Based on simulated catch data, this contribution shows that standard length-converted catch curves cannot be used for accurately estimating total mortality when growth oscillates seasonally. Some implications for length-based stock assessment methodology are discussed, and the need for the...

A general form of the yield equation is presented. This is used to investigate the effects of seasonal growth oscillations on estimation of yield per recruit. The results show that these effects will be strongest in short-lived organisms such as penaeid shrimps.

This article discusses difference between the newly released Compleat ELEFAN Software Packag (Vers. 1.1) (Gayanilo and Pauly 1989, Fishbyte 7(2): 20-21) and its predecessor (Vers 1.0). Also, a number of "bugs" found in Version 1.1 are documented; this led to releaase 1.11 which costs US$75.