ing 1974, as compared with 1 yr later, coincided 

 with a larger population of speckled sanddabs. The 

 population density variability shown in Figure 3 

 results, at least in part, from the patchy distribu- 

 tion of the fish. Even at the time of year of greatest 

 density the occasional transect found no fish. 

 When fish were observed at these times of year, 

 however, the numbers were high. 



We grouped the abundance of speckled 

 sanddabs per transect data according to the ob- 

 served field temperature at the time of the survey 

 to help explain the distribution of the fish (Table 

 2). The mean abundance per transect was deter- 

 mined for each observed field temperature (11°- 

 20°C ), and we calculated the percent occurrence at 

 each temperature after correcting for the varia- 

 tion in occurrence of each temperature. This cor- 

 rection was accomplished by dividing the fish 

 abundance at each temperature by the number of 

 times the temperature occurred. We compared the 

 temperature-specific field distribution with the 

 temperatures selected in the laboratory by speck- 

 led sanddabs as a step in trying to understand the 

 effect of temperature on field distributions. The 

 laboratory data of temperature-specific occur- 

 rences was recalculated using only data for fish 

 that were observed at 1 1 °C or higher temperatures 

 as if we had only sampled that part of the popula- 

 tion occurring above 11°C (Figure 4). Statistical 

 analysis of the arc sine transformed frequency dis- 

 tributions revealed no significant difference be- 

 tween laboratory and field data (X%df ~ 10.75, 

 0.25<P<0.50). We found a significant correlation 

 between percent occurrence ( arc sine transformed) 

 and field temperature (r^^f = -0.869, P<0. 01) of 

 the data in Table 2. This high degree of correlation 

 indicates that 769c (r^ x 100) of the variation in 



30-1 



LlI 



o 



25- 



0:20- 



13 

 O 



^ 15- 



S 10- 



o 



tr 



°- 5 



[J- Field 

 |- Laboratory 



I r r 



10 II 12 13 14 15 16 17 18 19 20 21 

 TEMPERATURE (°C) 



Figure 4 — Correspondence of temperature-specific occurrences 

 of speckled sanddabs in the laboratory and field. The frequency 

 distribution for the laboratory data was obtained from Figure 2 

 using only data for fish that occurred at 11°C or higher, which 

 matched the range of observed field temperatures. 



the field occurrence of speckled sanddabs in King 

 Harbor seems explained by temperature. The 

 similarity in temperature-specific distributions 

 for the laboratory and field data (Figure 4) indi- 

 cates that speckled sanddabs in King Harbor rep- 

 resented only that portion of the population found 

 in warm water. Comparison of Figures 2 and 4 

 indicates that the greatest density of these fish 

 may occur outside of the harbor in deeper, colder 

 water. Furthermore, these fish in King Harbor do 

 not appear to be a subpopulation endemic to this 

 harbor. This would be in agreement with Taylor 

 ( 1957) who suggested that there is but one popula- 



TABLE 2. — Frequency of occurrence of temperatures and speckled sanddabs in King Harbor, 



Redondo Beach, Calif. 



'X IS number of surveys ttiat occurred at the indicated temperature. 



^Y IS number of fish observed per transect during each survey that occurred at the indicated temperature 

 3% occurrence = [{1Y,X)I1{1Y<X)] a 100, where i(i.V,X) = 99.4. It is coincidental that this number approximates 

 100. 



870 



