Toole etal.. Otolith microstructure. microchemistry, and early life history of Microstomas pacificus 737 



Figure 2 



Sagittal section of right otolith from 67.2 mm Stage-4 Dover sole, Microstomias pacificus, larva marked with OTC and held in a 12°C 

 aquarium for 48 days. Magnification = 400X. (A) Photograph taken with ultraviolet light; arrows show fluorescent OTC marks. 

 (B) Same preparation taken with full-spectrum light; arrows show position of fluorescent OTC marks. 



fluorescent mark and countable increments (70% of 

 injected fish). Increment width was narrow, ranging 

 from 0.63 to 1.88 um. Because all counts underesti- 

 mated the true number of days since injection and 

 because larger marks were not apparent by adjusting 

 focus, the marks were not equiva- 

 lent to subdaily marks observed in 

 the first experiment. The OTC mark 

 deposited after first injection was 

 not visible in fish held until second 

 injection, so increments deposited 

 during the entire 183-day period 

 could not be counted. 



Precision of counts Maximum and 

 minimum increment counts for each 

 otolith differed from mean counts, 

 by an average of 5.7% (Range=0- 

 207c). Standard deviations associ- 

 ated with mean increment counts 

 averaged 1.84 (Range=0-7.8). 



Validation relationships Neither 

 variances (Bartlett's test, S=1.48, 

 P=0.11) nor mean observed/expected 

 increment counts (ANOVA, df=27, 

 F=2.21, P=0.10) differed between 

 the five experimental groups offish 

 (three aquarium temperatures in 

 the first experiment, March and 

 September marking groups in the 



second experiment). Similarly, regressions of observed 

 versus expected counts did not improve when a model 

 containing separate slopes and intercepts for each ex- 

 perimental group was compared with a model contain- 

 ing separate intercepts and one slope (P=0.313, df=5,22, 



Figure 3 



Left otolith, anterior end of frontal section; from 68.0mm Stage-4 Dover sole, 

 Microstomus pacificus, larva marked with OTC and held in a 10°C aquarium for 44 

 days. Arrow marks capture point, as identified by OTC fluorescence. Increments 

 prior to capture are well-defined, whereas increments formed in aquarium are nearly 

 indiscernible. Magnification = 400  . 



