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Fish Migrations

Are the fish mnigrating becuase of the water temperature?

From , former About.com Guide

Fish Migrations

Whiting Fishing

Photo by Ron Brooks
It’s interesting to see the reversal situations that occur each year up and down the Atlantic coast. I’m talking about fish in particular and where they can be found at any given point in time.

Here’s what I’m talking about. In South Florida, the big bite is on for sailfish, king mackerel, Spanish mackerel, and bluefish. Baitfish and mullet are everywhere, and the dolphin (mahi mahi) have become scarce. Off of New York, you won’t find any of these fish this time of year. In fact, it’s hard to find anyone even fishing this time of year in the northern areas of the country! Their boats have been winterized and are in storage!

But in the summer, these same fish, along with the baitfish, that were in South Florida can be found much farther north. In my experience, water temperature is the key. Fish migrate primarily to find more temperate water.

One reader argued that fish are cold blooded and therefore are not affected by water temperature. Biologists actually agree with him to a point, although the one I spoke with said that in actuality some fish migrate for reasons that we simply do not understand. All I can tell you is that I find these fish in warm water, and I don’t find them in cold water!

Whether for spawning, or nature’s way of spreading the species, or seeking food, many fish do migrate. I look forward every spring to the manta rays that show up along the Florida coast, just off the beaches. They are headed north, and right along with them are the cobia. The manta has no teeth and feeds on plankton, so they it’s not like the cobia are behaving like a remora on a shark – feeding on the sharks leftover tidbits. But, until the mantas show up, you will be hard pressed to find a cobia.

The interesting part is that you can follow their migration by tracking the water temperature. 70 degrees Fahrenheit is the key. Once the water reaches that mark, the mantas and cobia will be found, heading north along the beaches. Is the colder water too uncomfortable for them? Who knows – not even my biologist friend could tell me for sure. All I can tell you is that I can base my fishing success or lack of it on water temperature.

Ask any serious billfish angler whether water temperature makes a difference, and you will quickly see that they fish the temperature breaks, because the fish tend to run along those breaks. They look for Gulfstream currents and eddies – where warmer water mixes with colder water.

In the winter, I can tell you that the seatrout move to deep holes when the surface water temperature drops – they become lethargic and move very little. Snook, found in Texas and Florida will die when the water temperature drops below 56 degrees for any length of time. After several years of warmer than normal winters, snook had made their way north along the Florida coast to areas they normally do not inhabit. Then – bang – a really big cold front that dropped water temperatures into the forties killed literally thousands of them overnight. That was in 2010, and the season on them remains closed in most parts of Florida. The fish simply could not get back to warmer water quickly enough.

Grouper and red snapper along the Atlantic coast move in close to shore or farther offshore all year long. Are they moving because the food moved, or because the water temperature changed? And if they move because the food moved, did the food move because of the water temperature?

I know that I can catch certain fish in the winter and other fish in the summer. In south Florida the fishing is great year round because of the trade off in migrations. In the northern climes, fishing sort of comes to a halt during the cold months because most of the fish have moved south – I would suspect to warmer waters.

So, while the fish may be cold blooded, my experience is that water temperature does affect them, and it does create certain responses from them. I believe migrating to warmer water is one of them. To my readers who challenged me – I agree that fish are cold blooded. But I have a hard time arguing with the fact that their migrations are in tune with water temperature changes!

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