Bay squid, continued 



Table 5.05. Relative abundance of bay squid in 31 

 Gulf of Mexico estuaries (Nelson et al. 1992, 



Relative abundance: 



® 

 O 



V 

 blank 



Highly abundant 



Abundant 



Common 



Rare 



Not present 



Life stage: 



A - Adults 



S - Spawning 



J - Juveniles 



L - Larvae (paralarvae) 



E - Eggs 



na No data available 



juveniles, and adults are pelagic. 



Habitat 



Type : The bay squid occurs in the upper salinity 

 regions of estuaries around marsh grasses to the 

 inshore continental shelf when the estuarine salinities 

 are unfavorable. It is nektonic in the shallow waters of 

 these areas with most specimens found in depths of 

 <30 m. It has been observed as deep as 475 m on a 

 steep rock face (Vecchione and Roper 1 991 ), although 

 this is probably not typical. In areas where salinities are 

 favorable, squid are found in relatively deep passes 

 and/or channels where current velocity is usually high 

 (Dragovich and Kelly 1 967, Hargis 1 979a, Hargis 1 979b, 

 Laughlin and Livingston 1982, Hargis and Hanlon 

 1984, Vecchione and Roper 1991). This species is 

 unique among the cephalopods in that it can withstand 

 low salinity waters (down to 17.5%o) and become 

 common inhabitants of bays (Hixon 1980a, Hixon 

 1 980b). Paralarvae are much more abundant near the 

 bottom than near the surface in both coastal and 

 estuarine waters (Vecchione 1 991 b). Overall paralarval 

 abundance is much greater in coastal rather than 

 estuarine areas. 



Substrate : Due to its pelagic life style, the bay squid 

 occurs over a wide variety of bottom substrates, but 

 appears to be found in association with soft mud 

 bottoms (Dragovich and Kelly 1 967, Hargis and Hanlon 

 1984). 



Physical/Chemical Characteristics: Abundance is gen- 

 erally correlated with lower salinity and higher tem- 

 perature (Hixon 1980a, Hixon 1980b). 



Temperature - Paralarvae: The reported temperature 

 range for paralarval bay squid taken in nearshore 

 waters off Louisiana is 1 1 -32°C, with the highest abun- 

 dance occurring at 20-29°C (Bane et al. 1985). 



Temperature - Adults and Juveniles: Temperature 

 tolerance ranges from 1 1 ° to 33°C, and possibly as low 

 as 7°C. Low temperatures exclude squid from bays 

 during the winter months, usually December to Febru- 

 ary (Hixon 1980a, Hixon 1980b). Benson (1982) 

 reports a range of 5-34. 9°C, and a preference of 13- 

 16°C. 



Salinity - Paralarvae: Paralarval bay squid do not seem 

 to be as euryhaline as the adults and were not found 

 below 22%oOff of coastal Louisiana (Vecchione 1991b). 

 In another study, salinities where paralarval bay squid 

 were collected in nearshore Louisiana waters ranged 

 from 20-36%o, with the highest abundance occurring at 

 32-33%o (Bane et al. 1985). Tolerance of moderate 

 salinities may develop ontogenetically late during 

 paralarval development (Vecchione 1991b). 



50 



