are released on the sea bottom within 5 to 15 

 min from the time the unit enters the water, 

 depending on the size of the salt block. 



The release tube (Fig. 8), intended for use 

 in shallow water, consists of two telescoping 

 aluminum pipes, each about 3 m (10 ft) long. 

 To release shrimp, the outer pipe is lowered to 

 the bottom and shrimp are poured from a pail 

 into the funnel. After each pail of shrimp is 

 poured into the unit, the apparatus is flushed 

 with several pails of water to insure that shrimp 

 do not remain in the tube. The pouring and 

 flushing of one pail of shrimp usually take about 

 1 min. 



The new equipment described herein and the 

 improved techniques for staining and tagging 

 described by Neal (1969) enabled us to hold. 



(lOIN ) 



FUNNEL 



TELESCOPING 

 ALUMINUM PIPES 



LINE FOR 

 LOWERING ' 



12 7 CM 

 5 InT 



3 1 M (10 FT) 



mark, and release large numbers of shrimp. 

 We can now process between 1,500 and 3,000 

 shrimp per day, depending on the type of mark 

 used. 



Literature Cited 



COSTELLO, T. J. 



1964. Field techniques for staining-recapture ex- 

 periments with commercial shrimp. U.S. Fish 

 Wildl. Serv., Spec. Sci. Rep. Fish. 484, 13 p. 

 Neal, Richard A. 



1969. Methods of marking shrimp. FAO (Food 

 Agr. Organ. U.N.) Fish. Rep. 57, 3: 1149-1165. 



Dennis A. Emiliani 



National Marine Fisheries Service 

 Biological Laboratory 

 Galveston, Texas 77550 



AN ADULT BLUEFIN TUNA, Thunnus thynnus, 



FROM A FLORIDA WEST COAST 



URBAN WATERWAY' 



The bluefin tuna, Thunnus thymius (Linnaeus), 

 is a wide-ranging pelagic species occurring in 

 most tropical and temperate seas (Gibbs and 

 Collette, 1966: 119). In the Gulf of Mexico 

 exploratory and commercial catches have been 

 limited to the northern, western, and central 

 parts, from waters beyond the continental shelf. 

 The collection of a large adult from the Florida 

 west coast represents a new record for the Flor- 

 ida shelf. 



The specimen, a female, was captured by local 

 fishermen with harpoons in a waterway at 

 Hudson, Fla., (lat 28°21'24" N, long 82°42'42" 

 W) on 10 May 1970. It weighed 239 kg (525 

 lb.), was 244 cm (96 inches) in fork length and 

 168 cm (66 inches) in girth, and appeared to 

 be in healthy but lean condition, characteristic 

 of post-spawning fish in May on the Bahama 

 Banks (Rivas, 1955: 139). 



Histological examination of gonadal tissue 

 sectioned at 6 ,u, and stained with Harris hema- 

 toxylin and Eosin Y showed early and late atretic 



Figure 8. — Release tube used to place marked shrimp 

 on the bottom. 



' Contribution No. 154. 



251 



