HUNTER: BEHAVIOR OF LARVAL ANCHOVY 



for the two data sets w^ere nearly the same, and 

 consequently I combined the data and obtained 

 the relationship of V/A = —1.11 + 1.59F,sj = 

 8.311 for all data (Figure 2). 



The principal difference between the above 

 equation and ones derived by Bainbridge (1958) 

 or by Hunter and Zweifel (1971) for adult fish- 

 es was that amplitude was the estimator of size 

 instead of length. Amplitude was required in 

 the present study because during bursts of con- 

 tinuous swimming larvae modulated the ampli- 

 tude of their tail beat. Inclusion of length in 

 addition to amplitude and frequency did not im- 

 prove the relationship. In the study by Hunter 

 and Zweifel (1971) fish did not modulate the 

 amplitude of the tail beat because they swam 

 at a steady speed. Amplitude is known to change 

 during acceleration (Gray, 1968), and the be- 

 havior of larvae during bursts of continuous 

 swimming was no exception to this rule. 



During intermittent swimming, amplitude 

 was not modulated but was maintained at a min- 

 imum value of about one-fifth of a body length. 

 The relationship between amplitude and length 



during intermittent swimming was obtained by 

 the equation A = 0.112 + 0.170 L where Si = 

 0.066 (Figure 3). 



Figure 3. — Relationship between anchovy larval length 

 (cm) and tail beat amplitude (cm) for intermittent 

 swimming. 



Table 2. — The speed, tail beat frequency, and tail beat amplitude for anchovy larvae of various lengths during con- 

 tinuous and intermittent swimming. Each value is a mean for a single swimming sequence swum by one larva. 



Continuous swimming 



Intermittent swimming 



Length 



Speed 



Tail beat 

 frequency 



Tail beat 

 amplitude 



Length 



Speed 



Tail beat 

 frequency 



Tail beat 

 amplitude 



825 



