No. It is not vegan because imitation crab is a food item mostly made up of fish. It also has other components that vegans are not supposed to eat. As a matter of fact, even vegetarians should not eat it. The food item does not even contain crab. But I think I know why you have this doubt. Vegan versions of either meat or non-vegetarian food items are named with words such as ‘fake’, ‘faux’, and ‘plant-based’.
 
For instance, some describe fake meat as imitation meat. So, I presume the ‘imitation’ part of the product name has made you think that it is vegan. It happens. We are sometimes easily deceived by certain product names. For instance, I used to have friends who thought the ladies finger is just what the name implies, i.e., the finger of a lady.