Atlantic Silversides Know the Wisdom of Crowds - The New York Times
Silversides are abundant in the late summer. Drag a two-handled seine net along any shallow, salty shoreline in the five boroughs this time of year and a large part of the gleaming, wet mass of fish in the net will be Atlantic silversides. Dip that same net anywhere along the coastline from southern Canada to Florida and the results will be the same. Silversides may be small fish, but they play an outsize role in the ecology of the Atlantic coast.
Menidia menidia prefers life in shallow back bays and estuaries but can also be found in the churning Atlantic surf. Wherever they swim, life is brutal and usually brief. Predators come in every shape and size, with fins, wings, even furry paws. Skimmers, terns, gulls, herons, snappers, striped bass, fluke, even opportunistic raccoons hunt these fish relentlessly.
Ranging from three to six inches long at this time of year, silversides have little with which to defend themselves but their numbers; the fish congregate in tight schools that dart and skip nervously at any disturbance. Their color is a dun-green above to match their sandy or muddy bottoms, but each fish bears a striking silver stripe along its sides that runs the fish’s length, from gill to tail. The changing reflections on this stripe and the shifting patterns of the school are intended to confuse predators, which have trouble distinguishing one fish from another within the swirling mass. The shallow waters found at places like Pelham Bay Park or Brooklyn’s Plumb Beach are particularly good sites to observe the skittish behavior of these tiny fish.
As the days grow cool in the late autumn, most Atlantic silversides move out to deeper water, where they spend the winter, returning in spring as the waters warm. The fish spawn on high tides from earliest April through late June. Over the course of these months, a large female may produce as many as 5,000 eggs, though only a handful will reach adulthood, and those that live to reproduce almost never experience a second spawning season. Interestingly, eggs laid in cooler waters hatch more slowly and generate more female silversides than those laid in warmer waters, which produce proportionately more males.