DITTY: ICHTHYOPLANKTON IN NERITIC WATERS 



January-February and off western Louisiana (Shaw 

 et al. 1985) in February-March. Stuck and Perry 

 (1982) found larval menhaden most abundant be- 

 tween January and March adjacent to Mississippi 

 Sound. These data agree with past studies (Fore 

 1970; Christmas and Waller 1981) from this area 

 that reported high densities of menhaden eggs 

 between December and February. All three of the 

 north-central Gulf studies (Stuck and Perry 1982; 

 Williams 1983; and the present study) reported 

 greatest densities of Atlantic croaker during Octo- 

 ber and November; densities of sand seatrout were 

 greatest in April, with a second smaller peak in den- 

 sity during either July or August. Both Atlantic 

 bumper and Spanish mackerel were most abundant 

 from July to September in each of these three 

 studies. Stuck and Perry and the present study also 

 found the greatest density of red drum in Septem- 

 ber; Williams did not sample in September. In the 

 present study, Atlantic thread herring were most 

 abundant in June, with a second peak in September; 

 scaled sardine were most abundant during July and 

 August. Few scaled sardine and Atlantic thread her- 

 ring larvae were collected by Williams; no Atlantic 

 thread herring and few scaled sardine were collected 

 by Stuck and Perry. All three of these north-central 

 Gulf studies also reported a bimodal peak in abun- 

 dance of engraulids but differed slightly in month 

 of peak density. Stuck and Perry, and Williams 

 found greatest densities in April, with a second 

 smaller peak in August. The smaller of the two 

 peaks in abundance of engraulids occurred in April, 

 with the greatest density in June in the present 

 study (Table 1). 



Comparison of dominant families and taxa col- 

 lected overall in the present study with those of 

 other ichthyoplankton surveys throughout the Gulf 

 of Mexico are presented in Tables 2 and 3. Lower 

 bay/coastal surveys were those conducted primarily 

 inside the 10 m depth contour, except for Hoese 

 (1965), who had a single transect of six stations out 

 to 50 m. Offshore surveys were those conducted 

 mainly in waters deeper than 10 m but shoreward 

 of the edge of the continental shelf. Although not 

 all the data listed in Tables 2 and 3 are directly com- 

 parable because of differences in gear type, mesh 

 size, or tow, these studies provide general informa- 

 tion on larval composition and abundance. 



Most of the surveys from coastal waters (Hoese 

 1965; Blanchet 1979; Williams 1983; Collins and 

 Finucane 1984; and the present study) found that 

 engraulids dominated the summer ichthyoplankton, 

 whereas Stuck and Perry (1982) reported engraulids 

 second to Atlantic bumper in abundance. However, 

 Stuck and Perry may have undersampled small 

 engraulid and clupeid larvae because of the large 

 mesh (1.050 mm) of their nets. Menhaden dominated 

 the winter ichthyoplankton in all of the aforemen- 

 tioned coastal surveys, except Collins and Finucane 

 (1984). These authors found that pigfish, Orthopris- 

 tis chrysoptera, larvae were the most abundant taxa 

 during the winter in waters off the Everglades of 

 south Florida. All of these surveys also consistent- 

 ly placed engraulids and sciaenids at or near the top 

 in total larval abundance. Overall, clupeids were 

 relatively more abundant off south Florida (Collins 

 and Finucane 1984) than in the other coastal 

 surveys, except Hoese (1965), who sampled only the 



Table 2.— Comparison of the five most abundant families collected overall from neritic waters off Louisiana with other ichthyoplankton 



surveys throughout the Gulf of Mexico. 



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