Mote Marine Laboratory

On The Line with Aaron Adams, Ph.D.

Using the right technique for the right season

The subtropics are a great mix of the tropics to the south and the warm-temperate climate to the north, and if you want to catch fish in the subtropics, you need to understand how these merging environments affect them.

From my work studying how fish use different habitats at different times of the year – and as an avid fly fisherman I’ve learned a few things: If you want to catch a snook in Belize, for example, you can use the same strategy all year. But if you’re a snooker in south-central Florida, the northern extent of that fish’s range, you must change your ways with the seasons.

In the tropics, water temperature stays pretty much the same – from the upper 80s to the mid-70s, and in some places, there isn’t even that much variation. The subtropical waters of Charlotte Harbor, on the other hand, can bounce from the upper 80s in summer to the mid-50s in winter. And when winter cold fronts blow through, water temperature can drop so quickly that fish, including snook, can die of cold shock.

Because of the overlap in temperatures between tropical and subtropical, and subtropical and warm-temperate regions, there is a considerable amount of overlap of both fish habitats and species, which means that if you know snook use ambush to catch prey by waiting in mangrove shadows for an unsuspecting pinfish to pass by in one place, they’ll do it in another. Anglers in Southwest Florida and Belize can do equally well by casting into the shadows of a mangrove-lined shoreline.

But observant anglers also need to employ some of the differences in these regions to maximize their fishing strategies. These differences range from the way that similar habitats function, to the behavior of some gamefish species that range across different environments.

Let’s use snook as an example. In south-central Florida, snook undergo notable seasonal changes in behavior. They have the highest activity in warm summer months, and the lowest activity nearly semi-dormant at times during winter months. Their seasonal behavior variations in Central America are minimal in comparison.

Since fish are cold-blooded, temperature is a controlling factor in their distribution. That’s why you generally don’t find snook north of Tampa Bay, or striped bass south of northern Florida. Each species has a range of temperatures that it can tolerate, and within this tolerance, each species has a preferred temperature range. A species is most active, with more feeding, growth and energy, within its preferred temperature range. When the water temperature exceeds or drops below a particular species’ range, fish often become lethargic. Learning those tolerances for your favorite gamefish will go a long way toward helping you choose locations, times of day, and seasons where you are most likely to find fish ready to take the bait.

But there’s a catch: How a fish reacts to today’s temperature also depends on what temperatures that fish was exposed to yesterday, and even for some days before. Gradual changes over days or weeks influence a fish differently than a rapid temperature change in one day. Usually slower changes result in better fishing, but sometimes a rapid temperature change will stimulate a feeding rush by gamefish.

Since temperatures vary by season and by region, knowing the local nuances can help you be a more effective – and successful – angler. A good strategy is reading up on your favorite species to learn their preferred temperature ranges, regional life cycles and habitat use. You can also seek tips from more experienced anglers and at local bait shops. Or you can employ one of my favorite methods – practice, practice, practice.

Dr. Aaron Adams, manager of Mote’s Fisheries Habitat Ecology Program in the Center for Fisheries Enhancement, has published articles in Saltwater Fly Fishing magazine. His book, “Fisherman’s Coast,” is an angler’s guide to marine warm-water gamefish and their habitats.

Learn more about: Fisheries Enhancement