Heritability estimation for okadaic acid algal toxin accumulation, mantle color and growth traits in Mediterranean mussel (Mytilus galloprovincialis) Ania Pino-Querido a,b , José María Álvarez-Castro a , Jorge Guerra-Varela a,c , Miguel Angel Toro d , Manuel Vera a,e , Belén G. Pardo a , José Fuentes f , Juan Blanco f , Paulino Martínez a, ⁎ a Departamento de Genética, Facultad de Veterinaria, Universidad de Santiago de Compostela (USC), Campus de Lugo, 27002 Lugo, Spain b Evolutionary Genetics Group, Instituto Gulbenkian de Ciência, 2780-156 Oeiras, Portugal c Geneaqua S.L., Calle Primavera, 40-1B, 27002 Lugo, Spain d Departamento de Producción Animal, Universidad Politécnica de Madrid, 28040 Madrid, Spain e Laboratori d'Ictiologia Genètica, Departament of Biology, Faculty of Sciences, University of Girona, Campus de Montilivi, 17071 Girona, Spain f Centro de Investigacións Mariñas (CIMA), 36620 Vilanova de Arousa, Pontevedra, Spain abstract article info Article history: Received 1 October 2014 Received in revised form 16 January 2015 Accepted 31 January 2015 Available online 7 February 2015 Keywords: Mytilus galloprovincialis Algal toxins Diarrheic shellfish poisoning (DSP) Okadaic acid (OA) Heritability Mussel production Mediterranean mussel (Mytilus galloprovincialis) is one of the main species of the European aquaculture, Galicia being (NW Spain) the main productive region (~200,000 t/year). The main problem for mussel production is the accumulation of toxins coming from microalgae blooms, which have even increased in recent years determining the banning of commercialization for long periods. We estimated the heritability and correlations (genetic and phenotypic) for toxin concentration after a toxic episode related to the main diarrheic toxin, okadaic acid, and after a depuration period at indoor facilities using a large amount of full-sib (170) and half-sib families (above 600 both via father and via mother). We took advantage of the experimental design to estimate the same parameters for other relevant traits for mussel production like growth-related traits and color. Heritabilities were moderate and significant after both the accumulation and detoxification periods (h 2 ~ 0.35), suggesting the possibility of reducing toxin concentration through breeding programs in mussels. Growth-related traits also showed moderate heritabilities (~0.30), while color showed a very high heritability (~0.90), making them suitable for selection depending on producer and consumer demands. Interestingly, growth-related traits showed negative and significant genetic and phenotypic correlations with toxin concentration, while color showed positive ones, strongly suggesting that bigger and whitish mussels may accumulate less toxin. The results of our study support the viability of breeding programs to face the main problems of mussel industry, but this approach will determine a change in seed production, the wild seed being replaced or complemented with hatchery-produced seed. © 2015 Elsevier B.V. All rights reserved. 1. Introduction The Mediterranean mussel (Mytilus galloprovincialis) is one of the most important aquaculture species in Spain and in European marine- culture. Mussel production in Spain is mostly concentrated in Galicia (NW Spain) (www.pescadegalicia.com: 183,167,729 kg in 2013 with an economic income of 74,510,625 €), where it has an important eco- nomic and social impact. From the biological point of view, cultivation has good health, because neither severe pathological problems nor im- portant drops in growth and production of mussels have been detected until now. Moreover, no problems have been found in the supply of wild seed, as it happens in other European countries, where the supply is not constant between years and the collection of wild mussel seed is criticized because of the potential damage to bottom habitats and the resulting limitations of food for mussel-eating birds (Kamermans et al., 2013). However, a recurrent ecological event, the appearance of toxic epi- sodes of phytoplankton origin, is seriously threatening the cultivation of this and other marine bivalves in Galicia (Blanco et al., 2013). Since toxic episodes are natural processes, it is difficult to find a straight- forward and definite solution to this problem. The reduction of the im- pacts associated to these episodes could be managed in three basic ways. One would be to prevent toxic phytoplankton blooms, but this seems impracticable because they occur in unconfined water masses af- fecting large geographical areas. Another way would consist in reducing the accumulation of toxic phytoplankton by changing the balance be- tween the toxin uptake and the detoxification processes in mussels. Aquaculture 440 (2015) 32–39 ⁎ Corresponding author. Tel./fax: +34 982822428. E-mail address: paulino.martinez@usc.es (P. Martínez). http://dx.doi.org/10.1016/j.aquaculture.2015.01.032 0044-8486/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Aquaculture journal homepage: www.elsevier.com/locate/aqua-online