BRUSHER and OGREN: PENAEID SHRIMPS IN ST. ANDREW BAY SYSTEM 



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Penaeus duorarum 



Trachypenaeus iimilis 



Sicyonia brevirosfris 



Sicyonio dorsalis 



Trachypenaeus constrictui 



LOWER AREA 

 UPPER AREA 



Penaeus aziecus 



Penaeus setilerus 



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Figure 4. — Mean total lengths of seven 

 penaeid shrimp species in the upper and 

 lower areas of the St. Andrew Bay system, 

 Fla., 1972-73. 



of the Gulf of Mexico (Brusher et al. 1972). The 

 mean total lengths of the penaeids with the ex- 

 ception of T. constrictus (Table 7) were similar to 

 those reported by Brusher et al. (1972) for speci- 

 mens caught in the Gulf of Mexico. We believe 

 that species of Trachypenaeus and Sicyonia 

 utilize St. Andrew Bay as a nursery area owing to 

 the similarity of the bay to offshore oceanic 

 habitats. 



Of the three species oi Penaeus caught in this 

 study, P. duorarum was the most abundant. High 

 abundance of P. duorarum was expected, because 

 the highest concentration of this species in the 

 Gulf of Mexico occurs in the eastern areas (Cos- 

 tello and Allen 1970). Costello and Allen as- 

 sociated P. duorarum with grass beds; grass beds 

 are abundant in St. Andrew Bay. Low abundance 

 of P. aztecus and P. setiferus was expected also, as 

 these are found most abundantly in the north- 



western (Texas coast) and north central (Louisi- 

 ana coast) portions of the Gulf of Mexico, respec- 

 tively (Cook and Lindner 1970; Lindner and Cook 

 1970). 



Although similar gear and trawling methods 

 were used, mean total lengths and length ranges 

 of P. aztecus and P. duorarum caught in the St. 

 Andrew Bay system differed greatly from those 

 caught in other gulf estuaries (Saloman 1965; 

 Trent et al. 1969; Dimham 1972). Our catches in- 

 cluded many specimens over 13.0 cm total length 

 which, according to Joyce (1965), is well above the 

 size at which shrimps of the genus Penaeus are 

 believed to leave estuarine areas. Shrimps of this 

 genus greater than 10 cm total length are usually 

 found in offshore waters (Lindner and Cook 1970; 

 Cook and Lindner 1970; Costello and Allen 1970). 



We conclude that the St. Andrew Bay system is 

 unusual among estuaries of the northern Gulf of 



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