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of the Namibian Fur Seal Population Aerial surveys. Aerial surveys are used to monitor the number of fur seal pups born at colonies in South Africa and Namibia. The aerial surveys began in 1971 under the auspices of the Sea Fisheries Research Institute of South Africa, and have continued to the present day. Vertical, overlapping, black-and-white photographs are taken with a large-format camera from a fixed-wing aircraft flying at 350ft to provide complete coverage of the colony. The same aircraft and camera are used for all colonies in South Africa and Namibia, and the photographs are counted by the same technicians. Surveys are carried out in the period 18-24 December each year when the oldest pups are less than 6 weeks old. At this time the maximum number of live pups is expected to be present in colonies. Al colonies are surveyed each year.Methods currently used to recommend total allowable catches. Since 1987 the Marine Mammal Section of the Directorate of Resource Management has had the task of advising the Ministry on management of the seal population, and of recommending harvest levels annually for the different colonies and for the different age and sex classes. These recommendations are based on the analysis of aerial census results, population trends, fecundity rates, pup and adult survival rates, changes in sex-ratio, indices of pups and adults, and past harvesting rates. These data are used in a model which predicts the ideal harvest levels for maintaining sustainable yields. Recommended pup harvests may be as high as 30% of pups born, while recommended bull harvests vary depending on the strength of cohorts 7 to 8 years earlier. Biological data are also used to recommend on other management-related issues, such as harvesting seasons, harvesting methods and size limits. Scientific recommendations are submitted in confidentiality to the Permanent Secretary of the Ministry of Fisheries during June each year. They are reviewed by the Management component of the MFMR which provides a socio-economic perspective and considers the input of the sealing industry. After review, recommendations are then forwarded to the Minister of Fisheries for consideration and amendment before submission to the Cabinet. Quotas are allocated annually to the 2 concessionaires and the harvesting season usually begins on the 1st of August and lasts until mid -November. State of the Stock Pup production: 188,681 (1998 est.) Total population: Uncertain Mean annual change in pup production: r = 0.58 (1997 -1998) r = -0.032 (1993-1998); Distribution: 18° 24'S – 27° 40'S Recent harvesting level: Increased Overall stock indicator: Partial recovery (80% of 1993 level) Stock definition and geographic range. Cape fur seals occur along the African coast from Cape Frio in the North of Namibia to as far South as the Cape Peninsula, and as far East as Algoa Bay in South Africa. The Namibian stock hauls out in aggregations at some 21 sites along the coast and on adjacent islands, of which 15 are regarded as breeding colonies. The two largest breeding aggregations, Cape Cross, and Wolf Bay and Atlas Bay colonies (near Lüderitz) are responsible for 75% of Namibian pup production. Catch trends. In 1998, 4,983 bulls were harvested, which is an increase of approximately 34% compared to the 1997 harvest and 39% compared to the mean annual harvest from 1995 to 1997. A total of 24,441 pups were harvested in 1998, which is approximately 11% greater than the 1997 harvest and 40% greater than the 1995 to 1997 mean. Recent population changes. The 1998 total Namibian Cape fur seal pup production (most recent data) is estimated at 188,681. Changes in the population since the 1970's are mirrored in variations in the pup production of the two major breeding aggregations. These show the increase of the population to a peak value in 1993, the 1994 mass mortality event, subsequent three years of low pup production, and partial recovery in 1998 (to 80% of 1993 values). Pup production for 1999 is expected to be similar to the 1998 value. |
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