There has been an interesting post on the forums regarding the drop rate of Mudcrab Chitin that I have been following. The Chitin are a new alchemical reagent used in poisons and potions that are found on, you guessed it, mudcrabs. Over past few days I’ve been mapping fishing holes and taking out a few of the nearby mubcrabs to hopefully find some chitin enroute to the next fishing hole.
My experience seems to confirm what people on the forums are saying: that the larger mudcrabs, especially the darker red ones have the best drop rate. Also, people report that they haven’t had much luck farming crabs in Wrothgar, so you may want to try somewhere else.