Most successful offshore fishermen rely on Sea Surface Temperature (SST) and taken by satellites for trip-planning purposes
It's a vast ocean out there and SST imagery helps captains locate those areas that are more likely to hold fish. Rather than burning fuel in search of good water, captains can use this modern technology to find potential hot spots before they ever leave the dock.
For many recreational fishermen, however, figuring out how to use satellite imagery to identify the best fishing areas is still a bit of a mystery. Using SST imagery does not require any advance degree, it's actually pretty straightforward. You just need to know the basics, which are outlined below.
Plenty of anglers simply head out to an area where they caught fish in the past or target an area where they heard the fish were biting the day or weekend before. While there's nothing wrong with this approach to fishing, particularly if conditions have remained stable or clouds have prevented any decent satellite imagery becoming available, conditions often change on a daily basis, if not hourly. There is probably another area that might be equally productive where the rest of the fleet isn't fishing and you can find that spot using satellite imagery. With a little practice, anyone can increase their chances of getting a bite by studying satellite charts for a few days before heading out on the water.
In this article we'll focus on identifying potential hot spots using satellite imagery. There are numerous factors to consider when identifying the best areas and times to target offshore game fish such as mahimahi, tuna and billfish:
1. Water Temperature
2. Water Clarity
3. Location of Structure
4. Altimetry (sea surface height)
5. Current direction
6. Movement or rotation of bodies of water
7. Thermocline depth
9. Wind strength and direction
10. Tides, moon phase, moonrise and moonset
All of the factors mentioned above play into billfish movements. For this article we're going to simplify (perhaps over-simplify) the process and focus on the absolute basics that will help you find more fish. The basics include water temperature, water clarity and structure.
Rips are visible disturbances on the water's surface that appear as long, narrow bands of calm water bracketed on either side by rough water.
Rips form at or near temperature boundaries. These boundaries are called soft edges when the change across them is only 1/2°F to 1°F, and hard edges when the change is 2°F to 4°F or more.
The rough water at hard edge rips is more pronounced than that at soft edges.
Plankton gathers along temperature boundaries, setting up a food chain that draws bait to the area. NOTE: Plankton tends to concentrate on the cool side of a rip. This is because coastal water has a higher nutrient content and lower salinity level than Gulf Stream core water. The higher nutrient content in coastal water provides plankton with a food source, and the higher salinity level in Gulf Stream water makes this water denser than coastal water, in effect creating a barrier that the floating plankton cannot cross. Because plankton (and the nutrients on which it feeds) clouds the water, sight oriented hunters like marlin and tuna will tend to stay on the warm side of rips.
Floating weeds and debris will collect in the calm area of rips. Floating debris attracts bait, which attract game fish. The shade from floating debris also attracts some game fish, especially dolphin.
Temperature boundaries, especially hard edges, can act as a "wall" when the temperature on one side falls within a game fish's comfort range and that on the other side does not. Game fish will tend to move along the these edges when they encounter them instead of crossing them.
The most productive rips are those over good bottom structure. These should be explored first.
When you encounter rips along the edge of the Gulf Stream or one of its edge features (see below), it is often most productive to continue running perpendicular to those first rips, watching subsequent rips for better formed weed lines and/or signs of actively feeding fish, such as feeding birds.
Concentrate on rips containing floating debris and/or bait. If there have been reports of weed lines in an area, remember that things are moving out there. The western edge of the Gulf Stream has its fastest current, which is north at between 2 and 4 knots.
Weed lines that are not holding bait seldom hold gamefish. Always pull up to a weed line and check for bait before beginning to fish it.
Lures should be trolled along the edge of rips. Because the Gulf Stream flows north, and fish tend to swim with the current, trolling from south to north along rips gives lures a more natural presentation when that rip is along the edge of the Gulf Stream. Rips along the western edges of fingers or warm eddies, however, should be trolled from north to south because the currents in these features move in a circular counterclockwise direction.