Report of the Mackerel Working Group

At the 68th Statutory Meeting it was decided (C.Res.1980/2:6/10) that the Mackerel Working Group (Chairman: MJ. Guéguen) should meet at lCES headquarters from 7 to 14 April 1981 to:

i) assess the mackerel stocks in Sub-areas II, III, IV, VI, VII, VIII and IX, '

ii) give further clarification of the biological reasoning under1ying the selection of 30 cm as the length below which catching mackerel is undesirable, both for the North Sea and the Western stocks,

iii) provide the best statistics available, sub-divided by gear type and by month (or season) of catches of horse mackerel, pilchard, sprat and mackerel in the area recommended for closure in paragraph 205 of the ACFM Report of 1980,

iv) assess the benefits to the mackerel stock of the closure proposed in the paragraph of the ACFM Report mentioned ahove, including data available on the length distribution of catches, the mortality per age group, by months, and by gear type and mesh sizes,

v) assess the effects of a 40 mm minimum mesh size for trawl gears for mackerel in Sub-area IV.

The Working Group was asked by the Chairman of ACFM:

- to re-assess the mixing of the stocks or reinterpret the tagging data,

- to try an assessment on both North Sea and Western mackerel combined.

The Group was also asked by Portugal to include the assessment of horse mackerel of ICES Divisions VIllc and IXa in its Agenda.