Linkages between environmental conditions and recreational king mackerel catch off west-central Florida Carrie C. Wall Frank E. Muller-Karger Chuanmin Hu University of South Florida College or Marine Science Institute for Marine Remote Sensing Mitchell A. Roffer Roffers Ocean Fishing Forecasting Service, Inc.

Or: where to catch a king in the Gulf Institute for Marine Remote Sensing Mitchell A. Roffer Roffers Ocean Fishing Forecasting Service, Inc.

Study Focus   Pelagic Fisheries   Remote Sensing   Physical / Biological Oceanography Hypothesis: Stronger and persistent fronts have greater influence on fish abundance, increased catch efficiency

Fisheries   King Mackerel (kingfish) Scomberomorus cavalla Highly migratory species SST range ( °C) Expected to concentrate in areas of high primary productivity and prey Catch data collected through interviews at local kingfish tournaments

Fisheries – Survey Fisheries – Survey Where are the fish? What pass did you leave from? What time? Where did you start fishing? What time did you start? What method of fishing was used? Troll? Anchor? Drift? Number of fishing lines? Number of fish hooked? Number of fish caught? Were bait fish present? Did you see kingfish? What time did you stop? Did you fish anywhere else? Did you run to the next site?

Remote Sensing   Sea Surface Temperature AVHRR + MODIS   Chlorophyll concentrations MODIS + SeaWiFS Proxy for primary productivity   Turbidity MODIS + SeaWiFS Water-leaving radiance at 443 nm   Red Tide MODIS Fluorescence Line Height

Frontal Detection   Automated frontal detection algorithm   Measure gradients near fronts   Measure distance between catch and fronts Deg C Sea Surface Temperature 9 April 2005

Detection of Bathymetric Gradients Areas of greater bathymetric gradient may influence frontal stability

Bathymetry Gradients and Sustained Fronts c. d. Sea surface temperature Chlorophyll a Locations where fronts are more likely to occur may aggregate more kingfish High: 0.19 Low: 0.00 High: 0.67 Low: 0.00

Physical Oceanography   University of South Florida buoy data Wind Velocity Current Velocity Strong and variable winds and currents occurred throughout this study i. j.

Turbidity at Fishing Locations c. CPUE

Turbidity at Fishing Locations High fishing success associated with intermediate turbidity c. CPUE

Turbidity at Fishing Locations Low fishing success and turbid water during fall 2005 c. CPUE

Effects of Fall 2005 Red Tide  Reduced kingfish catch Spring 2004: 444 Spring 2004: 444 Fall 2004: 818 Fall 2004: 818 Spring 2005: 538 Spring 2005: 538 Fall 2005: 208 Fall 2005: 208  Increased fishing w/ no baitfish Spring 2004: 46% Spring 2004: 46% Fall 2004: 46% Fall 2004: 46% Spring 2005: 49% Spring 2005: 49% Fall 2005: 62% Fall 2005: 62%  Increased turbidity + chlorophyll FLH fronts November 12, 2005

Principal Component Regression Analysis  Environmental factors influencing kingfish catch: Baitfish Presence (56%) Baitfish Presence (56%) Turbidity Gradient (30%) Turbidity Gradient (30%) Chlorophyll Gradient (7%) Chlorophyll Gradient (7%) SST Front (6%) SST Front (6%) Turbidity Front (2%) Turbidity Front (2%)

Conclusions  Relationships observed between: Bathymetry and fronts Bathymetry and fronts Baitfish and fishing success Baitfish and fishing success Water clarity and fishing success Water clarity and fishing success  Red tide in fall 2005 FLH characterized features FLH characterized features Observed baitfish and kingfish abundance Observed baitfish and kingfish abundance  High variability within fisheries data Anglers Anglers Strong and variable wind Strong and variable wind

Recommendations  Apply findings to other pelagic migratory species Aid in fisheries management Aid in fisheries management Continue to strengthen link between scientists and fisheries community Continue to strengthen link between scientists and fisheries community  Continue to characterize seasonal physical processes within the study area and relate to kingfish abundance Pop-up satellite tags Pop-up satellite tags Frontal probability Frontal probability