TagRetYear: Calculate Return Year for Angler Tag Returns.

In jasondubois/sportfish: Methods and Function for CDFW Sportfish Unit Data

Description

Angler tag returns are classified based on the difference (in days) between the reported capture date and recorded release (tagging) date. This difference is converted to years (by dividing by 365.25 [0.25 accounts for leap year]) and is assigned as the 'return year' for the returned tag. A tag returned within 365.25 days post released is classified as return year = 1, and so on. Return year is used (for example) in exploitation estimates, where only tags with return year = 1 are used.

Usage

TagRetYear(data, dcap, drel)

Arguments

data	Dataframe containg angler tag return information (at the very least tag, date captured, and date released).
dcap	Field name (unquoted) in 'data' containing capture date.
drel	Field name (unquoted) in 'data' containing release date.

Value

List. See 'values'.

values

• DAL Numeric vector. Difference in days between dates. ('DAL' = days at large)

• RetYear Numeric vector. Calculated return year.

• CountNAsDAL Numeric scalar. Count of 'NA' values. (i.e., where RetYear or DAL could not be calculated.)

• CountNegativeDAL Numeric scalar. Count where capture date before release date (illogical).

• RecordNumsNegDAL Numeric vector. If 'CountNegativeDAL' not 0, then herein are record numbers where capture date before release date.

Note

Date fields should be of class 'Date' or 'POSIX'.

Examples

# coming soon

jasondubois/sportfish documentation built on July 3, 2020, 1:01 p.m.