Linkages between environmental Linkages between environmental conditionsconditions and recreational king mackerel catchand recreational king mackerel catch

off west-central Floridaoff west-central Florida

Carrie C. WallCarrie C. WallFrank E. Muller-KargerFrank E. Muller-Karger

Chuanmin HuChuanmin HuUniversity of South Florida University of South Florida College or Marine ScienceCollege or Marine Science

Institute forMarine Remote Sensing

Mitchell A. RofferMitchell A. RofferRoffers Ocean Fishing Roffers Ocean Fishing

Forecasting Service, Inc.Forecasting Service, Inc.

Or: where to catch a king Or: where to catch a king in the Gulfin the Gulf

Institute forMarine Remote Sensing

Mitchell A. RofferMitchell A. RofferRoffers Ocean Fishing Roffers Ocean Fishing

Forecasting Service, Inc.Forecasting Service, Inc.

Study FocusStudy Focus

Pelagic Fisheries

Remote Sensing

Physical / Biological Oceanography

Hypothesis: Stronger and persistent fronts have greater Hypothesis: Stronger and persistent fronts have greater influence on fish abundance, increased catch efficiencyinfluence on fish abundance, increased catch efficiency

86°W

86°W

84°W

84°W 82°W

82°W

80°W

80°W

26°N 26°N

28°N 28°N

30°N 30°N

±

±

0 5025 Kilometers

Gulf of Mexico

Tampa Bay

CharlotteHarbor

Atlantic Ocean

FisheriesFisheries

King Mackerel (kingfish) Scomberomorus cavalla

Highly migratory species SST range (20 - 26°C) Expected to concentrate in

areas of high primary productivity and prey

Catch data collected through interviews at Catch data collected through interviews at local kingfish tournamentslocal kingfish tournaments

Fisheries – SurveyFisheries – SurveyWhere 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 SensingRemote 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 DetectionFrontal Detection

Automated frontal detection algorithm

Measure gradients near fronts

Measure distance between catch and fronts

Deg C25

17

Sea Surface Temperature9 April 2005

Detection of Bathymetric GradientsDetection of Bathymetric Gradients

84°W

84°W

83°W

83°W

82°W

82°W

26°N 26°N

27°N 27°N

28°N 28°N

29°N 29°N

Tampa Bay

CharlotteHarbor

0 10050 Kilometers

Areas of greater bathymetric gradient may influence frontal stabilityAreas of greater bathymetric gradient may influence frontal stability

Bathymetry Gradients and Sustained FrontsBathymetry Gradients and Sustained Fronts

Sea surface temperature Chlorophyll a

Locations where fronts are more likely to occur may Locations where fronts are more likely to occur may aggregate more kingfishaggregate more kingfish

84°W

84°W

83°W

83°W

82°W

82°W

26°N 26°N

27°N 27°N

28°N 28°N

29°N 29°N

±

0 5025 Kilometers0 10050 Kilometers

sust_sst_g-mean

Value

High : 0.194173

Low : 0.0098555

High: 0.19

Low: 0.00

84°W

84°W

83°W

83°W

82°W

82°W

26°N 26°N

27°N 27°N

28°N 28°N

29°N 29°N

±

0 5025 Kilometers0 10050 Kilometers

sust_sst_g-mean

Value

High : 0.194173

Low : 0.0098555

High: 0.67

Low: 0.00

Physical OceanographyPhysical Oceanography University of South Florida buoy data

Wind Velocity Current Velocity

Strong and variable winds and currents occurred Strong and variable winds and currents occurred throughout this studythroughout this study

i. j.

Turbidity at Fishing LocationsTurbidity at Fishing Locations

10-2

10-1

100

101

102

0

1

2

3

4

5

6

7

8

9

10

log nLw 443 (mW cm-2 m-1 sr-1)

CP

UE

Spring 04

Fall 04

Spring 05

Fall 05

c.

CP

UE

Turbidity at Fishing LocationsTurbidity at Fishing Locations

High fishing success associated with intermediate turbidity High fishing success associated with intermediate turbidity

10-2

10-1

100

101

102

0

1

2

3

4

5

6

7

8

9

10

log nLw 443 (mW cm-2 m-1 sr-1)

CP

UE

Spring 04

Fall 04

Spring 05

Fall 05

c.

CP

UE

Turbidity at Fishing LocationsTurbidity at Fishing Locations

Low fishing success and turbid water during fall 2005Low fishing success and turbid water during fall 2005

10-2

10-1

100

101

102

0

1

2

3

4

5

6

7

8

9

10

log nLw 443 (mW cm-2 m-1 sr-1)

CP

UE

Spring 04

Fall 04

Spring 05

Fall 05

c.

CP

UE

Effects of Fall 2005 Red TideEffects of Fall 2005 Red Tide

Reduced kingfish catchReduced kingfish catch Spring 2004: 444Spring 2004: 444 Fall 2004: 818Fall 2004: 818 Spring 2005: 538Spring 2005: 538 Fall 2005: 208Fall 2005: 208

Increased fishing w/ no baitfishIncreased 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 Increased turbidity + chlorophyll FLH fronts

November 12, 2005

Principal Component Regression AnalysisPrincipal Component Regression Analysis

Environmental factors influencing kingfish catch: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%)

ConclusionsConclusions

Relationships observed between:Relationships observed between: Bathymetry and frontsBathymetry and fronts Baitfish and fishing successBaitfish and fishing success Water clarity and fishing successWater clarity and fishing success

Red tide in fall 2005Red tide in fall 2005 FLH characterized featuresFLH characterized features Observed baitfish and kingfish abundanceObserved baitfish and kingfish abundance

High variability within fisheries data High variability within fisheries data Anglers Anglers Strong and variable windStrong and variable wind

RecommendationsRecommendations

Apply findings to other pelagic Apply findings to other pelagic migratory speciesmigratory species

Aid in fisheries managementAid in fisheries management Continue to strengthen link between Continue to strengthen link between

scientists and fisheries communityscientists and fisheries community

Continue to characterize seasonal physical processes Continue to characterize seasonal physical processes within the study area and relate to kingfish abundancewithin the study area and relate to kingfish abundance

Pop-up satellite tagsPop-up satellite tags Frontal probabilityFrontal probability