Aquatic Conservation-Marine and Freshwater Ecosystems最新文献

The Alboran Sea, located at the western Mediterranean Sea, hosts a diverse and ecologically important cetacean community, including endangered species. However, current marine protected areas (MPAs) in the region are limited in scope, and existing conservation strategies are insufficient to address the wide-ranging ecological needs of cetaceans. This study aims to synthesise existing national and international conservation initiatives in the Alboran Sea, develop a prioritization framework and propose a global protection framework for the basin. Our main results highlight that the Alboran Sea presents diverse protection figures including multiple sites of community importance (SCI) for the conservation of cetaceans, as well as it has been designated a cetacean critical habitat, and three different important marine mammal areas (IMMAs) have been identified. In addition, by using species distribution models and a prioritization approach, we identified key areas requiring enhanced protection for multiple cetacean species. The prioritization analysis considered various conservation scenarios, including minimising area costs and accounting for human threats such as fishing and pollution. Three critical areas emerged from our analysis, bridging existing SCIs. So, in this context, we propose the establishment of new protected areas in the northern site of the basin and advocate for a large-scale marine sanctuary—the Mediterranean Gate Sanctuary—due to the overlap of several national and international proposals for protection. A threat-based, species- and space-oriented conservation approach is recommended to effectively safeguard the region's biodiversity. By fostering stakeholder engagement and transnational collaboration, this sanctuary could address the ecological challenges cetaceans face and ensure sustainable marine management in the Alboran Sea.

The Mediterranean brown trout (Salmo trutta species complex) comprises genetically and ecologically distinct lineages primarily distributed across the Western Mediterranean region. Conservation of the Mediterranean brown trout is complicated by unresolved taxonomy. Although some populations have recently been recognised as distinct species, most—including those in the Iberian Peninsula—remain classified under the nominal S. trutta, which is currently listed as Least Concern by the IUCN. This taxonomic ambiguity masks severe conservation threats, particularly the widespread genetic introgression from stocked Atlantic-origin trout. In this study, we assessed introgression patterns, environmental drivers and conservation implications for Mediterranean brown trout populations in Catalonia (northeastern Iberian Peninsula). Genetic data from 134 sites were analysed using microsatellite markers and LDH-C1* allele frequencies, and the influence of historical stocking intensity and climatic variables on introgression was evaluated using hierarchical partitioning and regression models. Our results revealed extensive introgression, with only 10.4% of the populations retaining genetic purity. Stocking intensity was the primary predictor of introgression, followed by temperature and precipitation seasonality. Although the overall distribution of brown trout in the region remains stable, genetically pure Mediterranean populations have experienced severe range contraction, with a 61.5% reduction in extent of occurrence (EOO) and an 89.6% reduction in area of occupancy (AOO). This decline might meet IUCN criterion B for Endangered, although a formal assessment is currently impeded by taxonomic uncertainty and data limitations. The recognition of Mediterranean brown trout as a distinct species, alongside urgent measures to halt ongoing introgression and preserve remaining pure populations, is essential for its long-term conservation.

Coral reefs are among the most biodiverse ecosystems on Earth, yet they are rapidly declining due to climate change and other anthropogenic stressors. Population reductions threaten sexual reproduction in sessile coral species, as increased distances between colonies hinder gamete encounters. Once populations fall below critical density thresholds, natural recovery may become impossible even after stressors are removed. Biobanking of coral germplasm has therefore emerged as a key strategy to preserve genetic diversity and support reef restoration. This study developed and validated a cryopreservation protocol for sperm of the Brazilian endemic reef-building coral Mussismilia harttii, representing a milestone in coral conservation for the Southwestern Atlantic. Spermatozoa were exposed to dimethyl sulfoxide (DMSO) and methanol (MeOH) at concentrations of 10%, 15% and 20% and subjected to controlled slow freezing and ultra-rapid freezing. Postthaw analyses assessed motility, mitochondrial activity and viability. The best results were obtained with 20% DMSO and controlled slow freezing, yielding 29.7% ± 0.84% motility and 83.6% ± 2.2% viability. Mitochondrial activity (MTT assay) was higher with 15% MeOH (1.63 ± 0.17) than with DMSO (0.74 ± 0.17). Cryopreserved sperm (20% DMSO + slow freezing) achieved a 100% fertilization rate, statistically equivalent to fresh sperm (p = 0.4533). This optimized protocol enabled the establishment of the first coral sperm repository in the South Atlantic, currently storing 2.4 billion viable M. harttii spermatozoa. This repository provides a crucial resource to safeguard genetic diversity, strengthen assisted breeding programs and enhance the long-term conservation and restoration capacity of Brazilian coral reefs.

The red seaweed Asparagopsis taxiformis (common name: red sea plume) is attracting global attention because of its ability to reduce methane emissions in livestock systems. However, its habitat and distribution within the Great Barrier Reef (GBR)—one of the world's most iconic marine ecosystems—remain largely unexplored, posing challenges for conservation and the sustainable development of the seaweed industry. To help bridge this gap, we used habitat suitability modelling to identify areas in the GBR with favourable environmental conditions for A. taxiformis. We combined traditional and community-contributed data with marine spatial datasets to generate a predictive model using a machine learning approach (MaxEnt). Our findings indicate that A. taxiformis may occupy a broad habitat range along the GBR, spanning nearshore and offshore areas from the northern to southern sectors, albeit with some gaps. These potential habitats include areas with no previous records. Highly suitable habitats were found in areas with water depth of less than 20 m, minimum average seawater velocities of 0.3–0.5 m s⁻¹, and minimum photosynthetically active radiation levels of 25–28 E m⁻² day⁻¹. Future projections suggest that more areas will become more suitable by 2050, possibly indicating habitat expansion. The identification of unreported potential habitats of A. taxiformis in the GBR provides a foundation for targeted monitoring and adaptive conservation and management strategies at both species and ecosystem levels.

The location of shark egg nursery areas in the Mediterranean Sea is not well known. Moreover, decades of trawling have depleted flat muddy bottoms of both organic (sessile colonial organisms) and inorganic (rocks) three-dimensional structures in the western Mediterranean Sea. Here, we present observations of 263 egg cases of small-spotted catshark (Scyliorhinus canicula) that were found attached to artificial mooring structures located within a demersal no-take MPA at 300- to 400-m depth. The area is located within a previously identified suitable habitat for small-spotted catshark egg nurseries, and where conservation measures, such as a no-take MPAs, have been implemented to recover the heavily-impacted ecosystem. However, the slow growth of habitat-forming sessile organisms combined with previous extraction of rocks and other objects from the seabed is hampering the recovery of these areas and the reproduction of oviparous sharks such as the small-spotted catshark. Our findings reveal that three-dimensional artificial structures with ropes and other attachments placed within suitable egg nursery habitat are effectively used by small-spotted catsharks to complete their reproductive cycle. Passive conservation tools such as no-take MPA may be coupled with active restoration activities such as the deployment of artificial structures in order to improve the conservation and recovery of oviparous elasmobranchs and other marine fauna.