Adult-mediated connectivity and spatial population structure of sardine in the Bay of Biscay and Iberian coast
|Author(s)||Silva Alexandra1, 2, Garrido Susana1, 2, Ibaibarriaga Leire3, Pawlowski Lionel4, Riveiro Isabel5, Marques Vitor1, Ramos Fernando6, Duhamel Erwan4, Iglesias Magdalena7, Bryere Philippe8, Mangin Antoine8, Citores Leire3, Carrera Pablo5, Uriarte Andres9|
|Affiliation(s)||1 : IPMA, Ave Brasilia 6, P-1449006 Lisbon, Portugal.
2 : Univ Lisbon, Fac Ciencias, MARE Marine & Environm Sci Ctr, P-1749016 Lisbon, Portugal.
3 : AZTI, Txatcarramendi Ugartea Z-G, E-48395 Sukarrieta, Bizkaia, Spain.
4 : IFREMER, Fishery Sci & Technol Unit, 8 Rue Francois Toullec, F-56100 Lorient, France.
5 : Inst Espanol Oceanog, Ctr Oceanog Vigo, Subida Radio Faro 50, Vigo 36390, Spain.
6 : Inst Espanol Oceanog, Ctr Oceanog Cadiz, Muelle Levante S-N, Cadiz 11006, Spain.
7 : Inst Espanol Oceanog, Ctr Oceanog Baleares, Apartado Correos 291, Palma De Mallorca 07015, Spain.
8 : ARGANS FR, 260 Route Pin Montard,BP 234, F-06904 Sophia Antipolis, France.
9 : AZTI, Portualdea Z-G, E-20110 Pasaia, Bizkaia, Spain.
|Source||Deep-sea Research Part Ii-topical Studies In Oceanography (0967-0645) (Pergamon-elsevier Science Ltd), 2019-01 , Vol. 159 , P. 62-74|
|Keyword(s)||Metapopulation, Source-sink dynamics, Adult-mediated connectivity, Cohort dispersal, Small pelagic fishes, Stock identity, Fisheries management|
This work investigated adult-mediated connectivity and spatial population structure of sardine in the European Atlantic waters. The spatial and temporal progress of cohorts was modelled using abundance-at-age survey data by area in the period 2000 to 2016, covering the region from the northern Bay of Biscay to the eastern Gulf of Cadiz. A novel methodology was used to calculate indices of cohort movement between areas. Movement was relatively low between three large regions, the Bay of Biscay, the northern Spanish and Portuguese waters and the Gulf of Cadiz, each hosting a recruitment hotspot. On the other hand, one half of the sardines recruited in North Portugal and a quarter of those recruited in Southwest Portugal moved to northern Spanish waters and South Portugal, sustaining local populations and fisheries. Movement was mainly driven by recruitment strength and, in a less extent, by food availability during fall. The connectivity and dynamic patterns suggest a metapopulation with three weakly connected populations and density-dependent source-sink movement within the northern Spanish and Portuguese waters population. While the weak connectivity does not invalidate the management boundary between the Bay of Biscay and the Iberian Peninsula, the Gulf of Cadiz may be treated as a separate stock. Multi-area/metapopulation assessment approaches should be applied to account for complex population structure, the higher risks of depleting source areas and/or less productive populations.