Density dependence only affects increase rates in baleen whale populations at high abundance levels

Most baleen whale populations are increasing after the end of industrial whaling, but their recovery patterns challenge long-standing assumptions about density dependence. It has long been assumed that population growth rates will decline with recovery, until reaching equilibrium (“carrying capacity”, K). Indeed, the International Whaling Commission assumes that growth rates will slow long before K is reached, with maximum productivity at 0.6K. This 0.6K population level is used as an international benchmark that forms the basis of whaling regulations and decisions about whether baleen whale populations are declared depleted. We fit models to four long-term datasets for baleen whales with multiple abundance estimates that span the range from low to high abundance, finding strong evidence that increase rates remain at near-maximal levels across a wide range of abundance levels, and only decline as the population nears K. As a result, maximum productivity occurs at 0.69–0.87 of K across t..., , , # Density dependence only affects increase rates in baleen whale populations at high abundance levels ## Overview of files hosted on Dryad Each file contains a time series of catch records by species/population and location, with two columns: 1. year, and 2. catch number. ***Models*** \"StanSimulation0.stan\" (Stan code for the logistic model with fixed *z* =2.39) \"StanSimulation.stan\" (Stan code for the logistic model with estimating *z* value)  ## Overview of files hosted on Zenodo **Abundance time-series** \"Abund.Bowhead.csv\" (Abundance data for bowhead whales) \"Abund.GR.csv\" (Abundance data for gray whales) \"Abund.Hbk.csv\" (Abundance data for USWC humpback whales) \"Abund.HbkAusNoad2019.csv\" (Abundance data for EAUS humpback whales) \"Abund.HbkAusSpueBb.csv\" (Relative abundance data for EAUS humpback whales) \"Abund.HbkAusSpueppc.csv\" (Relative abundance data for EAUS humpback whales) \"Abund.HbkAusSpuesol.csv\" (Relative abundance data for EAUS humpback whales) ## Descrip...工业捕鲸活动结束后，多数须鲸种群数量正逐步恢复，但其恢复模式却对学界长期以来有关密度依赖（density dependence）的假设提出了挑战。长期以来，学界普遍认为种群增长率会随着恢复进程逐渐下降，直至达到平衡状态（即承载量（carrying capacity），记为K）。事实上，国际捕鲸委员会（International Whaling Commission）假设，种群增长率会在远未达到K值时便开始放缓，且种群最大生产力出现在0.6K的水平。该0.6K的种群水平被用作国际基准，以此为基础制定捕鲸相关法规，并作为判定须鲸种群是否被列为濒危的依据。本研究针对4组涵盖低丰度至高丰度范围的多估计值须鲸长期数据集拟合模型，结果发现：在广泛的丰度区间内，种群增长率始终维持在接近最大值的水平，仅当种群接近K值时才会出现下降。据此，种群最大生产力出现在0.69–0.87K的区间内…… # 密度依赖仅在高丰度水平下影响须鲸种群的增长率 ## Dryad平台托管文件概览 每份文件均包含按物种/种群及地域分类的捕捞记录时间序列，共包含两列：1. 年份；2. 捕捞数量。 ***模型代码*** "StanSimulation0.stan"（固定z=2.39的逻辑斯蒂模型（logistic model）Stan代码） "StanSimulation.stan"（可估计z值的逻辑斯蒂模型（logistic model）Stan代码） ## Zenodo平台托管文件概览 **丰度时间序列** "Abund.Bowhead.csv"（弓头鲸丰度数据） "Abund.GR.csv"（灰鲸丰度数据） "Abund.Hbk.csv"（美国西海岸座头鲸丰度数据） "Abund.HbkAusNoad2019.csv"（东澳大利亚座头鲸丰度数据） "Abund.HbkAusSpueBb.csv"（东澳大利亚座头鲸相对丰度数据） "Abund.HbkAusSpueppc.csv"（东澳大利亚座头鲸相对丰度数据） "Abund.HbkAusSpuesol.csv"（东澳大利亚座头鲸相对丰度数据） 描述……