Fishing Spider, Dock Spider, Six-spotted Fishing Spider
Dolomedes triton or related Dolomedes species (Fishing Spiders)
Pisauridae (Nursery Web Spiders), Order Araneae. Key family characteristics include strong legs, similar eye sizes arranged in two curved rows, and carrying egg sacs in the chelicerae until just before hatching.
Physical Description
Robust body with a relatively long cephalothorax and elongated oval abdomen. Covered in fine, water-repellent hairs. Moderately hairy with prominent spines visible along the legs.
Size Estimate
Body length approximately 15-20 mm with a leg span reaching up to 70-80 mm, which is typical for a medium-to-large adult fishing spider specimen.
Coloration & Markings
Mottled brown, grey, and olive background with lighter whitish or cream-colored stripes along the sides of the cephalothorax and abdomen, providing excellent camouflage against tree bark, dock wood, and shoreline rocks.
Web Type
Fishing spiders do not build traditional webs to capture prey. Instead, they are active wandering hunters that roam around water surfaces or vertical wooden structures, using silk primarily for safety lines and nursery webs.
Eye Arrangement
Eight eyes arranged in two distinct, recurved rows of four, with eyes being relatively equal in size, which is characteristic of the Pisauridae family.
Leg Characteristics
Long, robust legs held in a sprawling, crab-like or splayed posture. The legs feature distinct dark and light banding, prominent spines, and specialized scopulae pads that allow them to walk smoothly on water surfaces.
Venom & Safety Information
Venom Information
Contains neurotoxic components effective against small invertebrates and vertebrates. Low potency relative to humans, primarily designed for rapid immobilization of aquatic prey.
Medical Significance
Harmless to humans. A bite can cause mild localized pain, swelling, and redness similar to a mosquito or bee sting, but it is not medically significant and poses no serious danger.
Safety Recommendations
Avoid handling bare-handed to prevent accidental defensive bites. If found indoors or on a dock, safely guide the spider into a container using a piece of cardboard for relocation outdoors.
Habitat & Behavior
Habitat & Range
Found throughout North America near aquatic habitats such as lakes, ponds, slow-moving streams, swamps, and frequently around wooden docks, boathouses, and damp structural walls.
Behavior & Temperament
Active nocturnal or crepuscular hunter. They are generally non-aggressive toward humans, choosing to flee or dive underwater when disturbed, though females guarding nursery webs may act defensively.
Diet & Prey
Predatory carnivore feeding on aquatic insects, small fish, tadpoles, and occasionally other small amphibians. They detect ripples on the water surface to locate and snatch prey.
Seasonal Activity
Most active during spring through early autumn, with mating occurring in early summer and overwintering happening beneath loose bark or in debris.
Description
The fishing spider is a magnificent, agile hunter frequently encountered near water and damp wooden structures. With its impressive leg span and remarkable ability to skate across water surfaces, it serves as a fascinating top invertebrate predator in aquatic ecosystems.
Key Features
Sprawling leg posture, distinct light lateral stripes along a mottled brown body, prominent leg spination, and lack of a traditional prey-capturing web.
Similar Species
Wolf spiders (Lycosidae) and grass spiders (Agelenidae). Unlike wolf spiders, pisaurids have eyes of more uniform size and carry egg sacs with their jaws rather than attaching them to spinnerets.
Life Cycle
Females construct silken nursery webs for their egg sacs near the end of summer. Spiderlings hatch and undergo multiple molts over a multi-year lifespan before reaching maturity.
Ecological Importance
Acts as an important natural regulator of aquatic and shoreline insect populations, serving as both predator and prey within wetland food webs.
Conservation Status
Not evaluated by the IUCN, but populations remain stable and widespread across their natural geographic range.
Interesting Facts
Fishing spiders can skate rapidly across the water surface, run across the bottom of shallow water, and even submerge themselves for several minutes to escape predators or hunt small fish.
Photography Tips
Use a macro lens with a fast shutter speed and natural side lighting. Capture from a slightly elevated side angle to highlight the eye arrangement, leg banding, and body markings clearly.
Identified: 2026-09-29T14:07:05.980093