Population Dynamics of Weddell Seals (Leptonychotes Weddelli) in McMurdo Sound, Antarctica
Population Dynamics of Weddell Seals (Leptonychotes Weddelli) in McMurdo Sound, Antarctica
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南极洲麦克默多海峡威德尔海豹 (Leptonychotes Weddelli) 的种群动态
DOI：
10.2307/1942622
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发表时间：
1987
影响因子：
6.1
通讯作者：
D. Siniff
中科院分区：
文献类型：
--
作者：
J. Testa;D. Siniff
1970 ~ 1984年，采用标记-再捕获法、航空调查、年龄结构、捕获量和幼仔产量等方法，对南极麦克默多湾威德尔海豹的种群动态进行了研究。早期研究的类似数据被用来重建1956年后人类存在期间的人口历史。Jolly-Seber估计的人口规模表明，从1970年至1976年，在1976年和1978年的低数字，1979年至1984年的相对稳定在-1500成年海豹的一般下降。从1970年到1983年，成年雌性和雄性威德尔海豹的平均年存活率估计为0.85和0.76。在1982/1983年和1983/1984年夏季进行的航空调查中所作的计数大大低于1960年代的类似调查计数。1967年至1976年，繁殖群的幼犬产量也有所下降，但自1979年以来已经恢复并保持稳定。收集跨越28年的人口经历了快速增长，然后下降的年龄结构特征的显着变化。两性的年龄结构表明，一个恒定的年龄招聘到成年人口在5岁，这与女性的成熟年龄密切相关。广义最小二乘法和标准回归分析未能检测到任何相关性的成人生存或女性生殖估计与人口规模或冰条件，但有显着的趋势，生存估计从1970年至1983年，可能是由于年龄结构的变化。对这些数据最合理的解释是，在20世纪50年代中期，为了喂养狗队而大量捕杀海豹，严重耗尽了成年威德尔海豹的常住人口。1960年代初开始人口研究时，人口迅速增长，可能是青少年移民的结果。1976-1978年，种群数量下降到较低水平，自1979年以来一直相当稳定，可能低于开始收割前的水平。这些威德尔海豹的生存和繁殖参数相对于其他鳍足类动物较低，这表明成年种群与环境处于平衡状态。
Population dynamics of Weddell seals in McMurdo Sound, Antarctica, were studied from 1970 to 1984 using mark-recapture estimation, aerial surveys, age structure and magnitude of harvests, and direct counts of pup production. Similar data from earlier studies were used to reconstruct the history of the population during the period of human presence after 1956. Jolly-Seber estimates of population size indicated a general decline from 1970 to 1976, low numbers in 1976 and 1978, and relative stability from 1979 to 1984 at - 1500 adult seals. From 1970 to 1983, mean annual survival of adult female and male Weddell seals was estimated at 0.85 and 0.76. Counts made in aerial surveys in the summers of 1982/1983 and 1983/1984 were substantially below similar survey counts in the 1960s. Pup production in the breeding colonies also declined from 1967 to 1976, but has recovered and been stable since 1979. Collections spanning 28 yr indicated significant shifts in age structure characteristic of populations undergoing a rapid increase and then decline. The age structure of both sexes indicated a constant age of recruitment to the adult population at 5 yr, which corresponds closely with age of maturity in females. Generalized least squares and standard regression analyses failed to detect any correlation of adult survival or female reproductive estimates with population size or ice conditions, but there were significant trends in survival estimates from 1970 to 1983 that may be due to shifting age structure. The most plausible interpretation of these data is that heavy harvests of seals to feed dog teams in the mid-1950s severely depleted the resident population of adult Weddell seals. When population studies began in the early 1960s the population was expanding rapidly, probably as a result of immigration by juveniles. The population declined to low levels in 1976-1978 and has been fairly stable since 1979, probably at a level lower than before harvesting began. Survival and reproductive parameters of these Weddell seals are low relative to other pinnipeds, suggesting that the adult population is at an equilibrium with its environment.