Population biology of monkfish Lophius americanus

Abstract

This paper provides an overview of the biology of monkfish in US waters of the Northwest Atlantic Ocean using data from resource surveys spanning the period 1948-2007. Monkfish exhibited seasonal onshore-offshore shifts in distribution, migrated out of the southern Mid-Atlantic Bight (MAB) in mid-spring, and re-appeared there in autumn. Sex ratios at length for fish 40-65-cm long were skewed towards males in the southern MAB, but approximated unity elsewhere, suggesting that a portion of the population resides outside sampled areas. Growth was linear at 9.9 cm year-1 and did not differ by region or sex. Maximum observed size was 138 cm for females and 85 cm for males. Length at 50% maturity for males was 35.6 cm (4.1 years old) in the north and 37.9 cm (4.3 years old) in the south; for females 38.8 cm (4.6 years old) in the north and 43.8 cm (4.9 years old) in the south. Ripe females were found in shallow (<50 m) and deep (>200 m) water in the south, and in shallow water (<50 m) in the north. © 2008 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.