Dolomedes – Fishing Spider

A the name suggests, the fishing spider is a semi-aquatic genus of spiders that are found all over the world. Various species of Dolomedes can be found in every US state.

Dolomedes are a genus of the Nursery Web Spider family. They are large hunter spiders that usually find their prey around water. They will place their legs on the water surface and feel any movement that is caused by insects or even small fish.

When the Fishing Spider lays eggs, it wraps them in a sac and carries it underneath them. Before they hatch, it will tend to attach it to something and protect it.

Description of the Fishing Spider

While there are several species of the Dolomedes spider in the United States, the most common species are Dolomedes tenebrosus, Dolomedes triton, and Dolomedes vittatus.

Dolomedes tenebrosus

D. tenebrosus has a brown and black patchy pattern over the entire spider that mixes in well with the banded legs of the same colors.  One of the smaller markings, which usually helps me recognize this spider, is the black mask around the eyes.  If you see the brown and black pattern and the mask around the eyes, you likely have a Fishing Spider.

Dolomedes triton

D. triton Is basically all brown or black with a white stripe running the length of both body parts on each side. Slightly visible in the picture (sometimes not very visible on the spider) are two rows of white dots just to the inside of the stripes on the abdomen. There are six dark spots on the underneath side of the cephalothorax for which it gets its common name of Six Spotted Fishing Spider.

Dolomedes vittatus

D. vittatus can be medium brown with white trim running down its side, or almost black with no distinguishable trim line. They will have the white dots on the abdomen and in the center of the cephalothorax will be two dark triangular marks side by side. This spider can look very similar to D. scriptus males.

Size of the Fishing Spider

The Fishing Spider is one of the largest spiders in the United States, as the females of some species can grow up to 4” (102mm), including the legs.

Web

The Fishing Spider spins a web to protect its eggs. She will carry the egg sac underneath her until they are ready to hatch and then she will spin a web to attach the sac to a leaf or some wood or some other object. Once the egg sac is attached to something, she will stand guard over them. They do not spin webs to catch prey, as they are hunters and will wander around looking for their meal.

Bites

Dolomedes are not usually aggressive spiders, except when they are protecting their eggs or young. If you are bitten by a fishing spider, it is not considered to be dangerous. At its worse, you might have some localized swelling and pain that will heal on its own.

Dolomedes Scientific Classification

• Kingdom: Animalia
• Phylum: Arthropoda
• Subphylum: Chelicerata
• Class: Arachnida
• Order: Araneae
• Infraorder: Araneomorphae
• Family: Pisauridae
• Genus: Dolomedes

Common names

All common names of Dolomedes are in reference to its semi-aquatic behavior. They are: fishing spider, dock spider, wharf spider, raft spider.

Distribution of the fishing spider in the USA

Various species of the fishing spider can be found in every US state – Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming