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Seagrasses are highly sensitive to human-induced disturbances and global environmental changes. Since the 1980s, Zostera marina meadows along the West Swedish coast (Skagerrak) have declined significantly, as evidenced by changes in morpho-anatomical traits, reductions in area coverage, and shifts in associated communities. However, infaunal assemblages within Z. marina meadows remain understudied compared to epifaunal communities and have not been previously used as indicators of seagrass regression. To investigate spatial variability in infaunal composition, we analysed samples from 15 coastal stations at depths of 1.5–3 m depth. Using an n-dimensional hypervolume framework, we assessed functional differences between infaunal and epifaunal communities. We examined infaunal community descriptors—such as species richness and individual abundance—biotic indices, environmental drivers (including wave exposure and Z. marina biomass), and correlations with epifauna. Variability in infaunal composition across sampling stations was primarily driven by differences in the abundance of dominant taxa, including the polychaete Capitella capitata , oligochaetes, nematodes, and chironomids. Several coastal stations, such as Marstrand and Finsbo, were classified as moderately polluted, though biotic indices, i.e., AMBI, M-AMBI and ISI, showed discrepancies. Spatial patterns in infaunal assemblages were mainly influenced by Z. marina biomass and maximum fetch, with a good representation of oligochaetes and chironomids in exposed stations. These findings suggest that infauna respond differently from epifauna but provide valuable additional insights into the ecological status, functional traits, and trophic diversity of Z. marina meadows. Integrating multiple community components is essential for a more comprehensive understanding of the processes and patterns driving seagrass ecosystem regression.

Human-driven fragmentation of natural habitats increasingly threatens biodiversity, particularly in coastal ecosystems like seagrass meadows. Fragmentation breaks continuous habitats into smaller, isolated patches, amplifying edge effects and disrupting community structures and ecosystem functions. This study examines the effects of habitat fragmentation on large (> 1 mm) and small (0.2–1 mm) epifauna, as well as infauna, within eelgrass ( Zostera marina ) meadows along the Skagerrak coast in western Sweden. We assessed faunal responses across three fragmentation levels (low, medium, and high) and patch zones (Edge, Near-Edge and Center), providing a novel multi-assemblage analysis of these dynamics. Field surveys and statistical modeling revealed distinct community responses: large epifauna, especially amphipods, dominated low and moderately fragmented meadows, whereas highly fragmented areas showed more even species distributions. In contrast, small epifauna exhibited consistent abundance across zones and fragmentation levels. Infaunal communities varied most, with high fragmentation linked to increased evenness and shifts in species composition. These findings underscore the importance of conserving less fragmented meadows and highlight the need for targeted restoration efforts to enhance biodiversity and ecological resilience in degraded areas. By addressing both patch- and seascape-level fragmentation effects, this study offers critical insights into the ecological impacts of habitat fragmentation, supporting the development of targeted conservation strategies for coastal ecosystems.

The most important marine coastal ecosystem in the Chilean coast are kelp forests. This review is based on ecological studies regarding different aspects of subtidal kelp ecosystems along the Chilean coast. It highlights the most interesting findings in (1) biology of subtidal kelp in Chile, with particular reference to (2) habitats formed by kelp, and considered the successful examples and promising results in the (3) kelp as an industrial resource (Biotechnological approach of kelps and aquaculture). The impact caused by (4) El Niño-Southern Oscillation is discussed as an important climatic event that could help to forecast the future of the kelp ecosystem. In addition, this literature review outlines the knowledge gaps on subtidal kelp along the Southeast Pacific Coast of Chile, so that research can be strengthened in the future.

IntroductionArtificial substrates are increasingly employed in marine ecosystems to support benthic communities by providing habitat and enhancing biodiversity, particularly in areas where natural substrates are limited. Understanding the ecological role of these structures is essential for conservation and management, especially in regions undergoing industrial development, such as offshore oil and gas areas.Materials and methodsTo investigate the vertical distribution of mobile epifaunal assemblages, stainless-steel settlement plates were deployed across depths ranging from 10 to 44 meters for a duration of 13 months. The study was conducted between the Al Shaheen Oil Platforms and nearby offshore natural reefs within the Qatari Exclusive Economic Zone (EEZ).ResultsThe survey recorded a total of 2,302 individuals from 42 operational taxonomic units (OTUs), including the first documented presence of Galathea sp. in Qatari waters. Distinct patterns of species distribution were observed, with polyclads and sipunculids predominantly occurring in shallow waters, while deeper sections showed reduced abundance, diversity, and biomass. Although no significant horizontal patterns were detected between reef sites, strong ecological connectivity was evident, indicating that the artificial substrates acted as effective \"stepping stones\" for mobile fauna.DiscussionThe dominant functional groups included surface deposit feeders (sipunculids), carnivorous flatworms, and polychaetes. Notable depth-related associations were found, such as sipunculids and flatworms with sessile bivalves in shallow areas, and crabs with dead barnacles at deeper depths. These findings provide valuable baseline data on mobile benthic communities inhabiting offshore artificial reefs and highlight their role in promoting biodiversity and connectivity between natural reef habitats. The study also offers important implications for the design, commissioning, and decommissioning of oil and gas infrastructure, with relevance to reef restoration and fisheries enhancement strategies in the region.

Studies on microbial communities are pivotal to understand the role and the evolutionary paths of the host and their associated microorganisms in the ecosystems. Meta-genomics techniques have proven to be one of the most effective tools in the identification of endosymbiotic communities of host species. The microbiome of the highly exploited topshell Phorcus sauciatus was characterized in the Northeastern Atlantic (Portugal, Madeira, Selvagens, Canaries and Azores). Alpha diversity analysis based on observed OTUs showed significant differences among regions. The Principal Coordinates Analysis of beta-diversity based on presence/absence showed three well differentiated groups, one from Azores, a second from Madeira and the third one for mainland Portugal, Selvagens and the Canaries. The microbiome results may be mainly explained by large-scale oceanographic processes of the study region, i.e., the North Atlantic Subtropical Gyre, and specifically by the Canary Current. Our results suggest the feasibility of microbiome as a model study to unravel biogeographic and evolutionary processes in marine species with high dispersive potential.

Gonadal development in limpets is well-known. However, the integration of fecundity data on coastal management actions remains overlooked. Here, we use fecundity of two exploited limpets ( Patella ordinaria and P. aspera ) to demonstrate its potential as a conservation tool to preserve the harvested populations of both species. From October 2021 to June 2022, 158 females of P. ordinaria and 70 of P. aspera were collected from the coastal rocky shores of the archipelago of Madeira (NE Atlantic Ocean). The fecundity in both species appears to be determinate, and estimated batch fecundity 365,638 ± 204,462 oocytes for P. ordinaria and 73,029 ± 43,496 oocytes for P. aspera . The presence of spawning individuals of both species until May is of significant relevance to their management and conservation. A harvest-ban (November-March) is currently implemented in the coastal governance actions of P. ordinaria and P. aspera . Based on the fecundity results, small adjustments can be made to further improve the conservation of adult individuals, which are important for the continuity of future generations. So far, fecundity data constitute an overlooked life trait of key importance to preserve populations of exploited species, primarily those with limited mobility such as semi-sessile littoral limpets.

The integrated biochemical condition (IBC) of gonads is closely related to the reproductive success of highly migratory marine species. The IBC of gonads can be influenced not only by size and/or age, but also by environmental conditions. Here, female swordfish, Xiphias gladius , that migrate to temperate regions with a marked seasonality ( e.g ., the Southeastern Pacific Ocean, SEPO) were compared in relation to the IBCs (lipids, proteins, glucose and, fatty acid profiles) of their gonads; individuals with two body size ranges and distinct degrees of sexual maturity were evaluated, and considered as: small and/or virginal (SV: <170 cm lower jaw fork-length (LJFL), oocyte size (OS) <0.08 mm) vs large and/or maturing females (LM: >190 cm LJFL, OS >0.133 mm). This comparison was conducted in two environmentally contrasting seasons (winter vs spring). Our results showed that the gonadosomatic index (GSI) was significantly higher in LM than SV. Lipid contents varied significantly between seasons and body sizes. The highest lipid concentrations were recorded in the spring in large females. No significant differences were found when comparing the protein and glucose contents of the two evaluated seasons or body size ranges of the studied females. In turn, the fatty acid (FA) profiles of female gonads significantly varied for both seasons and body size ranges. A high content of saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and poly-unsaturated fatty acids (PUFAs) were recorded in female gonads in the spring. The SFAs C16:0 and C18:0, the MUFA C18:1 n 9, and the essential PUFA C22:6 n 3 were the main contributors to the observed differences between spring and winter. These results could be used as indicators of the nutritional condition and health status of swordfish individuals. Hence, the IBC of female swordfish gonads have great potential to aid in estimating survival rates and stock abundances of this species. The integration of this information constitutes an asset in fishery management models with an ecosystem approach.

Most of the marine bivalve production comes from aquaculture and only 11% comes from the wild fishery. For example, mussel aquaculture still strongly relies on spat - the recently settled juveniles. Gaps of information on the recruitment and settlement of spat are important drawbacks for the development of mussel aquaculture in several geographic regions. We here study these processes using three collectors (Anchovy mesh, Rope and Raschel mesh) throughout one year in two coastal sites of Central Chile (Coliumo and Punta Lobería) at three depths (2, 4 and 6 m). Five spat species were settled in the collectors, i.e. Aulacomya atra, Choromytilus chorus, Mytilus chilensis, Mytilus galloprovincialis and Semimytilus algosus . Recruitment was consistently higher during summer and autumn at both sites. Different seasonal recruitment patterns were observed regarding the spat species. Spat collection of the former mytilid species occurs from spring to autumn with the exception of M. galloprovincialis in Coliumo and M. chilensis in Punta Lobería. M. galloprovincialis is settled mostly in autumn and summer, and M. chilensis during winter. There were also differences when considering the collector type, mostly due to A. atra and S. algosus which peaked in nylon rope. Spat collection of the commercial species M. chilensis should be preferentially carried out in nylon rope during autumn in Coliumo and summer and autumn in Punta Lobería. During summer and autumn, also S. algosus will be settled. These results will enable the implementation of management measures to promote mytilid culture on the coastal zone of the Biobío region.

This work was conducted within the framework of the NPRP project ‘Connectivity, diversity and genetic between offshore natural coral reefs and oil platforms – NPRP No. 7‐1129‐1‐201’, funded by the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors. F.T. is supported by a CNPq/Brazil fellowship through the program Science without Borders (Proc. 232875/2014‐6). We are also grateful to Filipe Vieira (University of Copenhagen) for his advice on population genetic analyses.

Total marine fisheries catches within the exclusive economic zone of the Canary Islands, Spain, were reconstructed to include catches from the various small-scale artisanal fleets and their discards, as well as subsistence, recreational and other unreported catch. Total reconstructed catch was estimated at 38600 t in 1950, increasing to 81200 t in 1985, declining to approximately 43700 t year–1 in the early 2000s, and finally spiking to about 65300 t year–1 by the late 2000s. These catches coincide with a severe depletion of fish stocks, especially those of demersal species, due in part to fishing overcapacity in the artisanal sector, despite attempts to limit effort by the government. Spain only started to report catches to the FAO in 2006, and from 2006 to 2010 reconstructed catch was seven times the reported catch. Nearly 70% of this catch was from the recreational fishing sector, due in part to technological advancements and increased investments in the construction and improvement of secondary ports.