one could measure the normal thick- 

 ness in heahhy mammals and compare 

 with abnormal animals and any avail- 

 able necropsy specimens. 



As a pilot program, echographic 

 measurements were made in both the 

 gray whale. E. robitstus. and the 

 porpoise. T. nunccUiis. Necropsy cor- 

 relation in Tursiops showed that the 

 measurements were easy to perform 

 and were highly accurate. (Figures 

 4-8.) 



Applications 



Figure 6. — A-scan of Tursiops 

 cross section. Lettered spikes 

 conform to radiograpfis and 

 tissue boundaries as measured 

 in necroscopy section: (A- 

 B) blubber ttiickness = 2 

 cm. (C-D) fat thickness = 

 1 cm, and (D-E) muscle 

 ttiickness = 8.2 cm. 



Ideally, to make this method most 

 useful, measurements should be made 

 and necropsy correlation measure- 

 ments obtained whenever these mam- 

 mals are found deceased. Due to the 

 expense and shortage of the species, 

 flying a small team to the animal site 

 with the easily portable battery or 

 generator operated scanning equip- 

 ment should be the most effective 

 means of collecting this invaluable 

 data. 



Further observations on the nutri- 

 tional status during development com- 

 paring captive and free animals, as 

 well as disease effects, should prove 

 to be a new approach to the study of 

 marine mammals. Such research data, 

 if accumulated, may be of great bene- 

 fit in the protection and treatment of 

 valuable, trained marine mammals 

 and their free swimming counterparts. 



CONCLUSION 



A-mode echography is an effective 

 means of measurement of tissue layers 

 and should be an effective tool in the 

 study of marine mammal nutrition 

 and health status. 



Figure 7. — A-scan of gray 

 wtiale dorsal-lateral surface 

 posterior to axilla demonstrat- 

 ing blubber thickness of 4.1 

 cm (A-B) and fat thickness of 

 4.6 cm B-C). C represents 

 fat-muscle interface. 



Figure 8. — A-scan of gray 

 whale for polyethylene suture 

 localization. (A) Skin. (B) 

 Blubber-fat interface at 3.5 

 cm. (C) Polyethylene suture 

 at 5.5 cm. (D) Fat-muscle 

 interface at 7 cm. 



Figure 5. — Radiograph of Tursiops cross section 

 demonstrating (A) skin-blubber interface, (B) 

 blubber-fat interface, (C) fat-muscle interface. 

 (D) muscle-fascial layer interface, and (E) re- 

 flective bone (dorsal spinous process). 



19 



