick. The body is hairy. Often confused with wolf spiders when found away from water.

## Behaviour
Dock spiders are semi-aquatic hunters. They can walk on water using surface tension, and can dive and breathe underwater briefly by trapping air against body hairs. They detect prey (insects, tadpoles, small fish) through vibrations on the water surface and on substrates they rest on.

They do not build webs to catch prey. Webs are only used for egg sac construction and nursery webs for young.

## Habitat
Primarily found near water: lakeshores, rivers, streams, docks, boat houses, and cottage decks. In Ontario, they are most heavily concentrated in:
- Muskoka, Haliburton, Kawarthas (cottage lake regions)
- Grey-Bruce (Georgian Bay, Lake Huron shoreline)
- Niagara Region (near the Great Lakes)
- Norfolk/Haldimand/Elgin counties (Lake Erie shoreline)

They move onto docks, boathouses, and cottage structures to hunt and rest, which is where most human encounters happen.

## Seasonal Pattern
Active from late spring through fall. Females carrying egg sacs or nursery webs are most visible in June and July. Peak activity and visibility: July to September.

## Danger Level
Not dangerous to humans in practical terms. They are large and alarming in appearance. Bites are possible if handled and can cause localized swelling and mild pain, but are not medically significant for most people.

They are not aggressive toward humans. They do not bite unprovoked. The size makes them psychologically alarming even when harmless.

## At Cottages and Waterfront Properties
Dock spiders establish themselves quickly on waterfront structures and can reach very high densities on docks, under decks, in boathouses, and around shoreline access points. A single boathouse can harbour dozens.

Spider Squad's waterfront treatment specifically addresses dock spider populations at cottage and lakefront properties. This is a distinct application from standard residential treatment — it accounts for nearness to water and uses approaches appropriate for waterfront zone compliance.

## To Book Waterfront Treatment
Call 905-935-7498 or visit the waterfront service page at spidersquad.ca/waterfront/