Mortality and Growth of Young-of-the-Year Striped Bass in the Hudson River Estuary

Mortality rates for striped bass (Morone saxatilis) larvae and young-of-the-year juveniles in the Hudson River estuary were estimated from weekly population estimates during 1975 and 1976. Mortality rates declined from 15–18% day-1 during the postyolk-sac stage to 0.5% day-1 for early juveniles. In 1976, the first of two spawns was almost completely killed as yolk-sac larvae by a rapid decline in water temperature from 15 to 12 C during late May. Larvae and early juveniles of the 1973–1976 year classes showed periods of slow growth during May and June (0.2 mm day-1), rapid growth during July and August (0.8 mm day-1), and decreasing growth during September and October. For the 1965–1967, 1969–1970, and 1972–1976 year classes, larval instantaneous growth rates were significantly and positively related to mean water temperature since peak spawning. However, instantaneous growth rates for the juvenile stage during July and August were not significantly related to mean water temperature, mean freshwa...