SHLOSSMAN and CHITTENDEN: REPRODUCTION OF SAND SEATROUT 



opment was distinct at 140-200 mm TL as most 

 specimens entered the early developing stage 

 ( Figure 2). Fish began to enter the late developing, 

 gravid, or ripe stages at 180 mm TL. These data 

 are supported by regressions of ovary weight on 

 total length (Table 2, Figure 3) in which extrapo- 

 lated x-intercepts were 120-170 mm TL in the 

 March-September spawning period. Age composi- 

 tions and sizes presented later indicate that C. 

 arenarius matures to first spawn at 12 mo. 



Sand seatrout spawn from early March 

 through September. The collections off Freeport of 

 fish 45-55 mm TL in mid-May 1978, 25-80 mm TL 

 in mid-May 1979, and 60-120 mm TL in June and 

 July of 1978 and 1979 (Figure 4) indicate that 

 spawning began in early March and continued 

 through May. This is supported by the collections 

 of 1) fish 50-75 mm TL off Port Aransas in late 

 May and late June of 1977 and 1978 (Figure 5), 2) 



Stage 1 



n=260 



Stage 2 



n=105 



5 



LU 

 D 

 O 5 



LU 



cr 



Stage 3 



n=4t0 



yw^ 



Stage 4 



n = 31 



^ -^ /'~~ n--^— 



stage 5 



n = 21 



I >  £3_ 



Stage 6 



n=5 



Stage 8 



100 150 200 250 



TOTAL LENGTH (mm) 



Figure 2. — Length frequencies (moving averages of three) of 

 immature and female Cynoscion arenarius in maturity stages 

 1 through 8. Maturity stages are described in Table 1. No stage 

 7 fish were caught. 



Table 2. — Analysis for regressions of gonad weight (grams) on 

 total length (millimeters) for female Cynoscion arenarius each 

 month, October 1977-December 1978. All regressions are signifi- 

 cant at a = 0.05. 



)60 200 240 280 320 



TOTAL LENGTH (mm) 



Figure 3. — Monthly ovary weight-total length regressions for 

 Cynoscion arenarius. The length of each line shows the observed 

 size range. X-intercepts indicate total length at which gonad 

 development begins in what would be a curvilinear regression if 



smaller lengths were available. 



fish 50-80 mm TL in Galveston Bay in May 1978 

 and 1979 (Figure 6), and 3) fish 20-70 mm TL at 

 Cedar Bayou in the period 1 May-2 July 1979 (Fig- 

 ure 7). Spawning also occurred in August and Sep- 

 tember; because a distinct group offish 25-60 mm 

 TL were collected off Freeport in late September 

 1979 (Figure 4), and fish 65-130 mm TL collected in 

 early December of 1977 and 1978 were too small to 

 represent spring spawning. This is supported by 

 the collections of: 1) fish 25-50 mm TL at Cedar 

 Bayou in September 1978 (Figure 7), 2) fish 70-120 

 mm TL in Galveston Bay in December 1977 and 

 50-80 mm TL in September-December 1978 (Fig- 

 ure 6), and 3) fish 70-150 mm TL off Port Aransas 

 in February and December 1977 (Figure 5). 

 Spawning did not occur from October through 

 February, because no fish 25-60 mm TL were col- 

 lected from November through April in the gulf 

 (Figures 4, 5), in Galveston Bay (Figure 6), or at 

 Cedar Bayou (Figure 7). 



Gonad maturity and weight data suggest that 

 females spawned from February or March through 

 September in agreement with length frequencies. 

 Two gravid females were collected in mid- 

 February 1978 and late developing, gravid, or ripe 

 stage fish from March through July 1978 and in 

 September 1978 (Figure 8). No spawning occurred 

 from October through December, because all fish 

 then were in resting, maturing virgin, or early 

 developing stages. Gonad size increased during 

 February (Figure 3), reached a peak in April and 

 May, and rapidly declined through July. Increased 



651 



