MONTHS (OCTOBER 1979 THROUGH SEPTEMBER 19801 



FIGURE 3. — Summary by number and by weight of the catch 

 data for southern kingfish at stations sampled monthly from 

 October 1979 through September 1980. 



the distribution of this species in these offshore 

 areas of Mississippi are available for comparison. 



Salinity Range 



Southern kingfish were captured in waters 

 ranging in salinity from 2.0 to 36.61., with the 

 majority found above 20.0 (Table 1). The mean 

 salinity for the Mississippi coastal waters where 

 southern kingfish occurred at regularly sampled 

 stations was 23.4/.. During the fall groundfish 

 cruise, bottom salinities where southern kingfish 

 were taken ranged from 31.4 west of the Missis- 

 sippi River Delta to 36.6 south of Horn Island, 

 with an average bottom salinity of 34.51 . No bot- 

 tom salinities were available during the spring 

 offshore cruise because of equipment problems. 



Temperature Range 



Young-of-the-year and adult southern kingfish 

 were captured in waters with bottom tempera- 

 tures ranging from 8.0°C in December to 37.3°C in 

 August. The largest catches were taken in waters 

 ranging from 20.0° to 30.0°C. Larval and postlar- 

 val fish (0.5-20.0 mm SL) were found from May 

 through November in the shallow inshore waters 

 and northern tidal zones of the barrier islands at 

 temperatures ranging from 12.0° to 37.3°C. 



The bottom water temperatures where southern 

 kingfish were taken for the fall groundfish cruise 

 ranged from 22.4° to 25.5°C (average of 23.2°C) 

 and for the spring cruise ranged from 22.4° to 

 25.5°C (average of 22.3°C). In general, bottom 

 temperatures on offshore cruises decreased with 

 increasing depths. 



Length- Weight Relationship 



The length-weight relationship was calculated 

 for the 1982 southern kingfish (ranging from 0.5 to 

 291.0 mm SL) by the following regression equa- 

 tion: 



Log W = -4.48683 + 2.92908 Log L 



where W = weight in grams and L = standard 

 length in millimeters (Fig. 4). The coefficient of 

 determination R 2 was 0.9779. 



Length-Frequency Data 



At stations sampled monthly, southern kingfish 

 juveniles (<50 mm SL) were most common from 

 May through October; fish in the 100-150 mm SL 

 range were fairly constant all year with a peak in 

 March; and fish in the 150-250 mm SL range were 

 rare during all months except April (Fig. 5). 

 August was the only month where fish 10 mm SL 

 or less were captured. The majority of the fish cap- 

 tured during the two offshore cruises were > 100 

 mm SL with an average of 174 mm SL (Fig. 6). 



The mean sizes of southern kingfish taken at the 

 monthly stations were generally much smaller 

 than those from the offshore groundfish cruises 

 because young-of-the-year utilize the estuaries 

 and inshore waters as nursery grounds. Gear 

 selectivity must also be taken into account be- 

 cause the larger trawls used offshore are ineffi- 

 cient for capturing juveniles. 



Discussion 



Young-of-the-year frequented estuaries and in- 

 shore waters, while adult southern kingfish were 

 found to be more abundant offshore in deeper 

 waters. This was also reported by Pearson (1941) 

 for the Chesapeake Bay area and by Geagan ( 1962 ) 

 for the coastal waters of Louisiana. Irwin (1970) 

 found the most common habitat for juveniles <50 

 mm SL to be open surf on sandy beaches, whereas 

 in this study they occurred most often in sandy 

 tidal zones of the barrier islands and estuaries. 



High offshore catches and very low inshore 

 catches from December through April support 

 reports by Gunter (1938, 1945) and Christmas 

 and Waller (1973) that adult southern kingfish 

 migrate offshore during winter months and are 

 summer residents of the estuaries. Similar reports 

 were made by Mcllwain (1978) for recreational 



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