The Tortugas Ecological Reserve – How Is This ‘Seascape of Promise’ Working?
How are things working?
That deceptively simple question lies at the heart of a series of at-sea studies NOAA scientists are undertaking on the Tortugas Ecological Reserve.
Their goal: to better understand the “real world” impacts of the landmark July 2001 designation of a 151-square mile “no take” ecological reserve in a remote area west of the Florida Keys National Marine Sanctuary.
Using a comprehensive “before-and-after” assessment approach, the scientists have spent the equivalent of nearly four months at sea aboard NOAA research vessels and a fishing boat to study marine organisms in the Tortugas Ecological Reserve, TER, or what NOAA has labeled “a seascape of promise.” The NOAA scientists seek to better understand how the ecosystem and marine life in the area are responding to the 2001 establishment of the nation’s largest marine ecological reserve, about 70 miles west of Key West, Florida, and about 140 miles from mainland Florida, at the transition between the Gulf of Mexico and the Atlantic Ocean.
The Tortugas (Spanish for “turtle”) is widely recognized as home to some of the most productive and unique marine resources in the entire Florida Keys National Marine Sanctuary. Healthy baitfish populations support extraordinary seabird communities, including sooty and noddy terns, masked boobies, and the only roosting population of frigate birds in the continental United States. Located at the juncture of several major ocean currents, the Tortugas “plays a dynamic role in supporting marine ecosystems throughout the Keys and south and Southwest Florida,” NOAA says. The agency points to “a persistent system of currents and eddies that provide the retention and current pathways necessary for successful recruitment of both local and foreign spawned juveniles.” Valued for its transfers, or “exports,” of the larvae of fish, lobster, and other marine organisms to the Keys and Florida east coast, the Tortugas’ unique location benefits from “upwellings and convergences of the current systems provid[ing] the necessary food supplies” to support larval growth stages.
The Tortugas Ecological Reserve officially established by NOAA in 2001 is in the westernmost part of the Florida Keys National Marine Sanctuary (FKNMS), which was itself established by law in 1990. FKNMS consists of roughly 9,660 square kilometers (about 15,455 miles) of coastal and oceanic waters and submerged land surrounding the Florida Keys and the Dry Tortugas string of islands. The new Ecological Reserve expands the boundary of the FKNMS with a 151-square mile no-take zone, with the goal of protecting deep-water coral reefs in the area from degradation resulting from human activities. A Tortugas North portion of the reserve consists of diverse coral reefs, carbonate banks at depths of 30 to 75 feet, and low-relief hardbottom habitats. The Tortugas South portion of the reserve includes a wide range of deep water coral reef habitats and numerous rare and unusual reef species. The deepest portions of Tortugas South, at depths of 1,600 to 1,800 feet, are comprised of limestone ledges with unusual deep-dwelling sea life such as lantern fish, tilefish, golden crabs, and giant isopods.
The goal of the 2001 Ecological Reserve designation is to protect the critical coral reef ecosystem of the remote Tortugas and important spawning areas for snapper and grouper and the deep-water habitats essential for other commercial species. An area known as “ Sherwood Forest ” has coral covering more than 30 percent, about triple the coverage found elsewhere in the Florida Keys , and scientists have found one bizarre mushroom-shaped coral — a coral fairly characteristic of Sherwood Forest — to be some 400 years old.
As impressive and remote as the area is, however, the environmental impact statement on the Tortugas Ecological Reserve management plan points to trouble-in-Paradise concerns in the absence of efforts to manage and protect the area. For instance, commercial and recreational fishing pressures have reduced the average size of black grouper in the Tortugas from more than 22 pounds to just nine.
As Florida State University’s Research in Review magazine reported in its Summer 2003 issue, “The age-old concept of the world’s oceans being a vast, inexhaustible resource impervious to the whims of man began to ring hollow [in the 1970s] with fish managers and marine biologists everywhere…What scientists found really scary is what they saw happening to whole marine ecosystems – from sea grasses to coral reefs – from the impact of raw pollution and coastal development.”
Large freighters traversing between port visits had routinely used an area known as Riley’s Hump as a safe place to anchor. Anchors weighing several tons have damaged parts of the Tortugas, and impacts from fishing gear have been observed on sand and limestone in some deep-water areas. “The several-ton anchors and chains of these ships have devastated large areas of fragile coral reef habitat that provide the foundation for economically important fisheries,” NOAA said in establishing the Tortugas Reserve.
Adding to the stresses on the Tortugas ecosystem is the growing number of tourists and other visitors. Visits to the Dry Tortugas National Park increased from 18,000 to 72,000 between 1984 and 1998. A growing population in south Florida , improved navigational technologies, and faster and faster boats are expected to further stress the fragile Tortugas ecosystem.
Under the Ecological Reserve designation, the area remains open to SCUBA diving once phone-in permits are approved, but the taking of any marine life is prohibited, and stringent regulations apply to vessel discharges and anchoring and mooring. All but Sanctuary-permitted research and enforcement vessels must remain in transit through the area, giving new meaning to the term “No Loitering.”
Return for a moment to that opening question: “How are things working?”
A scientific team from the NOAA National Centers for Coastal Ocean Science, Center for Coastal Fisheries & Habitat Research, in Beaufort , N.C. , is expressing cautious optimism based on its studies to date.
Based on its nearly four months at sea over a three-year period, the scientists say “the refuge status of this area endows it with tremendous downstream spillover and larval export potential for Florida reef habitats.” The Ecological Reserve designation, they continue, “promotes the maintenance of their fish communities.”
There’s a lot that goes into that assessment, not the least of which is an extensive and expensive isotope data set providing a rigorous foundation for the scientists’ conclusions. “Some isotopes are stable (non-radioactive) and maintain their identity as the compound moves through the food chain, from plants up to top predators.,” explains NOAA/NCCOS project coordinator Mark S. Fonseca, Ph.D., in explaining the importance of that data set. “Therefore, following the adage, ‘you are what you eat’, scientists can compare the isotopic signature of plants, intermediate prey, and top predators and determine how the food chain is working. That’s an important tool for determining how the ecosystem is balanced among food supply and use – the foundation of fish production for the Reserve.”
The geographers, chemists, biologists and other NCCOS scientists nonetheless freely acknowledge that their work is far from finished. In fact, after all of the multi-partner and multidisciplinary work they have completed so far, they describe themselves as now “poised to document and quantify the post-implementation effects” of the Ecological Reserve designation, in part because their Before After Control Impact (BACI) technique requires at least three years after implementation of the Reserve before trends can be assessed.
The strategy they are using to reach their scientific conclusions focuses on a five-part research effort:
- habitat characterization, in which the scientists seek to better understand physical features and processes in the area to inform their knowledge of how various marine organisms are distributed throughout it. Understanding environmental and habitat changes occurring as a result of the Ecological Reserve designation is critical to their understanding of the quantity and distribution patterns of the region’s living organisms – Progress to Date: The scientists have performed detailed, multiple scale characterizations, using satellites, aircraft, towed sonar and video and diver surveys to allow them to detect spatial scales of organization that influences fishery resource recovery;
- deep exploration and characterization, using remotely operated vehicles and sophisticated video taping at depths exceeding 240 meters (787 feet). Scientists here are trying to better understand dusk and dawn fish migrations from coral to non-coral habitats and surrounding flats, information they could then use to consider appropriate levels of protection for various areas; – Progress to Date: an integrated effort among NOAA, National Geographic and USGS uses divers, deep camera drifts, Remotely Operated Vehicles, One person submersibles (Deepworker – down to 2000 feet) and sonar technology to partially map and conduct a biological inventory of the deepwater portions of the Ecological Reserve;
- biological boundaries involving substantial changes in physical structures, food quality, and movement of marine organisms. “As scientists and managers, we tend to scale experiments and establish ecological boundaries based on our own experiences and our human perceptions of what they should be,” the scientists note in a report analyzing the Tortugas Ecologoical Reserve. “It is especially important to avoid this pitfall when considering areas for reserve or protected area status,” as when targeting coral reefs for protection. “It is easy to overlook the importance of less structurally diverse habitats adjacent to reefs,” the scientists caution; – Progress to Date: Thirty randomly located stations at the reef – sand and seagrass border are regularly surveyed to provide clues on how the coral reef per se is linked with and, in many ways, dependent on the productivity of the surrounding non-reef environment to provide energy needed to sustain the exceptional biodiversity found over the hard coral areas;
- spillover/larval export effects – preserving a critical reproductive population of fish to maintain recruitment of larvae into fished area; – Progress to Date: Extensive use of ARGOS drifters, a device that drifts passively with ocean currents and indicates its position via satellite to scientists on shore, reveals that fish larvae produced at the TER could not only reach the entire Florida Keys tract within their ~30 day larval stages, but could regularly reach as far north as Tampa Bay on the west coast of Florida and Cape Canaveral on the east coast – revealing the tremendous spillover potential for a pivotally located reserve; and
- effectiveness of marine protected areas in ecosystem recovery – Time will tell just how successful the Ecological Reserve designation is in increasing fish populations and size within the protected area, but here again the scientists express cautious optimism based on their findings so far. “The numbers of fish more than 20 centimeters total length appear to have increased in the New Reserve” they report. “Six fish species (representing the most abundant species in each of six important reef fish families) show an increase in number and size within the Reserve” when compared to the Tortugas Park and other areas. “In 2002, both large red and black grouper, on the order of five years old, were conspicuous parts of the fish assemblage at the reef soft bottom interface. In 2001, only large red grouper were abundant.” – Progress to Date: Although still too early to provide a statistically irrefutable argument, the data suggest that fish size and numbers are increasing in the reserve areas compared to non-reserve areas, and that the relaxation of trawling in the extensive soft bottom areas along the northern boundary of the TER is resulting in the expansion of deepwater seagrass and increases in pink shrimp abundance.
Armed with scientifically based answers to these and other questions involving the Tortugas Ecological Reserve, NOAA scientists are confident that their multi-year research will help the American public better understand the potential for such marine protected areas. “We actually can turn to the American public and say ‘Yes, this actually is what’s happening out here,” NOAA/NCCOS’s Mark Fonseca told National Public Radio.
As it said in announcing the TER effort, “By designating this area an ecological reserve, NOAA hopes to create a seascape of promise – a place where the ecosystem’s full potential can be realized and a place that humans can experience, learn from and respect.”
The scientists’ ongoing work will tell the agency and the public how things are working in proceeding toward that goal.
Shorter web link for sharing: https://coastalscience.noaa.gov/news/?p=354