to identification of Atlantic bluefin tuna stockB. Int. 

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Mather, F. J., m. and H. a. Schuck. 



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Parks, W. W. 



1977. Cohort and equilibrium yield-per-recruit analyses 

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 two system configurations and two natural mortality 

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 PIENAAR, L. v., AND J. A. THOMSON. 



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In press. Proposed terminology for size groups of the north 

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RAYMOND E. BAGLIN, JR. 



Southeast Fisheries Center Miami Laboratory 



National Marine Fisheries Service, NOAA 



75 Virginia Beach Drive, Miami, Fl 33149 



Present adireBa: National Marine Fisheries Service, NOAA 



do Alaska Department of Fish and Game 



P.O. Box 686, Kodtak, AK 99615 



DEVELOPMENTAL ANATOMY AND INFLATION 



OF THE GAS BLADDER IN STRIPED BASS, 



MORONE SAXATILIS 



In 1974, a percentage of striped bass, Morone 

 saxatilis, fingerlings reared at the Cooperative 

 Fishery Research Laboratory, Southern IlUnois 

 University, lacked an inflated gas bladder. The 

 purpose of this study was to describe the de- 



velopmental anatomy of the gas bladder and its 

 associated structures in striped bass so that a bet- 

 ter understanding of the inflation mechanism 

 could be obtained. 



With regard to gas bladder morphology, bony 

 fishes are classified as physostomes or physocUsts. 

 Generally, the more ancient, soft-rayed fishes 

 (Malacopterygii) are physostomous, while the 

 more modern, spiny-rayed fishes (Acanthop- 

 terygii) are physoclistic (Lagler et al. 1962). A 

 physotome possesses a hollow connection, the 

 pneumatic duct, between the gut and the gas blad- 

 der throughout its entire life. Some physotomes 

 gulp surface air through the pneumatic duct to 

 initiate inflation of the gas bladder (Tait 1960). 

 Fish that are physoclistic do not possess this open 

 connection as adults. Some physoclists, however, 

 do possess a pneumatic duct as larvae, but the duct 

 atrophies prior to adulthood. Giinther's (1880) 

 examinations have shown that adult striped bass 

 are physoclistic. Doroshev and Comacchia ( 1979) 

 give a partial description of the development of the 

 gas bladder in striped bass. 



Several theories have been advanced to explain 

 how the gas bladder is initially inflated in fishes 

 that do not gulp surface air or are physoclistic 

 prior to initial inflation. Some of these theories 

 include: gases produced by the disintegration of 

 organic materials (Powers 1932); production of 

 gasses as a result of digestion (Johnston 1953); 

 vacuolation of the gas bladder epitheUa (McEwen 

 1940); and functioning of a rete mirabile, or gas 

 gland (Schwarz 1971). 



Methods 



Histomorphological Studies 



Striped bass larvae were obtained from the 

 Hudson River, N.Y., and Lake Charles, La. Upon 

 arrival, the 1- to 4-day-old larvae were transferred 

 into 200 1 aquaria and maintained at 16°-18° C. 

 Brine shrimp, A rfemta salina, were fed regularly 

 to the larvae. Eighty-three striped bass larvae 

 4.3-24 days old (from the time of hatching) were 

 removed from the aquaria and prepared for his- 

 tological study. The larvae were fixed in either 

 10% Formalin^ or Bouin's fluid, dehydrated in a 

 series of graded alcohols, cleared in benzene, and 

 embedded in Carbowax. From a representative 



'Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



1000 



FISHERY BULLETIN VOL 77. NO 4. 1980 



