Ensuring the sustainability of European stalked barnacle fisheries requires effective management strategies. Insights into the experience of resource users with different management strategies can help to assess their success. To explore the opinion of the harvesters on the management of local fisheries, we conducted a multi-regional survey in Spain, Portugal and France with varying degrees of co-management. We analysed their responses using a multinomial logistic regression to understand what drove the observed differences. No single optimal strategy to achieve sustainability emerged, and the analysis revealed that geographic region was the most significant variable explaining the preferences of harvester. In less developed co-management systems they favored general input and output restrictions and expressed a desire for greater involvement in co-management processes. Conversely, in highly developed co-management systems with Territorial User Rights for Fishers (TURFs) they preferred the most restrictive and spatially explicit management strategies, such as implementing harvest bans and establishing marine reserves. These preferences indicate that harvesters in TURF-based systems exhibit a high level of stewardship and commitment to sustainable resource management. Moreover, our results indicate that the majority of harvesters in the regions in Portugal and France, areas with less developed co-management, are willing to make changes to current management strategies, reflecting their awareness of the need for improvement. To enhance the development of sustainable management practices across the distributional range of fishery resources, management strategies do not only need to be tailored to each region's particular practices, needs, and characteristics, but also consider the readiness of resource users for specific strategies.

The stalked barnacle Pollicipes pollicipes is an important economic resource in Portugal and Spain. Two extreme phenotypes can be identified, based on their morphology. More elongated barnacles are associated with bad quality and have a lower commercial value. The fishers perception about the existence, definition and causes for this phenotypical/quality variation was evaluated through a survey performed in Portugal and Galicia, Spain. The existence of two extreme commercial qualities was validated. Good quality barnacles were mainly defined as thick and short in both countries. In Spain (Galicia), the definition of bad quality animals corresponded mainly to the terms long and thin, while in Portugal, fishers used a wider variety of terms including watery, thin and soft. The characteristics of the rock and the hydrodynamics were the causes most referred by the fishers for this variation. The morphological variation of P. pollicipes was described by the ratio between maximal rostro-carinal length (RC) and total height (TH): RC/TH values > 0.4 indicate good quality barnacles; and values < 0.4 indicate bad quality barnacles. Although morphological variation between the two extreme qualities/phenotypes was found, no genetic (amplified fragment length polymorphism - AFLP) or epigenetic (methylation sensitive amplification polymorphism - MSAP) differences were detected.

We have followed the recovery of gaps produced either by harvesters or by scientists in stands of stalked barnacle (Pollicipes pollicipes) during two years in four regions of Europe (SW Portugal, Galicia and Asturias in Spain and Brittany in France; n = 423 gaps), which was extended to four years in Asturias (n = 252 gaps). The presence of adult conspecifics in the margins of the gaps increased by at least four times the probability of initiation of their recovery. After two years of follow-up in the four regions, 90

Environmental variables are known to regulate the reproductive output of marine intertidal organisms, but typically these variables are studied as averages and interpreted at a macroscale level. Along 200 km of coast in NW Iberia, great variability in the reproductive activity of the stalked barnacle Pollicipes pollicipes was found among 7 different locations. We found the highest number of broods reported to date in this species and suggest a more realistic method of predicting reproductive success that takes into account sea surface temperature (SST). At these same locations, we studied 13 yr of SST, thermal upwelling index (UI), ground skin temperature and chlorophyll a (chl a) satellite data, using spectral analyses to partition their temporal variability over ecologically relevant time scales. SST played the most relevant role as an environmental driver, explaining 48% of the variability in the proportion of breeding individuals (BI), but the SST-BI goodness-of-fit decreased sharply northwards. Variance-partitioning analyses indicated that cycles between 20 and 100 d in SST and UI were more important southwards, which is consistent with a latitudinal gradient in upwelling intensity and frequency along this coast. Thus, we found better biophysical coupling towards the south, where shorter fluctuation time scales in SST match the gonadal development period (around 1 mo). This pattern may explain the spatial variability in the strength of association between key environmental variables and the reproductive cycle of coastal species along their distribution range.

Understanding large-scale spatial and temporal patterns of marine populations is a central goal in ecology, which has received renewed attention under climate change. However, few studies explore the large-scale dynamics of populations using standardized protocols and during the same time frames. We studied the phenology and intensity of reproduction and recruitment for the intertidal stalked barnacle Pollicipes pollicipes over an European scale and described their potential linkages with environmental variables. This species supports profitable fisheries in the Iberian Peninsula (Spain and Portugal). In Brittany (France), we had observed a significant lower reproductive effort (long non-breeding season, short breeding period in summer) and low values of recruitment intensity. This pattern may be related to the fact that Brittany corresponds to the northern limit of the distribution of this species in continental Europe. On the Iberian Peninsula, the most different region was Galicia (Spain), with Asturias (Spain) and SW Portugal being more similar. In Galicia, we have observed a contradictory pattern characterized by the absence of a non-breeding period and by a shorter recruitment season than observed in other Iberian regions. Our results suggest that air temperature, SST and chlorophyll-a might be related to the variability in reproduction and recruitment patterns of P. pollicipes . Moreover, spring and early summer upwelling in SW Portugal and Galicia might be inhibiting recruitment in this period. At the northern limit, the expected increase in performance under climate change might facilitate the recovery of populations after exploitation, increasing the resilience of the resource to fishing pressure.

Small-cale fisheries are important for livelihoods, food security, jobs and income worldwide. However, they face major challenges, including the increasing effects of climate change that pose serious risks to coastal ecosystems and fishing communities. Although scientific research on climate change impacts has increased in recent years, few studies have explored the social impacts on small-scale fisheries. Using Galicia (Spain) as a case study, we investigated individual and household-level adaptive responses to climate change among fishers in three fishing guilds (Cambados, Campelo, and Redondela). Specifically, we estimated the economic vulnerability of shellfishers and assessed the diversity of social adaptive responses used to deal with climate change. Although fishers’ income strongly depends on shellfishing in all studied areas, our findings show that less fishing experience and lower engagement in fisher associations tend to increase the economic vulnerability of the fishers. The fishers’ vulnerability decreases as the size of households increases, while fishers who pay a mortgage and who live in households with fewer active members tend to be more vulnerable. The findings also show that Galician shellfishers have developed a wide range of adaptation strategies to anticipate and respond to climate change impacts, namely harvesting pricier and more abundant species, reducing household expenses and increasing social involvement in shellfishery associations. Although the adaptive strategies have helped Galician fishers to deal with climate change impacts, several threats to the sustainability of shellfisheries remain, such as a decrease in the abundance of key native shellfish species, and a high dependence on public and private aid to ensure reasonable incomes for shellfisheries. These findings are of interest and relevance to other similar small-scale fisheries around the world facing similar climate change challenges.

In January 2020, a stakeholder workshop was organized as a knowledge sharing strategy among European stalked barnacle fisheries. Management of this fishery differs greatly among regions and ranges from less organized and governed at large scales (>100 km, coasts of SW Portugal and Brittany in France) to highly participatory systems which are co-managed at small spatial scales (10's km and less, Galicia and Asturias). Discussions revealed that poaching is ubiquitous, hard to eradicate, and adapts to all types of management. The stakeholders identified some key management initiatives in the fight against poaching: granting professional harvesters with exclusive access to the resource, increasing social capital among harvesters through tenure systems (e.g. Territorial Use Rights in Fisheries) that empower them as stewards of their resource and intensification of surveillance with the active participation of the harvesters. Furthermore, increased cooperation between fishers associations and regional fisheries authorities, improved legal frameworks, adoption of new technologies and the implementation of market-based solutions can also help coping with this systemic problem.

Numerical biophysical models are a standard methodology used to provide estimates of larval dispersal and population connectivity for marine species with a bi-phasic life cycle. However, confidence on biophysical models, tested by confronting model estimates with empirical evidence, is seldomly assessed. We compared time-series estimates of larval supply of the stalked barnaclePollicipes pollicipesto rocky shores in 3 regions around the Iberian Peninsula (Asturias, Galicia, SW Portugal) with recruitment observations made at monthly intervals for 2 yr. Supply estimates were made with the Regional Ocean Modelling system using several larval behaviour scenarios, while the number of recruits on the stalks of adult barnacles was used as a measure of recruitment intensity. Cross-correlation analysis showed that passive, surface-dwelling and ontogenetically migrating larval scenarios generally produced significant positive correlations at time lags of 0 to +2 mo at the regional level but not at sub-regional or site levels. None of the scenarios produced a substantially better fit than the others, and all 3 produced estimates of average realized dispersal (-73 to +63 km in the S/W and N/E directions) and larval retention (2.0 to 2.4%) that were numerically very similar. These estimates indicate high levels of connectivity, either during larval life or via steppingstone processes, within and between the 3 regions. Based on these estimates, we advocate that the management of theP. pollicipesfishery requires an interactive, polycentric governance system at transregional, regional and local scales, which will give the resource a higher possibility of persistence by diversifying the fishery’s management portfolio.

The stalked barnacle Pollicipes pollicipes inhabits rocky shores from the Atlantic coasts of Brittany (France) to Senegal. Because of the culinary traditions of southern Europe, stalked barnacles represent an important target species for local fisheries on the Iberian Peninsula. To manage this fishery sustainably, it is therefore important to assess the dynamics of local populations over the Iberian coast, and how they are interconnected at a wider scale using finely tuned genetic markers. In this work, a new enriched library of GT microsatellites for P. pollicipes was prepared and sequenced using Ion Torrent™ Next Gen-Sequencing Technology. 1,423 adults and juveniles were sampled in 15 localities of three geographic regions: southern Portugal, Galicia and Asturias (both in northern Spain). Twenty polymorphic loci arranged in five multiplex PCRs were then tested and validated as new molecular tools to address the spatial and temporal genetic patterns of P. pollicipes . Our results revealed high genetic diversity among adults. However, juveniles were genetically more structured than their adult counterparts, which alternatively displayed much more connectivity among the three studied regions. The lack of spatial genetic heterogeneity in adults may be due to the overlapping of several generations of settlers coming from different geographic origins, which mainly depends on the orientation of residual currents along the coast during reproduction. The genetic differentiation of juveniles may indeed be congruent with Iberian Peninsula hydrodynamics, which can produce chaotic genetic patchiness (CGP) at small temporal scales due to sweepstake reproductive success, collective dispersal and/or self-recruitment. Remarkably, most of the genetic heterogeneity of juveniles found in this work was located in Galicia, which could represent an admixture between distinct metapopulations or an old refuge for the most northern populations. To conclude, high genetic variation in P. pollicipes can lead to the false impression of population panmixia at the Iberian scale by masking more restricted and current-driven larval exchanges between regions. This possibility should be taken into consideration for further specific management and conservation plans for the species over the Iberian Peninsula.

Environmental controls on the biogeographic distribution of species are becoming increasingly relevant under the present climate change conditions. The reproductive cycle of the acorn barnacle Semibalanus balanoides at its southernmost European distribution limit in Galicia (Northwest Iberian Peninsula) was studied in two locations (42.57°N 8.96°W, 42.61°N 8.89°W) with different temperatures during a 4-year time series (2012–2016), where an isolated population breeds even though the temperature thresholds documented for northern populations of the species are exceeded. Ovary production, total number of embryos and pre-hatching developmental stage were significantly higher in the colder location than in the warmer one. Fecundity was higher in colder reproductive seasons mediated by upwelling regime and food supply 3 months prior to fertilization. Investment in ovary tissue was favored by high temperatures and food availability, whereas suspended sediment was negatively correlated with investment in ovary tissue. Larvae release was associated with high temperatures and suspended sediment. Phenology of reproductive events was similar to what was described in farther north populations. Results indicated that reproductive output of the species at its southernmost European distribution limit is comparable to that reported in northern latitudes and suggest adaptation or acclimatization to local environmental conditions as maturation of gonads and fertilization was successfully carried out at higher temperatures than documented in northern European populations.

Heat waves are expected to increase in duration and frequency, impacting coastal ecosystems, especially intertidal organisms living near their thermal tolerance limits. Sedentary infaunal species are limited to some extent in escapes from sudden temperature changes, rather modifications to their physiology and behaviour are expected. This may lead to strong ecological and economic impacts on commercial bivalve species, such as Venerupis corrugata, Ruditapes decussatus, the introduced Ruditapes philippinarum and Cerastoderma edule, the most relevant in NW Spain. We investigated lethal and sublethal effects of heat during low tide on these species in the laboratory. Summer temperatures experienced within field, shallow sediments at approximately 2 cm depth i.e. 20 degrees C (control), 27 degrees C, 32 degrees C, and 37 degrees C, were replicated during four consecutive days and the diffusion of heat at the burrowing depth of each species was estimated; temperature exposure was expressed as degree hours above 22 degrees C. After two days of tidal exposure, C. edule and V. corrugata suffered significant mortalities, and also the most dramatic decrease in scope for growth (SFG) as well as reduction in burrowing activity. After four days under stress, all species had negative SFG. On recovery, species showed compensation at longer exposures, particularly C. edule. These effects of temperature on mortality, growth potential and burrowing ability may increase the time to achieve commercial size and exposure to predation. Particularly, V. corrugata, with a center of distribution lower in the intertidal and subtidal, and C. edule, shallower in the sediment, may be the most affected. Clearly the intensity and frequency of heat waves will affect these key species in the intertidal sediment flats changing ecosystem functioning and fisheries management strategies.

Small-scale fisheries (SSFs), which provide an important source of livelihood for many coastal communities, are at risk from climate change. Benthic organisms are likely to be particularly affected by the impacts of climate change due to their low spatial mobility, which limits their capacity for adaptation. Therefore, SSFs that target sedentary resources (“S-fisheries”) will potentially be among the most impacted types of fishery. The pathways of such impacts can be studied in an integrated approach by means of social-ecological vulnerability assessment. The stalked barnacle (Pollicipes pollicipes) fishery, one of the most important S-fisheries in Galicia (NW Spain), represents a complex social-ecological system rooted within the culture of the region. Along Galician coast, this benthic resource is co-managed by the territorial use rights in fisheries (TURFs) scheme. The vulnerability assessment involves ranking TURF systems according to the exposure of the resource to climate hazards, the sensitivity of dependent people and the capacity of the system to adapt to the impacts. After analyzing 26 stalked barnacle TURFs (79% of all Galician TURFs), we identified the most vulnerable zones (Muxía and O Pindo), as indicated by high levels of ecological vulnerability and social sensitivity and low adaptive capacity. We discuss different ways of increasing the adaptive capacity of TURFs based on local knowledge and literature reviews. Vulnerability assessment represents a powerful tool that can be used to help policy-makers develop adaptation strategies needed at different time scales, ultimately contributing towards better informed, sustainable and efficient fisheries management.

The abilities of estuarine species to respond to salinity fluctuations by behavioural and physiological responses can determine the maintenance of populations, particularly in the context of climate change. The native clams Ruditapes decussatus and Venerupis corrugata, the native cockle Cerastoderma edule and the introduced clam Ruditapes philippinarum are important resources in Galician (NW Spain) coast. As inhabitants of estuaries, these species are exposed to frequent salinity fluctuations as a result of heavy rains. This study investigated the short-term sublethal effects of salinity drops on their physiological (scope for growth, SFG) and behavioural (valve closure and burrowing activity) responses. Bivalves were exposed to simulated tidal cycles and similar salinities to the field conditions, i.e., four salinity ramps (5-20, 10-25, 15-30 and 30-30) during six days over three different periods of the year (autumn, winter and spring). The overall response was the same for all species under the lower salinities (5, 10 and 15), with a dramatic reduction of pumping activity, SFG and burrowing. Results differed among species under the higher salinities (20, 25 and 30). While C. edule was the most affected species in autumn showing no recovery despite having higher SFG compared to the venerids, R. decussatus was more resistant in all seasons despite having the lowest SFG compared to the rest of species. In winter, V. corrugata was the most vulnerable due to lower SFG at the lowest salinities. All species showed a compensation pattern in spring that led to non-recovery of individuals. Burrowing ability had similar patterns to SFG in autumn and winter but differed in spring, when recovery was the general pattern. The decrease of burrowing ability at lower salinities during stress seen to some degree in all species can increase vulnerability to predation. Results suggest that differential responses of lower activity over time could be related to the physiological condition and habitat preferences of each species and should be taken in consideration for management plans in the context of climate change. The results drive a discussion of the usefulness of SFG as the metric with which to assess salinity stress in adult bivalves and the need in future research to increase frequency and duration of stresses in concert with variables such as food availability.

The link between the behavior of organisms living within the sediment and benthic-pelagic coupling is critical to our interpretation of impacts of physiological stress. The rapidity with which organisms respond to a stress and recover once a stress is removed impacts the cascade of secondary effects that result from such behavioral changes. Such behavioral responses, although critical to our understanding, are difficult to quantify, particularly for organisms such as bivalves that inhabit sediments, the most common spatial habitat on Earth. Sublethal responses to fluctuating stressors such as salinity are rarely quantified in terms of activity. Here we do so using a combination of direct observations and pressure sensors, which allow us to record burrowing and other hydraulic activities. Based on our field observations and the literature, we predicted that there would be a breakpoint in behavior between salinities of 15 and 20 and that below this breakpoint the animals would significantly reduce activities including burrowing and feeding. The data presented support this prediction; burrowing was reduced in all three species at salinities at or below 15 as were fecal deposition and appearance of siphons above the sediment surface. These data are consistent with the prediction that under conditions of large fluctuations in salinity the magnitude of the link to primary productivity and nutrient availability from the benthos will be significantly reduced.

Event Abstract Back to Event Adapting fisheries management to the spatial variability in the reproductive cycle: the case of the sword razor clam in Galicia (NW Spain) Ana Tubío Gómez1*, Tania Ballesteros Otero1, Alba Hernández1, Rosana Rodríguez1, Mariana Herrera1, Roberto Gómez1, Enrique Poza1, Damián Costas1, Gonzalo Macho2 and Elsa Vazquez2 1 Estación de Ciencias Marinas de Toralla (ECIMAT), Spain 2 Department of Ecology and Animal Biology, University of Vigo, Spain The knowledge of the spatial variability of the population dynamics of benthic organisms is essential for sustainable fisheries management, not only from a biological point of view, but also with a socioeconomic focus. More and more fisheries are intended to be managed with a social-ecological systems approach, but this approach requires a large amount of information. Fishers in Galicia point out two problems regarding sword razor clam fisheries management; 1) the two-month reproductive closure causes local market shortages and the importation of foreign razor clams, 2) excessive discards of broken razor clam during some months (foot breakage when harvesting fully mature individuals). Both problems are related and remain unsolved. Razor clams stocks, like many other sedentary organisms, are highly spatially structured, forming meta-populations. By inhabiting spatially heterogeneous environments razor clams are patchily distributed within populations, which generates a spatial variability in their population dynamics (e.g. reproduction), even between very near areas (e.g. Robinson and Richardson, 1998; Rabaoui et al., 2007). Thus, studies of the reproductive cycle need to take into account the spatial variability of this resource in order to adapt the fisheries management, with the intention to reduce the problems highlighted before. The sword razor clam Ensis magnus is the most important commercial species of the razor clams in Spain and one of the most important shellfisheries in Galicia (NW Spain), being the Ría de Vigo the second most productive area of Galicia (landings accounted for 130t and ~1.5 million €; 23% of the landings in 2018). The reproductive cycle of E. magnus in the Ría de Pontevedra (Galicia) revealed spatial differences in the reproductive pattern caused by variations in environmental conditions (Hernández-Otero et al., 2014). And, although this species has already been studied in the Ría de Vigo (Darriba, 2001), the variability in reproduction at a mesoscale level in the ria is still unknown. Consequently, the aim of the study is to describe the reproductive cycle of E. magnus in several beds of the Ría de Vigo and its relation with environmental factors, in order to adapt the fisheries management to the biological spatial variability. From January to December 2018, reproductive cycle of E. magnus was studied in five exploited beds of the Ría de Vigo using histological methods (following the scale proposed by Hernández-Otero et al., 2014). These five beds were chosen taking into consideration their location in the ria: two in the inner part, two in the middle part, and one in the outermost part of the ria. Samples were taken monthly, during the sexual rest (July-September) and fortnightly, during the sexual period. Environmental variables (temperature, salinity and chlorophyll a concentration) were downloaded from the INTECMAR (Technological Institute for the Control of the Marine Environment of Galicia, Xunta de Galicia; http://www.intecmar.gal). Results show a reproductive cycle of E. magnus in the Ría de Vigo characterized by a sexual rest stage during summer and early autumn, a start of gametogenesis in autumn and a period of successive spawns interspersed with gonadal restoration during winter and spring, as it was found before in this ria (Darriba, 2001) and in the Ría de Pontevedra (Hernández-Otero et al., 2014). This reproductive cycle is similar to the one previously described in the intertidal in the Ría de Vigo (Darriba, 2001), and in the subtidal beds of the Ría de Pontevedra (Hernández-Otero et al., 2014). The relation with environmental conditions was found to be similar to the results reported by Darriba (2005) and Hernández-Otero et al. (2014). During summer, when temperature is higher and the water is rich in nutrients, E. magnus accumulates reserves and stay at sexual rest. In autumn, when temperature and nutrients decrease, gametogenesis started at the expense of the reserves stored. These results may be used for managing the fishery, adapting the rotational harvesting plan and the closure period to the spatial variability found in the gametogenic stage of the razor clams within the ria. This approach would avoid harvesting in fully mature beds, reducing therefore the discards due to the break of razor clams when its gonad is fully mature, and reducing as well the closure period, without reducing the reproductive output of the population. Nevertheless, reproductive timing varies from year to year due to environmental conditions, and moreover, monitoring the reproductive status of each fishing bed is very time (and money) consuming. To tackle this, easy and cheap data collection programs should be implemented in the fishery under an adaptive system that allows quick decisions to be collectively taken between stakeholders. Acknowledgements To all the personnel of the Toralla Marine Science Station (ECIMAT), to the fisher´s guild of Vigo and Cangas, and to the Galician cooperative society Cíes Artesanais SL. This study was conducted under the project "Study of the spatial variability of the reproductive cycle of the sword razor clam (Ensis magnus) in the Ría de Vigo and its application to fisheries management", financially supported by the Consellería do Mar, Xunta de Galicia. References DARRIBA, S. (2001). Biología de la navaja (Ensis arcuatus Jeffreys, 1865) de la Ría de Vigo (N.O. de España): Crecimiento y reproducción. Tesis doctoral, Universidad de Vigo. 283pp DARRIBA, S.; SAN JUAN, F. and GUERRA, A. (2005). Gametogenic cycle of Ensis siliqua (Linnaeus, 1758) in the Ría de Corcubión, Northwestern Spain. J Molluscan Stud, 71:47-51 Hernández-Otero, A.; Martínez-Castro, C.; Macho, G.; and Vázquez, E. (2014). The reproductive cycle of the sword razor clam Ensis magnus in the Ría de Pontevedra (NW Spain): spatial variability and its relation with environmental conditions. Journal of Sea Research 91: 45-57 RABAOUI, L.; ZOUARI, S.T.; KATSANEVAKIS, S., and BEN HASSINE, O. K. (2007). Comparison of absolute and relative growth patterns among five Pinna nobilis populations along the Tunisian coastline: an information theory approach. Marine Biology 152, 537-548 ROBINSON, R.F. and RICHARDSON, C.A. (1998). The direct and indirect effects of suction dredging on a razor clam (Ensis arcuatus) population. ICES Journal of Marine Science 55, 970–977 Keywords: sword razor clam, Ensis magnus, reproductive cycle, Fisheries Management, Galicia Conference: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) , Braga, Portugal, 9 Sep - 12 Sep, 2019. Presentation Type: Oral Presentation Topic: Fisheries, Aquaculture and Biotechnology Citation: Tubío Gómez A, Ballesteros Otero T, Hernández A, Rodríguez R, Herrera M, Gómez R, Poza E, Costas D, Macho G and Vazquez E (2019). Adapting fisheries management to the spatial variability in the reproductive cycle: the case of the sword razor clam in Galicia (NW Spain). Front. Mar. Sci. Conference Abstract: XX Iberian Symposium on Marine Biology Studies (SIEBM XX) . doi: 10.3389/conf.fmars.2019.08.00053 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 Apr 2019; Published Online: 27 Sep 2019. * Correspondence: Dr. Ana Tubío Gómez, Estación de Ciencias Marinas de Toralla (ECIMAT), Vigo, Spain, atubio@uvigo.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ana Tubío Gómez Tania Ballesteros Otero Alba Hernández Rosana Rodríguez Mariana Herrera Roberto Gómez Enrique Poza Damián Costas Gonzalo Macho Elsa Vazquez Google Ana Tubío Gómez Tania Ballesteros Otero Alba Hernández Rosana Rodríguez Mariana Herrera Roberto Gómez Enrique Poza Damián Costas Gonzalo Macho Elsa Vazquez Google Scholar Ana Tubío Gómez Tania Ballesteros Otero Alba Hernández Rosana Rodríguez Mariana Herrera Roberto Gómez Enrique Poza Damián Costas Gonzalo Macho Elsa Vazquez PubMed Ana Tubío Gómez Tania Ballesteros Otero Alba Hernández Rosana Rodríguez Mariana Herrera Roberto Gómez Enrique Poza Damián Costas Gonzalo Macho Elsa Vazquez Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Climate may influence biogeography through effects on adult survival and reproductive success. The acorn barnacle Semibalanus balanoides is the most widespread intertidal barnacle in the Northern Hemisphere. At its southernmost European distribution limit in northwestern Iberia (Galicia, northwestern Spain), winter temperatures are close to the thermal limit for penis development, and it is expected that a temperature increase would acutely reduce reproductive success. We studied the effect of temperature on penis development in the laboratory and related the results to field data to estimate fertilization probabilities at different temperatures and population densities. Exposure to colder water temperatures (14 and 17 degrees C) allowed full penis development, but this was inhibited at warmer temperatures (20 and 23 degrees C). Penis annulations and penis length were greater in barnacles exposed to colder water treatments than in those held at warmer temperatures. In the laboratory experiments, fertilization probability was higher at the lowest temperature (similar to 100%). In the field, fertilization probability was higher in the localities with colder temperature as well as those with higher barnacle density. The results support the prediction that rising temperatures will likely reduce reproductive success of S. balanoides at its southernmost distribution limit through failure in fertilization. If similar mechanisms apply in other boreal species, climate change may shrink distribution ranges through large-scale reproductive failures at the southern limits.