In order to estimate the spawning stock biomass of horse mackerel
in the North Atlantic Spanish waters, a series of egg and adult
cruises were carried out by lEO (Instituto Español de Oceanografía)
and AZTI -SIO (Instituto de Investigación y Tecnología para la
Oceanografía, Pesca y Alimentación) .
The survey was carried out from 23 April to 25 May 1992. A total
of 627 plankton samples and 37 adults samples were collected.
A total daily egg production of 3.3 X 1012 egg (SE = 7.26 X 1011
,
CV = 0.22) was estimated for the whole area sarnpled (ICES Division
Vlllc and subdivision northern IXa north). The estirnate of horse
mackerel spawning biornass ranged from 486,549 tons (CV = 0.34, when
using adult pararneter estirnates exclusively frorn the Spanish
survey, down to 368,814 tn (C = 0.32), when alternatively using an
estimate of relative batch fecundity from the southern region of
horse rnackerel western stock
