FISHERY BULLETIN: VOL. 86, NO. 2 



was estimated from both field-caught and labora- 

 tory fish. 



MATERIALS AND METHODS 

 Collection of Samples 



Spotted seatrout were collected in Redfish Bay 

 or Lydia Ann Channel near Port Aransas, TX, 

 U.SA. at depths of 1-3 m (Fig. 1). Fish were cap- 

 tured using a 300 m gill net (82 mm stretch) or a 

 300 m trammel net (outer panels, 178 mm 

 stretch; inner panel, 89 mm stretch) over shallow 

 beds of turtle grass, Thalassia testudinum or 

 shoal grass, Halodule wrightii, bordered by a 1-2 

 m drop-off into a channel. Fish <300 mm SL were 

 captured with hook and line in 1-2 m of water. 



Samples were collected weekly or twice 

 monthly from March 1982 through early May 

 1985. No samples were taken in November and 

 December 1983, October and December 1984, and 

 February 1985. During 1982, samples were col- 

 lected at dusk only; in 1983, 1984, and 1985, sam- 

 ples from dawn, midday, and midnight were also 

 taken. During each sampling period, salinity and 



temperature were recorded as well as the time of 

 capture. 



Analysis of Fish and Gonads 



Total length (TL) and standard length (SL) 

 were measured to the nearest mm for each speci- 

 men and total body weight (WT) was determined 

 to the nearest 10 g. Gonads were removed and 

 weighed to the nearest 0.1 g (gonad weight, GW) 

 and the gonadosomatic index (GSI) was calcu- 

 lated, using the formula: GSI = (GWAVT) x 100. 



Reproductive stage of the gonads was assessed 

 macroscopically using the criteria in Table 1. The 

 macroscopic criteria used were similar to those 

 used by Overstreet (1983) and Macer (1974). A 

 small portion of tissue was removed from the 

 anterior or midsection of one gonad from each fish 

 and preserved in Davidson's fixative for histolog- 

 ical analysis (Jones 1966). Tissues were dehy- 

 drated and embedded in paraffin. Seven micron 

 sections were cut and stained with Harris' hema- 

 toxylin and counterstained with eosin. Reproduc- 

 tive stage of each sample was assessed microscop- 

 ically using the criteria in Table 1. Fish with 



^Area enlarged 



Gulf of Mexico 



Figure 1. — Location of spotted seatrout sampling sites in South Texas. Asterisks denote sampling sites. 



374 



