The relation of menhaden to estuaries.
Menhaden, genus Brevoortia, use estuaries along the Atlantic and Gulf coasts of the United States as nursery areas for more than half of their first year of life. The Atlantic menhaden, B. tyrannus, and Gulf menhaden, B. patronus, support the largest fishery in North America and observations reported concern mainly these species. Spawning occurs in the Atlantic Ocean and Gulf of Mexico. After hatching and early development the larvae move into estuaries. The time spent in the ocean before entering the estuaries is not known. Larvae move into the tributraries near the upstream limits of saline water. Water temperatures below 3 C deter entry into the estuaries, inhibit movements into the tributaries, and cause mass mortalities. Temperatures below 3 C killed larvae confined in the laboratory at salinities of 24 o/oo but effects varied somewhat whith acclimation temperatures. Larvae and juvenile menhaden were collected in salinities of 1 o/oo or less along the Atlantic and Gulf coasts of the United States. Along the south Texas coast juveniles survived salinities up to 60 o/oo but were killed by 80 o/oo. Other physical, chemical, and biological factors affecting young menhaden are mentioned but supporting data are few. Literature citations include most of the publications on the estuarine phase of the menhaden's life history.