Ecology of the stalked barnacle, Pollicipes pollicipes (Gmelin, 1970): reproduction, recruitment and relation with the environmental conditions Salvador Rom´an*1, Carlota Mu~niz1, Alba Agui´on2, Jos´eA. Santiago3, Pablo Seoane4, Berta Barreiro5, Elsa V´azquez1 and Gonzalo Macho1 *Corresponding author: [email protected] 1Dpto Ecolox´ıae Biolox´ıaAnimal, Facultade de Ciencias do Mar, Universidade de Vigo, 36310 Vigo, Spain 1Future Oceans Lab, Universidade de Vigo, 36310 Vigo, Spain 1Cofrad´ıade Pescadores La Anunciada de Baiona, 36300 Baiona, Spain 1Cofrad´ıade Pescadores de A Coru~na,15006 A Coru~na,Spain 1Cofrad´ıade Pescadores San Jos´ede Cangas, 36940 Cangas, Spain Keywords: Barnacles, Pollicipes pollicipes, Reproduction, Recruitment, Environmental conditions Introduction The barnacle Pollicipes pollicipes (Gmelin, 1970), commonly known as stalked barnacle is a marine sessile crustacean (Class Hexanauplia, Subclass Thecostraca, Infraclase Cirripedia, Order Scalpelliformes, Family Pollicipedidae) that lives adhered to rocks or other artificial hard substrata of intertidal shores. Its distri- bution extends along the East Atlantic coast from French Brittany to the coast of Senegal, including the Canary Islands (Fernandes et al., 2010). P. pollicipes is an economically important resource in fisheries in Spain and specifically in Galicia, where in 2018 the price ranged between 17.9 and 97.1 euros Kg−1 in the localities addressed in the present study (Xunta de Galicia, 2019). Further knowledge on the ecology of the organism is required to improve the management of the fishery. Materials and methods Reproduction and recruitment of the stalked barnacle (Pollicipes pollicipes), were studied in three sites along the Atlantic coast of Galicia (Figure1). Adult individuals (rostro-carinal length, RC > 15 mm), were sampled monthly between August 2017 and February 2019. For each month and site, the reproductive stage of 40 individuals was determined assessing the presence of egg masses and their maturity status. Recruitment rates were obtained counting the presence of recruits (RC < 2 mm) in the peduncle of 20 adult individuals. The relationship of reproductive state and environmental conditions was studied for a set of environmental predictors including sea surface temperature (SST), mean, maximum and minimum air temperatures, and upwelling index (UI). Environmental conditions were averaged during the period of gonadal development (25 days). Reproductive state in each site was modelled against the set of environmental predictors through Multiple Linear Regression (MLR), and the best model was selected using the Akaike Information Criterion. The same analyses were carried out for recruitment, considering three size clases of recruits. 1 Figure 1: Study area specifying the location where the biological data were obtained (indicated in the map as "Muestreo") and environmental data (Buoy of "Puertos del Estado", INTECMAR Buoys, location of the METEOGALICIA stations and the "SyP del sol" stations). Results and discussion A Coru~naand Cangas showed a similar reproductive pattern throughout the year, with higher percentages of adults carrying egg masses in Cangas (Figure2). In both sites, more than 50% of the individuals were carrying egg masses from the end of spring until autumn, with a peak during summer. In Baiona, reproduction was continuous throughout the year, showing more than 25% of the individuals with brooding activity during winter months (Figure2). The number of broods per year was close to five in A Coru~na and Cangas, and close to eight in Baiona, showing the highest values recorded to this date, despite the time series being incomplete. Model results showed that the best predictors of reproductive state for the three sites were minimum air temperature and upwelling index (MLR, p < 0.001). Figure 2: Percentage of adult individuals in reproduction differentiating individuals that carry mature egg masses. The error bars show the confidence interval at 90%. The x represent the months in which no sample was collected becouse the bad conditions of the sea. 2 Two recruitment periods appeared in the three sites during the period of study, extending from August until February, with maximum recruitment rates in September (Figure3). Comparison of recruitment among sites and periods showed that recruitment during the first period studied in Baiona was significantly lower than on the other sites and periods (ANOVA, p < 0.05). MLR showed significant results only for Cangas, where the selected model showed a positive relationship with maximum air temperatures and a negative relationship with SST (MLR, p < 0.05). Figure 3: Time series of total recruitment (RC < 2 mm) in the three localities studied. The error bars show standard deviation. The x represent the months in which no sample was collected becouse the bad conditions of the sea. References Fernandes, J., Cruz, T., Van Syoc, R., 2010. Pollicipes caboverdensis sp. nov. (Crustacea: Cirripedia: Scalpelliformes), an intertidal barnacle from the Cape Verde Islands. Zootaxa , 29{38. Xunta de Galicia, 2019. Pesca de Galicia, Xunta de Galicia, Conselleria do Mar. URL: http://www. pescadegalicia.gal. 3.