(At the Captian's meeting in Clearwater in April 2006
Carrie presented anglers with important red tide information)

by Carrie Wall, M.S. Biological Oceanography, University of South Florida College of Marine Science

It was April 2004. The king mackerel were beginning their annual journey from their winter haven in the Florida Keys to their summer home off Louisiana and the Florida Panhandle. The kingfish were on the move! And I was just starting in the master’s program in the College of Marine Science at the University of South Florida. I had been invited to work with Roffer’s Ocean Fishing Forecasting Service, Inc (ROFFSTM), who had partnered with the Institute for Marine Remote Sensing (IMaRS) at USF to figure out if one can study where the kingfish are using satellites – they had received funding from NASA to advance the science of looking at fish habitat from outer space.

As a biologist, I thought this was an incredible opportunity to learn about the ocean – but I was taking a big leap into the field of fisheries research and remote sensing so I had many questions, like: How can you measure the oceans from space? How would I relate that to fish? And how in the world do satellites work?

To answer these questions and others, I first had to study where the kingfish are. Well, there is no better way to find that out than to talk to the anglers who chase after them – and the best place to do this is at local kingfish

tournaments. The study I designed called for comparing the results from anglers to satellite data collected by NASA and NOAA satellite sensors. NASA is the National Aeronautics and Space Administration, and NOAA is the National Oceanic and Atmospheric Administration. These are the government agencies that launch satellites to look at Earth.

The satellite data I used came from the USF IMaRS (www.imars.usf.edu). They have antennas that collect images scanned by the satellites as they zip over Florida during an orbit - it takes about one and a half hours for each satellite to fly around the Earth over the poles.

One satellite sensor measures the infrared energy that radiates from the surface upwards, from the ocean out to space. I used this to measure the surface temperature of the Gulf water – it is the same technology used to measure body temperature, with an infrared thermometer placed against a child’s ear.

The other satellite cameras measure the color of the ocean. Ocean color has a lot of information, especially about the clarity of the water and the amount of chlorophyll (a pigment of phytoplankton, or tiny drifting ocean plants, that are the food for small fish).

I figured that these variables affect the location and movement of fish, and geared up to test the idea (my hypothesis) that fish concentrate near fronts. Fronts in the ocean are areas of sharp changes in either water temperature, transparency, or the amount of food available to baitfish. The front itself is the boundary between colder and warmer waters, or clearer and more turbid waters. These can form when offshore waters move into the coast and meet waters coming out of an estuary like Tampa Bay. They can also form over reefs or ledges that stretch along the coast on the bottom.

Recreational kingfish tournaments in west-central Florida are held in the spring (April to May) and in the fall (October to November) in Clearwater, Madeira Beach, Treasure Island, Tierra Verde, and Sarasota. The tournaments are planned around the anticipated arrival of the kingfish through the west-central Florida waters during their seasonal migration up and down the eastern Gulf of Mexico.

The key to my research was to work with the anglers. So I worked closely with the tournament organizers, Mr. Jack and Mrs. Deona Holmes of the Southern Kingfish Association, Mr. Tom Verdensky and Ms. Jill Foraker of the Old Salt Fishing Foundation, and Mr. Doyce Mathis of Treasure Island Charities. I also spent a lot of time explaining my project to the anglers, and asking them for their ideas on how to make this work.

(Carrie Wall gathering Kingfish data)

After a long day out on the Gulf, anglers bring in their candidate prize-winning kingfish to the weigh-in station. That is where my team of student helpers came into action: we interviewed a fisherman or fisherwoman from each fishing boat as they lined up to weigh their catch. We collected information on where and when they had kingfish biting, how long they fished in one spot, the number of kingfish caught, and whether they saw baitfish or not. We asked for as much detail as possible, a tall order when there are great prizes on the line. But the help we got from the anglers was wonderful and the data collected at the tournaments provided the backbone of this research.

We had 22 tournaments over the spring and fall of 2004 and 2005, with nearly 600 interviews in which anglers reported a total of 2,008 kingfish hooked or landed at 792 fishing locations. We found that trolling was the preferred fishing method at 74% of the fishing locations, and it accounted for 70% of the kingfish catch. Fishing while anchored accounted for 17% of the fishing locations and 22% of the catch, and drifting accounted for 4% of the fishing locations and 2% of the catch. Some people combined techniques, and this accounted for 3% of the fishing locations and 4% of the catch. And 2% of the interviews, accounting for 2% of the catch, did not have a recorded fishing method.

Frequently, throughout this study, fishermen have asked me to tell the secret of where the big kingfish were caught during the last tournament. They ask where Pennywise, a very successful fishing team in 2005, fished. I have been unfazed by various offers and been unwavering in keeping my promise, repeated at every Captain’s meeting, that the data each angler gives me is TOP SECRET-MY EYES ONLY – and that I will use it for scientific purposes only.

Using the NOAA and NASA satellites, I measured the temperature, water clarity, and chlorophyll concentrations at each fishing location reported by the anglers. I combined all this information using a computer program called a Geographic Information System (GIS), designed to make digital maps. I identified oceanic fronts, and used the GIS program to calculate the distance from each fishing location to each front I found in each satellite picture. I measured the strength of the front (how quickly the temperature changed from warm to cold across a front) and checked the type of bottom (flat bottom, reef, wreck, or shipping channel).

All these parameters were thrown into the GIS program to help me figure out which factors helped increase fishing success.

Red Tide
A frequent visitor to our coast of Florida is a little plant called Karenia brevis. This tiny plant is toxic, and it frequently grows to huge concentrations off Tampa Bay and to the south along the west coast of Florida. These are our red tides.

In 2005, we had a particularly strong and long-lasting red tide. This red tide left a stinking mess of dead algae, sponges, birds, turtles and marine mammals along our coast, and many people suffered respiratory problems. Our coast was also littered with many, many dead fish that year because of the toxicity of the red tide. As the red tide rotted, bacteria decomposing all this biomass consumed the life-sustaining oxygen dissolved in the water. We ended up with very low (hypoxic) and, in some places, zero (anoxic) oxygen concentrations along the coast. The result was even more dead fish.

Despite this red tide, anglers went out with enthusiasm to fish in 2005 like every year, but caught especially few kingfish in the fall of 2005 kingfish and saw very few baitfish. During this season, anglers caught one kingfish about every two hours, when the previous fall they caught about one kingfish per hour. The satellite images showed much higher concentrations of plants during the fall of 2005, in waters with very low clarity, in a red tide that stretched over some 68,000 km2 (a little over 26 thousand miles squared, an area slightly larger than West Virginia). The satellite data were definitely an important tool to measure the size and location of the red tide.

The Results
It took me two years to complete my study, to sift through all the data, finish my thesis and graduate in December of 2006. As a result of all that work, I found that marine fronts off the west coast of Florida move very fast because of the constant changes in the wind and ocean currents. So, most of the kingfish catch had nothing to do with the position of a front. I concluded that baitfish and kingfish don’t have time to aggregate near fronts because these oceanographic features move so fast.

What I did find is that there is a relationship between baitfish presence and water clarity. Baitfish prefer intermediate water clarity, not completely clear or completely turbid waters. And where the satellite identified waters that had intermediate clarity, I found that anglers were more successful catching kingfish. Waters that have an intermediate clarity contain plenty of algae (chlorophyll), and attract baitfish and then kingfish, while at the same time still allowing the kingfish to find their prey by sight.

Anglers have long realized that dumping chum into the water lures kingfish making them easier to catch. I can identify with the kingfish, because graduate students are also drawn to abundant sources of free food.

As for knowing where the big kingfish were caught - my conclusion is that there is no single location, or single primary environmental condition, that will help an angler increase catch rates. The ocean is changing all the time, but the kingfish will migrate through the area every year. Several factors play a role in defining where a kingfish will be at any one time, and the availability of baitfish and relatively (but not completely) clear water seems to be the combination of factors that increase the chances of successful kingfish fishing.

Lastly, the most important things are that we practice safe boating and environmentally friendly fishing, taking from the ocean only what we need. Learning about the ocean and how it is changing helps us all be better fishermen and fisherwomen, and makes sure there will be fish to catch next year!

Acknowledgements:
This project was a collaborative effort between USF and Dr. Frank Muller-Karger, Roffer’s Ocean Fishing Forecasting Service, Inc (ROFFSTM) and Dr. Mitchell Roffer, and NASA. Funding was also provided by the Alyesworth Foundation for the Advancement of Marine Sciences, Inc. and the Old Salt Fishing Foundation. I am deeply grateful to Jack and Deona Holmes of SKA; Tom Verdensky and Jill Foraker of OSFF; Bob and Dawn Alyesworth of the Alyesworth Foundation, Doyce Mathis of Treasure Island Charities; and Billy Moore and Steve Fennell of Billy’s Stone Crab Restaurant.

The Southern Kingfish Association’s Marine Science Fellowship was established in 2005 to provide funds to offer support for outstanding graduate students in the College of Marine Science at the University of South Florida. Through the generous donations of our members and our Corporate Partners the SKA was able to provide $100,000, $20,000 a year over five years, to further our understanding of this precious natural resource. A portion of these funds were allocated to Carrie Wall’s study of king mackerel during 2005 and 2006. We were lucky enough to catch up with Carrie and get some of her impressions of her two years on the tournament trail.

Angler:
Carrie, you recorded information from 22 tournaments and almost 600 interviews, that’s quite a lot of work! Did you manage to have a little fun working on the trail with the SKA anglers?

Carrie Wall:
Yes, I absolutely did. A lot of the work in the project came from preparing for and attending the tournaments, but it was also the most enjoyable part. I went to every Captain’s meeting and introduced myself to all the fishermen, letting them know what I was going to be doing the next day at the tournament. Just being able to talk with them so much was a lot of fun.

A:
In the introduction to your synopsis, you mentioned that this was a “big leap” for you.

CW:
It was a big jump. I did have a pretty strong background in marine science, my Bachelor’s Degree was in biology, but a lot of the work that I did towards that degree was focused on wetland areas and estuaries. After I got out of college, I did a couple of internships that focused on science education and marine mammal research. So I really didn’t have any prior experience with fisheries science or, more specifically, fishing. So it was quite a bit of a jump for me. I was also delving into remote sensing using satellites for the first time. Fortunately, I was able to adapt and I had a lot of help and support from the angling community, which made my job so much easier.

A:
Were there any data or trends that you found immediately surprising when you started interviewing at tournaments?

CW:
What we were expecting to find was an increase in fishing success, say you catch more kingfish per hour, in areas that are near oceanic fronts or sharp changes in gradients, whether it be temperature or ocean color. As soon as I started looking at the data I found nearly the exact opposite, there was no correlation at all. That threw us on our heels a little bit. The important part of that is to not only identify that the results differed from expectations, but to find out why.

Certainly when I’m doing interviews a lot of the anglers have their own special spots or inside knowledge that they think helps them catch more fish; it’s always interesting to talk to them about that. A lot of these guys would always go for the bait or they would go for certain ocean colors. The anglers were a little inconsistent in what they believed was right, and it didn’t necessarily impede them or help them catch fish.

A:
Do you believe that if conditions had been ideal for this study and there had been more events with very slow moving fronts in the immediate area that the results would have been more as predicted?

CW:
I would certainly think so. Based on past research that is certainly that theory that has been proven.

A:
The 2005 red tide certainly had to make some aspects of the study frustrating for you and your team.

CW:
Not only myself, but the anglers were not a happy bunch. Nobody could find bait, and that made for a pretty slow tournament. It was a little interesting on my end as I was able to record the impact, or at least what we were observing as coinciding with the red tide, upon the king mackerel catch rate. So it was very interesting, however, I certainly feel for all the anglers who could not find bait.

A:
Here at the magazine we sometimes have problems squeezing information out of tight-lipped fishermen, especially on day one. Did you have any difficulty with some anglers being less than forthcoming?

CW:
Oh, absolutely. I’ve had them much less than forthcoming. Some straight up denied me or walked away, and that’s fine. I’m definitely a new person in the community and it did take some time for me to gain a lot of their trust. But I was more than happy to take that challenge on. These guys just come in to weigh their fish and they have been up since three or four in the morning. They’ve been beaten up all day out in the sun and the water, and maybe that beer is beginning to wear off, and the only thing that’s keeping them from their next beer is me, asking questions. So certainly I ran into some guys that weren’t willing, but on the whole everyone was helpful.

A:
You mentioned Penny Wise in your synopsis. Were there any other teams that distinguished themselves or that you just saw an awful lot of at the scales?

CW:
Well, certainly in the last year, 2005, Penny Wise was very prominent. In 2004, Et Tu Brute was a very good boat, that was John Smith’s team, and Hook’er was also at the scales a lot. It’s always good to have a couple boats that are regularly weighing in when I’m interviewing because it helps create some consistency in the fisheries data.

A:
In conclusion, is there any one kingfishing truth or fishing tip that you picked up during the study that you’d like to share with the SKA?

CW:
Really, the most important thing is to fish in an area where there is bait. This was very evident during the red tide. If you couldn’t find bait, there certainly weren’t going to be kingfish. These guys are visual predators, and they’re going to be looking for food pretty constantly. A relative clarity in the water is also important. If it’s really clear water, there’s most likely not going to be any bait. If it’s really murky water there may be bait there, but the kingfish aren’t going to be able to see it.

A:
Well, Carrie, thank you very much for your two years of hard work and taking the time to speak with our readers.

CW:
Thank you to the SKA for the incredible support provided since the very beginning of this study and for helping fund this and future scientific research at the USF College of Marine Science. In addition, I would like to thank all the willing fishermen for helping make this study a success.