Back-calculating lengths of fish at previous ages from measurements made on calcified structures (scales, otoliths, etc.) is fairly common practice within some fisheries agencies and institutions. The FishBC software distributed by the Amer...

Back-calculating lengths of fish at previous ages from measurements made on calcified structures (scales, otoliths, etc.) is fairly common practice within some fisheries agencies and institutions. The FishBC software distributed by the Amer...

Introduction Much of my work is with undergraduates who are first learning to analyze fisheries data. A common “learning opportunity” occurs when students are asked to compute the mean catch (or CPE), along with a standard deviation (SD), across multiple gear sets for each species. The learning opportunity occurs because some species will invariably not be caught in some gear...

Introduction I have received a few queries recently that can be categorized as “How do I collapse a list of categories or values into a shorter list of category or values?” For example, one user wanted to collapse species of fish into ...

A user of my Introductory Fisheries Analyses with R book recently asked me how to compute standard errors (SE) for the various PSD indices by using the usual equation for the SE of a proportion (square root of p times (1-p) divided by n). B...

e-mails with the latest R posts.

(You will not see this message again.)