Project Insight: Tagging Billfish
*This post was originally uploaded on February 20th, 2019 on a website that has since been deleted. Posts from that website will be re-uploaded here at a later date.
Along with studying the fish communities around the FADs (Fish Aggregating Devices, or fast-food restaurants), we will also be placing hi-tech tags on sailfish and blue marlin off Costa Rica to track where they go for months at a time. The goal of this is to better understand how these fast fish move around depending on the environmental conditions (ocean temperature, ocean color, currents, bathymetry, or depth, etc.).
These fish likely swim long distances along Central America, following ideal ocean conditions and food availability. Along the way, they are likely to encounter many international and national fishing fleets. From recreational fisherman who release the fish alive after catching them, to long-line and purse seine fisherman who are likely targeting other species for food like tunas and Mahi-Mahi (dorado), but who will sell sailfish and marlin back at the dock if they are caught as well.
But what happens if a fast fish doesn't have to travel far for its next meal? Are these fast-food restaurants changing the behavior of the fish, and potentially reducing their chances of getting caught in commercial food fisheries? Or are these fast predators susceptible to exploitation by commercial fisheries when they are concentrated in small areas like on the FADs?
We are hoping that using satellite tags, along with our underwater video surveys of fish communities and behavior at the fast-food restaurants, we will begin to be able to answer some of these questions.