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rain impact on fishing indian river lagoon

How does significant rainfall impact our inshore fishery? Knox Robinson gives the run-down on runoff and other implications of heavy rain on the lagoon.

Heavy Rains & the Indian River Lagoon: What It Means for Fishing

This past weekend, the inclement weather kept me off the water, so I decided to use some time indoors to do a little research into the effects of heavy rains on our local inshore fishery. One skill that I have mastered over the past 12 years of being an educator is to be able to speed read a variety of sources, and turn those into digestible pieces of information for an audience, so I figured if I am stuck inside while the wind howls and the rain pours, I might as well put that skill to use for our Spacefish audience.

It’s no secret that we’ve had some serious rain lately, and while the fresh water is welcome in some ways, it can be tough on our lagoon. Heavy rains don’t just raise water levels — they wash all kinds of stuff into the river system, and that impacts fishing in a big way.

UPDATE: I thought I was not going to be able to fish at all this weekend. After sending over the original draft of this report, the weather cleared, I got out and looked at a couple of potential launch spots in Melbourne. The water levels Crane Creek, and the Eau Gallie River are way, way, way up. Docks are almost underwater, boat ramps are practically underwater, and the usual shoreline at Ballard Park is about 10 yards out from where the water had overflowed onto the grass as of Sunday afternoon.I launched out of Ballard Park and went south to tuck in against the shoreline to protect from the gusting east winds. I fished for about an hour, and 15 minutes. I caught a small Snook, and a Ladyfish on topwater. I also saw a few Snook hanging out near the surface after the rain cleared up. I had a nice Snook blow up on my topwater plug, but I got over-excited and didn’t get a good hookset on her.

Heavy Rains & the Lagoon’s Chain Reaction

When the skies open up, the Indian River Lagoon feels it in a big way. Heavy rains don’t just freshen the water — they wash in nutrients, bacteria, and pollutants that set off a domino effect across the ecosystem. Fertilizers, septic runoff, and animal waste fuel harmful algal blooms, which rob the water of oxygen, block sunlight, and choke out seagrass beds. That loss of seagrass means less food for manatees, less habitat for fish, and a weakened foundation for the lagoon’s entire food web.

The rains also stir up muck from the bottom — a stew of decomposed matter laced with metals like copper and zinc that are toxic to marine life. Add in freshwater surges from the storm run-off, and salinity levels drop fast, stressing everything from shrimp to dolphins.

On top of that, aging sewer systems and storm drains often get overwhelmed, spilling sewage and washing urban debris straight into the water. The result is poor water quality, habitat loss, and a chain reaction of stress for the entire cast of characters that call the Indian River Lagoon home.

Fishing the Lagoon After Heavy Rains

For anglers in Brevard, heavy rains are a double-edged sword. In the short term, rain can actually fire up the bite. Cloud cover and stirred-up water create low-light, high-oxygen conditions that get fish moving. Runoff flushes food into the system, drawing baitfish — and the predators that chase them — to culverts, spillways, and other runoff points. Snook, Redfish, and Trout often take advantage, hunting more aggressively when visibility is low.

But the story changes a few days later. As the runoff settles in, water quality starts to slide in a negative direction. Fertilizers, pesticides, pet waste, and other pollutants feed algae blooms that cloud the water and drain oxygen. Salinity levels drop as freshwater lingers, and many fish scatter from their usual haunts, pushing toward deeper channels, inlets, or even offshore in search of more stable water. Visibility tanks, seagrass suffers, and the bite gets tougher.

So how should anglers adjust?

Fish the rain: Work spillways and culverts during and right after storms, when bait is flushed in and predators are active.
Go deeper after: Once conditions degrade, shift to deeper channels, drop-offs, or inlets where salinity and oxygen are more stable.
Make some noise: In the glassy calm that follows a storm, topwater plugs with extra vibration can help get attention. In dirty water conditions darker baits, as well as those that vibrate, and create some flash may be more effective.
Be patient: After major downpours, sometimes the best option is to wait a few days for the water to settle and clear.

Heavy rains may shake things up, but with a little strategy — and the right timing — you can turn the storm into an opportunity instead of a setback.

Kayaks by Bo

Speaking of adapting, if you’ve been thinking about upgrading your fishing setup, Kayaks by Bo has been sharing some awesome news on their social media pages: they’re currently buying and selling used kayaks! That means you can trade in your old ride, snag a deal on a pre-loved boat, or finally grab that second kayak you’ve been eyeing for friends and family. It’s a smart way to get on the water — especially after a big rain, when being mobile and able to reach cleaner water can make all the difference.