FISHERY BULLETIN: VOL. 80. NO. 3 



it is about 1.5-2 times the eye width in C. arenar- 

 ius. Standard length (SL) was measured on all 

 fish captured off Port Aransas. A random num- 

 ber table was used to select 300 specimens each 

 month for intensive processing to determine age, 

 total weight (TW), standard length, girth (G) at 

 the anterior origin of the dorsal fin, sex, gonad 

 weight to the nearest 0.1 g, and gonad maturity 

 stage. All specimens were processed if <300 

 were collected in any month, and all fish larger 

 than the following sizes were processed: 150 mm 

 SL in April, 75 mm in September, 75 mm in 

 October, 150 mm in November, and 110 mm in 

 December. Maturity stages were assigned to 

 immature and female fish (Table 1) using a 

 slight modification of Kesteven's system (Bage- 

 nal and Braum 1971). Scales were taken above 

 the lateral line over the anal fin, where they 

 normally persisted. Cellulose acetate impres- 

 sions were examined, using a scale projector ini- 

 tially, but a dissecting microscope was employed 

 for a second reading made a year later. No scales 

 were taken from fish <60 mm SL. Annuli were 

 identified knowing the size and collection date of 

 each fish and using standard criteria (Tesch 

 1971) and procedures used for C. nebulosus and 

 C. regalis (Klima and Tabb 1959; Tabb 1961; 

 Massman 1963; Merriner 1973). Specific char- 

 acters used to identify annuli included 1) a defi- 

 nite clear zone between circuli in the anterior 

 field (Fig. 1), 2) appearance of secondary radii in 

 conjunction with the clear zone, 3) cutting over of 

 circuli in the lateral field, and 4) appearance of 

 these characters on all or most scales examined. 

 Marks interpreted as false annuli appeared on 

 only a few scales from a fish, usually lacked cut- 



Table 1.— Description of gonad maturity stages assigned to 



C. not h us. 



Stage 



Description 



Immature 

 Maturing virgin 

 Early developing 



Late developing 



Gravid 



Ripe 



Spawning/spent 

 Resting 



Gonads not visible or barely visible, 



sexes indistinguishable. 

 Gonads visible but very small, sexes 



indistinguishable to naked eye 

 Ovaries small, reddish, occupy 10% or 



less of body cavity, individual eggs 



not visible to naked eye. 

 Ovaries orangish yellow, extend length 



of body cavity and occupy 25-50% of 



it, opaque eggs clearly discernible 



to naked eye. 

 Ovaries occupy 50% or more of body 



cavity, up to half the eggs translu- 

 cent. 

 Ovaries fill over half the body cavity, 



no fat along inner margins of ovaries. 



over half the eggs translucent 

 Ovary flaccid, partially or completely 



empty, no opaque eggs. 

 Ovaries small but distinguishable in 



fish large enough to be mature. 



ting over, or lacked a clear zone between circuli 

 in conjunction with secondary radii. 



Additional specimens were collected monthly 

 from October 1977 through July 1978 off Free- 

 port, Tex., using double-rigged 10.4 m (34 ft) 

 shrimp trawls with 4.4 cm stretched cod end 

 mesh. These collections were made during the 

 day at 7-9, 11, 15-17, 18, 27, 37, and 46 m. Total 

 length (TL) was measured on all fish captured 

 and converted to standard length, using regres- 

 sion relationships presented herein. These 

 length frequencies were used to support findings 

 based on collections off Port Aransas. 



Spawned group identities (intrayear class 

 cohorts) within each year class were indicated by 

 specifying the year and probable month when 

 they hatched, e.g., August76- Spawning periodic- 

 ity and group identities assume that a 30 mm TL 



i 



V, 





Figure 1.— Scale from a 177 mm SL C. nothus captured in 

 June showing one annulus (A). The annulus is identified by cut- 

 ting over in the lateral field and secondary radii in conjunction 

 with a clear zone between circuli. A false annulus (FA) lacks 

 cutting over and was absent on several scales. The axis de- 

 picted by the long arrow indicates where scale measurements 

 were made. 



488 



