| Summary: | Age, sex, and length (ASL) data provide population dynamics information that can indicate how population trends occur and may be changing. These data can help researchers estimate population growth rates, age-class distribution, and population demographics. Knowing population demographics, growth rates and trends is particularly valuable to fisheries managers who must perform population assessments to inform management decisions. These data are therefore important in valuable fisheries like the salmon fisheries of Alaska. This dataset includes age, sex, and length data compiled from annual sampling of commercial and subsistence salmon harvests and research projects in Bristol Bay, Alaska from 1957-2009. It includes data on five salmon species: chinook, chum, coho, pink, and sockeye. Age estimates were made by examining scales or bony structures (e.g. otoliths - ear bones). Scales were removed from the side of the fish; usually the left side above the lateral line. Scales or bony structures were then mounted on gummed cards and pressed on acetate to make an impression. The number of freshwater and saltwater annuli (i.e. rings) was counted to estimate freshwater and saltwater ages in years. Fish sex was determined by either examining external morphology (eg. head and belly shape) or internal sex organ. Length was measured in millimeters, generally from mid-eye to the fork of the tail. This data package includes a .csv of formatted ASL data (ASL_formatted_BristolBay.csv), an R script detailing the data processing steps (ASL_Formatting_BristolBay.R), the original .csv file (BB_ASL.csv), and the Microsoft Access Database file from which the original .csv was extracted (ADFG_Bistol Bay ASL and count.mdb).
|
|---|