Climate change impacts on fish and fisheries in the Florida Keys National

Marine Sanctuary

Barbara MuhlingJohn Lamkin

NMFS: Southeast Center

Potential impacts of climate change on marine fish and fisheries

Warming sea temperatureso Changes in species dominance, occurrence and distributiono Changes in reproductive behaviors and spawning effort

Changing current patternso Alteration of larval dispersal pathwayso Changes to larval survival and recruitment to adult

populations, and fisheriesRising sea levels

o Loss or degradation of nearshore habitatChanging precipitation regimes

o Changes in nearshore water quality

The Florida Keys National Marine SanctuaryLinked to the Dry Tortugas, Gulf of Mexico and

Caribbean via the Loop CurrentThe degree of northward penetration of the Loop

Current is highly variableFlow from the intra-American seas

through the Gulf of Mexico and onto the Florida Keys

The Loop Current and Tortugas Gyre

The Florida Keys National Marine SanctuaryFreshwater inflow enters Florida Bay from the

EvergladesWater quality in Florida Bay and the Florida Keys

influences the health of seagrass meadows and coral reefs

These are important habitats for adult and juvenile fishes

Mean surface salinity across Florida Bay in summer, and winter

-81 -80.8 -80.6 -80.4

Salinity

-81.2 -81 -80.8 -80.6 -80.424.6

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South Florida

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Atlantic Ocean

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Climate change impacts of primary concern to fish and fisheries in the FKNMS

1) Changes in species occurrence and distribution2) Changes in spawning behaviors and recruitment3) Changes in larval supply to nursery habitats

Potential changes are most likely to be linked to changes in water temperatures, Loop Current dynamics, and health of fish habitats

Examples demonstrating these mechanisms follow, highlighting research capacity at the SEFSC

Potential impacts on fish and fisheries - 1

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1980 1985 1990 1995 2000 2005 2010

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Changes in species dominance, occurrence or distributions

Example: Increasing abundances of tropical Lane Snapper (Lutjanus synagris) in the northern Gulf of Mexico

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NMFS Trawl survey area: Northwest GOM Changing abundance of L. synagris in summer trawl surveys

y = -0.00x3 + 0.03x2 - 0.70x + 4.85R² = 0.83

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Potential impacts on fish and fisheries - 2Changes in spawning behaviors and thus

recruitmentExample: Spawning habitat of bluefin tuna (Thunnus

thynnus) in the northern Gulf of MexicoProbability of collecting larval

bluefin tunavs. sea surface temperature

Change in suitable spawning habitat with 2°C increase in SST

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Probability of larvae

Potential impacts on fish and fisheries - 3

Changes in larval supply to nursery habitats in the FKNMS

Example: Changes in magnitude and timing of connection between Yucatan Peninsula, Dry Tortugas and Florida KeysSnapper larvae collected off Yucatan Generalized Loop Current

flowEddies provide retention and transport mechanisms for larvae

Data and modeling needs1) To predict and quantify the types of

mechanisms described, we need better information on how climate change would affect:Water temperaturesCurrent patternsFreshwater inflows

A downscaled climate model would be very helpful in addressing these points

2) To help explain past trends and predict future trajectories, access to historical datasets and collaboration with scientists within and outside of NOAA is essential

Downscaled climate modelsCoarse-scale (~100km) climate models have already

been produced through the IPCCDownscaling these to a regional level allows the

predictions of temperature, rainfall, and regional oceanographic conditions under various climate change scenarios

A downscaled model covering the Gulf of Mexico and Florida Keys would help to predict water temperatures, precipitation and Loop Current flow across the region under future CO2 emission scenarios

These parameters are highly important for predicting future stressors to the FKNMS, and fish populations