Why Angler Surveys Do Not Work

Have you ever filled out an angler card after fishing? Or maybe you signed up for a logbook program where you fill out a logbook over a season and mark down various bits of data. Data points often including species, length, weight, time spent fishing (fishing effort), location, catch per unit of effort, and other various fishing related data. From a non-scientific perspective, you may think, this is a great way to gain insight into a fishery. Utilize those that are using the resource to gather data, after all, anglers know best right? On top of helping anglers feel like they are part of something, it’s free labor. Fisheries managers, particularly in Maine, are understaffed and simply do not have the working power to properly survey all the fisheries in Maine. Additionally, properly surveying a fishery is not cheap. It requires a lot of equipment, working hours, and data analysis. You essentially need highly trained statisticians along with fisheries biologists, if you’re lucky, you can find one person that can do both, but this is incredibly rare, a lot rarer than you think. So, from the outside looking in, you can see benefits, why not? Why not utilize something that has been going on in Maine and around the country for decades, if not longer? I’m here to tell you why these surveys are one of the worst things to ever happen to fisheries.

I can tell you in words, but I’d like to use an example first. We are going to analyze River X, which is a catch an release only river with naturally reproducing landlocked salmon. Biologists are attempting to use angler surveys to gather data on the river in hopes to gain insight on the salmon population and angler usage. The main issue with these surveys is the amount of assumptions that are included. Statistical models are only as strong as their assumptions and with angler surveys, there are so many, it essentially renders any data useless. The first assumption that arises is the percentage of anglers that fish and fill out the surveys. Let’s say 100 surveys are filled out over a 1 month period on River X, with the average fishing time of 6 hours. From this, at a minimum, you assume cumulative fishing effort is 20 hrs/day. In reality, how many anglers used the river and for how long? You have no clue, it could be 50% more, could be 1000% more, the point is, you have no clue. Let’s say the same 100 surveys caught on average 2 fish per outing. Your catch per unit of effort (catch/hr) is 0.33 salmon/hr of fishing. So, from this data, you assume at a minimum anglers will be on the water cumulatively for 20hrs a day and will catch 0.33 salmon/hr, resulting in about 7 salmon caught per day. What if the anglers that filled out cards were the unlucky anglers? There are several assumptions even with the minimum estimate. What is the accuracy of the hours kept? Are anglers exact in their time estimates? Did they actually start fishing at time 0 or did they start walking from the parking lot? Same could be said when they ended. That alone puts into question your fishing effort and therefore ruins any chance of accurately calculating catch per unit of effort. Essentially rendering your results as nothing more than a guess. You may actually be more accurate simply using a random number generator.


The same logic can be applied to fish size. Are anglers accurately measuring every fish they mark down or are the estimating? Try estimating size or weight then actually measure and see the discrepancies that float to the surface. As someone who has weighed and measured thousands of fish for research, I can assure you your estimates are off, sometimes by a large margin. Also, if we are to weigh or measure each fish and want to practice proper catch and release techniques, a contradictory message is being sent. How can we minimize handling time while trying to get a length or weight? You can’t.

So, it then begs the question, what are biologists doing with this data if it is unreliable? Are they using it for management? This is the worst case possible, because surveys are driving managerial decisions that are based on inaccurate data. If they aren’t using it for management, what are they using it for? Historical reference? Again, that would be a travesty. This is often the case when we look at historical data. The accuracy of the numbers varies with each decade. As equipment became more sophisticated our measurements got more accurate, making it difficult to compare historical and present data sets.


What if they aren’t using it for anything other than to keep anglers happy? Conspiracy time ….. Fish biologists have often been said to manage people not fish.  While this is not entirely true, it does have some credence. If angler surveys are present, anglers will believe biologists are actively managing waters, thus creating a sense of acceptance from the community of anglers. A level of trust is built between angler and biologist making managerial practices more accepted by the community. If no angler surveys are being done, anglers begin to ask, well what exactly are biologists doing? Although they have incredibly busy schedules, this tension makes life a lot harder for fisheries managers. So as a scientist, I often wonder, are these surveys being implemented simply to calm anglers, to create a sense of peace within the community?


The simple matter of fact is angler surveys do not represent the truth in any way, shape, or form, thus what can they ultimately be used for? It leaves a lot to be desired for this angler.

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