Data collection like the siene collections we see here are only a small part of understanding fisheries, but still a useful tool.  After fisheries data is collected, it is eventually collated into a research article or report. Over time those reports are combined to create articles that explain trends. Then, after a large amount of data is collected, a researcher may even review the reviews, so she can create something called a synthesis, a document summarizing all the findings across the summary articles. These articles and reports can then be used to guide funding related decisions.   We must, of course, always consider the limitations of the data.