Outdoors Dave Sartwell The Gloucester Daily Times Fri Apr 29, 2011, 11:40 PM EDT
The American Shad (Alossa sapidissima to you Latin fans) will soon be running the Merrimack River in great numbers
As the warm weather and spring rains come to New England, the rivers that flow down out of the mountains start to play host to a number of fish species that use these waters as their spawning medium
This has been a particularly long and hard winter with a lot of snow still in the mountains. As a result the water has been cold. But, like politicians in November, there are a number of different species that will soon be running.
Herring, stripers, salmon and other species that use the rivers all have their own special way of interacting with their environment and do so in a way that strengthens all the others with which they make contact. The smaller herring are a food source for the larger fish that follow. The eggs that all of the fish lay are forage for every species as well. Each one of these different fish are part of a very complicated web that sustains the whole system.
The shad is very unusual in that it's life cycle depends on where it is found along the coast. Fish native to Florida and the Carolinas are semelparous, that is they return to their natal rivers to spawn at 4-years-old and die soon after. They lay between 300,000 to 400,000 eggs. In an oddity of nature, the farther north the fish are born, the later in the life cycle they spawn and increasing numbers are interoparous, that is they live to return another year to spawn.
For example, in the Delaware river the number of adults that survive to spawn a second time is 15%, while somewhere between 30-50% return in our Massachusetts rivers. In the St. Johns River in Canada almost 80% return to spawn. In the Merrimack and Connecticut rivers, the average age of the first spawners moves to 5, however, the number of eggs released drops to between 125,000 to 250,000.
Since the shad eggs cannot survive in salt water, the spawning adults will often run hundreds of miles upstream into fresh water to lay their eggs. Unlike salmon, however, they do not seek out tiny streams and make a bed into which they drop their eggs. Instead, the females release their eggs into the mainstream where any number of males that are hovering about just for that purpose instantly fertilize them. The females often release eggs several times on their way upstream.
The eggs mature in anywhere from 4 to 9 days. It is good that the females lay so many eggs, as the young produced become a major food source for almost every other fish in the river system. The young migrate out of the rivers in the early fall, having grown to become 2-3 inches long and weighing about half an ounce. When they hit the ocean, they fall prey to stripers, bluefish and numerous other ocean fishes. They are an important part of the natural food chain.
These tiny fish slowly migrate to a place in the ocean off the Carolinas where they spend the winter. In the spring they migrate north as young fish, summering in the Bay of Funday. At age 4 or 5 they return to their natal rivers to spawn. By this time they range in size from 2 to 7 pounds with the females being larger than the males.
The spawning fish have to overcome many obstacles as they head upstream. The first in the Merrimack River is the dam in Lawrence. Here a fish ladder has been constructed to help them move up the river. From there they run north, laying eggs all along the route. Shad have an unusual ability to detect ultrasound waves. This is important as Clupeid fishes (herring and shads) are the main source of food for the echolocating cetaceans such as the harbor porpoise and the bottlenose dolphin.
In studies by Mann, Higgs, Tavolga, and Popper, they have found that when the foraging fish "ping" a school of shad, they send out an ultrasonic sound that reflects off the fish and back to them. This way they can find the school without seeing them. The shad are one of the few fish in the ocean that can hear this "ping" and they use this to avoid being caught. In experiments with bottlenose dolphins, it was found that the shad can pick up the sound up to 187 meters away.
Catching these fish as they head upstream can be a bit of a challenge, but they sure can put up a good fight before they come to the rail. Using spinning gear with 4 to 8-pound test line works well. Although they will come to spinners and spoons, shad darts probably work the best. Darts range in size from very tiny to up to 1/2 ounce. Because you want to fish for shad near the bottom of the river, the terminal rig must be heavy enough to reach down to them. Using heavier darts will do that, but the fish prefer smaller bait. To get the small darts down, use split shot up the line about 18 inches.
The darts come in a host of colors, however, the traditional one is a redheaded, white-bodied dart with a white or yellow bucktail. If the fishing is slow, switch colors or use a set in tandem. Fly fishermen often use a quick-rate sinking line, a short leader, and a weighted, short-shanked streamer that is brightly colored. Check with Kay at Surfland on Plum Island to see what is working best. Don't be afraid to ask others on the river what is working for them. Look for a point of land along the river and fish in the slower water behind it. The shad will often move into a spot like that to rest as they migrate upstream.
Ocean Fishing There is good cod and haddock fishing right now when the weather permits. Be careful out there and pick your times watching the weather charts closely. This time of year the conditions can change quickly. The best bait always seems to be a big glob of clam on the end of a sharp hook. As my Dad used to say, "Meat Deep!" Pete Santini tells me they have been catching fish with green colored teaser rigs bounced off the bottom.
Try right along the Hills at 42-42-200 and 70-20-500 or the small bump called the Ups and Downs at 70-24-200 and 42-41-000. These spots seem to work well this time of year. Drift with the wind if it is a slow drift and put on enough weight to keep the bait on the bottom.Flounder are starting to move in as well. Use a flounder rig with seaworms next to the bottom for best results.
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