Literature Cited 



DOTSON, R. C. 



1977. Minimum swimming speed of albacore, Thunnus 

 alalunga. Fish. Bull., U.S. 74:955-960. 



Japanese Fisheries agency. 



1975. Report of tuna tagging for 1974. [In Jap.] Pelagic 

 Res. Sect., Far Seas Fish. Res. Lab., 18 p. 



LAURS, R. M., AND R. J. LYNN. 



In press. Seasonal migration of North Pacific albacore, 

 Thunnus alalunga, into North American coastal waters: 

 Distribution, relative abundance, and association with 

 Transition Zone waters. Fish. Bull., U.S. 75. 

 LAURS, R. M., H. S. H. YUEN, AND J. H. JOHNSON. 



1977. Small-scale movements of albacore, Thunnus 

 alalunga, in relation to ocean features as indicated by 

 ultrasonic tracking and oceanographic sampling. Fish. 

 Bull., U.S. 75: 

 MAGNUSON, J. J. 



1970. Hydrostatic equilibrium of Euthynnus affinis, a 

 pelagic teleost without a gas bladder. Copeia 1970:56-85. 

 SHARP, G. D., AND R. C. FRANCIS. 



1976. An energetics model for the exploited yellowfin 

 tuna, Thunnus albacares, population in the eastern 

 Pacific Ocean. Fish. Bull., U.S. 74:36-51. 



SIDWELL, V. D„ P. R. FONCANNON, N. S. MOORE, AND J. C. 

 BONNET. 



1974. Composition of the edible portion of raw (fresh or 

 frozen) crustaceans, finfish, and mollusks. 1. Protein, 

 fat, moisture, ash, carbohydrate, energy value, and 

 cholesterol. Mar. Fish. Rev. 36(3):21-35. 



Gary D. Sharp 



Inter-American Tropical Tuna Commission 

 La Jolla, CA 92038 



RONALD C. DOTSON 



Southwest Fisheries Center 



National Marine Fisheries Service, NOAA 



P.O. Box 271, La Jolla, CA 92038 



UNDERWATER SOUNDS FROM RIBBON SEAL, 

 PHOCA (HISTRIOPHOCA) FASCIATA 1 



Intense downward frequency "sweeps" and broad- 

 band "puffing" sounds were recorded underwater 

 in the presence of ribbon seal, Phoca (His- 

 triophoca) fasciata Zimmerman 1783. The record- 

 ings were made in the waters off Savoonga, St. 

 Lawrence Island, Alaska, on 16, 17, 18, and 23 

 May 1967. 



The seals were encountered in the final ice of the 

 spring made up of windrows of small to moderate 

 floes mixed with brash ice, and with stretches of up 



to 1 km of open water between. On this ice typi- 

 cally occur adults and pups of a variety of other 

 pinniped species (Phoca largha, Erignathus bar- 

 batus,Pusa hispida, andOdobenus rosmarus), but 

 during the spring of 1967 there was a preponder- 

 ance of Histriophoca in this area. This is reflected 

 in the records of the pinniped harvest for this area 

 (Alaska Department of Fish and Game) which 

 show that Histriophoca usually composes less 

 than 2% of the catch, but in 1967 it made up 60% of 

 the harvest and most of the Histriophoca were 

 caught during the last half of May. The 1967 

 underwater recordings showed similar differ- 

 ences, contrasting sharply with previous years 

 when Erignathus dominated the underwater 

 sound ambient (Ray et al. 1969). 



Relatively little is known of the behavior of His- 

 triophoca (cf. Scheffer 1958; King 1964). Breeding 

 assemblages occur on ice that rarely approaches 

 shore (Burns 1970) and other social behavior may 

 mostly occur in the water. 



Instruments and Methods 



Underwater sounds were recorded with a 

 Chesapeake Instrument Corp. 2 hydrophone sys- 

 tem and a Nagra III B tape recorder whose com- 

 bined response was 50 Hz to 18 kHz ( ±2 dB, deci- 

 bels). The sounds were studied by means of a Kay 

 Elemetrics 7029A spectrographic analyzer and 

 time sequences were measured by a Tektronix 565 

 oscilloscope. 



To make the recordings, appropriate His- 

 triophoca habitat in the sea ice was located with 

 the aid of Eskimo hunters, and their skin boat was 

 allowed to drift with the ice while the hydrophone 

 was in the water. Only a few of these seals were 

 seen as we approached, and they always sub- 

 merged and were difficult to find again. However, 

 some of their underwater sweep sounds were loud 

 enough to be audible in air, implying that these 

 seals were not far away. 



Taped sequences of 5 to 8 min duration were 

 analyzed from each of nine locations over 4 days of 

 field study. Higher level underwater sounds, pre- 

 sumably from nearby seals, were analyzed and 

 compared with background lower level sounds. 

 Sounds from distant animals were not used for 

 detailed analysis. 



As is usually the case with underwater record- 



contribution No. 3753 from the Woods Hole Oceanographic 

 Institution. 



2 Reference to manufacturers does not imply endorsement by 

 the National Marine Fisheries Service, NOAA. 



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