Stream to Salt VI: Understanding Tides

Written by: Evan Jones

The Stream to Salt series is designed to help anglers of all abilities identify and overcome specific challenges arising from subconsciously applying “trout brain” to saltwater fly fishing. The goal is not simply to provide a list of new habits to memorize, but also to foster a deeper understanding of why some of the habits and assumptions developed while trout fishing can be detrimental in the salt, and how to adjust. 

The effects of tidal flow on saltwater fish are complex, nuanced, and highly variable. Anglers can spend years fishing the same areas and still be surprised by unexpected conditions, so those who are new to the salt likely have a shallow learning curve ahead when it comes to understanding tides. While it may be tempting for trout anglers to compare high/low tides to high/low water levels on rivers or lakes back home–and to approach each one similarly–that can lead to some misconceptions and missed opportunities throughout the tide cycle. Without trying to cover every imaginable scenario, here are some general tips about the ways tides can influence fish behavior to help speed your learning process.

Fish rely on tidal flows to feed, whether by gaining access to the shallows as the water rises, or by falling back into choke points and waiting for currents to carry food to them as the water lowers. To find fish, then, you have to know what the tide is doing at all times. Charts and apps are fine to get a general sense, but because there are so many variables, nothing beats direct observation. 

The high-tide mark is often visible as a dark stain on dock pilings, seawalls, or mangrove roots, giving you an important visual clue about the current tide level. Likewise, areas that are exposed at low tide usually have a different type of bottom covering than areas that stay submerged throughout the tidal cycle. For example, eelgrass will grow over areas that are occasionally dry, while turtlegrass is viable only in areas that remain constantly wet, clearly marking the low-tide line. Once you’ve determined how high the water is, you can figure out whether the tide is incoming or outgoing by simply jamming a stick into the beach right at the waterline and waiting 15 to 20 minutes before checking it again. 

Neither dead-low tide nor dead-high tide are typically productive times to fish. When the water isn’t moving, neither the food nor the fish are moving. But that’s not to imply that more tidal flow is always better. In fact, the opposite can be true for fly anglers, particularly when you’re fishing choke points during outgoing tide, because strong currents can make it too difficult to get a fly down to feeding fish. There tends to be a “sweet spot” during both incoming and outgoing tides, when the current is strong enough for fish to line up and feed, but not so strong that it pushes your fly back up toward the surface.  

Speaking of sweet spots, crabs and other crustaceans can actually sense the height of the water above them by the pressure it creates, and once the water level reaches a height that could allow predatory fish to reach them, they’ll hide in burrows until the water lowers to a safe level again. But there is often a brief window during which the tide is just barely high enough for the boldest predator fish to push into the crabs’ habitat, but not quite high enough to alert the crabs that it’s time to hide. This lag results in a brief angling opportunity on both the incoming and outgoing tide that unaware anglers often miss, but can be remarkably productive when timed just right.

Evan Jones is the assistant editor of the Orvis Fly Fishing blog. He spent a decade living on the Florida coast and now makes his home on the Front Range of Colorado.