FISHERY BULLETIN: VOL. 84, NO. 4 



94°00W 



93 00 W 



92°00W 



I 



9100 W 

 i 



90°00W 

 I 



89 OOW 

 — J— 



31°00N 



30 OON- 



29 OON- 



GULF OF MEXICO 



Figure 1.— Location of study area. 



possible taxon, and standard length was measured 

 with an ocular micrometer; all specimens were sub- 

 sequently archived in 70% ethanol. Hydrographic 

 profiles of the water column were taken at approx- 

 imately 1-1.5 m intervals with a Martek Mark VI 

 water quality monitor, except during January, Feb- 

 ruary, and September 1982 when the Martek unit 

 was inoperable. During these 3 mo, water temper- 

 atures and salinities were measured with a Beckman 

 RS-5 inductive salinometer near surface, middepth, 

 and bottom. Estimates of monthly mean larval den- 

 sities were calculated by dividing total larvae by 

 total volume filtered at each depth and integrated 

 over depth. Densities are expressed as number/ 100 

 m 3 . Seasonal designations were based primarily on 

 mean surface water temperatures during the year: 

 <20°C (Winter: December-February); 20°-25°C 

 (Spring: April-May); >25°C (Summer: June- August); 

 and rapidly declining surface water temperatures 

 (Fall: September-November). 



Additional data on larval occurrence and season- 

 ality only were compiled from surface-towed meter 

 net (0.363 mm mesh) collections at stations sampled 

 between January 1981 and December 1982. These 

 data consisted of four nearshore stations located 



adjacent to the bongo stations and were sampled 

 monthly. Two additional groups of stations, one of 

 four and the other of five stations, were located 

 about 24 km south of the nearshore stations in 

 depths of about 30 m. Each group of offshore sta- 

 tions was sampled quarterly but on consecutive 

 months during 1981; thereafter, monthly samples 

 were collected only at the four station group. These 

 seasonality data are not discussed but are included 

 in the Appendix Table. 



Ancillary occurrence and seasonality data on lar- 

 val bothids, scombrids, and sciaenids collected off 

 Louisiana during the spring and early summer of 

 1982 were compiled from surface-towed 0.5 m ring 

 net (0.505 mm mesh), 60 cm bongo net (0.333 mm 

 mesh), and surface-towed 1 x 2 m neuston net 

 (0.946 mm mesh) samples (SEAMAP 1983). Bongo 

 tows were oblique and from the surface to 200 m 

 or within 5 m of the bottom at shallower depths. 

 Seasonality data for these taxa were compiled only 

 from stations located between long. 88°30'W and 

 93°30'W and shoreward of lat. 27°00'N and, al- 

 though not discussed, are also included in the 

 Appendix Table. Additional station and cruise data 

 are provided in Richards et al. (1984). 



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