Environmental control of Northeast Atlantic mackerel (
We investigate the effect of strong meteorological perturbations in early spring on the success of mackerel (Scomber scombrus) recruitment in the N/NW Iberian area (southern Bay of Biscay) for the period 1999–2008. In 2000, the year of the most pronounced recruitment failure on record, two consecutive multidisciplinary surveys sampled hydrographic conditions and mackerel eggs, larvae and post‐larvae over the main mackerel spawning grounds of the north and northwest coast of the Iberian Peninsula. Analysis of egg and larval abundance and birthdates based on the otoliths of mackerel juveniles caught between July and October 2000 showed that there were no survivors from the early spring spawns, indicating a massive loss of early spawning effort. Moreover, the abundance of 1‐year‐old mackerel estimated from an acoustic survey carried out in 2001 was the lowest observed within the 1999–2008 time series. This low or null survival from the early spawns in 2000 could be due to the meteorological and oceanographic conditions of that spring, in particular two storm events in April after a relatively calm March. The first storm event from the north caused strong local wind in the southern Bay of Biscay but a weak oceanographic response. The second storm event from the southwest was mainly felt west of Galicia and caused a notable increase in shelf currents and a shift of the hydrographical structure along the shelf. Detailed analysis of strong wind pulses in early spring within the historical recruitment record suggests that strong local turbulence generated by high wind speeds and advection of larvae caused by the enhancement of shelf currents can contribute to reduced recruitment. Our observations indicate that, in 2000, both mechanisms were present.
Document Type: Research Article
Affiliations: 1: Instituto Español de Oceanografía (IEO), Centro Oceanográfico (C.O.) de Santander, Promontorio de San Martín s/n, 39080 Santander, Spain 2: IEO-C.O. de Gijón, c/Príncipe de Asturias 70 Bis, 33212 Gijón (Asturias), Spain 3: Intergovernmental Oceanographic Commission of UNESCO, 1 rue Miollis, 75732 Paris, Cedex 15, France 4: IEO-Madrid, Avda. de Brasil 31, 28020 Madrid, Spain 5: IEO-C.O. de Vigo, Cabo Estay Canido s/n, 36200 Vigo, Spain 6: IEO-C.O. de Cádiz, Puerto Pesquero, Muelle de Levante s/n, 11006 Cadiz, Spain (Permanent addres). Institut de Ciències del Mar (CMIMA-CSIC) P. Maritim de la Barceloneta, 37-49 08003 Barcelona, Spain (Current addres). 7: IEO-C.O de Baleares, Muelle de Poniente s/n, 07015 Palma de Mallorca, Spain 8: Museo do Mar de Galicia, Avda Atlántida s/n, Vigo, Spain
Publication date: September 1, 2011