Whither the whitebait?

There are many misconceptions about why scaled sardines are here today, gone tomorrow. More concrete explanations come from biologists, who cite their makeup, air and water temperatures, and feeding habits.

By MIKE SCARANTINO

© St. Petersburg Times, published May 13, 2000

Baitfish schools -- more precisely, schools of scaled sardines (whitebait) -- are scarce this season along certain areas of our coastline. Why, is anyone's guess, and there are a lot of anyones venturing guesses.

One day whitebait is fairly abundant in some places, and the next you can't find a one.

Historically, Hudson and its surrounding waters have seen baitfish come in much earlier in the season than this. Not only have they come in early, they typically have been larger fish and very plentiful. Not so this season.

Fishing has never been an exact science, but anglers and biologists do learn from past performances. And past performances would dictate that by this late in the spring, baitfish populations should be thick everywhere along the southern portions of the Nature Coast and in reasonably good numbers in the northern areas.

Some snook anglers are beginning to feel a bit anxious over the scarcity of baitfish. Scaled sardines, also known as snook candy, are the most productive live bait for spring snook. In fact, there aren't many species that can ignore a large, healthy sardine.

Many anglers who use them as bait also use them to stimulate the appetites of lazy fish. By hand-chumming a few crippled baits into an area and waiting for that distinct pop when a snook eats a bait at the surface, it becomes easier to locate aggressive fish.

Guesses about the absence of whitebait run from simple to sublime. Some people think moon phases have not been right yet, or that there aren't enough predators offshore to push baitfish schools in. There are anecdotal theories about pollution from the land keeping fish away.

Then there are those who wonder -- are anglers who castnet for bait having a detrimental affect on baitfish populations, or are large commercial fishing companies scooping up these valuable baits for animal feed or fertilizer markets?

While there may or may not be any merit to these thoughts, there must be a definitive reason why baitfish schools are so slim.

During recent conversations with biologists at the Florida Marine Research Institute and with meteorologists at the National Weather Service, a few more concrete ideas began to surface.

As with any species of fish, understanding some basic biological facts helps to unravel the mystery -- though as mentioned before, fishing is not an exact science. By using standardized samplings, hydro-acoustic searches and mathematical equations, scientists over time can get very close assessments when estimating fish populations and health of stock.

Looking to the biology of the fish may dispell some of the misconceptions about their scarcity. First, these tempting baits only live approximately 400 days. They spawn during the months of March through September, with the highest availability to anglers occurring in the months of May, June and July.

Typically, they live in small scattered schools, and due to their sensitivity to temperature, move in and off shore with fluctuations in the water temperature, not moon phase or from being chased by predators.

This year, air and water temperature fluctuations have been numerous. In February, warmer than normal weather pushed water temperatures to the 80-degree mark and in came the bait. Within a short three-day period, high winds and cold fronts dropped water temperatures a staggering 16 degrees, enough to shock snook and send schools of baitfish scurrying back offshore.

Another misconception that should be laid to rest is the one concerning commercial interests scooping up large amounts of whitebait. "Not so," said Dr. Behzad Mahmoudi of the Florida Marine Research Institute. "I don't know of any commercial markets for scaled sardines. Threadfin herring, yes, but not sardines. Because scaled sardines live in smaller schools, it becomes less economically feasible to the industry to seine them."

Finally and most important, by examining their feeding habits we may find the answer to this year's bait scarcity.

At the top of the scaled sardine's food list are copepods and zooplankton. Copepods, also known as insects of the sea, make up the sardine's primary source of food. These tiny crustaceans are the largest biomass in the ocean. Even the largest of whales in the Northern Hemisphere rely on these tiny beings for sustenance.

It is the feeling of Mahmoudi that most of the problems with sardine scarcity are environmentally driven. Factors such as rainfall, or lack of it, and rapid temperature changes may be having a profound effect on the primary production of copepods and zooplankton.

This season we are experiencing drought-like conditions. Those conditions restrict freshwater and nutrient inflow to the gulf and production of the fish's primary foods, which may be negatively influencing the fish's movements and breeding patterns.

Meteorologist Rick Davis of the National Weather Service in Ruskin forecasts the weather to remain much the same until mid to late summer. If that is the case, learning to use artifical lures may become a necessity.

- If you have a question or comment, call Capt. Mike Scarantino at (352) 683-4868.

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