A sub-set of the anglers coming off of our striper/bluefish head-boat trip a few years ago was sampled/interviewed. On another occasion one or two of four of us coming off of a friend’s boat were interviewed regarding the striper catch.
General comments about angler surveys follow:
Angler surveys whether on a lake, beach, stream, river, dock, or by telephone or email are typically done across a broad sub-set of all participants. One need not interview every angler to get a representative sample of catches or opinions. Angler catches, as you know, can vary quite a lot from day to day, angler to angler, season to season, and by technique, thus large sample sizes (many interviews) are appropriate spread throughout the season.
To go a step farther, angler opinions, on the other hand, aren’t all that varied and I have found that when I conducted angler opinion surveys I already knew the answer to angler opinion survey questions by interviewing as few as 30 anglers. Continuing to interview 70 more just fine tuned the response percentages by a few percentage points. For example, let’s say there is a fishing reg proposal….with thirty responses perhaps 67 percent of the anglers approved of a proposal while with 100 responses that number might have changed to 71 percent. This minor magnitude of change was pretty typical. The point is that either way a good majority favored the proposal and increasing sample size did not change the overall response significantly. Add another 100 angler responses and the change might be 2 points one way or the other.
Anglers often say when discussing survey results something like “they didn‘t interview me.” Statistically speaking, with a large enough sample size they interviewed somebody like each angler who was not interviewed and that opinion was represented in the sample population in the same proportion that it occurred in the total population, give or take a small error.