What is Fisheries-Independent Monitoring?

Fisheries-Independent Monitoring (FIM) is a statewide program run by the Florida Fish and Wildlife Conservation Commission (FWC). The goal of the FIM program is to provide high quality fisheries data to state managers about fish abundance and population trends in estuaries. The data produced by the seven FIM programs around the state is used to make decisions about fisheries regulations such as size and bag limits. Therefore, the data must be collected in a scientific and rigorous manner.

The unit within FWC responsible for conducting FIM sampling is the Fish and Wildlife Research Institute (FWRI). Fisheries biologists in the FIM program collect samples of fish and invertebrates at randomly selected sites each month. The sampling is “stratified” meaning that it captures different habitats and uses different types of gear, like small or large seine nets, to get a complete and balanced picture of fish populations. The sampling is called “fisheries-independent” because the data are not linked to what people are actually catching. There is another program in FWRI called Fisheries-Dependent Monitoring (FDM) that collects data on actual catch and landing rates in commercial and recreational fisheries. Together, the FIM and FDM programs provide managers in FWC reliable data on which they can base their decisions.

What is it like to be a FIM biologist?

I wanted to learn a little more about the FIM program so I volunteered to ride along and help out on one of the regular FIM sampling trips in Cedar Key, FL. We launched the boat at sunrise on a chilly morning from the marina in downtown Cedar Key. Before we launched the boat, we had to don heavy boots to protect against razor-sharp oyster shells and other hazards in the water. We also put on thick waders to keep us warm and dry while pulling seine nets through the cold water (well, cold for Florida, at least).

Our captain for the day was Anthony “Taj” Knapp (pictured left), a fisheries biologist with FWRI who has been working on these waters for over 15 years. The other fisheries biologists on the crew were Johnny Polasik and Shannan McAskill – and then there was me, volunteering to help and hoping learn more about how fisheries research is done.

Capt. Taj plugged in the coordinates for the first randomly selected site and off we went. In Cedar Key’s FIM program, the boat of choice is the “mullet skiff” or “bird dog boat”. The motor is located in the front of the boat, allowing easy deployment of sampling nets from the stern and allowing the boat to access shallow water with ease. Bird dog boats are popular among other working watermen, especially clam farmers in Cedar Key.

Soon enough, we arrived at the first site – a stretch of salt marsh north of Cedar Key. The gear type for the first site was the small seine net (21.3 meters, ~70 ft). You can see Johnny (below left) stepping out of the boat to start the seine pull. The biologists also collect data on water temperature, dissolved oxygen, pH, salinity, habitat type, and shoreline type at every site. When the seine pull is finished, all of the organisms in the net are collected into a bucket and brought onto the boat. Johnny and Shannan (below right) sort the fish and invertebrates by species, count them, and measure the size a subset of each species. While the counting and measuring is going on, Capt. Taj pilots the skiff to the next site.

The small seine pull along the marsh site had several small fish, shrimp, and crabs. At our next site – also a marsh bank – we deployed the large seine (183 meters, ~600 feet, below left) designed to capture larger fish. This net is so large that it is deployed by boat. Johnny and I jumped out of the boat to hold one of the net poles while Taj and Shannan stayed on the boat. Once we were set, Taj piloted the boat first away from shore and then back toward shore so the the net formed a large arc between two points on the marsh shore. And now it was time to haul in the big net — by hand! With two crew members on each end, we began to steadily haul in the net.

Up until this point, the day had been quite enjoyable. We had a beautiful sunny sky above us and I was thinking that the FIM biologists had a pretty great gig. About halfway through pulling in the 600-ft seine, my mind started to change. Of course, I put on a tough act and kept pulling on pace with the pros. But my biceps were burning and my fingers were getting sore, even though we were wearing gloves!

As the immensely heavy net inched closer and closer to shore with every pull, we began to march toward Taj and Shannan’s end of the net. By the time the net was pulled all the way in, we had a neat little purse containing all of our catch, which included quite a bit of drifting macroalgae. After estimating the volume of the algae and clearing it from the net, we brought in all of the fish to be sorted, counted, and measured. In the first 600-ft seine haul, there were lots of striped mullet, several spotted sea trout and pinfish, a handful of stingrays, and a few red drum. We finished off the field day by pulling a few more small seines and two more of the large seines – I was pretty worn out! 


FIM data and fisheries management

Most of the large fish were released after they were measured. A sample of the important recreational fishery species, like spotted sea trout and red drum, were taken back to the lab for more detailed work (below right). In the lab, the fish were dissected and data collected on their gut contents (tells scientists their diet) and age using the otoliths (ear bones that lay down annual rings like a tree). Detailed data like these are needed for fish stock assessment models and ecosystem models that take into account the food web connections and age structure of fish populations.

There’s a whole lot more to fisheries management than just knowing how many fish are out there (abundance). For example, reproductive rates can change with size or age so understanding the distribution of fish size and age yields better information about the future of the fishery. Better information makes for better planning and better decisions across the board. The field and lab portions of FIM sampling both provide different kinds of data to researchers and managers. See this site for a few examples of how the FIM program provided information about the impacts of environmental disturbances such as red tide and cold snaps.

In short, the work of FIM biologists is very technical and physically difficult but extremely important and meaningful for anyone who enjoys fishing in Florida’s coastal waters! The work they do every day provides long-term, ongoing information about Florida’s fisheries so we can all keep enjoying the fun and satisfaction of great fishing.