Table l. — Daily mean body measurements of fed and starved jack mackerel larvae maintained in 10 1 and 100 1 containers. 



Preserved measurements. 



Probabilities for equal body measurements between container sizes (multivariate analysis: Hotelling T 



Table 2. — Daily histological condition of fed and starved jack mackerel larvae maintained in 10 1 and 100 1 containers. 



^ Total number of larvae within each treatment does not agree with Table 1, as several larvae were lost during the microtechnique procedure. 

 Probabilities for equal histological grades between container sizes (two-sample nonparametric Kolmogorov-Smirnov Test) 



until age 10 d when it was significantly better in 

 the large containers (P = <0.05; Kolmogorov- 

 Smirnov Test; Table 2); fewer larvae were classed 

 as "starved" in the larger containers. For larvae 

 given no food, no difference existed in condition of 

 larvae between large and small containers. 



Fed larvae died at ages 12-13 d in the small 

 containers. On day 13 there was also a major 

 mortality in the large containers, but a few larvae 

 survived through the juvenile stage, and one fish 

 lived for 49 d, 31 mm SL. I did not sample these 

 survivors unless they appeared to be dying. For 

 jack mackerel there is no well-defined metamor- 

 phosis; the juvenile stage begins at the comple- 

 tion of fin formation, 12-16 mm (Ahlstrom and 



Ball 1954). In the large container, fin forma- 

 tion was complete at 14 mm, 39 d of age (n - \)\ 

 size at age for this laboratory-reared fish was 

 similar to field-collected fish (age of wild fish is 

 being determined by reading daily growth incre- 

 ments in otoliths (MethotM). 



Conclusions 



Relating experimental results from laboratory 

 to field conditions must be done with caution. 

 Blaxter (1975) compared morphology, chemistry, 



'R. Methot, Southwest Fisheries Center La Jolla Laboratory, 

 National Marine Fisheries Service, NOAA, P.O. Box 271, La 

 Jolla, CA 92038, pers. commun. January 1980. 



790 



