Home Fishing Tips & Advice How to Identify a Soft-Shell Crab

How to Identify a Soft-Shell Crab

Soft-shelled crabs are abundant along coast regions of the Pacific Northwest and even the Eastern coast of the United States. Statistics show that some 50% of all Dungeness crab varieties caught by crabbers are those with soft shells. While all crabs will have an exterior exo-skeleton, soft-shell crabs are those who are still in the process of molting, meaning these outer shells have not yet hardened. The ability to discern whether or not a crab is soft-shell or not is paramount. Not only do most states require you to release a soft-shell crab if you should catch one, but bringing them home into the kitchen often leads to excessive waste due to poor meat quality. 

All too often, crabbers and novice crab-hunters will catch a soft-shell crab anticipating the same tasty treat they garner with a hard-shell crab. In reality, this leads to disappointment, as soft-shell meat is quite watery. Due to this, many end up simply tossing the crab out entirely without eating the meat. This hurts a valuable resource to our oceans. With that said, it is important to understand how to identify a soft-shell crab before you go crabbing in these regions.

Below, we’ll carefully outline how to identify the various soft-shell crab species with ease. 

What is a Soft-Shell Crab?

Odds are, you’ve heard of soft-shell crab time and time again. Yet, many people aren’t clear on what makes a soft-shell crab unique. Let’s start with the basics. Crabs are defined as arthropods. This means that their skeletal support system is on the outside of their bodies. This outside skeleton protects the crab from harm.

Unfortunately, it can also prove problematic as the grab grows. In order to grow, a crab has to shed (molt) this outer skeleton to form a larger one. Soft-shell crabs are simply crabs that have recently molted. The shell is soft because the new outer exoskeleton has not had time to harden. Crabs can molt at least 12 times a year until age two. Then they will molt once a year until age six.

Once a crab has molted, it will head to the sea. The salty waters cause its body to grow to larger proportions as the new shell begins to harden and muscle tissue fills the shell. The process can take 2-3 months. Until a crab fits into its new exoskeleton, the crab meat will be very watery and jelly-like. Not exactly ideal for eating.

This is why most states want you to leave soft-shell crab alone, rather than attempting to make them work.

Identifying Soft-Shell Crab Species

There are several key species of crab you will want to bear in mind when learning to identify soft-shell crab. Each will have distinct characteristics and markers. 

Dungeness Crab

By far one of the most common crab species that people will come across is the popular Dungeness crab. Not only are these crabs popular to eat, but they tend to be rather well known on the western and eastern coasts of the US. When identifying a Dungeness crab, look to the coloration first. The shell is purple-like, gray, or brown on the back. The tips of their claws will be white. They tend to be around 10 inches across the back, but it isn’t uncommon to find crabs that are 6 to 7 inches. 

Box Crab

Box crabs may look like their close relatives the King Crab, but they don’t have much in common in terms of size or stature. Much like a King Crab, Box Crabs are farily easy to recognize in the water. While some crabs have smoother outer shells, a Box Crab will have distinctive spines and wart-like structures known as tubercles. These “warts” create a very bumpy outer shell. When they are laying with their legs close to their body, they look just like a craggy wart-ridden box.

Shore Crabs

If you live in the Pacific Northwest, you’ll find that Shore Crabs are a pretty common place. These paltry little crabs love to hide under rock-cover. Generally, they are smaller than a finger tip. At their largest, they may be as big as a gallon milk-bottle cap or a silver dollar. Aside from their size, Shore Crabs are distinguished by their small black hairy outer structures. They aren’t great for eating, but crabbers still feel a thrill when they see these little crabs in the wild.

Red Rock Crab

This is a crab that is quite similar to its cousin the Dungeness. In fact, they are quite similar in appearance. The only major difference between these two crabs is their size. Dungeness crabs are far larger. A Red Rock crab will typically only be about 6-inches in length across the back. Another notable difference is claw size. Red Rock crabs have almost comically large oversized claws. Despite this, they tend to be less meaty than the Dungeness. You’ll be able to notice a Red Rock crab by its size, sclaws, and the black markings on claw tips that are red in hue. Like many soft-shell crabs, they prefer to hang round in rocky outcroppings. 

Blue Crab

On the east coast of the United States and in portions of the South, you’ll find the soft-shell blue crab. These are not found in the western half of the US or the Pacific Northwest, but they are worth mentioning. As the name implies, these tasty creatures have a shell that varies in hue from blue to olive green. They tend to be about 9 inches across with marginal teeth on each side. The claws on these crabs are bright blue. They also have three pairs of walking legs and paddle-shaped swimming legs. 

Also read: How to Keep Blue Crabs Alive

How to Identify a Soft Shell Crab

Now that you know how to identify crab species that can have a soft-shell you need to know how to actually identify and recognize a soft-shell crab. One of the most important things to recognize is that a soft-shell crab will be bluish-white in hue. They will also be free from barnacles and algae and be very lightweight.

The easiest way to identify a soft shell crab is via the pinch test. When you haul in your crabs, pick up each crab and squeeze the very edge of their shell near the lateral spine. You can also pinch a large section of their walking legs. Pinch the shell with your thumb and gradually increase pressure. Do not break the shell, as this can cause the grab to bleed to death.

If after doing the pinch test, you find that the shell gives quite easily, you have a soft-shell crab on your hands. This is not a crab that will be good for meat. Most of its weight is mushy and jello like. In other words, this meat is not suitable for eating. While performing the pinch test, you may find that some crabs will give just a little, but these are still soft-shell crabs and should not be eaten.

The shell of a hard crab, regardless of species, will not give at all when performing the pinch test. If you find that you have caught a soft-shell crab, make sure to release it into the water as gently as possible. Do not drop the crab on a hard surface such as a boat deck or dock and definitely do not throw the crab back into the water. Simply place it within gently.

Why Release a Soft-Shell Crab

You release a soft-shell crab for the same reason you wouldn’t hunt a fawn or reel in a baby fish — morals aside, you’re not getting anything out of the experience. The meat in these crabs is of very poor quality when compared to a hard-shell crab. It can best be described as jelly-like or mushy. Due to the texture, most people will not eat soft-shell meat and it is often tossed. By simply releasing a soft-shell crab upon catching it, you eliminate wasting the crab and allow it to be harvested later after its exoskeleton properly hardens.

If you do catch a soft-shell crab and determine that straight away, what should you do with it? Simply put, place the crabs back in the water. In a few month’s time, their shells will harden and the meat will be much higher quality. This will grant future crabbers the opportunity to catch that crab when it is at its best and can actually be enjoyed.

Don’t hold on to a soft-shell crab just because you feel thrilled to have caught something. Perform the pinch test and do the right thing by releasing it back into the water. The only exception to the soft-shell crab rule of thumb is the blue crab. Many people do enjoy eating soft-shell blue crab and it is not mandated in native states to release a blue crab back into the water.

Final Thoughts

When crabbing, always be mindful of the species you have caught and whether or not a crab is of the soft-shell variety. Use the guidelines above to identify the crab species you have procured in your pot. Once you have identified the species, go about performing a pinch test or other indicators that a crab may be soft in the shell. Remember, soft shell crabs are simply crabs that have recently molted. They need proper time to allow their exoskeletons to re-harden and for tissue to grow as it should. 

While it can be thrilling to catch a crab of any variety, a soft-shell crab will not offer the quality of meat or the flavor of a hard-shell crab. Soft-shell meat is mushy and watery, almost inedible. Hard-shell crab is much more dense, flavorful, and overall delicious to indulge in. Whether you’re crabbing off the coast of the Pacific Northwest or the Northeast, keep these tips for how to identify a soft-shell crab in mind and go from there.

Always do the responsible thing and place a soft-shell crab back into the water if caught. Mother nature and the crab species will thank you!

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Growing up on the south shore of Long Island, Chum Charlie has always had a passion for fishing. His favorite fish to catch is a striped bass and his favorite bait to use is bunker. Off the water, he enjoys blogging and sharing his favorite fishing tips & tricks that he has learned over the years.