Age and growth of anglerfish (Lophius piscatorius) on the Porcupine Bank (west of Ireland) based on illicia age estimation

Abstract

The age of white anglerfish (Lophius piscatorius) on the Porcupine Bank was estimated based on the age estimation of 979 illicia (first dorsal fin ray) obtained from a series of 9 annual groundfish surveys (2001–2009). Modifications in the methodology of illicia preparation and in the traditional biased age estimation criterion are presented. This is the first time that a growth pattern of white anglerfish based on illicia age estimations can be indirectly validated by tracking cohorts using the abundance indices per age class from surveys and length-frequency analyses. Previous studies of cohort tracking using the traditional illicia age estimation criterion showed a mismatch, suggesting a faster growth. With the new proposed criteria, abundant cohorts from 2001 to 2004, and scarce ones, from 2005 to 2007, can be tracked over the time throughout several age groups. A new growth pattern and von Bertalanffy growth parameters are presented (L∞: 162.31; k: 0.088; t0: −0.894). The results are compared with previous studies in other areas.