image: Mac Stone

The danger of development and “shifting baseline syndrome”

When sight-fishing as a sport debuted in the Upper Keys and Florida Bay, boat-makers modified their hulls, fishing companies developed faster and lighter rods, and tackle shops sprouted up all over the islands. By the 1950s an entire industry was formed around a specific shallow-water grassland habitat dominated by tarpon, redfish, permit, snook, and bonefish. Nowhere else in the world were fishermen given the chance to target such a variety only miles from a boat ramp. To many, it seemed Florida Bay was an infinite resource. But what Floridians failed to realize was that the productive waters of Florida Bay owed their fame to a slow-moving watershed that was rapidly diminishing.

Fueled by freshwater flow from the Everglades, Florida Bay proved a highly productive estuary, providing ample prey to support everything from redfish to crocodiles to millions of wading birds. For decades, hundreds of thousands of anglers came to the Bay for tarpon, permit, and bonefish, with shallow-water sight fishing becoming the purest form of backcountry angling. It didn’t take long for the Florida Keys to earn their reputation as the sportsfishing capital of the world. Meanwhile, Florida was becoming one of the fastest-growing states in the nation, particularly in the southern half of the state. As cities and agriculture expanded, the demand for water and land increased, and soon Florida Bay’s freshwater supply had come to a crawl, decreasing by nearly two thirds. What little water made it to the tidal creeks and bays brought with it a heavy cargo of fertilizers and pesticides from the vast agricultural fields to the north.

From 1970 to 2000, Florida’s population more than doubled, and local anglers began noticing fewer bonefish in Florida Bay. By the mid-2000s, the grass flats once teeming with stingrays, bonnethead sharks, and bonefish were gradually being vacated by these symbolic species. Professional guides that made their living poling the waters of Isla-morada and the Upper Keys found fewer fish in their favorite spots. Some bonefishermen focussed their attention south to the Lower Keys, where populations appeared more stable and the habitat less influenced by freshwater flows.

What was causing this drop in bonefish numbers? A topic gaining considerable attention in fisheries conservation is habitat protection. For estuaries like Florida Bay, the health of the ecosystem is greatly determined by external factors, primarily water. If the inputs to the system are askew, then the entire machine fails to produce. Floridians are concerned with this issue from not only a biological standpoint, but an economic one. Florida has the largest recreational and commercial fisheries economy in the United States. Flats fishing is known as a low-volume but high-dollar industry, leaving a small footprint on habitat, yet beneficial for both the economy and the ecology of the state. By the latest accounts, bonefishing alone contributes about $1 billion to Florida’s annual economy. The most recent census data estimated around 330,000 bonefish from the upper Keys to Key West, meaning that a single bonefish is worth $3,100 per year, and over its lifetime, brings $57,000 to the state’s fishing industry.

For the newest generation of anglers and guides to Florida Bay, the current population of game fish may be adequate to fulfill their fishing needs. However, to the anglers and guides with decades of experience, the current fishing pales in comparison. When a new generation of anglers and guides replaces an older one, the perception of what is “natural” or “good” is redefined. This “shifting baseline syndrome” —as ecologists refer to it—has plagued and divided fisheries management and the science community for years. Accepting a fishery decline is bad for business, especially one as popular as bonefish. But without identifying a problem, it’s impossible to find a solution. Fortunately, a few privately funded organizations are dedicating resources to understanding the science behind the Florida Bay bonefish in hopes of reviving their populations.

In the fall of 2011, the Bonefish & Tarpon Trust sponsored a grant dedicated to studying the communities of popular bonefishing flats in Biscayne Bay, Florida Bay, and the Lower Keys. National Audubon Society’s Tavernier Science Center was awarded the yearlong grant and conducted its first surveys this spring. Led by backcountry fishing guide and biologist Peter Frezza, Audubon is basing its research on past studies within these same areas to look for clues as to how the system has changed over time. By sampling five distinct seagrass flats, scientists are analyzing the crustaceans, fish, and other bottom feeders to assess the numbers, diversity, and composition of the bonefish food-base. They’re also analyzing seagrass and water-quality to search for possible shifts over time on these flats. While other gamefish species are still prominent in these areas, bonefish are believed to be more susceptible to a changing environment.

Previous research within this region has shown that about 75 percent of an adult bonefish’s diet consists of mud crabs, toadfish, swimming crabs, and shrimp—in that order. Submerged grass beds seem to provide the ideal habitat for invertebrates, but populations may be responding to changes in the water, thus limiting the bonefish’s access to food. This important study will help scientists dissect the food web of these historic fishing grounds and reveal its response to habitat changes.

With Everglades restoration underway and projects aligned to bring clean freshwater back to its historic path, scientists are hopeful about seeing a positive change in the ecosystem. Bonefish stand an excellent chance of returning to their favorite foraging grounds, and anglers may once again find the legendary numbers of fins slicing across the flats of Florida Bay.

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