One of the United States’ largest fisheries is hiding in plain sight. Recreational freshwater anglers in the lower 48 states catch – and keep – far more fish than any official body has estimated, according to new research from our team of North American fishery scientists.

Specifically, our analysis, which integrated thousands of recreational fishing surveys across the U.S., found that people who engage in recreational fishing in the country’s lakes, ponds and reservoirs catch between 2 billion and 6 billion fish each year. Many of them practice catch-and-release fishing, but even after accounting for all the fish released, we estimated that they keep between 230,000 and 670,000 metric tons of fish in the U.S. alone.

That’s between 17 and 48 times more fish than prior U.S. estimates that have been reported to the United Nations’ Food and Agriculture Organization.

And it’s about 20% of the United States’ total recorded annual consumption of fresh fish that has not been frozen. We estimated the value of the recreational fish catch is roughly US$3 billion a year. By contrast, domestic commercial processed fishery products are valued at about US$12 billion a year.

Not just for fun

Historically, most researchers and policymakers viewed recreational fishing as a leisure activity rather than a significant part of the nation’s food supply.

However, for many households, recreationally harvested fish – fish that people catch and keep, often to eat – represent a meaningful source of protein at very low cost. By recognizing this unseen harvest as a significant food source, policymakers can recognize that changes in recreational fishing opportunities don’t just affect anglers’ enjoyment, but also millions of households’ food security.

The immensity of recreational fishing also likely has effects on freshwater ecosystems that have gone unrecognized by fisheries managers.

For example, a 2019 analysis of nearly 200 lakes in northern Wisconsin found that around 40% of walleye recreational fisheries were overfished. Even when fish are released and not kept for eating, they can die shortly after release or be injured or stressed from having been caught. Injured and stressed fish may produce fewer offspring, be more vulnerable to predators and be less capable of catching prey.

Together, these effects on fish populations and the act of fishing can substantially change how freshwater ecosystems function. For example, removing top predators like walleye can lead to an increase in small fish, which eat tiny zooplankton, which feed on phytoplankton. If zooplankton populations fall, that can ultimately lead to more frequent algal blooms.

Effective fisheries management requires accurate estimates of fishing activity. Without that information, officials may overestimate fish population size, which could lead to unexpected population collapses and new fishery regulations and closures.

Why the numbers don’t add up

Official harvest statistics for fisheries, which are collected by the U.N. from national governments, usually focus on ocean fisheries, which are typically the largest and most lucrative.

As a result, the only official statistics for the U.S. freshwater fisheries harvest cover commercial fisheries that primarily operate in the Great Lakes.

Collecting data on recreational fisheries is challenging. Unlike commercial fisheries that unload their catch at centralized ports, it is impossible to know where recreational fishers are and what they are catching across the entire country. With an estimated 35 million people fishing across millions of rivers, lakes, ponds and reservoirs, the amount of recreational fishing makes it an extremely difficult activity to track.

Recreational fisheries data tends to be collected by state agencies that conduct angler surveys. Angler surveys involve counting and interviewing anglers at specific rivers, lakes, ponds and reservoirs to provide snapshots of who is fishing, how they fish and what they catch. Each state collects data differently, and surveys typically focus on a few locations rather than the entire state.

Without a coordinated national effort, the total recreational catch has remained effectively invisible because one state’s questions and findings do not always align with those in other states.

From local surveys to national statistics

Our new research, a collaborative effort between myself and four colleagues from the U.S. Geological Survey, the University of Missouri and Louisiana State University, sought to improve the quality of recreational fishing data. Over the past several years, our team has worked to compile angler surveys from across the country into a single database.

We have not received data from every river, lake, pond and reservoir; in fact, we have not even collected data from every state. But we have collected over 15,000 surveys from 40 states, and we are collecting more surveys every day.

To calculate our estimates, we combined three major factors:

• Nationwide numbers of fish caught and hours spent fishing.

• Assumptions about how many lakes, ponds and reservoirs people fish based on the relationships between water body size and known fishing locations.

• The proportion of caught fish that aren’t thrown back.

We arrived at an estimate of 2 billion to 6 billion fish caught.

Rethinking recreational fisheries

Even our most conservative assumption of harvested fish – 236,000 metric tons – is much higher than the prior U.N. estimates of 13,388 metric tons. We hope these new numbers will serve as initial estimates that will be continually refined as we and other researchers collect more data and better understand where and how people fish.

Getting this first estimate provides a baseline for fisheries managers to ensure fishing policies line up with the actual effects of recreational fishing.

We also note that recreational freshwater fishing happens across the globe. If the actual recreational fish harvest is significantly higher than has previously been estimated in the U.S., the same is likely true worldwide.

Matthew Robertson receives funding from a Marine Institute of Memorial University Start-Up Fund, the Canadian Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant, the Newfoundland and Labrador Innovation and Business Investment Corporation’s Research and Development program, the Atlantic Groundfish Council, the Environment and Climate Chance Canada (ECCC) Environmental Damages Fund, and the Robert and Edith Skinner Wildlife Management Fund. This research was funded by a grant for the U.S. Geological Survey Climate Adaptation Science Center.