CHAO and MUSICK: LIFE HISTORY OF JUVENILE SCIAENID FISHES 



TOTAL LENGTH (mm) 



FIGURE 17. — Length-frequency distributions of croaker, Micro- 

 pogonias undulatus, by river distance (strata) upstream of the 

 York River estuary. Pooled total, September to November 

 1972-74. Strata: A-G in York River, M = Mattaponi River, P = 

 Pamunkey River. Frequencies expressed as log (x + 1) at 5-mm 

 increments. 



(Figure 19) caught yearlings exclusively. The 

 15.25-m seine caught almost no croakers. 



In summary, young-of-the-year croaker entered 

 the estuary in May and from August on. The ear- 

 lier group entered in May and left the estuary in 

 November, as did older year classes. The later 

 group (August-November) stayed in the estuary 

 until the summer months of the following year. 

 Young croaker moved to the upper part of the York 

 River and the saline portions of major tributaries 

 after first entry, then moved down the York River 

 into more saline waters as they grew. Smaller 

 fishes ( <130 mm TL) stayed in the river through- 

 out the winter. 



OTHER STUDIES.— Croakers occur from the 

 Gulf of Maine to Argentina, along the coasts of the 

 Atlantic and Gulf of Mexico. Length-frequency 

 distributions exist for different areas of the United 

 States [see Wallace (1940) and Haven (1957) for 



the lower Chesapeake Bay and York River (Table 

 4)]. Studies usually show that small croakers 

 (10-20 mm TL) are present in the estuary during 

 all except the summer months (June-August). 

 Croakers seemingly have a long spawning season 

 since small individuals (<20 mm TL) are present 

 from September to May in different estuarine 

 areas (Table 4). Some croakers may be very small 

 ( <15 mm TL) in spring because of slow growth of 

 fish spawned late in winter, or because they were 

 spawned in spring. Such a group was also found in 

 the present study (Figure 16, mode II) but not in 

 previous Chesapeake Bay studies. Croakers from 

 Maryland and Virginia tagged by Haven (1959) 

 showed springtime movement of croakers up the 

 estuaries and up Chesapeake Bay, and oceanward 

 and southerly in fall (some recoveries were from 

 off the North Carolina coast). Pearson (1932) re- 

 ported a high percentage of croakers in the catches 

 of the commercial trawl fishery during November 

 (88%) and December (76%) from the fishing 

 grounds off the North Carolina coast. Hildebrand 

 and Cable (1930) implied that croaker spawning 

 probably began in August in Chesapeake Bay and 

 northward, in September at Beaufort (North 



2.5-j 

 1.5- 

 0.5 

 2.5 

 l.5 : 

 0.5 

 2.5 

 1.5- 

 0.5 

 2.5 

 1.5- 

 0.5 : 

 2.5 

 1.5 

 0.5- 



N=0 



N = l? 



20 40 60 80 100 120 140 160 180 200 220 240 

 TOTAL LENGTH (mm) 



FIGURE 19. — Length-frequency distributions of croaker, Micro- 

 pogonias undulatus, from beach seine catches of York River, 

 May to September 1972. Frequencies expressed as log (x + 1) at 

 5-mm increments. 



FIGURE 18.— Length-frequency dis- 

 tributions of croaker, Micropogonias 

 undulatus, by depth of York River. 

 Pooled total, September to November 

 1972-74. Frequencies expressed as log 

 (x + 1) at 5-mm increments. 



2.0- 



i.o- 

 o.o- 



n r-H 



90 110 130 150 



TOTAL LENGTH (mm) 



170 190 210 230 250 



677 



