Reported retained annual catch from Commonwealth fisheries logbooks

##Description\r\nWhile at sea, Commonwealth fishers must record all catch and effort in their AFMA daily fishing logbooks. This dataset shows the annual retained catch (meaning the catch that is not returned to the sea) in kilograms, by species and fishery, for Commonwealth fisheries managed by the Australian Fisheries Management Authority (AFMA). \r\nThese data are sourced from AFMA daily fishing logbooks, which fishers complete while at sea, where generally the weights are estimates only. Fish discarded at sea are not included in this dataset. Location of catches within a fishery is not included.\r\n\r\n##Appropriate use and limitations of the data\r\nThe catch weight data in logbooks are estimates only, which have been recorded by fishers while at sea. Fishers usually cannot accurately weigh fish at sea, so the estimated weights are mostly based on volume (i.e. the size and number of boxes of fish caught). Catch data are used in combination with gear, effort, and spatial data to inform stock assessments.\r\nThese data may differ from other summations over the same time period (such as stock assessment reports) due to differences in data handling procedures. For example, scientists may filter out catches from their assessments because of data quality issues or group species differently. In addition, the data may be different in other datasets with different summations such as catch by season or catch from the date fish were landed at port.\r\nCare should be taken when interpreting trends in this data because there are many factors that can affect catches each year. Catch quantities can be impacted by management measures such as: total allowable catch, closures of fishing areas, reducing boat numbers, or banning the catch of a particular species. Similarly, changes in market demand can affect which species are targeted. \r\nWhen the fish are landed at port, the accurate weight of fish is recorded in AFMA catch disposal records by both the fisher and fish receiver permit holder. This information can be found in the “Reported landed annual catch from Commonwealth fisheries catch disposal records” and its metadata, which is published on data.gov.au. \r\n\r\n##Disclaimer\r\nThe dataset provided by AFMA is comprised of raw (unprocessed) data as received from fishers, and may contain errors or be incomplete. Errors are more likely in the species caught in low volumes. AFMA makes no warranty or representation that the data is accurate or complete. Those who choose to use this data should make their own enquiries as to its accuracy and completeness, and AFMA assumes no liability for any errors or omissions in the data provided, or for any decision by a person who chooses to rely on the data.\r\n

### 数据集说明
在海上作业期间，英联邦籍渔民须将所有渔获与捕捞努力量记录在澳大利亚渔业管理局（Australian Fisheries Management Authority，AFMA）的每日捕捞日志中。本数据集按物种与渔业类型统计了由AFMA管理的英联邦渔业的年度留存渔获量（即未被放回海洋的渔获），单位为千克。

本数据集的数据来源于渔民海上填写的AFMA每日捕捞日志，其中渔获重量通常仅为估算值。本数据集未纳入海上丢弃的渔获，也未包含某一渔业内部的渔获具体位置信息。

### 数据的合理使用与局限性
日志中的渔获重量数据仅为估算值，由渔民在海上作业时记录。由于渔民通常无法在海上精准称量渔获重量，因此估算重量主要基于渔获体积（即捕捞渔获所用箱具的尺寸与数量）。本渔获数据将与渔具、捕捞努力量及空间数据结合使用，为渔业资源评估提供依据。

由于数据处理流程存在差异，本数据集与同期其他汇总数据（如渔业资源评估报告）可能存在出入。例如，科研人员可能因数据质量问题将部分渔获数据从评估中剔除，或对物种进行不同的归类。此外，若其他数据集采用不同的汇总方式（如按季节汇总渔获、按渔船靠港卸货日期汇总渔获），其结果也可能与本数据集存在差异。

解读本数据集的年度渔获趋势时需格外谨慎，因为每年的渔获量受诸多因素影响。渔获数量可能受到多项管理措施的影响，包括总可捕量、捕捞区域禁捕、缩减作业渔船数量，或是禁止捕捞特定物种。同理，市场需求的变化也会影响渔民的目标捕捞物种。

当渔船靠港卸货时，渔民与渔获接收许可持有人需在AFMA渔获处置记录中登记渔获的精准重量。该精准数据可在data.gov.au平台发布的"Reported landed annual catch from Commonwealth fisheries catch disposal records"及其元数据（metadata）中获取。

### 免责声明
AFMA提供的本数据集为直接从渔民处获取的原始（未经过处理）数据，可能存在错误或信息不全的情况。低捕获量的物种相关数据更易出现误差。AFMA不对本数据的准确性与完整性作出任何担保或声明。使用本数据集的用户应自行核查数据的准确性与完整性，AFMA不对所提供数据中的任何错误、遗漏，或因用户依赖该数据作出决策所导致的后果承担任何责任。