termed this ecological death-point the “point-of-no-return” (PNR). Starved 
larvae may live after the PNR has been reached but with no likelihood of 
ultimate survival. The time span between the development of the ability to 
feed and PNR determines how important the period of transition to exogenous 
feeding will be to the survival of larvae of a particular species. 
The rate of growth and development of larval fish is very much temperature 
dependent. Among the studies in which the relationship between rearing 
temperature and larval growth rate have been demonstrated are those of 
Kramer and Zweifel (16), Houde (14), and Shelbourne et al (33). In all these 
studies, larval growth rate increased with increasing temperature, except where 
survival limits were approached. 
Weight specific metabolic rate (oxygen consumption) also increased with 
increasing temperature among fish larvae of the same weight in studies such as 
those of Holiday et al (13) and Laurence (20). 
The striped bass, Morone saxatilis (Walbaum), is a commercially important 
anadromous teleost native to the Atlantic coast of North America. The natural 
range of the striped bass extends along the Atlantic coast of North America 
from the St. Lawrence River to Louisiana, with its center of abundance 
between Cape Cod and Cape Hatteras (26). There have been many introduced 
populations ranging from the extremely successful Pacific coast estuarine 
population, introduced in the 1880’s, to the many landlocked populations 
which have been established in natural and man-made freshwater 
impoundments in the southeastern states. 
Sexually mature striped bass enter and ascend rivers to the spawning 
grounds within the period between March and July. Peak spawning generally 
occurs at a water temperature on the spawning grounds of 15 to 18°C. 
Spawning sites are typically well into the freshwater portion of the estuary, 
although often within the range of tidal influence (35). Each ripe female may 
produce from one to three million eggs. Newly shed eggs are 1.28 to 1.38 mm 
in diameter. Upon water hardening they swell to a diameter of approximately 
3.0 mm. Newly hatched larvae average 3-4 mm in length, and have a large yolk 
sac and oil globule (22). For several days after hatching, young prolarvae spend 
much of their time in a vertical, head-up position drifting in the current. Larvae 
develop functional mouth parts and are capable of feeding within 2-10 days 
after hatching at normally encountered river temperatures. Yolk is generally 
completely absorbed by the time the larva reaches 6 mm in length. 
Metamorphosis into essentially adult form occurs by the time the larvae are 
approximately 17 mm in length, generally 2 to 3 weeks after hatching. Feeding 
larvae are capable of consuming relatively large organisms as their first food. 
Planktonic Crustacea and their developmental stages predominate in their diets 
through most of their first year (27, 10). 
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