Florida Fish and Wildlife Conservation Commission

Western Dry Rocks

Draft Rule December 16, 2020

This is a draft rule presentation on Western Dry Rocks, located in the Florida Keys, which is a known multi-species spawning aggregation site and popular fishing location.

Division: Marine Fisheries Management Authors: CJ Sweetman, Kali Spurgin, Jessica McCawley, and Martha Guyas Contact Phone Number: 850-487-0554 Report date: Nov. 6, 2020

Unless otherwise noted, images throughout the presentation are by FWC.

Outline

Fish spawning aggregations

Western Dry Rocks

Influence of ocean currents

Fish spawning seasons

Shark interactions at Western Dry Rocks

During today’s draft rule presentation, staff will discuss the multi-species fish spawning aggregation site 10 miles southwest of Key West called Western Dry Rocks (WDR). As part of the presentation, staff will review fish spawning aggregations, and provide lessons learned from past management experiences. Additionally, staff will describe WDR, how ocean currents near this location can drive enhanced recruitment to the Keys and South Florida, and when various species are known to aggregate there. Finally, staff will present research on shark interactions with anglers at WDR.

Spawning Aggregations

Form at highly predictable times and locations

High risk of over-exploitation

Some species travel far distances

Hotspots for productivity ▫ Apex predators feed on spawning fish

▫ Planktonic feeders consume eggs

Fish spawning aggregations form at highly predictable times and locations (typically during full or new moons). Due to the predictable nature, size, and number of fish that occur at these aggregations, they are also often popular fishing locations. However, research indicates fishing spawning aggregations can lead to over-exploitation by decreasing abundance and size of spawners, creating changes in population sex ratios, and creating the potential for the disappearance of aggregations. Some species, such as permit, can travel far distances (greater than 50 miles) to reach these locations, so impacts that result from fishing these aggregations can have regional ramifications that extend beyond just one site. In general, fish spawning aggregations serve as productivity hotspots because these small areas attract large numbers of fish to reproduce, apex predators to feed on spawning fish, and planktonic feeders to consume protein-rich fish eggs.

Lessons Learned from Nassau Grouper

Once a highly important reef fishery in the Caribbean

Targeting of spawning aggregations caused population collapse in 1980s ▫ Overfishing masked by high catch rates ▫ Spawning aggregations ceased to form

Slow recovery

Photo courtesy: NOAA Fisheries

The next few slides provide lessons learned from the management of fish spawning aggregations using specific regional examples.

First, Nassau grouper was historically one of the most important fisheries in the Caribbean. Previous management measures varied by country, with some regulating their respective fishery through size limits, gear restrictions, and quotas. However, the targeting of large, mature individuals at spawning aggregations ultimately led to overfishing and caused the fishery to collapse. Part of the issue in targeting these spawning aggregations is that catch rates can continue to remain high despite a population that is being depleted (i.e., hyperstability). As a result of this overfishing, some spawning aggregations ceased to form and of the 50 Nassau grouper spawning aggregations identified throughout the Caribbean, less than 20 probably remain today.

The impacts of overfishing were so great in the Caribbean that Nassau grouper were listed as “threatened” under U.S. Endangered Species Act in 2016 and are currently prohibited from harvest in the United States. Following regional collapses of Nassau spawning aggregations, many Caribbean nations sought to protect their remnant populations through a variety of management actions, including seasonal closures, the establishment of protected areas at the spawning aggregation locations, and harvest moratoria. The importance of these spawning aggregations to the overall Nassau grouper population was understood a bit too late in this example. In locations where protections of the Nassau grouper spawning aggregations were enacted, only recently has recovery been documented, indicating that recovery of these spawning aggregations can take decades to occur.

Lessons Learned from Riley’s Hump

Area closure implemented in 2001 following decline of mutton snapper spawning aggregations

Impact of comprehensive management measures Spawning aggregations of mutton snapper reformed Increases in abundance/size of black and red grouper,

yellowtail and mutton snapper Black grouper and cubera snapper spawning aggregations

identified

Regional effects Evidence of increased mutton snapper densities throughout

the Florida Keys (influence of ocean currents) Commercial reef fish catch increased

Mutton snapper spawning photos courtesy: Chris Parsons

The story of Nassau grouper in the Caribbean is contrasted with actions taken at Riley’s Hump, which is located in the Dry Tortugas region. In the late 1990s, declines were observed in the mutton snapper spawning aggregation at Riley’s Hump, which resulted in an area closure that was implemented in 2001. Since implementation of the area closure, spawning aggregations of mutton snapper have reformed and benefits have also been observed in other important fisheries. Specifically, increases in the abundance and size of black and red grouper, and yellowtail and mutton snapper in the region have been observed and this is largely attributed to the area closure at Riley’s Hump. Further, research by FWC has identified spawning aggregations near Riley’s Hump for other species such as black grouper and cubera snapper.

Overall, the protection of mutton snapper spawning aggregations at Riley’s Hump has been widely regarded as a fisheries management success story. The combination of providing protections for mutton snapper spawning aggregations with traditional management measures, such as changes in the minimum size and daily bag limits, represents a comprehensive, holistic management strategy to ensure the sustainability of this important south Florida fishery. To this point, evidence from FWC research indicates that mutton snapper densities have increased throughout the Florida Keys. Ocean currents in the Tortugas/Lower Keys region, such as those near Riley’s Hump, provides a mechanism for potential enhanced recruitment throughout the Keys and South Florida. The proximity of these ocean currents to the reformed mutton snapper spawning aggregation is likely an important factor for the observed increased densities in the Florida Keys.

A common concern regarding area closures is reduced access to fishery resources. However, since the 2001 Riley’s Hump area closure, and in combination with traditional management measures, commercial reef fish catch has increased in the region. This further supports the potential that the spawning aggregation protection at Riley’s Hump provides for positive contributions to regional reef fish populations.

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Sand Key SPA

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Western Dry Rocks

Located 10 miles SW of KeyWest

Popular fishing location

Multi-species spawningaggregation location

Western Dry Rocks (WDR) is a high-relief area with a well-developed coral reef located about 10 miles SW of Key West. The site is a popular fishing location and many guides out of Key West target this area for their half-day charters. The area is popular, in part, because of the abundance and size of fish that are present at WDR. The size and number of fishes observed there is largely a function of the area being a multi-species spawning aggregation site. In the previous examples that were highlighted, the implications of spawning aggregation management for only one single species were discussed. However, WDR is somewhat different from the previous examples because multiple recreationally and commercially important species are known to form spawning aggregations there.

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* The ocean currents in the Keys that can provide a mechanism for enhanced recruitment of fish spawned at Riley’s Hump also influence WDR. While physical oceanographic currents are not static and are subject to changes in position and strength, the Tortugas and Pourtales Gyres can trap and then deposit fish eggs and larval fish along the Florida Keys and South Florida nearshore waters.

The mechanism starts with a gyre, or a system of rotating currents, that forms off the Loop Current and settles near the Tortugas region. These gyres move in a counter-clockwise motion which traps fish eggs, zooplankton, and fish larvae that are unable to swim beyond the gyre. The Tortugas Gyre remains in place, typically for 2-3 months, until another gyre forms off the Loop Current and pushes the Tortugas Gyre towards the Florida Keys.

The Tortugas Gyre then moves along the coast of the Keys and transitions into the Pourtales Gyre. When the Pourtales Gyre passes areas like WDR, fish that are spawning at that location can have their eggs become trapped in the rotating water currents. As the Pourtales Gyre diminishes in size and strength, newly hatched fish larvae can be deposited in nearshore waters and ultimately replenish populations. Multiple gyres can form in a given year, and when the timing of the gyre movement overlaps with fish spawning events they can promote strong fish year classes to inshore waters. To this point, strong year classes can potentially sustain a fishery for many years.

 

 

 

 

 

 

 

 

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Spawning Season for Species that Aggregate at WDR

Species JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC. Permit Yellowtail snapper Mutton snapper Gray snapper Schoolmaster Atlantic spadefish Black grouper Scamp Nassau grouper Gag grouper Red hind

= spawning season = peak spawning season

Many recreationally and commercially important fishes are known to aggregate to specific locations at predictable times of the year for the purpose of spawning. Western Dry Rocks is somewhat unique in that multiple-species aggregate at this location during the same time of the year. The figure on the slide depicts the spawning season for various species observed to aggregate near WDR. The orange cells indicate the overall spawning season for a species, whereas the red cells indicate the time of year when peak spawning occurs. In the spring and summer, permit; various species of snapper, including yellowtail, mutton, gray, and schoolmaster; and Atlantic spadefish aggregate during their spawning seasons at WDR. Grouper spawning tends to occur during colder months of the year (e.g., winter and early spring). Recent FWC tagging research further supported WDR as a potential spawning aggregation location for multiple grouper species including black grouper, Nassau grouper, and gag grouper. However, grouper are already prohibited from harvest throughout the Atlantic and state waters off Monroe County during their spawning season (Jan. 1 through April 30).

Aggregations

Black Grouper

9 Gray Snapper

e Multiple species

Mutton Snapper

e Permit

• Black Grouper: Most used acoustic receiver ::,,a/i_ Concentrations of boats from aerial surveys

········· Bathymetry (ft)

D FWC proposed boundary

D FKNMS proposed boundary

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Proposed Draft Rule

Create an annual 1-square-mile fishing closure at Western Dry Rocks from May – June

Western Dry Rocks

The proposed draft rule for Commission consideration is for an annual one-square-mile fishing closure near Western Dry Rocks (WDR) from May through June.

The figure on the slide characterizes the area FWC is proposing to be protected (in black), which is smaller than what the Florida Keys National Marine Sanctuary previously proposed (in red). The actual location of WDR is slightly to the north of the proposed protected area, but the entirety of the area is commonly referred to as WDR. The different colors of the background represent the topographic features of WDR with yellow/orange colors representing shallow parts of the reef and green/blue colors representing deeper regions. To highlight some key features of this figure, the different colored circles represent known spawning aggregation locations for several species. The red represent mutton snapper, the gray represents gray snapper, the blue represents permit, and green represents black grouper. Additionally, the purple circles represent spawning aggregation locations that involve multiple species, such as crevalle jack and various other kinds of snapper and grunts. The fishing boats that are depicted in this figure represent where fishing effort is primarily concentrated based on aerial survey data. As you can tell, the fishing effort tends to be centered around the known spawning aggregations.

Shark Interactions at Western Dry Rocks

Apex predators naturally attracted to spawning aggregations

Research showed that 39% of permit hooked were consumed by sharks ▫ Catch-and-release during spawn could have

population-level implications

Hooked fish = easy prey

Continued concern regarding shark interactions

Requests for no-entry, April – July closure to minimize impact during spawning season

Photo courtesy: NOAA

As previously discussed, fish spawning aggregations are hotspots for productivity. For the same reasons that people like to fish these locations, sharks like to hunt here as well. Due to this overlap, there has been documented conflict with sharks and anglers at fish spawning aggregations like WDR. Fish that are getting ready to spawn are focused on reproduction and less so on predators in the area. As a result, spawning fish generally make an easy meal for an apex predator. This is further exacerbated by sharks having learned that a hooked fish represents an even easier prey item.

Shark interactions were evaluated at WDR in a study that included catches by researchers, fishing guides, and recreational anglers on guided trips from March 2016 through June 2018. This study showed that 39% of all permit that were hooked at WDR were consumed by an apex predator (all identified predators were sharks). Although harvest of permit is allowed outside of their spawning season, many fishers in the Florida Keys practice catch-and-release. However, this research indicates that even the practice of catch and release on spawning aggregations could have population-level effects due to these shark interactions.

Because of this, several stakeholders have requested that WDR be designated as a no-entry April through July closure to minimize the impact of shark interactions while multiple species are aggregated to spawn. The proposed draft rule would prohibit all fishing at WDR from May through June, which would eliminate shark interactions during this portion of the spawning season.

Considerations

Protecting spawning aggregations is part of an overall conservation strategy ▫ Used in coordination with other management tools

Proposed timing includes part of the peak spawning season for mutton, gray, and yellowtail snappers, and permit

Groupers already prohibited from harvest in winter months

Currents may enhance recruitment in the Keys and SE Florida

Area closure could reduce impacts of shark interactions

Will impact charter fishers from Key West

Overall, there are several important considerations for evaluating the proposed area closure at Western Dry Rocks (WDR) from May through June. First, the protection of fish spawning aggregations used in coordination with other management tools represents an overall conservation strategy aimed to sustain and potentially enhance some of Florida’s most iconic fisheries. The timing of the proposed May through June one-square-mile closure is aimed to provide benefits to several important fisheries, including mutton snapper, permit, and gray snapper. Although groupers are already prohibited from harvest during winter months, there are some grouper species that have the potential to spawn through June (e.g., scamp) and therefore could also receive additional protection.

Another important consideration is the impact of prevailing oceanographic currents in the region and their potential to enhance recruitment for those species spawning at WDR. FWC research indicates that the Riley’s Hump mutton snapper spawning aggregation closure, in part, contributed to increased densities of mutton snapper in the Florida Keys. The currents that contributed to the observed increases at Riley’s Hump are the same currents that would impact enhanced recruitment resulting from the protection of spawning aggregations at WDR. The negative shark interactions observed at WDR highlight that catch-and-release may still result in high rates of fishing mortality and therefore a total fishing closure (including catch-and-release) from May through June is proposed in the draft rule.

The importance of WDR for fishing guides out of Key West is another meaningful consideration. Based on past discussions with fishing guides out of Key West, it is unlikely that they will support any sort of closure at this location due to the perceived impact that a closure would have on their fishing operations.

Staff Recommendation

Approve the proposed draft rule to protect multi-species spawning aggregations near Western Dry Rocks Prohibit all fishing in a 1-square-mile area from May – June

Come back in 5 years to provide research updates and to evaluate performance of management actions

If approved and directed, staff intend to conduct public workshops in early 2021 to gather stakeholder input and return to the Commission for a final public hearing in Feb. 2021

Photo courtesy: Bob Glazer

In order to protect multi-species spawning aggregations near Western Dry Rocks, staff recommends that the Commission approve the proposed draft rule to prohibit all fishing in a one-square-mile area from May through June. Additionally, staff recommend a 5-year review of the performance of the management actions at Western Dry Rocks and a research update.

If approved and directed, staff intend to conduct public workshops in early 2021 to gather stakeholder input. Further, staff intend to provide the results of these workshops and bring this item back to the Commission for a final public hearing in February 2021.

The following slides are considered backup material and are not anticipated to be part of

the actual presentation

FWC Regulations for Species that Aggregate at Western Dry Rocks JAN ... MAR ... ..., ... ... AUG SEP OCT NOY DEC BAGUMn MtNSIZE

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