Four-spot megrim (Lepidorhombus boscii) in Atlantic waters: growth parameters and age corroboration in Porcupine Bank
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1
Instituto Español de Oceanografía (IEO), Spain
The four-spot megrim (Lepidorhombus boscii), a flatfish distributed in European waters, has relevant commercial importance in the bottom fisheries of Spain and Portugal. Although the biological aspects and state of its Iberian Atlantic population are annually studied, information from northermost waters is lacking. In recent years, probably influenced by climatic variations, the size of these northernmost populations of L. boscii (northern Bay of Biscay, Celtic Sea, west of Ireland) has increased, with annual catches of about 600 t (~ 6 M €) of which Spain captures around 70%. ICES (International Council of the Exploration of the Sea) requires information of the biological aspects of these populations, mainly growth, to be able to properly assess its stock state, allowing an adequate management of this resource.
The present work studies the age and growth of L. boscii in one of the main fishing areas for the Spanish fleet and relevant in the European demersal fisheries, the Porcupine Bank (west of Ireland). The growth parameters obtained are here compared with those from other areas, mainly Bay of Biscay and Portuguese waters, offering a broader knowledge of the global growth of the species. These parameters obtained are available for the upcoming analytical stock assessment.
The age and growth of L. boscii is here estimated based on the interpretation of the translucent bands (annuli) of the sagittal otoliths, following internationally standardized protocols. Otoliths were obtained from specimens caught in five annual bottom trawl research surveys (2008-2012) carried out by the Instituto Español de Oceanografía (IEO).
The age interpretation consistency is here evidenced by analyzing the regularity of the distances of the annuli to the otolith primordium and by the back-calculation of the annuli. The growth patterns obtained from direct otolith age estimation and from back-calculation are also compared.
The tracking of the strength of the year-classes in the survey abundance matrix at age and year of L. boscii allows corroborating the age estimation and showing the preponderance of the abundant 2008 year-class.
Keywords:
Age Estimation,
Growth,
Lepidorhombus boscii,
Northeast Atlantic,
Porcupine Bank,
otolith
Conference:
XX Iberian Symposium on Marine Biology Studies (SIEBM XX) , Braga, Portugal, 9 Sep - 12 Sep, 2019.
Presentation Type:
Poster Presentation
Topic:
Fisheries, Aquaculture and Biotechnology
Citation:
Hernández
C and
Landa
J
(2019). Four-spot megrim (Lepidorhombus boscii) in Atlantic waters: growth parameters and age corroboration in Porcupine Bank.
Front. Mar. Sci.
Conference Abstract:
XX Iberian Symposium on Marine Biology Studies (SIEBM XX) .
doi: 10.3389/conf.fmars.2019.08.00082
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Received:
07 Jun 2019;
Published Online:
27 Sep 2019.
*
Correspondence:
Dr. Carmen Hernández, Instituto Español de Oceanografía (IEO), Madrid, Spain, carmen.hernandez@ieo.es