A CENSUS OF THE CALIFORNIA GRAY WHALE _«lv»n!i! %\ ..vii SPECIAL SCIENTIFIC REPOKT-FISHERIES Na 342 United States Department of the Interior, Fred A. Seaton, Secretary- Fish and Wildlife Service, Arnie J. Suomela, Commissioner Bureau of Commercial Fisheries, Donald L. McKernan, Director A CENSUS OF THE CALIFORNIA GRAY WHALE by Raymond M. Gilmore Formerly, Biologist, Marine Mammal Research [Edited by Dale W. Rice] United States Fish and Wildlife Service Special Scientific Report: Fisheries No. 342 Washington, D. C. May I960 HUMP BLOWING ".* — CRENULATIONS Frontispiece: Identification features of the gray whale. ii CONTENTS Page Summary ^ Introduction ^ Objectives ^ Acknowledgments ^ Taxonomy and distribution of the gray whale 3 Taxonomy ^ Distribution 4 Distribution and migration of the California population 6 Summer range o Bering -Chukchi area 6 California-Oregon area 6 Southward migration 7 Winter range 1 Areas of migrating and wandering 9 Calving areas 9 Northward migration 14 Behavior studies 15 Behavior during migration 15 Orientation to land 15 Daily cycle of observations 15 Social behavior 16 Behavior on the winter range 16 Outer and intermediate area 16 Inner nursery area 18 Reproduction and mortality 18 Reproduction 18 Mortality 18 History of the California gray whale population, 1850-1952 19 Shore census of the southward migration, 1952-53 to 1956-57 20 Methods 20 Areas 20 Procedure 21 Extrapolations 21 Results 22 Census of 1952-53 22 Census of 1953-54 22 Census of 1954-55 23 Census of 1955-56 23 Census of 1956-57 23 Summary of shore censuses 23 Aerial surveys of the wintering grounds, 1952-57 25 Methods 25 Areas 25 Procedure 25 Results 26 Survey of 1 952 26 Survey of 1953 26 Survey of 1954 28 Survey of 1955 28 Survey of 1956 28 Survey of 1957 28 Summary of aerial surveys 29 Literature cited 29 Page FIGURES Frontispiece: Identification features of the gray whale ii 1. Distribution of the gray whale 5 2. Migratory routes of the gray whale (southern part) 8 3. Daily counts and extrapolations of gray whales passing San Diego during the southward migration, 1954-55 9 4. Gray whale winter grounds 10 5. Northern area of migrating and wandering 11 6. Vizcaino area of migrating and wandering 11 7. San Juanico area of migrating and wandering 11 8. Cabo San Lucas area of migrating and wandering 11 9. Former San Diego calving area 12 10. Vizcaino -Scammon calving area 13 11. San Ignacio calving area 13 12. Magdalena calving area (northern part) 13 13. Magdalena calving area (southern part) 13 14. Yavaros calving area 14 15. Reforma calving area 14 TABLES 1. Frequency distribution of group size of gray whales during the south- ward migration past San Diego 17 2. Frequency distribution of group size of gray whales on the breeding ground 18 3. Counts and extrapolations of gray whales passing San Diego, California, during daylight hours, 1956-57 24 4. Summary of shore censuses of gray whales in southward migration, 1952-53 to 1956-57 25 5. Summary of air censuses of gray whales on winter range, 1952-57 .... 27 IV SUMMARY Gray v/hsil e s, Eschrichtius gibhosus (Erxleben) 1777, were originally three isolated stocks, termed the Atlantic, California, and Korean populations. The Atlantic population has long been extinct; the Korean population has been severely reduced in numbers. The present study concerns only the Cali- fornia population. Most California gray whales spend the summer (June through September) in the northwestern Bering Sea and the Chukchi Sea. A few summer along the coast of northern California and southern Oregon. The southward migrating whales strike the Pacific coast of North America between Vancouver Island and San Francisco. They then travel within about 4 miles of the shore until they reach Baja California. A few are believed to leave the coast at Point Conception, moving past the offshore side of the Channel Islands before striking the coast again south of San Diego. Most southbound whales pass San Diego between the middle of December and the middle of Feb- ruary. In winter (early January to the end of February) gray whales are scat- tered along the Pacific coast from about San Diego to Cabo San Lucas, and in the southern end of the Gulf of California. A few stragglers have been observed in the northern Gulf and at Guadalupe and Clarion Islands as well as at various points as far north as the coast of British Columbia. Calving takes place in shallow la- goons, bays, and esteros. The five important calving areas are: (1) Viz- caino-Scammon; (2) San Ignacio and (3) Magdalena, along the Pacific Coast of Baja California; and (4) Yavaros and (5) Reforma, on the east shore of the Gulf of California. San Diego Bay, California, is no longer a calving area. The northbound migrants pass San Diego mainly in March and April. They move along the coast, and many pass the west side of Vancouver Island before turning off into the North Pacific, The rate of migration is fairly uni- form throughout the day. Movement apparently is slightly greater in the afternoon, when the fog tends to lift. No data are available on rate of mi- gration at night. For census purposes, movement at night is held to be 50 percent of the daylight rate of 4 knots. Gray whales are not strongly gre- garious during migration. They usu- ally travel singly or in groups of two or three. Singles, presumably pregnant females, are common in the early stages of the southward migration. Immature individuals and nonbreed- ing adults predominate in the outer channels near the entrances of breed- ing lagoons; pairs and trios of courting adults predpminate in the intermediate areas, and cows with calves predomi- nate in the inner "nursery" areas. Adult cows bear one calf at 2 -year (or longer) intervals. Gestation ap- parently lasts 11 to 12 months. Ehiring a 4 -season study in Laguna Scammon, 12 dead calves and 2 dead adults were found. The mean length of 7 calves, measured in January and February, was 13.25 feet. From 1850 to 1890, whaling opera- tions along the coast of California and Baja California reduced the California gray-whale population of 25,000 to 50,000 to perhaps a few thousand. From 1890 to 1924, the population increased. From 1924 to 1937, whaling was again carried on. Since 1937, the species has had complete legal pro- tection. Counts of gray whales during their southward migration past San Diego, in the seasons 1952-53 through 1956- 57, suggest that the population is in- creasing, possibly as much as 10 percent a year. The estimated popu- lation, including corrections for whales passing unseen during periods of dark- ness and poor visibility, and whales passing offshore, was 2,894 in 1952-53 and 4,454 in 1956-57. Aerial censuses of the winter range indicate the extent of the breeding grounds and their relative use by whales. The most important areas are: (1) Vizcaino -Scammon, with 1 ,500 to 2,000 whales (about half the total population); (2) San Ignacio, with about 500 whales (one -eighth to one-sixth the total population); and (3) Magdalena, with 1,000 to 1,500 whales (about one- third the total population). A CENSUS OF THE CALIFORNIA GRAY WHALE INTRODUCTION OBJECTIVES The main objectives of this study have been ( 1 ) to estimate the size of the total population and its pres- ent rate of increase, (2) to deter- mine the extent of the breeding grounds and their relative impor- tance, (3) to determine the time and nature of the southward migration past California, and (4) to establish a basis for detecting, in the future, any unusual changes in population size. The study was carried on by the author for five years. With minor exceptions, biological information based on specimens was not obtained. The International Convention for the Regulation of Whaling, which protects the gray whale, provides for taking scientific specimens. Exact informa- tion on age and reproduction can be obtained in the future from specimens. Observations in Bering and Chukchi Seas will be needed to provide infor- mation on food habits as well as refinements in knowledge of migration routes. ACKNOWLEDGMENTS The help of the following individuals is gratefully acknowledged: G. Bara- cott, Patricia Barton, O. Beasley, J. Berdegue', D. Brown, C. Caito, C. Chamberlain, W. Clinkscales, R. Coughlin, Mr. and Mrs. D. E. Day, L. Dean, D. Douglas, G. C. Ewing, L. Farrar, A, Flechsig, R. Grom, D. Hall, W. Hapgood, W. Harder, K. Harris, E. Hess, R. Hoffman, A. Hourston, C. L. Hubbs, J. Isaacs, J. Jenks, S. Jewell, A. Kelly, R. L. King, R. Lankford, D. Lear, C. Limbaugh, J. McFall, R. Menzies, R. Meryman, J. H. Millard, D. Miller, Madeline Miller, Gladys Niebur, F. Nolan, K. Norris, Grace Orton, F. Phleger, G. C. Pike, A, B. Rechnitzer, D. Robinson, A. Rodriguez, W. E. Schevill, M. Shear- son, J, Snodgrass, J. Stackleberg, H. Stewart, C. Tuthill, S. Z. Varnes, A. M. Vrooman, T. Walker, P. D. White, J. Whitehead, and T. Widrig. Special thanks are due to C. L. Hubbs and G. C. Ewing, both of Scripps Insti- tution of Oceanography. The contribu- tions of these two will be explained in the text. TAXONOMY AND DISTRIBUTION OF THE GRAY WHALE TAXONOMY The scientific name of the gray whale has been changed several times in the past 30 years. The living species commonly called the gray whale was long known by the specific name Agaphelas glaucus, given by Cope (1868). Later (1869) Cope placed the species ^Zaucus in the new genus Rhachianectes. Rhachia- nectes glaucus means "the gray swimmer along the rocky shore," and a more fitting name hardly could have been coined. However, a prior name existed which would eventually be recognized to include glaucus and by the interna- tionally recognized rule of priority, Rhachianectes has been superseded. To Tomilin (1957), Cope's name for the living gray whales of the Pacific is antedated by the name Balaena agamachschik Pallas, 1811. In 1937, subfossil bones of gray whales, believed identical with the living species, were described in de- tail by van Deinse and Junge, from Recent deposits in the drained polders of the Zuider Zee, Holland, These investigators identified earlier -de- scribed fossils from Sweden and England, which possess names that antedate glaucus, as those of the living species of gray whale. One of these early names for a fossil gray whale from Gras6, Sweden, in the Gulf of Bothnia, was Balaenoptera robusta Lilljeborg, 1861. Three years later Gray (1864) set up a subgenus Eschrichtius with robusta as type species. Later (1865), Gray raised Eschrichtius to ge- neric rank, and Lilljeborg followed suit, calling the Graso whale Eschrichtius robustus. Van Deinse and Junge, however, discovered an even earlier name, Balaena gibbosa Erxleben, Mil, based on the "scrag" whale of New England origin and first mentioned by Dudley in 1725 with a description suspiciously like the gray whale, which stated, "A Scrag Whale. Is near akin to the Fin-back, but instead of a fin upon its back is scragged with half a dozen knobs or knuckles. He is nearest the Right Whale in figure and quantity of oil. His bone [whalebone] is white but wont split." Van Deinse and Junge applied the name Eschrichtius gibbosus to all popu- lations of gray whale, living and ex- tinct, thus assuming that the gray whale lived on the New England coast in the 18th Century. The gray whale has never been known, either from other reports or from specimens, to inhabit the entire western North At- lantic . This action proved too much for Schevill ( 1 954), who termed the "scrag" whale and its name gibbosa a "literary curiosity." In a neat turn of logic, he stated that if the fossil gray whales could not be shown different from the living form, as stated by van Deinse and Junge, then, neither could they be shown identical, presumably because soft parts were not examined and complete fossil skeletons were not available. Schevill thereby held Eschrich- tius robustus to be the proper name for the fossil specimens from the north- eastern Atlantic, and E. glaucus for the living form of the Pacific. In this he was followed by Miller and Kellogg (1955). Such reasoning can lead only to taxonomic chaos. Until nnorphological differences have been demonstrated between the extinct Atlantic and the living Pacific populations, a single name must be applied to all popula- tions. It is unlikely that the populations were miore than subspecifically dis- tinct, at most. At any rate, the name glaucus Cope would be invalid for the Pacific populations because the name agamachschik Pallas has priority. The name Eschrichtius gibbosus Erxle- ben, \in , has been adopted by most recent authors (e.g., Cederlund 1939; Ellerman and Morrison-Scott 1951; Tomilin 1957; Slijper 1958). Although this name rests on a somewhat debat- able basis, it is used by the present writer. If this name were rejected, the correct name would become fscAric^.- tius agamachschik Pallas, 1811. Such ac- tion would be unfortunate as Pallas' name was overlooked for many years and has never been used by other authors. DISTRIBUTION There are two distinct populations of living gray whales: one known as the California population, in the eastern North Pacific; the other, known as the Korean population, in the western North Pacific. A third population, now ex- tinct, occupied the eastern North At- lantic (fig. 1 ). There is some evidence that the two Pacific populations have not mixed in the 20th Century (Andrews, 1914). Zenkovich (1934) believed that the east coast of Kamchatka was, in his time, unoccupied by gray whales in summer and constituted a large unbridged gap between the respective summer ranges. Risting (1928), however, reported a catch of gray whales made on the east Figure 1.— Distribution of gray whale. coast of Kamchatka. Thirty -one whales (19 males, 12 females) taken from July 27 to August 22, 1925, with Na- thalia Bay as a base, ranged from 25 to 36 feet in length. This was a smaller and younger group of whales than was taken by the same vessel from Bahfa Magdalena, Mexico. Risting believed they had migrated from Mexi- can, rather than Korean, breeding grounds. Sleptsov (1955) stated that the populations "probably nnixed before each herd was reduced to very low figures." Distribution and migration of the California population will be discussed in detail in the next chapter. Gray whales of the Korean popula- tion spend the summer in Okhotsk Sea. The same whales were reported by Scammon (1874), Andrews (1914), and Mizue (1951) to spend the winter in the waters of South Korea, and per- haps the Yellow Sea. These whales apparently calve in the channels, in- lets, and bays along the rocky coast of South Korea. Fraser (1937) reported that gray whales were taken with nets by the Japanese as far back as the 17th century, but the harvest was unim- portant. After 1903, gray whales were captured in unrestricted numbers by modern whaling equipment and by 1938 the population was so low that all further whaling ceased because it was unprofitable. There are no estimates of the number remaining when whaling stopped. Subfossil remains of gray whales of the Atlantic population have been un- earthed from Recent deposits at three localities in Europe: (1) Grisd, Swe- den; (2) Cornwall and Devon, England; and (3) Zuider Zee, Holland (van Deinse and Junge 1937). The gray whale ap- parently survived into historical times off the coast of New England, where it was captured by early 18th century whalers under the name "scrag" whale (Dudley, 1725). DISTRIBUTION AND MIGRATION OF THE CALIFORNIA POPULATION SUMMER RANGE Most California gray whales appar- ently spend the summer in the Arctic -- in the Bering and Chukchi seas. No gray whales have ever been followed from one ground to the other, nor marked in one area and recovered in the other. However, the times of dis- appearance and reappearance of gray whales in the winter grounds off Baja California and in the summer Arctic grounds, along with the direction of movement, lead to the assumption that these whales are of the same herd. A few have recently been found in summer on the coast of northern Cali- fornia and southern Oregon. cording to Zenkovich ( 1 934) and Sleptsov (1955), gray whales arrive in north- western Bering Sea and Chukchi Sea in June and stay through September, Ichihara (1958) reported a single gray whale in Unimak Pass on May 29, 1957, and another seen from a whale catcher on July 28, west of St. Law- rence Island. Also, on August 2, be- tween 63034'N., 172°48'W. and 63° 54'N,, 170°50'W. (west of St. Lawrence Island) three groups consisting of 3, 20, and about 150 gray whales, 36 to 41 feet in length, were seen and photo- graphed by Keiji Nasu of the Whales Research Institute. The larger ag- gregations were divided into smaller groups of one to three whales. Bering-Chukchi Area No studies of gray whales were con- ducted in the Bering -Chukchi area during the present investigations. Ac- California -Oregon Area A whaling company operating out of Humboldt Bay, California, in the 1940's, found a small herd of gray whales spending the summer around Crescent City, St. George Reef, and Pelican Bay, Oregon, 75 to 100 miles north of Humboldt Bay. In September 1947 and June 1948, the writer saw 12 to 15 gray whales in Pelican Bay. SOUTHWARD MIGRATION California gray whales, in the course of their southward migration, are as- sumed to move across the open waters of the North Pacific from the vicinity of the Aleutian Islands to the coast of the United States. They reach the coast at points well north of San Diego, and even north of San Francisco. Gor- don C. Pike (in lit.) has stated that south-migrating gray whales strike the North American coast at a point south of Vancouver Island. Most of them travel close to shore. The main migratory path is several miles wide and usually within one to three miles from shore. Gray whales have not been recorded migrating south at sea, far off the coast of southern Cali- fornia or off Baja California (figs. 1 and 2). However, some gray whales do mi- grate southward offshore, since they have been seen at Isla Guadalupe and Isla Clarion. The route used in reach- ing these islands is not known. It has been suggested, with little factual basis, that the same whales may move along the Santa Barbara (or Channel) Islands, San Miguel, Santa Rosa, Santa Cruz, Santa Barbara, Santa Catalina, and San Clemente. Gray whales have been seen approaching land at La Jolla, and off the Coronado Islands, 12 miles south of Point Loma. Others have been seen from aircraft, making their way southward toward the mainland from the tip of San Clemente Island. Records of offshore movements are so few that any attempt to outline routes must be largely speculative. Southbound gray whales are usually seen at San Diego during the latter half of November, though not com- monly until after the middle of De- cember. The bulk of the population passes in January, mainly during the middle two weeks of the month. By mid -February, the southward migra- tion is virtually over, although a few stragglers have been seen moving south as late as March 25. The intensity and duration of the southward migration are illustrated in figure 3. Here are shown the num- ber of whales counted daily at San Diego, with extrapolation for whales passing unseen during the day because of bad weather, during the period from December 19, 1954, to February 15, 1955. (In preparing this figure, no extrapolation was made for whales passing unseen at night. See page 21.) Earlier, from November 19 to Decem- ber 18, 28 whales were seen and another 56 estimated, or a total of 84. Later, from February 16 to 28, 8 whales were seen and another 8 esti- mated, or a total of 16. The whaling vessel Vega (Risting 1928) began whal- ing on November 14, 1924, in Bahia Magdalena but took only humpback whales until December 27, when the first gray whale was captured. In 1925 and 1926, the first gray whales were taken on December 29 and December 28, respectively. Migrants began to arrive regularly on January 4, the migration reached its height on Jan- uary 22, and the last whale was taken on February 16. The first arrivals were pregnant females. Males gradu- ally became numerous in January. Gray whales (82) taken here ranged from 30 to 42 feet in length. WINTER RANGE From early January to the end of February, the California gray whale population is concentrated in the coastal area from about San Diego southeast to Cabo San Lucas and the southern end of the Gulf of California. For convenience, the winter range may be divided into ( 1 ) migrating and wandering areas which are utilized by nonbreeding whales and by whales en route to more southern parts of the winter range, and (2) calving areas, utilized by whales for mating and calving (fig. 4). Figure 2.~Migratory routes of the gray whale (southern part). ^ WHALES COUNTED EEl EXTRAPOLATION FOR WHALES UNSEEN Figure 3.— Daily counts and extrapolations of gray whales passing San Diego during the southward mi- gration, 1954-55. Areas of Migrating and Wandering For census purposes, areas of mi- grating and wandering have been broken down as follows: Northern area. --The northern area extends for 350 miles from San Diego along the west coast of northern Baja California to Punta Santo Domingo, at the northeast periphery of the huge, open Bahia de Sebastian Vizcaino (fig. 5). Vizcaino area. --The Vizcaino area extends from Punta Malarrimo on the south shore of Bahia de Sebastian Vizcaino, not far from Laguna Scam- mon, west and then south around the Peninsula de Vizcaino to Punta Abreo- jos at the northern end of Bahia Ballenas, near Lagiina San Ignacio. A few gray whales were seen at Isla de Cedros and the Benitos, 30 miles northwest. Bahia San Bartolome was never seen occupied by gray whales during the period of the censuses (fig. 6). San Juanico area. - -A 75 -mile stretch of low, sandy coast extends from Boca Querante to Boca Las Animas, and includes the important open bay, or bight, of San Juanico. No whales were seen within the small, but apparently deep Laguna San Gregorio at any time during the censuses. Cows and calves were seen in Bahia San Juanico and it was possible that the calves were born there, although the area was not considered a true calving ground (fig. 7). Cabo San Lucas area. --The large Cabo San Lucas area comprises the entire coastline of the "Cape Area" of the Peninsula of Baja California, from Boca Santa Marina to near La Paz, around Cabo San Lucas. Before the discovery of calving grounds in the Gulf in February 1954, whales seen in this area were thought to be nonbreeding wanderers, but it is real- ized now that the gray whales seen in the Cape area were, at least in part, migrants to and from the Gulf (fig. 8), Extralimital areas. --Gray whales were observed a number of times in winter outside their normal range, in the Gulf of California and near offshore islands in the Pacific. In the Gulf, north of the regularly used La Paz and Y^varos areas, 10 gray whales have been seen (1) four adults at Canal San Lorenzo near La Paz; (2) a cow and calf at Bahia Concepcidn, 250 miles north on the east side of the Gulf; (3) two adults, slightly north of Santa Rosalia; (4) one adult, 100 miles north of Santa Rosalia; and (5) one adult at Punta Final, 500 miles north of Cabo San Lucas, on the east side of the Gulf. In the Pacific, gray whales have been seen at Isla Guadalupe, 125 miles off northern Baja California, and at Isla Clarion, the westernmost island of the Revilla Gigedo group, 375 miles southwest of Cabo San Lticas. One whale was seen within 100 yards of the beach of the northeast bay on Isla Guadalupe, on February 15, 1957, by Arthur Flechsig, zoologist from Scripps Institution of Oceanography. On March 13, 1957, Daniel Brown, also from Scripps, saw 1 5 gray whales, 4 of which were calves, at the south- west end of Isla Clari<4n. Calving Areas The female California gray whale normally resorts to lagoons, bays. Figure 4.— Gray whale winter grounds. 10 / ISLA DE SAN BENITO "^ XeBASTIAN VlZCAINo/ LAGUNA GUERRERO NEGRO SALT CAMP LAGUNA SCAMMON <■■"■ ABREOJOS 115° Figure 5.--Northem area of migrating and wandering. figure 6.-- Vizcaino area of migrating and wandering. \4 \t_A^ BAHIA \ ri ISLA OE \ B.MIA V»^ nAPAZ^"'^ PARTI OA 5»NL0«Nl° YL ISL* OE CEHRALVO \^ ^^A PAZ Un /'' ^^a^'MgCENTES BUENA ^'^W^ ^ VISTA " - ■^^Vi ^ h\ / NTOS I )t ' N JOSE -J EL CkBO ^^^^y' " • CABO SAN LUCAS Figure 8.— Cabo San Lucas area of migrating and wandering. Figure 7.— San Juanico area of migrating and wandering. 11 and esteros* to bear her calf. Occa- sionally, calves are born in shallow, open water close to shore. Calving occurs, or formerly occurred, in six general areas: (1) San Diego (aban- doned), (2) Vizcaino -Scammon, (3) San Ignacio, (4) Magdalena, along the Pa- cific Coast of southern California and Baja California, (5) Yivaros, and (6) Reforma, along the east shore of the Gulf of California in the states of Sonora and Sinaloa (figs. 2 and 4). San Diego area. --Gray whales used to breed in large numbers in San Diego Bay, but these were largely exterminated by two whaling stations at the entrance in the 1850's, 1860's, and 1870's. Subsequently, boat traffic, water pollution, and harbor improve- ments have effectively prevented re- occupation. However, gray whales occasionally calve, and more often mate, in open waters just outside the bay. A lobster fisherman, visiting his pots in kelp beds south of La Jolla in January 1955, saw "many times'* a gray whale cow and calf. This account was recorded by Carr Tuthill of the aquarium of Scripps Institution of Oceanography. During the 1955-56 season, two calves were bornin waters off the San Diego area (fig. 9). Two bays in northern Baja Cali- fornia, Bahia de Todos Santos (in- cluding Estero de Punta Banda) near Ensenada, and Bahia San Quintin, near San Quintin, also appear to be suitable as calving areas for gray whales. No whales were seen in either bay. Gray whales surely inhabited both areas, although no historical evidence to this effect has been uncovered (fig. 5). Vizcaino -Scammon area. --The Viz- caino-Scammon area includes ( 1 ) the shoreline of Bahia Vizcaino from Punta Santo Domingo to Punta Malarrimo, (2) Laguna Guerrero Negro, and lAn estero is a long, narrow body of water parallel to the coast and separated from the sea by a barrier beach. A channel between an estero and the sea is a boca. A lagoon (lagunaj, as the term is used here, is a large body of water which extends several miles inland and is par- tially cut off from the sea by a bar across its mouth. A bay (bahia) is a marked indentation of the coastline not usually separated from the sea. Figure 9. --Former San Diego calving area. (3) Laguna Scammon. It includes about 30 miles of coastline and bars, and 100 to 200 square miles of channels navigable by gray whales, in Laguna Guerrero Negro and Laguna Scammon. Laguna Manuela was not occupied by gray whales during the period of the censuses (fig. 10). San Ignacio area. --Included in the San Ignacio area are (1) the open bight of Bahia Ballenas; (2) the large and important Laguna San Ignacio; and (3) the small, as yet unnamed, lagoon farther south, called here "Laguna Querante" (from a nearby ranch so marked on the U. S. Navy hydrographic chart 1493, based on surveys made in 1890-95). Perhaps 30 to 50 square miles of lagoon channels are navi- gable to the gray whale in San Ignacio and Querante. Gray whales were never seen in Laguna Coyote during the censuses (fig. 11). Magdalena area.- -A distinct calving and mating ground, the Magdalena area 12 Figure 10.--Vizcarno-Scammon calving area. Figure 11. --San Ignacio calving area. includes (l)the long esteros (Las Animas, Santo Domingo, and Soledad) north of Bahia Magdalena, parallel to the ocean beach but separated from the ocean by a continuous sand barrier with three bocas, (2) the upper reaches of the bay, such as Canal San Carlos, (3) the wide and deep Bahia Magdalena itself, and (4) Bahia Almejas, the south arm of Bahia Magdalena. This entire area includes 130 miles of low or rocky coast, and also sonne 200 to 2 50 square miles of esteros, lagoons, and bays accessible to the gray whale (figs. 12 and 13). Figure 12.— Magdalena calving area (northern part). Figure 13. —Magdalena calving area (southern part). 13 In the 19th century, the enormous and complex Magdalena area was probably the principal breeding ground of the California gray whale. However, because its central waters were ac- cessible to sailing ships and its shal- lower tributaries to whaleboats, its whale population was soon exploited. From 1952 through 1957, boat traffic was often seen in the main bay. Gray whales consorted in numbers only in the more inaccessible tributaries. Yavaros area. --In February 1953, an aerial survey of the Yavaros area disclosed breeding grounds at Yavaros and Bahia Refornna, on the eastern side of the Gulf of California. Whales had never before been found here, even by early whalers. The Yavaros area is about 6 to 8 miles south of the port and bay of Yavaros, Sonora. It seems to have no distinctive feature which would attract gray whales. The water is only 2 to 5 fathoms deep. The whales observed were from 200 to 800 yards from the beach, leaving mud trails behind them as they swam in waters believed to be as shallow as 2 fathonns (fig. 14). There are perhaps 10 to 20 square miles of lagoon in the northern part well suited to gray whales (fig. 15). Figure 14.~Yavaros calving area. Reforma area.--Bahia Reforma is a huge lagoon-like bay 120 nautical miles southeast of Yavaros, in the State of Sinaloa. It is about 35 miles long and is navigable by whales and small boats. Figure 15.— Reforma calving area. NORTHWARD MIGRATION The northward migration first passes San Diego in mid -February, is in full swing in March and April, and tapers off in early May. Gray whales going north seem to veer off the coast at Point Loma, passing La Jolla several miles at sea, as though on direct course across the great bight of the coast of southern California from San Diego to Palos Verdes Peninsula. Because movement apparently is away from the coast, it does not seem possible to count the migration north with the same accuracy possible for the southward migration. From Palos Verdes Peninsula, most whales mi- grate parallel to the coast on their way north. Vessels engaged in fur-seal research for the Bureau of Commercial Fish- eries, in 1958 and 1959, sighted gray whales during March from 36°46'N. in Monterey Bay to 41°23'N. off Gold Bluffs, California. April obser- vations ranged from 40°47'N. off the Eel River in California to 47°54'N. off James Island, Washington. On April 14 24, 1959f personnel on the vessel Tacoma saw more than 200 gray whales from about 19 miles off Destruction Island to near James Island. On that day they saw a bloated, dead gray whale rise to the surface. On April 25 the vessel ran out of the gray-whale concentration 9 miles off James Island (C. H. Fiscus, T. C. Juelson, and K. Niggol, in lit.). Observers on the Canadian research vessel Pacific Ocean saw gray whales off Cape Flattery, Washington during the last 2 weeks in May (Gordon C. Pike, in lit.). Annually, large numbers of whales concentrate close to the west shore of Vancouver Island in March and April, many passing through the mile- wide channel between Solander Island and Cape Cook on the northern part of Vancouver Island. After passing along the west coast of Vancouver Island, the whales disappear in a westerly direction into the North Pacific Ocean. As late as May 17, 1959, gray whales were observed off the north end of Vancouver Island by whalers from the station at Coal Harbour, Quatsino Sound. Nine gray whales were taken for scientific purposes in April 1952 from the station at Coal Harbour under special permit issued in accordance with the provisions of the International Convention for the Regulation of Whal- ing. Northward migrating whales were too thin to be of commercial value. Eight gray whales, in pairs, were seen on May 11, 1957, moving very close to the kelp between Kodiak and Ugak Islands toward Narrow Cape, Alaska (F. Wilke, in lit.). BEHAVIOR STUDIES BEHAVIOR' DURING MIGRATION Actions which will enable them to arrive quickly at the breeding grounds seem completely to dominate the be- havior of gray whales as they swim past San Diego. They do not wander or feed. Occasionally, whales stop and attempt to court or mate, but even these rarely stay long or wander from the migration route. Orientation to Land Close adherence to the coasts of southern California and Baja Cali- fornia is an outstanding feature of their migratory behavior. The herd passes along the coast, skirting head- lands and sometimes cutting across bays, generally remaining within three miles from shore. Such behavior must help them find the entrance of shallow bays and lagoons for calving and mat- ing. A gray whale will often thrust its head completely out of the water, almost to the flippers, and hold it out for about 10 seconds. Or when "blow- ing" at the surface, the whale will merely raise its head out as far as the eyes. Subsequently, the whale's movennents will suggest reorientation based on visual stimuli. Gray whales sometimes follow the walls of deep submarine canyons in La JoUa Bay instead of the shoreline. This suggests that they may be following, in pref- erence to the coast, a bottom contour of 100 to 150 feet depth. The extent to which vision may aid navigation along the shore, nor the extent to which darkness may slow travel, could not be measured. Fog is believed by some observers to slow travel but this has not been proved. Daily Cycle of Observations During a count in 1954-55 from Point Loma, sightings of 1,319 whales were recorded by hour of day. For each consecutive hour between 7 a. m. and 5 p. m., the following number of sightings was recorded: 50, 145, 113, 103, 134, 99 (noon to 1 p. m.), 156, 189, 175, 155. The higher figures of afternoon are probably the result of 15 improved visibility --lifting of haze. The low values at 7 a. m. and noon may (?) represent human errors of some kind. Increased visibility in late afternoon was demonstrated again in 1956-57, when the count of whales at La JoUa- Scripps from 3 p. m. to 5 p. m. equalled 29 percent of the count at Point Loma from 7 a. m. to 5 p. m. (2 hours against 10). Had whales been observed at the same rate for the 2 hours as for 10 hours, the proportion would have been one -fifth or 20 percent. Social Behavior Gray whales, like most large whales, travel singly or in small groups. The frequency distribution of groups in the 1952-53, 1954-55, and 1956-57 seasons is given in table 1 . Single animals predominate in November and Decem- ber. These are mostly large individ- uals, presumably pregnant females, traveling alone to the lagoons and bays to calve, and presumably not physiologically ready to mate. Most single animals, traveling later, are thought to be adult males, nonbreeding females, or yearlings. Little is known about differences in migratory behav- ior according to age and sex. Groups of two and three are com- monest in January. At that time, the animals are mating or courting en route. Groups of three would perhaps most logically be composed of two males and one female. (See section, below, on behavior on the winter range.) Groups of four perhaps include three males and one female, or two pairs joined by coincidence. Pregnant females are probably solitary, as are the yearlings not yet integrated into social groupings. BEHAVIOR ON THE WINTER RANGE Some observations of behavior were made during the aerial census, when animals were seen on the breeding and calving grounds and wandering nearby. Most behavior studies, how- ever, were made at close range from small boats propelled among the whales during special visits to the breeding lagoons. Behavior studies on the winter range were made at Estero Las Ani- naas on February 22, 1953, and at Laguna Scammon on February 17-25, 1954, February 4-14, 1955, January 25 to February 8, 1956, and February 9-18, 1957. In and near the breeding lagoons, gray whales appear to be segregated by age, sex, and reproductive condi- tion. Outer and Intermediate Area Most whales seen outside the en- trances of lagoons are evidently idle adults, courting adults, or imnnatures. No calves and no recently parturient females are found here. The intermediate area consists of channels within the entrance. Many nuptial groups, some cows and their newborn calves, and some wandering singles are found in these locations. Mating and courting is done between adults without calves present. Pairs of courting adults are the commonest reproductive group, but groups of three are also common. On one occasion, three adults were identified by copu- latory activity as a female, a dominant male, and probably a complemental male. The sex of the latter was not definitely ascertained, but its nervous, "sideline" participation suggested that it was a male. (If only half the females breed each year, as the author sus- pects, and if the sex ratio is 50 : 50, there will be twice as many eligible males as females on the breeding grounds.) Breeding pairs and trios are most contimon near the outer en- trance of the lagoon but also penetrate the lagoon to its very head, and are observed outside the lagoon. Segrega- tion of courting groups and cows with calves is more distinct in the Mag- dalena area than in the Scammon area. 16 o I I B ISl a. I « CO ■|J C 03 OJ a to 0 o ,p 3 z: *