Focus on Current data with SportFishing Ocean-O

Introduction

In previous articles, we saw how to use surface temperature (SST), chlorophyll, and SSH (altimetry) data to find the best fishing spots. In this article, we will explore the last piece of data included in the SportFishing Ocean-O package: Currents.

A marlin leaping out of the ocean waters, splashing as it dives back into the sea.
Photo Richard Hamilton

This final article will show you how to interpret current data to optimize your trips and maximize your chances of success.

Display Currents in TZ iBoat

To identify ideal fishing areas based on currents, here’s how to activate the Currents data display in TZ iBoat. Start by activating the SportFishing Ocean-O layer to display the data. SportFishing toggle

Next, activate the Currents layer to display currents as particles.

Icon representing current particles in ocean data visualization.

Definition and importance of currents

Ocean currents have a significant influence on the distribution of nutrients and therefore the presence of fish. Understanding them means identifying where prey—and predators—are concentrated. In this chapter, discover how different types of currents—strong, swirling, or converging—can transform an ordinary area into a real fishing hotspot.

Strong currents

In sport fishing, the currents that are too strong are generally unfavorable. When the water flows too quickly, nutrients tend to disperse, reducing the concentration of prey and, consequently, the activity of predatory fish.

In TZ iBoat, these strong currents are easy to spot. They appear on the screen as large arrows or very distinct particles, indicating a high current speed.

Comparison of two smartphone screens showing ocean current data, with one screen indicating high currents using particle visuals and the other using arrows.
Left: Displaying currents as particles in TZ iBoat. | Right: Display of currents as arrows in TZ iBoat.

To maximize your chances, it is often best to focus on areas where the currents are moderate, as these are more conducive to fish presence.

Eddies (ocean eddies)

Eddies are small whirlpools that form when large ocean currents break away or change direction. They can take different shapes: complete circles, semicircles, or ripples.

Let’s take a closer look at how eddies form from a theoretical perspective:

Illustration showing the flow of ocean currents, including their main direction, areas of varying temperatures, and the formation of eddies.

These eddies are very interesting for fishing because they bring nutrients up from the depths (a phenomenon called upwelling), which attracts plankton, then small fish, and finally predators.

A smartphone screen displaying ocean current data with black arrows indicating current direction, and a highlighted area labeled 'Eddie' in red.
Example of a cold Eddie in the Northern Hemisphere.

Eddies act as veritable mobile mini ecosystems, where feeding activity is often intense. They are therefore areas with high potential for spotting fish.

Note: their direction of rotation depends on the hemisphere. In the Northern Hemisphere, cold eddies (rich in nutrients) rotate counterclockwise. In the Southern Hemisphere, it is the opposite: they rotate clockwise.

Current convergence zones

Convergence zones are areas where several ocean currents meet. They play a key role in ocean productivity. These zones concentrate nutrients, plankton, and floating debris (such as algae, moss, or dead wood), creating an ideal environment for phytoplankton to thrive. This abundance attracts forage fish, which in turn attract large predators such as tuna, swordfish, and dolphinfish. These zones are therefore hotspots that should be targeted as a priority, as they concentrate the entire food chain.

Two smartphone screens displaying ocean current maps with marked convergence zones, showing swirling currents and navigational icons.
Left: Example of a convergence zone in western Mexico. | Right: Example of a convergence zone in the Gulf of Mexico.

The influence of underwater topography on vertical currents

The structure of the seabed (or bottom structure) plays a decisive role in current dynamics, particularly in the generation of vertical upwelling currents, also known as upwellings. These upwellings of cold, nutrient-rich water have a direct impact on the biological productivity of the areas concerned.

Illustration showing the influence of bottom structure on vertical currents, with arrows indicating horizontal current and upwelling near a submarine canyon.

Effect of underwater canyons

Underwater canyons, which are deep gorges in the continental shelf, act as natural funnels. When horizontal currents encounter these steep reliefs, some of the water is forced upward, creating a vertical upwelling. This phenomenon is amplified by the geometry of the canyon, its narrow walls, and its varying depth, which promote eddy movements and turbulence.

A smartphone displaying a detailed map of underwater topography, featuring contour lines indicating depth, with various depth measurements shown.
Bottom Structure in TZ iBoat.

Biological consequences

These vertical currents bring nutrients accumulated in deep layers to the surface, stimulating the growth of phytoplankton. This explosion of life at the base of the food chain attracts forage fish, followed by predators such as tuna, swordfish, and dolphinfish.

Interest in fishing

For fishermen, areas located near underwater canyons are therefore strategic locations. They offer conditions that are conducive to fish feeding activity. These areas often appear as “hotspots” on marine productivity maps or in data combining currents and chlorophyll.

Conclusion

Interpreting ocean currents is a key step in refining your fishing strategy. These currents directly influence the distribution of sea surface temperature (SST), sea surface height (SSH), and chlorophyll concentration—all factors that determine the presence of marine life. The fronts, eddies, and convergence zones created by these dynamics are valuable indicators to monitor.

By combining the data offered in SportFishing Ocean-O, you get a comprehensive view of high-potential areas. This integrated approach allows you to optimize your trips and increase your chances of success.

This article concludes our series on using oceanographic data in the SportFishing Ocean-O pack.

Happy Fishing !