FISHERY BULLETIN: VOL. 71, NO. 2 



acter, to measure such perturbations, but such 

 variation is complex and probably of little 

 use in measuring developmental homeostasis 

 or stability of individuals within a population 

 (Thoday, 1958; Soule and Cuzin-Roudy, in 

 press). The recent discovery that morphological 

 variation may be highly correlated with mean 

 heterozygosity based on electrophoretic analy- 

 sis (Soule and Yang, in press) reemphasizes 

 this point. 



Adams and Niswander (1967) suggested 

 that, "It is possible that an overwhelming 

 environmental stress (i.e., teratogen) could 

 [cause] . . . increased asymmetry." We, there- 

 fore, decided to examine fluctuating asymmetry 

 as a possible measure of environmental stress. 

 Previous studies of asymmetry have not em- 

 phasized the environmental component (for 

 references see Mather, 1953; Thoday, 1958; 

 Reeve, 1960; Sakai and Shimamoto, 1965). 

 The use of paired structures to analyze bilateral 

 developmental differences in fish was first 

 suggested by Hubbs and Hubbs (1945). 



MATERIALS AND METHODS 



To field test this hypothesis we chose three 

 species of marine teleost fish — barred sand 

 bass, Paralabrax nebulifer; grunion, Leuresthes 

 tenuis; and barred surfperch, Amphistichus 

 argenteus. These species belong to different 

 families and differ greatly in their life histories. 

 They are also abundant throughout the area of 

 study, they are easily captured, and large collec- 

 tions were available from museums for compara- 

 tive space and time series analyses. 



Barred sand bass are generalized carnivores 

 (Quast, 1968) and probably approach the 

 longevity of kelp bass (P. clathratus), which can 

 survive at least 32 years in the wild (Young, 

 1963). Barred sand bass are also of significant 

 importance to the sport fishing industry in 

 southern California (Pinkas, Oliphant, and Hau- 

 gen, 1968) and are apparently nonmigratory 

 (Young, 1969). Adults (those fish older than 

 1 year) live offshore in rock-sand ecotonal 

 areas, except during the spawning season when 

 they migrate short distances to sandy areas 

 to spawn (Turner, Ebert, and Given, 1969). 

 From examination of adults, barred sand bass 



appear to be secondarily gonochoristic, as are 

 kelp bass (Smith and Young, 1966), and are 

 undoubtedly broadcast spawners. 



Grunion are small atherinids that mature in 

 about a year, are thought to be nonmigratory, 

 live only 2 or 3 years, and are found in inshore 

 waters (Walker, 1952). They spawn on sandy 

 beaches during the high tides from late Feb- 

 ruary or March through August or September 

 (Walker, 1952). Grunion lack teeth and it is, 

 therefore, assumed that they feed on small 

 organisms (Frey, 1971). 



Finally, barred surfperch are found almost 

 exclusively in the surf zone and feed pre- 

 dominantly on sand crabs, Emerita analoga, 

 which constitute roughly 90% of their diet 

 (Carlisle, Schott, and Abramson, 1960). From 

 tagging studies, barred surfperch appear to be 

 nonmigratory (Carlisle et al., 1960). In contrast 

 to barred sand bass and grunion, surfperch are 

 viviparous (Eigenmann, 1894), with an apparent 

 maximum life span of 6 years for males and 9 

 years for females (Carlisle et al., 1960). 



All reference to length in this paper refers to 

 the standard length in millimeters, defined as 

 extending from the anterior notch between the 

 premaxillaries to the end of the hypural plate. 

 Variability is expressed as one standard error 

 (SE) or one standard deviation (S) on either 

 side of the mean. 



Character Analysis 



Seven characteristics were used for asym- 

 metry analysis: 



1. Number of pectoral fin rays: A count of 

 the total number of pectoral fin rays, including 

 the uppermost unbranched ray. 



2. Total gill rakers: A total count of rakers 

 and all raker rudiments that could be seen under 

 a dissecting microscope. "Secondary" rakers, 

 which frequently occur in barred sand bass 

 with badly deformed rakers (Valentine and 

 Bridges, 1969), were excluded from the count. 



3. Scales above the lateral line: A count 

 started approximately two scale rows in front 

 of the first dorsal fin spine and extending 

 ventral-posteriorly along a natural scale row to 

 the pored lateral line scales. 



4. Scales below the lateral line: A count 



358 



