Benthic Macroalgal Blooms as Indicators of Nutrient Loading from Aquifer-Injected Sewage Effluent in Environmentally Sensitive Near-Shore Waters Associated with the South Florida Keys

One proposed benefit of marine protected areas (MPAs) is increased larval export, potentially increasing recruitment in unprotected areas. Because most marine species have planktonic larvae, information regarding planktonic transport is needed to evaluate the benefit of larval export. We used satellite-tracked drifters to define planktonic transport routes and rates from three MPAs along the south Florida and southeast United States (US) continental shelves. Drifter tracks indicated both long-distance transport and local retention. A probability model was developed based on drifter releases. The region was broken into zones; zone-specific residence times and movements between zones were defined from the drifter tracks. Transport out of the region in association with the Loop Current – Florida Current – Gulf Stream was the most frequently observed outcome, yet retention was high in the lower Florida Keys and on the Georgia shelf. From the model results, long-distance planktonic transport and local retention are the endpoints of a continuum rather than a dichotomy. Further, the outcome of planktonic transport is spatially heterogeneous with some regions exhibiting more retention and others exhibiting more export. The spatial aspects of planktonic transport described here should be considered in designing MPAs with fishery management objectives in the south Florida and southeast US shelf ecosystems.

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Regional differences in an established population of invasive Indo-Pacific lionfish (Pterois volitans and P. miles) in south Florida

PeerJ ◽

10.7717/peerj.5700 ◽

2018 ◽

Vol 6 ◽

pp. e5700

Author(s):

David R. Bryan ◽

Jeremiah Blondeau ◽

Ashley Siana ◽

Jerald S. Ault

Keyword(s):

Coral Reef ◽

Florida Keys ◽

South Florida ◽

Population Status ◽

Coral Reef Ecosystem ◽

The South ◽

Pterois Volitans ◽

Western Atlantic ◽

Dry Tortugas ◽

Reef Ecosystem

About nine years ago (circa 2009), Indo-Pacific lionfishes (Pterois volitans and P. miles) invaded the south Florida coral reef ecosystem. During the intervening period of time, there has been substantial research on their biology, life history, demography, and habitat preferences; however, little is known concerning their regional population status and trends in the region. Here, we use a large-scale fisheries independent reef fish visual survey to investigate lionfish population status among three south Florida regions: Dry Tortugas, Florida Keys, and southeast Florida. Density estimates (ind ha−1) have been relatively stable since 2012, and are lower than other areas reported in the western Atlantic and Caribbean Sea. Low, stable population densities in south Florida suggest there may be a natural mechanism for lionfish population control. In the Dry Tortugas, lionfish density in 2016 was significantly lower (0.6 ind ha−1 ± 0.15 SE) than the two other south Florida regions. The Dry Tortugas region has the highest percentage of marine protected areas, the lowest level of exploitation, and thus the highest densities of potential lionfish predators and competitors. In the Florida Keys and southeast Florida in 2016, lionfish densities were greater (5.4 ind ha−1 ± 1.0 SE and 9.0 ± 2.7 SE, respectively) than the Dry Tortugas. Fishing pressure on lionfish was higher in these two regions, but densities of several potential predators and competitors were substantially lower. Despite relatively low regional lionfish densities that can be attributed to some combination of fishing mortality and natural biocontrol, lionfish are still well established in the south Florida coral reef ecosystem, warranting continued concern.

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