# Presentation: 063901

##      Influence of Satellite Observed Environmental Conditions     on Recreational King Mackerel Catches

**Further information**
- _cwall@marine.usf.edu__[u](mailto:cwall@marine.usf.edu)_

**Results**
- 19 tournaments surveyed 2004-2005: 415 interviews; 579 fishing locations; 1,599 fish hooked/landed
- Variable winds during the tournaments resulted in unstable ocean fronts
- Fall 2005:** **a** strong harmful algal bloom **coincided with** significantly decreased reported baitfish presence and king mackerel catch**
- Stable SST fronts were more strongly related to bathymetric gradients in the fall than the spring (*below left*); bottom gradients play smaller role in the fall for stable *nL**w*443 fronts (*below center*)
**Successful catch **depended on baitfish presence; **highest catch rates** were associated with **intermediate *****nL******w*****443 values** (0.7-1.0 mW cm-2 μm-1 sr-1) (*above, right*)
- Principal Component Analysis. The variance in CPUE accounted for by environmental parameters: distance to Chl front (38.0%), ***nL******w*****443 values (24.0%), Chl gradient (-15.7%), baitfish presence (11.8%),** distance to SST front (10.5%)

-      Influence of Satellite Observed Environmental Conditions     on Recreational King Mackerel Catches

-  • Carrie Wall1  • Frank Muller-Karger1,2  • Mitchell A. Roffer3 • Chuanmin Hu1

- 1 University of South Florida, College of Marine Science, St. Petersburg, Florida
- 2 University of Massachusetts Dartmouth, School for Marine Science & Technology
-    New Bedford, Massachusetts
- 3 Roffer’s Ocean Fishing and Forecasting Service, Inc., West Melbourne, Florida

**Abstract **
- Partial results of a three-year study (2004-2006) on the effect of the ocean environment on the catch rate of king mackerel (*Scomberomorus cavalla*) are reviewed. **Catch statistics from fishing off west-central Florida were derived from 415 interviews conducted during 19 seasonal tournaments in April-May and October-November of 2004 and 2005.  Satellite data (infrared & ocean color - MODIS) from NASA’s Terra and Aqua, SeaStar (ocean color – SeaWiFS), and NOAA’s (infrared - AVHRR) constellation of polar orbiting satellites were used.** Automated algorithms to detect frontal features in satellite-derived sea surface temperature, chlorophyll concentration, water clarity, and fluorescence images, as well as, high-resolution bathymetry data were successfully adapted for coastal waters off west-central Florida coinciding with the tournament periods. Front detection using the MODIS chlorophyll fluorescence images proved to be the most useful in defining the boundaries of phytoplankton blooms compared to the chlorophyll and water clarity data. Local winds estimated from a USF Coastal Ocean Monitoring and Prediction System observing station were analyzed with the frontal data and bathymetric gradients to determine factors that influence oceanic frontal formation and stability
**Fishing success was highest in waters with intermediate water clarity, where baitfish were reported present, on the clearer side of the chlorophyll front.** Non-persistent winds recorded throughout the study period led to unstable, non-persistent ocean fronts. The working hypothesis that more fish and higher catch rates would be associated with the nearest front was not shown to be statistically significant as the distance of catch relative to the nearest front varied substantially. Also, a persistent harmful algal bloom event, clearly detected in ocean color satellite imagery during fall of 2005, coincided with reports of significantly decreased baitfish presence and king mackerel catch** in fall of that year.**
**The automatic front detection techniques applied here can be an important decision making tool for resource managers to evaluate coastal oceanographic features, daily over synoptic spatial scales, and understand changes in fish catch rate and location.**

**Conclusions and Recommendations**
-  Front detection algorithms were improved and applied to coastal waters
-  Distance of fishing to the nearest front varied substantially, particularly when wind and front position were variable
-  **Fishing success was highest near intermediate water clarity, where baitfish were present, on the clearer side **
**  ****of the Chl front**
-  **1 km****2**** resolution, daily remote sensing data aided in identifying relationships between the fisheries data and **
**  ****the environmental data**
-  Future studies should consider continued characterization of frontal probability; application of pop-up satellite tags
-   concurrent with baitfish surveys
-  Fisherman were educated about the use of satellite data when planning fishing trips
-  **We aim to continue to strengthen the link between scientists and fisheries communities**

- Study area (inset): 28°30’ N, 81°30’ W; 26° N, 84°30’ W

- King mackerel are opportunistic feeders, with distributions linked to **prey distribution and abundance**, which are affected by front location, circulation, water clarity and food

- MODIS sea surface temperature (**SST**), chlorophyll concentration (**Chl**), water clarity index (***nL******w*****443**), and fluorescence line height (**FLH**) images for 12 November 2005. Frontal zones (white lines) derived from each dataset are shown in coastal waters off Tampa Bay. Arrows indicate known area of harmful algal bloom, which persisted throughout 2005.

-  Conducted interviews with anglers at local recreational tournaments
-  Collected data: catch location, number, presence of forage fish, fishing effort (CPUE)

- This study is funded by NASA, NNGO4GF13G, and greatly supported by the Southern Kingfish Association and the Old Salt Fishing Foundation

**Background and Methods**

- Mean front gradients of SST (left) and *nL**w*443 (center) for spring (greys) and fall (blues) with relatively steep bathymetric gradients identified by front detection of bathymetry grid data (red line)