effects of entrainment (87, 89), but there are no such studies that include 

 marine fish larvae from first feeding to metamorphosis stages. 



During the past 1 5 years temperature responses often have been investigated 

 in conjunction with effects of other environmental factors, usually variations in 

 salinity for embryos and yolk-sac larvae (e.g. 66, 86). Multi-dimensional 

 analysis has led to use of response surface models which permit evaluation of 

 interacting effects such as between temperature, salinity, oxygen, and dose 

 time (1). However, most of this research has dealt with the egg, embryo, and 

 pre-feeding larval stages (e.g. 2, 3, 4, 5, 68). 



Salinity 



The developing eggs and yolk-sac larvae of many marine teleosts are known 

 to tolerate wider ranges of salinity than they are likely to encounter under 

 natural conditions (e.g. 2, 5, 36, 38, 68, 77, 86), but there are few studies 

 dealing with salinity tolerances of typical pelagic marine fish larvae during the 

 actively feeding stages. 



In unaltered environments, the effect of changes in saUnity on larval survival 

 may be minimal, since pelagic larvae usually will be retained within a water 

 mass that does not undergo extreme salinity changes. In the lower latitudes, 

 where time for larval development to metamorphosis is short, the probability 

 of an extreme salinity change that might cause mortality seems even less 

 probable than in higher latitudes. Holliday (36), in reviewing data on salinity 

 tolerances of Atlantic herring and plaice, observed that newly hatched larvae 

 had a wider tolerance range for salinity than did metamorphosed juveniles. 

 Tolerance to high salinities decreased from about 60°/oo at hatching to about 

 40"/oo after metamorphosis, while low salinity tolerance changed little during 

 development, ranging from about 2-8°/oo for both species. Kurata (55) 

 obtained similar results for Pacific herring, C. harengus pallasi larvae which 

 could tolerate a salinity range of approximately 2-60°/oo at 10 days after 

 hatching, but only 2-42°/oo at 20 days. 



There are several investigations on salinity tolerances of non-typical or 

 non-pelagic marine fish larvae, from which conclusions about tolerances of 

 marine fish larvae in general perhaps can be inferred. For mummichogs 

 Fiindulus heteroclitus the range of salinity tolerance was very wide, 

 0.39-100.00°/oo (51). California killifish larvae F. parvipinnis also had a wide 

 salinity tolerance, but the tolerance for low salinities decreased with age (76). 

 Two atherinids, the CaUfornia grunion Leuresthes tenuis and the Gulf grunion 

 L. sardina, were tested for salinity tolerances during the larval stage (78, 79). 

 Gulf grunion had a wider salinity tolerance range than did California grunion, 

 but in both species the tolerance range decreased with age. A reasonable 



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