Dungeness and snow crabs are two vital commercial species that reside in temperate and polar regions. They live a surprisingly long time for an invertebrate and can lay huge quantities of eggs each spring. Snow crabs are slightly larger, though most people find that Dungeness crab to have sweeter and better-tasting meat.
Key Differences Between Dungeness Crab and Snow Crab
- Size: Dungeness crabs reach 2-3 pounds when fully grown. Snow crabs are bigger and can weigh up to four pounds when they reach maturity.
- Diet: Both species are scavengers that will feed on dead organisms that fall to the ocean floor. They’ll also predate on shrimp, clams, worms, smaller crabs, and mussels.
- Habitat: Dungeness crabs prefer temperate waters and can be found off the west coast of the United States and near England. Snow crabs need colder, polar waters though their habitats can overlap.
- Appearance: Dungeness crabs have a rusty or orange coloration but can have a reddish or even purple hue. Snow crabs are red or orange when young and often add spots as they age.
We’ll explore the differences between these amazing creatures below.
What is a Dungeness Crab?
Dungeness crabs, also affectionately known as Dungies, prefer shallower, sandy bottom habitats but can be found at a wide range of depths from intertidal zones to 2000 feet deep. They molt several times each year and are a vital commercial species throughout their habitat.
Dungeness crabs are relatively small, usually weighing between two and three pounds when fully grown. They have shorter legs, but their bodies are wider and are typically six to eight inches across when grown. Their coloration can vary depending on their habitat and time of year. Most Dungies have a rusty or orange color, though deep reds and varying shades of purple are not uncommon.
Dungeness Crabs are opportunistic feeders that will happily scavenge on any dead organisms it comes across as it traverses the ocean floor. They’ll also feed on live prey if they can find it, with their favorites being smaller crabs, shrimp, mussels, and worms.
These crabs can live in a range of ocean depths and conditions, ranging from intertidal zones to 2000 feet. Sandy bottoms are their preferred habitat, so they can borrow. As the water cools in winter, most crabs will migrate to deeper waters and immerse themselves in the sand and mud. As the water warms again during the spring and early summer, they emerge from their burrows and migrate toward shallower water, where food sources are more abundant.
Dungeness crab stocks have historically fluctuated, with peaks and valleys usually occurring every three-to-five years. However, it is difficult to gain an accurate assessment of the long-term sustainability of their various populations. Concerns include potential overfishing and increased ocean acidification via climate change that can weaken the carapace of crabs and reduce their lifespans and fitness.
What is a Snow Crab?
Snow crabs favor colder compared to Dungeness crabs, although their northern and southern ranges do overlap. They can be found in both the Atlantic and Pacific oceans, favor sandy or soft bottom areas, and are usually found in 1000 feet of water or less.
Snow crabs have similarly sized bodies that can measure 6-7 inches across, though their legs are much longer, giving them a higher overall body weight. Snow crabs begin their lives with an orange or red coloration but will often gain a green or olive color as they age, often accompanied by spots.
Snow crabs are also scavengers, preferring to feed on dead organisms that have floated to the ocean floor. But they can also feed on live prey such as shrimp, smaller crabs, worms, and mussels.
Snow crabs are more likely to be found in rocky areas than Dungeness crabs are, though they still favor sandy bottoms for molting. They avoid estuaries and shallow, intertidal areas, but are generally found in 1000 feet of water or less.
Snow crab populations have plummeted off the coast of Alaska over the last forty years from an estimated 4 billion to 250 million. Climate change is believed to be the primary culprit, along with a vigorous and active fishing industry. Decreasing sea ice has limited the habitat for young snow crabs and allowed fishing boats to probe into previously inaccessible areas that further decimates the remaining population.
Are crabs nocturnal?
The majority of crab species are nocturnal, meaning they sleep during the day and are more active at night. We don’t have a good understanding of how much sleep snow and Dungeness crabs need. As soft bottom dwellers, they will often burrow into the mud or dirt while sleeping for protection from predators.
Can crabs live out of the water?
Crabs are resilient when removed from the water. Most crab species, including Snow and Dungeness crabs, can survive out of the water for up to 24 hours. There are a lot of variables that can extend or shorten that timeline, such as extreme temperatures or changes in humidity.
How long do crabs live?
A Dungeness crab’s typical lifespan is 8-13 years, while snow crabs can live upwards of 20 years.
How do you fish for crab?
Crabs are caught using special pots, usually with three or four openings with vertical metal tabs so that crabs can enter the pot but cannot leave. Any sort of bait will usually work, such as fish scraps though there is specific crab bait available. Check your local fishery guidelines to see how many pots are allowed on a sport fishing license.
How many eggs can Snow and Dungeness crabs lay?
Snow crabs can lay up to 100,000 eggs in the springs, while a single female Dungeness crab can lay up to 2.5 million!