Earth Almanac: October/December 2002

With the line storms of late autumn and early winter, Atlantic menhaden—herringlike fish that spawn at sea—move in colossal schools out of Northeast bays and estuaries, setting a course for their offshore wintering grounds south of Cape Hatteras, North Carolina. On still days, watch for what looks like rain squalls sweeping across the ocean. If you are in a boat or standing on a dock or a bridge, you may see silver, oval fish, 4 to 15 inches long, streaming by with their mouths open and gills flared as they strain out phytoplankton with their gill rakers. Often a school will be attended below by crashing, boiling striped bass and bluefish, and above by screaming, diving gulls and terns—all swilling protein for their own southbound migrations. Sometimes the bluefish push menhaden onto beaches, where they pile up in windrows miles long and up to three feet high. Tuna, seals, porpoises, and sharks follow the orgy, consuming the menhaden as well as the bass and the blues. But by far the most efficient predators of menhaden are humans, who catch them in purse seines. During the past five years annual U.S. landings have averaged 227,000 metric tons—more than for any other fish save Gulf menhaden (a closely related subspecies) and Alaskan pollack. Most menhaden are rendered into animal feed and additives to plasticizers, resins, lipstick, shortenings, and margarine. Always the menhaden defend against the slaughter with a fecundity that defies human imagination; and while there can be sharp population swings, they appear to result only from natural causes. In 2002 the National Marine Fisheries Service reported the highest spawning stock since the early 1960s. 

Punctuation in Flight

'Tis the season when even lepidopterists forget about butterfly watching, and that's why finding winter butterflies can be so much fun. Species you'll meet are pretty much limited to overwintering anglewings, most notably the question mark, usually brighter than the summer form and named for the silver punctuation mark on each underwing. East of the Rockies (save the extreme northern range, too cold for hibernation and reinvaded by migrating adults each spring) you may encounter a flying question mark on mild winter days. Check woodpiles and outbuildings, where they briefly emerge from hibernation. These butterflies rarely feed on flowers, preferring rotten fruit, carrion, dung, and sap. You may be excused if you'd rather not set out the first three of these food sources. Break off a few birch or maple branches and you may find a question mark sipping the sugary flow.