Spatial and temporal distribution of spawning aggregations of blue ling (Molva dypterygia) west and northwest of the British Isles

Abstract

Fisheries on blue ling in ICES Areas Vb, VI, VII, and XIIb have mostly targeted spawning aggregations. ICES has repeatedly advised that blue ling are susceptible to sequential depletion of spawning aggregations and that closed areas to protect spawning aggregations should be maintained and expanded where appropriate. Information from a range of sources, including fishers, is analysed, and five main spawning areas are identified: (i) along the continental slope northwest of Scotland (ICES Division VIa); (ii) on, around, and northwest of Rosemary Bank (VIa); (iii) on the southern and southwestern margins of Lousy Bank (Vb); (iv) on the northeastern margins of Hatton Bank (VIb); and (v) along the eastern and southern margins of Hatton Bank (VIb). From the information available, it is suggested that, for management purposes, peak spawning be considered to take place at depths of 730-1100 m between March and May inclusive in VIa and Vb, and during March and April in VIb. Based largely on this information, the European Commission (EC) introduced in 2009 protection areas for spawning aggregations of southern blue ling in European Union (EU) waters within ICES Division VIa.