numbers recorded by the shore ob- 

 servers six times. In three instances of 

 poor (white caps and 4-6 foot swells) 

 sea state conditions, on the other hand, 

 the aerial observers were unable to 

 contirm groups or individuals sighted 

 by the shore observers. These data 

 suggest that, although aerial observa- 

 tions may be more directly limited by 

 sea conditions, they are useful in 

 quantifying the number of whales in 

 groups. Further, resolution of num- 

 bers present is faster from the air 

 than from shore. (It often takes the 

 shore observers up to 30 minutes to 

 determine their count for a given 

 group — during which time the in- 

 dividuals in the group may dissociate 

 or join with others.) 



Resolution of numbers of whales 

 in groups is more rapid and apparent- 

 ly more accurate from the air than 

 from shore. With a professional spot- 

 ter pilot working a limited area — 

 such as that scanned by the shore ob- 

 servers — in good sea state conditions, 

 essentially no whales will pass unno- 

 ticed. "Misses" by the aerial observers 

 were due to leaving the area premature- 

 ly in order to accomplish other tasks; 

 had the aircraft been consistently in 

 the shore observers' area (and immedi- 

 ately outside to prevent unnoticed 

 passage of individuals offshore) none 

 would have gone unrecorded. 



The aerial observers made ."^O ob- 

 servations of whales involving 149 

 animals. All these observations oc- 

 curred within 7 miles of the shoreline, 

 even though the area surveyed ex- 

 tended to 25 miles seaward. Of these 

 sightings. 98 percent were within 5 

 miles of shore. 96 percent within .^ 

 miles, and 94 percent within I mile. 

 Distances were estimated by making 

 timed runs at constant speed from 

 pi>sitions offshore to the coastline. 

 The observations of this study tend 

 to confirm Rice and Wolmans state- 

 ment that 95 percent of the whales 

 pass within 1.9 km (1.2 miles) ot the 

 shore near the Yankee Point site. 



Gray whales have been reported 

 interacting with other marine mam- 

 mals by Leatherwood (1974b). but 



during this study no other marine 

 mammals were observed "associating" 

 directly with gray whales. Feeding 

 behavior was observed on two occa- 

 sions. A calf was seen accompanied by 

 an adult. These two latter observa- 

 tions are of particular note and the 

 senior author intends to publish the 

 details elsewhere.' 



' Sund. P N Manuscript Evidence of feeding 

 during migration and of an early birtti of the 

 California gray whale 



LITERATURE CITED 



Leatherwood. J. S. l'J74a. Aerial observa- 

 tions of migrating gray whales. Eschrich- 

 liiis rubusitts, otT southern California 

 (1969-1972). Mar. Fish, Rev. 36(4):45-49. 



. 1974h. A note on gray whale 



behavioral interactions with other marine 

 mammals. Mar. Fish. Rev. 36(4):49-?0. 



Levenson, C. 1968. Factors aftecling bio- 

 logical observations from the ASWEPS 

 aircraft. U.S. Naval Oceanogr. Off., In- 

 formal Rep.No. 68-102, 6 p. 



Rice. D. W., and A. A. Wolnian. 1971. 

 The life history and ecology of the gray 

 whale {Eschnchtnts nihusius). Am. Soc. 

 Mammal., Spec. Publ. No. .3. 142 p. 



MFR Paper 1057. From Marine Fisheries Review, Vol. 

 36. No. 4. April 1974. Copies of this paper, in limited 

 numbers, are available from D83. Technical Information 

 Division. Environmental Science Information Center, 

 NOAA, Washington. DC 20235. 



MFR PAPER 1058 



Telemetering of Temperature and Depth Data 

 From a Free Ranging Yearling California Gray 

 Whale, Eschrichtius robustus 



W. E. EVANS 



ABSTRACT 



//; /y6(S' //((■ iiinlinr iiiiluilcti a .scries nf Miii.lics iisiiii; icidic iniii.sniillcr.s lo 

 jollow ilw nidViincnls iiiitl sliidy ilw cliviiii^ hchiivior ol snuill Icollwil whales. 

 This paper dc.si ril'cs the miulifu iilit'irs tij this ccpiipniciU necessary lo use this 

 Icchniquc on larj^cr wTnilcs. in this case a yciirliiii; California ,t,'/((y wliale, 

 Eschrichtius robustus. In addition lo the iransinission of positional data, i.e. 

 azinuilh anil deplh of dive, the ittsininicnlalion pnekaf^e used in this study was 

 desii;ncd lo trausnui environmental data (tcinperaturc-al-depihl. The animal 

 used in this study, a Jemalc E. robustus, U(/.v captured on /.■? March 1971. in 

 Smnimon's Lagoon. Baja California Siir. Mexico, hy Sea World, Inc., San Diei.;o, 

 and released on 13 March 1972. at hit. 32''4I.5'N. lonn- 1 17^^ 20.5' W {off Point 

 Loina. San Die.i^o. Calif.) hy the Naval Undersea Center (NUCI. San Diei;o. 

 Rtulio contact was maintained with the animal iinlil .'^ May 1972. Deplh oj dive 

 and leinperalure-al-deptli data w ere idnlniuouslv mniiiloreil for a 24-hoiir period. 



INTRODUCTION 



The present stud\ is an extension 

 of a 6-year research program designed 

 io evaluate the feasibility of usmg 

 medium-si/ed lo large cetaceans, in- 

 strumented with a combination data 

 collection and transmission system. 



to measure physical oceanographic 

 parameters at various depths, and to 

 evaluate the relationship of these 

 parameters to cetaceans' movement 

 patterns and secondary productivity 

 (Evans. 1970. 1971. in press). 



Because of the impending release 

 of a yearling California gra\ whale 



52 



