This article is within the scope of WikiProject Fisheries and Fishing, a collaborative effort to improve Wikipedia's coverage of fisheries, aquaculture and fishing. If you would like to participate, you can visit the project page, where you can register your interest for the project and see a list of open tasks.
The article claims that the main difficulty is defining unit effort. I would have thought a major difficulty was measuring catch. As just one of the possible examples, if you know for sure you are detecting 20% of the poaching then you can simply add five times the detected poaching to the legal catch. However if in reality you're only detecting 5%, then you're underestimating the illegal catch by a factor of four. When there's a lot of poaching, such an overestimate of detected poaching can lead to a significant underestimate of CPUE. Vaughan Pratt (talk) 08:13, 18 January 2016 (UTC)