FWC reviews Western Dry Rocks closure

A four-month fishing closure at one of the most important fish spawning sites in the Florida Keys, and possibly all of South Florida, appears to be paying dividends.

The Florida Fish and Wildlife Conservation Commission board will meet next week and receive an update on a seasonal fishing closure at Western Dry Rocks reef. The FWC board meets all day starting at 8:30 a.m. Wednesday, May 1, and Thursday, May 2, in Daytona Beach. The FWC board expected to discuss the three-year review of the seasonal closure at Western Dry Rocks on Thursday.

The meeting will be televised online at thefloridachannel.org.

When the FWC board approved the closure, board members directed staff to evaluate whether the regulations were having the desired effect and asked staff to provide three- and five-year updates to the board on progress made. The closed fishing season at Western Dry Rocks is scheduled to sunset after seven years and, at that time, staff will provide a comprehensive evaluation of the effectiveness of the seasonal fishing closure to the board.

At the April Florida Keys National Marine Sanctuary Advisory Council meeting, FWC research scientist Danielle Morley outlined the reasons behind the closure, which had been initially met with resistance from some recreational anglers in the Keys, and some of the benefits.

The seasonal closure was enacted in 2021 and came after years of debate about the impacts of fishing on Western Dry Rocks while snappers, groupers, permit fish and other species are actively spawning at that reef, according to Morley. The Lower Keys Guides Association led a coalition to enact the four-month closure and the coalition included the International Game Fish Association, Coastal Conservation Association, American Sportfishing Association, Angler Action Foundation and Bonefish & Tarpon Trust.

The roughly 1-square mile fishing closure at Western Dry Rocks reef off of Key West runs from April 1 to July 31.

The site is a popular fishing location and many guides and charter fishing captains out of Key West target this area for half-day charters. The area is popular, in part, because of the abundance and size of fish that are present. The size and number of fishes observed there is largely a function of the area being a multi-species spawning aggregation site for many recreationally and commercially important fisheries. Western Dry Rocks is a particularly important fish spawning aggregation site compared to others due to the number of species that are known to form spawning aggregations there, according to Morley.

Western Dry Rocks is somewhat unique in that those multiple species gather there during the same time of the year, Morley said.

Recent FWC tagging research further supported Western Dry Rocks as a potential spawning aggregation location for multiple grouper species including black grouper and gag grouper, which in addition receive extra protection from a harvest ban throughout the Atlantic and state waters off Monroe County during their spawning season that runs from Jan. 1 through April 30.

The ocean currents in the Keys can provide a mechanism for enhanced recruitment of fish spawned at Western Dry Rocks. While physical oceanographic currents are not static and are subject to changes in position and strength, the Tortugas and Portales Gyres can trap and then deposit fish eggs and larval fish along the Florida Keys and South Florida nearshore waters, according to Morley.

When the Portales Gyre passes areas like Western Dry Rocks, fish eggs and larvae become trapped in the rotating water currents. As the Portales Gyre diminishes in size and strength, newly hatched fish larvae can be deposited in nearshore waters and ultimately replenish populations, according to Morely.

The April to July timeframe was selected because that was the peak spawning season for many recreationally and commercially important species, including mutton snapper, gray snapper, yellowtail snapper and permit, according to Morley. Based on FWC’s comprehensive evaluation, staff will provide recommendations as to whether current regulations should be maintained, modified or eliminated.

FWC staff developed a science plan to evaluate the effectiveness of the seasonal fishing closure at Western Dry Rocks. The research and monitoring described in the plan focuses on a comprehensive approach to collecting information about the closure and has two main goals, to monitor changes in fish spawning aggregations at Western Dry Rocks and in surrounding fish communities, and to assess stakeholder opinions to Western Dry Rocks regulations and changes in resource use, Morley said.

This science plan outlines supporting methods to aid in addressing these two goals and contains metrics tables explaining how different research will be used to evaluate the effectiveness of this management decision. The science plan was developed by FWC scientists with the cooperation of resources managers in the Division of Marine Fisheries Management and is available for download on the Western Dry Rocks website maintained by FWC.

FWC staff are addressing the first goal of the science plan, to monitor changes in fish spawning aggregations at Western Dry Rocks and in surrounding fish communities, using several methods. Some include divers conducting underwater fish counts, deploying long-term underwater cameras at specific locations, using an autonomous underwater vehicle to look for hotspots of fish abundance and to map the habitat used by these fish, using acoustic telemetry to tag and track the movements of specific species, and collecting animals to document age, growth and reproductive patterns at these aggregations.

Staff has learned that some of these animals are traveling further than expected to reach Western Dry Rocks, according to Morley. One example was the movement of a mutton snapper that was tagged in 2022 at Western Dry Rocks. The fish spent the winter south of Miami, then began swimming down the Keys the following spring, briefly stopped at Western Dry Rocks, swam out to another known spawning aggregation in the Dry Tortugas, returned to Western Dry Rocks, went back up to Biscayne Bay, and then returned to Western Dry Rocks again in June 2023, according to Morely.

Protecting permitFollowing the implementation of this regulation, the fishing and conservation group Bonefish & Tarpon Trust (BTT) funded two three-year studies to evaluate the efficacy of the management action for permit fish, said Ross Boucek, BTT Florida Keys initiative manager. Each study evaluated permit aggregations using data from pre- and post-closure, and at Western Dry Rocks and two other sites that do not have a closed season, the Seven Mile Bridge Rubble and Thunderbolt artificial reef.

The first study, conducted by Florida International University, evaluated the behaviors of the aggregation, which includes schooling behaviors, the frequency the aggregation is present, changes to the size structure of fish and the abundance of fish at the three sites during spawning season for three years (2021-2023). Frequency of aggregation occurrence and size of the aggregation were greatest at Western Dry Rocks, which underscores the importance of the area to spawning permit, justifying continued protection, Boucek said. The Western Dry Rocks permit aggregation was present at 81% of surveys, the Seven Mile Bridge rubble site had permit present in 66% the surveys and the Thunderbolt had permit in 54% of the surveys.

Abundance of permit at Western Dry Rocks peaked in March and April, with an estimated 100 to 1,500 permit per survey, and declined in May. In contrast, at Seven Mile Bridge rubble and Thunderbolt, a permit aggregation was not present or too small or scattered to detect in March and April, according to Boucek. Abundance peaked in May at 100 to 700 permit at Seven Mile Bridge rubble and 500 to 1,300 permit at Thunderbolt. As expected because of the short time frame, both the average size of permit, and their abundances at Western Dry Rocks have not changed pre- versus post-closure.

The second study, conducted by Carleton University, tracked potentially early signs of recovery through studying individual permit spawning movements, and evaluated the effectiveness of the marine protected area boundary and seasonal closure window at Western Dry Rocks, Seven Mile Bridge rubble and Thunderbolt. Preliminary data indicate that permit are resident for longer periods at Western Dry Rocks and move less between Western Dry Rocks and other sites post-closure, which shows a positive early response of the seasonal closure, Boucek said.

Tracking data show that spawning permit spent significantly more time at Western Dry Rocks in the two years following the implementation of the closure than pre-closure, and spawning fish at Western Dry Rocks are now moving less frequently between other aggregation sites, Boucek said.

Evaluations of the seasonal closure show that the April-July window offers protections for permit during three of the four most active spawning months. March, when fishing is still allowed, is the third most active spawning month. During their spawning season, spawning permit spend 55% of the time inside the closed area and 45% of the time adjacent to and outside of the boundary.

“These findings provide guidance for any future revision to the marine protected area, such as including the month of March, and a slight expansion of the boundaries to include adjacent unprotected areas permit use,” Boucek said.

Boucek called the seasonal closure a “success” when it comes to protecting the spawning populations, but he said it could be several years before researchers see the long-term benefits when it comes to increased fish populations.

“The investment has truly paid off,” Lower Keys Capt. Will Benson, a Sanctuary Advisory Council member said after the presentation at the Sanctuary Advisory Council meeting.

Sawfish and spinning fishAlso on Thursday, the FWC board will discuss the recent deaths of the roughly 43 smalltooth sawfish in Keys waters in the past several months and hundreds of reports of fish spinning, whirling and behaving strangely. The discussion will be during the executive director’s report.

FWC, Fisheries biologists with Florida Gulf Coast University, BTT and the University of South Alabama continue to test fish and fish samples and the state Department of Environmental Protection (DEP) continues to test water samples, which have so far not shown unusual or high levels of pharmaceuticals and chemicals, including pesticides and herbicides, that can be found in stormwater runoff, human sewage and treated wastewater. DEP plans to test the waters for heavy metals next, according to Nick Parr, of the state Department of Environmental Protection.

The cause of the mysterious fish event and sawfish die-off continues to elude researchers tasked with finding a cause.

The first smalltooth sawfish rescued off of the Keys captured near Cudjoe Key and transported to Mote Marine Laboratory’s facility in Sarasota earlier this month is still recovering, but has yet to start feeding on its own and is being fed by staff via a tube.

National Oceanic and Atmospheric Administration (NOAA) Fisheries Service biologists and Mote staff have tried various ways to get the sawfish to start eating, such as feeding it dead fish, chunks of fish and squid and live fish, but the fish has yet to eat, said Adam Brame, NOAA’s sawfish recovery coordinator.

Researchers continue to look for clues. Fish and Wildlife Research Institute Director Gil McRae told The Keys Citizen there could be “multiple toxins and multiple algal species” playing a role in the odd fish behavior event.