The Science Behind Florida’s Marine Fisheries (Part 1, Marine Fisheries Research)

The Science Behind Florida’s Marine Fisheries (Part 1, Marine Fisheries Research)


Florida boasts an abundance and diversity of fish species throughout its 8,500 miles of coastline Every fish that swims in our waters proves to be a vital and valuable resource. The management and maintenance of these fisheries remains the sole responsibility of the Florida Fish and Wildlife Conservation Commission, known as FWC. Decisions by the Commission are based on comprehensive scientific investigation conducted by FWC’s Fish and Wildlife Research Institute and its satellite laboratories around the state. It is this professional approach on a continuous basis that insures long term sustainability of Florida’s fisheries and has earned Florida the title of “Fishing Capital of the World”. I’m Mark Sosin, a long time Florida fisherman and a strong supporter of the programs FWC has put in place to protect the great fishing we currently enjoy. Recreational angling adds five to eight billion dollars to Florida’s economy each year, it creates countless jobs, and lures some 2 ½ million anglers to our waters. This increased fishing pressure cause decreased fish populations as well as habitat. Effective fisheries management begins with quality science. Quality science depends on good data on the fisheries being managed and an understanding of the biology of the fish being harvested. The key lies in recognizing and isolating trends of abundance and mortality as early as possible so that corrective action can be taken. Six major teams of scientists funnel information to the Stock Assessment Group where it is combined and analyzed before being passed along to Marine Fisheries Managers and FWC Commissioners for corrective action. These teams of researchers include Fisheries Independent Monitoring, Fisheries Dependent Monitoring, Fish Biology (which encompasses age, growth, reproduction, and genetics), Fish and Wildlife Health, Stock Enhancement, and Artificial Reefs. These scientific programs and facilities rank among the finest in the world. Let’s take a closer look at them. Fisheries Independent Monitoring is a valuable tool relying on random sampling in specific areas, selected by computer, to analyze the relative abundance, spatial and seasonal distributions, and habitat use of fish populations. Fisheries independent data are not subject to changes in fishing regulations or supply and demand issues, but are a representation of what’s going on in the wild population. Estimates of relative abundance help to predict availability of a species in the future. It also provides numbers and information needed to assess the effectiveness of management measures once they are enacted, and can be used to determine the effects of natural or manmade disturbances such as oil spills, red tides, and cold water events. (Biologist calls out fish type) Additional data including species composition, size, sex, and age are important when creating and maintaining fishing regulations and assessing individual fish stocks. Data are collected in several ways. In offshore waters, a 45-foot boat is used to collect fish with either a fish trap or hook and line gear. Scientist: “Traditionally the Federal Government has used deep water trawls and stuff to sample a lot of fish populations. But reef habitat of course … reefs are not very friendly with trawls so you can’t sample in those types of areas. that’s why we’re using gears that are non invasive, it doesn’t damage the habitat. And we could put it down on a specific habitat, take our sample from it and get out and it doesn’t damage it. For some reef fish research, either SCUBA divers or stationary underwater cameras are used to conduct visual surveys to identify, count, and estimate the sizes of reef fish species observed. Monitoring inshore waters is usually done using a 70-foot seine or a 20-foot otter trawl which typically collect smaller fish within the estuary. A haul seine is a small, rectangular net that is pulled and retrieved by hand in shallow water over grass flats and mangrove shorelines. Larger fish of various species are collected using a 600-foot haul seine along shoreline and seagrass shoal habitats with the estuary. Fisheries Dependent Monitoring focuses on catches by recreational anglers. Fishermen are interviewed at dockside locations or by telephone to generate data on fish species, the number caught, size of the fish, where they were caught, how much effort was expended to catch the fish, and whether each fish was harvested or released. Catch cards are also used. They are filled out by anglers and returned to Dependent Monitoring. Providing this information to researchers is strictly voluntary rather than mandatory. The data recovered from anglers are extremely valuable in managing marine fisheries resources. Additional monitoring takes place aboard party boats and charter boats. Information gathered includes the species of the fish that were caught, the numbers, the location where the catch was made, the length of each fish, and whether it was harvested, released, or tagged and released. The primary task of the Age and Growth Department centers on studying the otoliths or ear stones of fish to gather age data. Otoliths form annual rings similar to those in the trunk of a tree. Each year some 30,000 otoliths are studied by researchers. From the age data, biologists can estimate growth rates, maximum age, age at maturity, and trends for future generations. Age-based stock assessment models allow scientists to estimate mortality and population structure so they can determine longevity of a given species. Otoliths also provide information on where a fish lived as a juvenile and as a mature adult. Marine Fisheries Biologist Sarah Walters summarizes the importance of age and growth studies. “In fisheries management, we have a variety of elements that go into helping us understand biology of a fish and are we properly managing it with our fishing regulations. So we’ll take little bits of information such as how old does a fish live, what does a fish eat, where does it reproduce, how often is it reproducing, the survival of the juveniles, trophic dynamics…all these elements go into the stock assessment, which is a mathematical model that in turn goes to the managers and the managers can incorporate the science as well as the needs of the public.” Biologists also rely on Acoustic Telemetry to study an assortment of species, including goliath grouper, along with the impact of catch and release fishing. This type of research helps to determine habitat use by various species. Fish and Wildlife Health researchers study fish disease and collect baseline data on marine sport fish. Through this research, they develop health guidelines for stock enhancement and investigate and document wild fish disease and mortality events around the state. These disease monitoring efforts benefit greatly from public reports of abnormal fish or fish kills, so the Fish and Wildlife Health group maintains the toll free Fish Kill Hotline. Biologists work with the public and other agencies to respond to and understand the causes of fish kills which are often the result of poor water quality or harmful algal blooms such as red tide. Such blooms may produce biological toxins that can impact fish health. They also study diseases which can be caused by fungal, bacterial, viral, or parasitic infections. “Usually parasites of marine fishes don’t cause disease in wild fish. It’s something that we expect to find in wild fish. People see them sometimes and they’re pretty concerned that they are seeing a significant disease. But, generally speaking, a low number of many different types of parasites is a good thing, it says something good about the environment. “Go ahead and go …” Stock Assessment is totally dependent on the information being fed into the decision making team. To be successful, science must combine data from studies of the ecosystem with continued investigations species by species. Currently, 48 species of fish are measured on a continuous basis through stock assessment, with another 90 species and groups looked at regularly. Florida has been a leader in stock assessment for many years with analysis skills that continue to improve constantly. Conserving the qualities of our fisheries the stock assessment team relies on the best science available. With increased fishing pressure coupled with loss of habitat, their work in maintaining viable fish populations becomes even more important. Stock Enhancement along with the Artificial Reef Program make valuable contributions to stock assessment by supplying vital information. Let’s take a closer look.

local_offerevent_note August 31, 2019

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