Barbieri et al.: Maturity, spawning, and ovarian cycle of Micropogonias undulatus 



673 



fixed midchannel stations in the York, James, and 

 Rappahannock rivers. 



Fish were measured for total length (TL, ±1.0 mm), 

 total weight (TW, ±1.0 g), and gonad weight (GW, 

 ±1.0 mm), sexed, and both sagittal otoliths were re- 

 moved and stored dry. The left otolith was sectioned 

 through the core with the diamond blade of a Buehler 

 low-speed Isomet saw. Sections 350-500 urn thick 

 were then mounted on glass slides with Flo-texx clear 

 mounting medium and aged under a dissecting mi- 

 croscope (6-12x) following criteria described in 

 Barbieri et al. ( 1994 ). The gonadosomatic index ( GSI ) 

 was calculated for individual fish as (GW/(TW- 



GW)100). Females were assigned a macroscopic go- 

 nad maturity stage (Table 1). Males were classified 

 only as sexually mature or immature. Female mac- 

 roscopic stages were verified microscopically by in- 

 specting fresh oocyte samples and histology slides of 

 a randomly selected subsample of ovaries in each 

 maturity stage. Fresh oocytes were removed from one 

 ovary, spread on a microscope slide, and examined 

 under a dissecting microscope (12— 50x). Color pho- 

 tographs were used to permanently record the ap- 

 pearance of fresh oocyte samples. This technique al- 

 lowed fresh oocytes to be compared with histology 

 slides in assessing gonad maturity stage and the 



