POD! Fish abundance measurements and related parameters used in first POD Change Point and MAR analyses (nceas_data_one).

These data were provided by Fred Feyrer on 29 April 2008. The data are intended for the change point and MAR analyses. The first sheet has the data and the second sheet has the definitions for each variable. The data sheet has 110 columns representing variables and 40 rows representing years (1967-2006). Because there are so many variables, Fred added columns indicating which variable is associated with which analysis (on the definition sheet). There is a column for every variable we discussed during the 7-11 April meeting at NCEAS with the exception of prickly sculpin. Fred looked at the data from the Bay Study and the catches were low and sparse enough that he didn't feel the information was meaningful. Fred included a few extra variables for the measures of fish abundance. Initially we decided to use average catch per trawl for age-0 fish that were collected in the fall midwater trawl survey. However, using age-0 actually limits the number of years available for analysis because not all fish were measured for length in all years. Accordingly, Fred also included total catch per trawl, which is available for all years when the survey was conducted. Fred also included the CA Dept Fish and Game Abundance Indices (age-0 and total) for the same species as a comparison. Most of these are correlated because the gear samples age-0 fish best. The point is that using total catch per trawl will increase sample size and likely provides a result very similar to using age-0 catch per trawl. Keywords:

本数据集由Fred Feyrer于2008年4月29日提供，用于变点分析与随机缺失（Missing At Random, MAR）分析。文件第一张工作表包含数据集主体内容，第二张工作表则给出各变量的详细定义。数据工作表共设110列（对应变量）与40行（对应年份，时间跨度为1967年至2006年）。由于变量总量较多，Fred在定义工作表中新增了标注列，用于指明各变量所关联的分析任务。本次在NCEAS举办的4月7日至11日会议中讨论的全部变量，除棘绒杜父鱼（Prickly sculpin）外，均设有对应数据列。Fred对海湾研究（Bay Study）的相关数据进行了检视，发现其捕捞量极低且分布稀疏，因此判定该数据不具备有效分析价值，故未纳入。此外，Fred额外新增了若干用于表征鱼类丰度的变量。最初我们计划采用秋季中层拖网调查中采集的0龄鱼的单位拖网平均捕捞量作为核心指标，但仅选取0龄鱼会限制可用于分析的年份范围——因为并非所有调查年份都对所有捕获鱼类开展了体长测量。为此，Fred新增了单位拖网总捕捞量指标，该指标在所有开展拖网调查的年份中均可完整获取。同时，Fred还纳入了加州鱼类与狩猎部（CA Dept Fish and Game）针对同一物种编制的丰度指数（包含0龄鱼指数与总丰度指数），用于后续对比分析。由于该采样渔具对0龄鱼的捕获效果最佳，多数指数间存在显著相关性。综上，采用单位拖网总捕捞量可有效提升样本量，且其分析结果与使用0龄鱼单位拖网捕捞量的结果高度近似。关键词：