The last coloney of northern elephant seals was found here in the late 1840's and it was the only breeding coloney from 1840's until the 1920's (Le Boeuf et al. Chapter 2). During a 1965 census, 3,668 pups were counted and 4,962 were counted during 1991. Counts made since 1960 show that only slight increases occured suggesting that this was when the carrying capacity for Isla de Guadalupe was reached. 150 miles offshore the Pacific Coast of Mexico, South of San Diego, and WNW of Punta Eugenia, Isla de Guadalupe is a 98 square mile island that is bathed by oceanic currents. This island lies between temperate and subtropical ecozones. The north end of this island reaches an altitude of 4200 feet and it is made up of steep cliffs and boulder beaches.
Coronados consists of three seperate islands and a small islet (North Coronados Island, Middle Grounds, South Island, and Middle Rock). Located off the coast of Baja California, the South Island, the largest of the three main islands, is a breeding ground for northern elephant seals. It is the largest of the three islands and the only one of the three that has human residents, which reside on a small navel station on the eastern side of the island. Elephant seals and California Sea Lions are found in a cove surrounded by high unstable cliffs, on the western side of the island. Elephant seal pup mortality on this island is between 5 and 10%(Elephant Seals, 1999). The waters to the east of this island are rich with invertebrates due to several offshore reefs.(Horizon Charters)
Once thought to be extinct, the northern elephant seal currently hauls-out on 15 rookeries with their largest coloney located on San Miguel Island. Located off the coast of Santa Barbara California, San Miguel is the western most island of the nine channel islands. It is a windswept pleateu approximately 120-150 meters in elevation, 13 kilometers long and 6 kilometers wide (Greer1). First seen on this island in 1925 the seals did not start breeding here until the 1950's. With 84 pups counted on San Miguel in 1958, the population on this island rapidly increased with 13,884 births recorded in 1991. In 1991 studies showed that this island accounted for 49.5% of all of northern elephant seal births (Le Boeuf et al. Chapter 2).
Far south of the other channel islands, Santa Barbara is a windswept 260 hectarer triangular island with a rugged coastline and steep cliffs which rise to a marine terrace. These terraces are topped by two peaks with its highest peak rising to 194 meters in elevation. The landscape of this island is dominated by non-native grasses such as oats, barley, and brome (Greer 1). Northern elephant seals were first seen on this island in 1948 and started breeding here in the early 1950's. Eleven pups were counted during a census in 1964 and a mere 94 counted in 1991 (Le Boeuf et al. Chapter 2).
San Nicolas is a mountainless island with shifting sand dunes. It is the outermost of the channel islands and is approximately 60 miles west of Los Angeles. San Nicolas is 22 square miles with its highest peak being 907 feet. Northern elephant seals were first seen on San Nicolas in 1949 with breeding first occuring in the early 1950's. With 48 pups counted during a census in 1949, the population grew to 4,082 pups counted in 1991 (Le Beouf et al. Chapter 2).
San Clemente Island
At 56 square miles, San Clemente is the fourth largest of the nine channel islands. Its highest peak rising to 1956 feet, this island is primarily made up of marine terraces and a shoreline cut with canyons. There is a gradual incline on the western side from the shoreline to the higher inland terraces. The eastern side of this island is made up of rocky formidable cliffs. Only a modest number of births have been recorded on this island. Only one pup was counted in 1977, none were counted in 1991, and the highest number of pups were born in 1982, when five pups were counted (Le Beouf et al. Chapter 2).
The newest of northern elephant seal breeding grounds, Piedras Blancas is a mainland rookery which is located approximately 7 km NW of San Simeon in San Luis Obispo County. With the first northern elephant seal seen on Launch Beach in 1978, this population has quickly grown to 2000 which reside on five beachs and coves.
Ano Nuevo mainland is a 300-350 acre low rocky windswept dune field, with its western portion driven by NW winds. Showing up first on Ano Nuevo Island in 1955, male northern elephant seals began hauling out on the mainland in 1965 although island carrying capacity wasn't reached until the late 1970's. The first pup was born on the mainland in January 1975 (Le Beouf et al. Chapter 2). During a census in 1961 12 births were recorded on the island, while in 1991 2248 total births were recorded for the island and the mainland, and there were approximately 2000 pups born on the mainland durning the 1994-1995 breeding season. This breeding area is mainly colonized by immigrants from San Miguel Island and San Nicolas Island and had an immigration rate of 3.9% between 1974 and 1986 (Le Beouf et al. Chapter 2). This coloney has a pup mortality rate ranging from 15 to 26%(Horizon Charters)
Approximately 30 miles offshore of San Francisco, these rocky islands are 211 acres and were colonized by northern elephant seals from San Miguel Island, San Nicolas Island, and Ano Nuevo Island (Le Boeuf et al. Chapter 2). This rookery has a pup mortality between 0-73%(Horizon Charters).
First arriving here in the early 1970's breeding started in 1981 with a male, female, and pup, Point Reyes is one of the newer northern elephant seal colonies. Populated by immigrants from South Farallon Islands and Ano Nuevo, a census taken in 1998 found 1500 seals hauled-out and close to 400 new pups(Henderson and Allen).
K. West - 1/27/00