skeletal elements from the stomach of a pinniped, 

 or forestomach of a small cetacean. I do not con- 

 sider it essential to be able to remove whole fish or 

 squid from marine mammal stomachs, as several 

 recent or current marine mammal food habit 

 studies have successfully utilized the above- 

 mentioned skeletal elements for prey species iden- 

 tification (Fitch and Brownell 1968; Evans 1975; 

 Burns and Lowry 1976). 



Soft tissue digestion in pinnipeds and small 

 cetaceans is normally quite rapid, thus it is possi- 

 ble to remove partially digested skeletal elements 

 from the stomachs of live animals a few hours 

 after the animal has eaten; and yet, because such 

 elements as otoliths, preopercular bones, and 

 squid beaks tend to resist this rapid digestion, 

 they are still available for removal several hours 

 after being consumed. In this paper I report on 

 development and testing of a lavage designed to 

 sample marine mammal stomach contents with- 

 out killing the animal. 



the entubation tube was modified by sealing the 

 distal end (stomach end) with a machined Nylon 

 plug, opening a side suction port (8.9 cm long by 

 1.25 cm wide) in the side of the tube 5 cm back from 

 the Nylon plug, and removing the inflation cuff to 

 allow passage of the irrigating solution into the 

 stomach opposite the suction port. The assembled 

 unit is detailed in Figures 1 and 2. The completed 

 unit was tested in the laboratory using a 2-liter 

 beaker in place of a marine mammal stomach. 



Marine mammals were first tested at the Naval 

 Undersea Center and Sea World, Inc. in San Die- 

 go, Calif., in December 1975. A total of five ani- 

 mals were lavaged, including two California sea 

 lions, Zalophus californianus, two Pacific white 

 sided porpoise, Langenorhynchus obliquidens, 

 and one bottlenose porpoise, Tursiops truncatus. 

 Animal weights ranged from 70 kg for the small- 

 estZ. californianus to 210 kg for the T. truncatus. 

 All animals except a 100-kgZ. californianus had 

 fasted for at least 24 h prior to being lavaged. The 



Methods 



Several design criteria were considered essen- 

 tial. The lavage unit had to be effective in remov- 

 ing skeletal elements, simple to operate, portable, 

 and capable of being used without injuring the 

 animal. Discussions with persons who had 

 pumped human stomachs or were familiar with 

 the characteristics of marine mammal digestive 

 tract anatomy resulted in the decision to utilize a 

 water-driven aspirator to create suction. A 30-mm 

 outside diameter by 1.0-m long Rousch Equine 1 

 endotracheal tube was modified for use as the irri- 

 gation and content removal device. These two 

 pieces were coupled to a machined Plexiglas 

 stomach content collection chamber with short 

 sections of clear vinyl tubing. A ball valve was 

 attached to the aspirator for vacuum control. The 

 completed unit utilized normal city water pres- 

 sure (35-50 psi) delivered through a 12-mm 

 diameter rubber hose to the ball valve as driving 

 source for the aspirator. A small hand pump was 

 connected to the irrigation port on the side of the 

 entubation tube so that warm (25°-35°C) water 

 could be pumped into the animal's stomach to 

 create a slurry which could be easily removed by 

 light suction. To facilitate removal of this slurry, 



FIGURE 1. — Schematic of lavage device. Entubation tube (a), 

 Nylon end plug (b), side suction port (c), irrigation port (d), 

 irrigating solution hand pump (e), stomach content collection 

 chamber (f). 



'Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



FIGURE 2. — Oblique view of the aspirator (a) and control valve 

 (b) attached to the top of the collecting chamber of lavage device. 



654 



