Phenological and geographical patterns of walleye pollock (Theragra chalcogramma) spawning in the western Gulf of Alaska
Phenological and geographical patterns of walleye pollock (Theragra chalcogramma) spawning in the western Gulf of Alaska
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阿拉斯加湾西部狭鳕 (Theragra chalcogramma) 产卵的物候和地理模式
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
N. Stenseth
中科院分区：
文献类型：
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作者：
L. Ciannelli;K. Bailey;Kung;N. Stenseth
20 多年来的卵采样数据被用来重建阿拉斯加湾 (GOA) 狭鳕 (Theragra chalcogramma) 产卵聚集的地理和物候模式。分析的时间序列（1972年、1978-1979年、1981-2000年）包括记录的气候变化事件（即1988-1989年）以及GOA狭鳕种群丰度和收成的升降。我们比较了两种广义加性模型 (GAM) 公式的结果：一种假设在所检查的时间序列（平稳）内鸡蛋分布和物候没有变化，另一种则承认在根据数据确定的时期内发生这种变化（非平稳）。两种模型公式的结果都证实了谢利科夫海峡存在高卵浓度，该海峡历史上是戈阿狭鳕的主要产卵区。然而，模型结果还强调了沿着GOA的陆架和斜坡区域的不同位置存在其他次要的、可能是暂时的鸡蛋分布中心。此外，非平稳（且统计上优越）公式的结果表明，非 Shelikof 聚集的丰度随着时间的推移而增加，并且有较早出现和向高蛋密度区域的较浅区域移动的趋势。
Over 20 years of egg sampling data were used to reconstruct the geographical and phenological patterns of walleye pollock (Theragra chalcogramma) spawning aggregations in the Gulf of Alaska (GOA). The analyzed time series (1972, 1978-1979, 1981-2000) included a documented event of climate change (i.e., 1988-1989) and the rise and fall of the GOA pollock population abundance and harvests. We compared results from two generalized additive model (GAM) formulations: one assuming no change of egg distribution and phenology over the examined time series (stationary) and the other admitting such changes (nonstationary) across an epoch determined from the data. Results from both model formulations corroborate the existence of a high egg concentration in Shelikof Strait, historically the primary spawning area of pollock in the GOA. However, model results also highlight the presence of other secondary, and possibly transitory, centers of egg distribution at various locations along the shelf and slope regions of the GOA. In addition, results from the nonstationary (and statistically superior) formulation indicate that the abundance of the non-Shelikof aggregations has increased over time, along with a tendency for earlier occurrence and displacement toward shallower areas of the high egg density regions.