Hi everyone!

So in my project plan I said that for my first round of research I would look into further detail about why crabs are important and previous population statistics.

Why are crabs important and population stats:

People have been harvesting and eating crabs as long as humans have lived near the shorelines. They are a delicacy around the world and are really quite tasty. Many though don't realise how much money they create in the aquaculture industry. In British Columbia alone, around 46 million dollars are made from commercial crabbing each year.(1) This number is only 31 percent of BC’s shellfish revenue. However because of over crabbing, poaching, and pollution, crab populations have been going down since 2010. As a result  some of the 221 commercial crabbing licensees have moved their boats and rigs to other locations because of a fear of reduced catch. This doesn’t just affect crab populations, but it also reduces the crabs for first nations people who use them as a source of food, and are a social and ceremonial fishery for them. Not only are crab populations decreasing, but they are also being mistreated. It was found that many people are illegally ripping off the claws(part with most meat on the crab) and throwing the crab bodies back in the water. Without claws they cannot eat or defend themselves. It is a slow and cruel death. Stephanie Duff, head of the fisheries and aquaculture program at University of Vancouver Island noticed an increased number of crabs with no claws in popular crabbing areas.(2) This may show that crabbing laws are not as enforced as we think.

Image result for commercial crabbing

Everything that I have brought up so far has been about the economy and us, humans, but what about the ecosystem? As I have mentioned before in my project plan, crabs are an important part of our local ecosystem, and pretty much any other ocean shoreline. Crabs stay normally in relatively shallow waters in what is called the mid-intertidal waters. They do many things in the ecosystem but one thing that is very important is that they are one of the main decomposers of the marine ecosystem. They go around and recycle decomposing plant and animal matter. Not only this, but they are a food source for many other species who would not thrive without them.  This includes animals such as fish, birds, sea mammals, octopuses, and even other crabs.(3)

Image result for octopus eating crab

I found it incredibly hard to find any formal crab population studies. Hopefully I will be able to find some in the future. However according to locals in northern BC, commercial crabbers have been spotted more and more often, and are setting up traps. "This is the second or third time they've come in. Each time we notice there are no crabs after.” said Nuxalk Chief Spencer Siwallace. Many of these locals noticed that after they left, almost no crabs were there. (4)

Image result for crabbing

So in conclusion, I was not able to find any formal population studies, but it is clear to me that there are and have been issues with the industry and sport. Hopefully my experiments will shed more light on the recreational side of things. As for the importance of crabs, you can probably see that they are a vital part of the ocean and definitely deserve protection from over fishing, poaching, and mistreatment. I hope you enjoyed this post.

Stay tuned for more!

http://www.pac.dfo-mpo.gc.ca/f...abe-sm-2017-eng.html (1)




Original Post

Hey Kian! 

Nice to see your post! 
I made a personal connection to it- i remember there was this one time someone had looked at crabs and how research has been using crabs but it has had a negative impact on the population.

Try taking a look at a specific research on crabs "blue blood" 




^.^ Hopefully it helps

Keep it up!


Hi Kian,

Although you didn't find the accurate amount of crabs' population, I appreciate your thinking of its function in the marine system. You wrote, ' They go around and recycle decomposing plant and animal matter. Not only this, but they are a food source for many other species who would not thrive without them.' It does let me think further and worry about the issue of over-fishing. Thanks for your post. You can probably look at some links which talk about the influence on pollution. Hope my though helps you. 



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