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The force required to dislodge mussels from the substrate is known as attachment strength. This feature has been mostly studied in mytilids inhabiting the intertidal of consolidated rocky substrates, whereas it has been less studied in sedimentary substrates. The aim of this study was to evaluate the attachment strength and the number of byssal threads of Brachidontes rodriguezii in two sites with mobile substrates in San Antonio Bay, Argentina [Punta Verde (PV) and Punta Delgado (PD)]. PV has relatively higher current velocities and coarser grain size than PD. Along coastal line transects at two different levels of the mid-intertidal of each site, the attachment strength was measured. The number of byssal threads in collected mytilids and the weight of the sediment adhered to them were recorded in the lab. The attachment strength, the number of byssal threads and the sediment adhered to the byssus differed significantly between levels and sites. Mytilids from the mid-level of both sites where the density was relatively lower, had a significantly greater number of byssal threads and higher weight of sediment adhered. This study reveals that a high amount of coarse sediment adhered to the byssus affects the attachment strength of B. rodriguezii in ecosystems relative to unstable substrates. We underline the importance of mobile substrates in understanding attachment features (attachment strength and byssal threads) of mytilids in this unstable ecosystem. [ABSTRACT FROM PUBLISHER]

The Ecosystem Approach to Fisheries (EAF) has been proposed as a holistic approach for managing fisheries. Although EAF is a widely accepted concept, many challenges remain in its practical implementation, particularly in small-scale fisheries (SSFs) in developing countries. Long-term evaluations of EAF performance in SSFs are scarce and even fewer when considering co-management (Co-M) as the institutionalized governance mode implemented under an EAF scheme (EAF/Co-M). This paper addresses the implementation, development process and performance of an EAF/Co-M in the yellow clam SSF of Uruguay through multiple fishery indicators for the period 2007–2015. EAF/Co-M showed a highly positive response in abundance and biomass of the harvestable stock through time, stabilization in individual sizes above the minimum landing size limit, and a fairly constant exploitation rate at low levels that did not exceed 25%, accompanied by relatively constant CPUE values through time. Temporal variations in unit price and revenues per unit of effort showed higher values after EAF/Co-M implementation. These indicators, taken together, suggest that the enhanced production capacity of the fishery during the EAF/Co-M implementation did not have a negative impact on the stock. The number of fishers involved in the activity has not changed markedly through time, but two remarkable positive changes occurred in the composition of the group: (i) an increasing number of licenses allocated twice in a row through time, which suggests the consolidation of a stable group of fishers; and (ii) a significant increase in the number of women directly involved in the fishing activity. This study provides solid empirical evidences to the idea that EAF, coupled with Co-M as a formal governance mode, could be helpful to address management tasks and to improve social–ecological conditions of SSFs. [ABSTRACT FROM AUTHOR]

• 56 sandy shore ecosystem services are identified from CICES v5.1. • Includes Regulation and Maintenance (n = 25 of 30), Provisioning (n = 16 of 39), Cultural (n = 15 of 15) services. • All components of the littoral active zone (foredunes, beach, surf zone) are important for service supply. • We identified 11 ecosystem service bundles that are generic to sandy shores and should be refined locally. • Sandy shores as social-ecological systems need well-planned management to sustain their ecosystem services. Sandy shores are highly regarded as sites for recreation, places to play in the sun, sea, and sand. In contrast, very little attention is given to beaches as ecosystems that support diverse biological communities, and comprise essential ecological infrastructure that provides numerous ecosystem services to people over and above recreation. Therefore, we aimed to comprehensively list and classify all ecosystem services provided by sandy shores based on an internationally accepted classification, compare service delivery by each component of the littoral active zone (LAZ: foredunes, beach and surf zone), and identify ecosystem service bundles for sandy shores for the first time. We identified and described all ecosystem services in the Common International Classification of Ecosystem Services (CICES, version 5.1) that apply to sandy shores. There were 56 (of 84, 67 %) of these services, including Biotic and Abiotic Provisioning (n = 16 of 39; 41 %), Regulation and Maintenance (n = 25 of 30; 83 %), and Cultural (n = 15 of 15; 100 %) services. All components of the LAZ are important for delivering services. Using multivariate statistics, we identified 11 ecosystem service bundles, which are mainly underpinned by the multifunctionality of the ecological infrastructure. We discuss three main threats to ecosystem service supply: the myriad of pressures these ecosystems face; discrepancies in service supply and demand; and limited ocean literacy regarding sandy shores. We propose actions to address these threats, including key areas for future research. Finally, we highlight the key role of management and governance in maintaining sustainable flows of ecosystem services and their benefits, and emphasize the importance of adaptive ecosystem-based management across the LAZ. [ABSTRACT FROM AUTHOR]

Ecosystem engineers can modify the environment, affecting the associated community. Studies of mussels as ecosystem engineers have been conducted mostly in the rocky intertidal zone, while those in sedimentary intertidals have been relatively scarce. The present study assessed the effect of varying densities of Brachidontes rodriguezii on local environmental variables (substrate weight, water content, organic matter, weight of sediments adhering to mussel byssus) and ecological attributes of the associated community (richness, abundance, diversity, evenness, and assemblage structure) at different intertidal levels, sites, and seasons, in a mixed-sediment intertidal region in San Antonio Bay (Patagonia, Argentina). We performed two independent manipulative field experiments at low and mid intertidal levels at two sites -Punta Verde (PV), with relatively higher current velocities and coarser grain sizes than Punta Delgado (PD)- in both winter and summer. Manipulative experiments consisted in reducing mussel density to 50% in the low intertidal and increasing that density to up to 100% in the mid zone. We hypothesized that local environmental variables and ecological attributes associated with B. rodriguezii depended on mussel density. The reduction in B. rodriguezii density increased the evenness and reduced the abundance at PD plus reduced the richness at PV. Also, when reducing mussel density, the assemblage structure differed in water content and organic matter at both sites between treatments and seasons. The sediment weight adhering to mussel byssus in PD and substrate weight in PV were the best descriptors of the assemblages. The increase in mussel density, however, produced a weak effect on the ecological attributes of the community, and the assemblage structure did not correlate with the environmental variables considered. Our results demonstrated a stronger engineering effect of B. rodriguezii at reduced, but not increased, mussel density. This study revealed that the ecological attributes associated with B. rodriguezii both were density-dependent and varied with sites along the year in mixed-sediment intertidal zones. • Manipulative experiments showed an engineering effect of the mussel B. rodriguezii. • Increasing and reducing the mussel-density modified the local environmental variables. • Manipulation of the mussel density affected the evenness, abundance and richness. • This effect was stronger in the low than in the mid-intertidal level in both sites. • The assemblage structure was explained by some environmental variables. [ABSTRACT FROM AUTHOR]

To assess how sandy beach biodiversity is influenced by the effects of environmental features and urbanization, we sampled the macrofauna in the whole across-shore gradient of 90 beach sites in Southeast Brazil. We found that morphodynamic features were the main drivers of macrobenthos, but urbanization-related variables, such as number of beachgoers and number of constructions on the upper shore, decreased species richness and biomass. We also found that submerged zones sustained the highest number of species and biomass in the across-shore gradient, but were the most impacted by human activities. By demonstrating the ecological importance of submerged zones, our results show that beach management practices, which are mainly focused on the upper shore, are missing important components of beach biodiversity. To secure the sustainability of beach ecosystems, management initiatives should include both their social and ecological components and consider the entire Littoral Active Zone as the proper management unit. • We unravel the effects of urbanization and environment on sandy beach biodiversity. • Morphodynamic variables were the primary drivers of beach macrobenthos. • Submerged zones had the highest biodiversity and were mostly affected by humans. • Number of visitors, buildings and grooming were critical indicators of impact. • The entire littoral active zone should be considered as the management unit. [ABSTRACT FROM AUTHOR]