Marine Protected Areas (MPAs) are an essential tool for marine biodiversity conservation. Yet, their effectiveness in protecting marine ecosystems from global stressors is debated. Biological ...invasions are a major driver of global change, causing biodiversity loss and altering ecosystem functioning. Here, we explored the relationships between MPAs and alien/native range-expanding fishes in the Mediterranean Sea, the world’s most invaded sea. We surveyed fish and benthic communities in nine MPAs and adjacent unprotected areas across six countries. In the South and Eastern Mediterranean MPAs, the biomass of alien and native range-expanding fishes often exceeded 50% of the total fish biomass. Conversely, in the North and Western Mediterranean, alien fishes were absent. A negative relationship was found between native and alien species richness. Average and minimum sea surface temperature (SST) over six consecutive years were positively correlated with the total biomass of alien species; no alien fishes were recorded below 20.5°C average SST and 13.8°C minimum SST. We also found a negative relationship between alien fishes’ biomass and the distance from the Suez Canal, which is the main pathway for the introduction of alien fish in the Mediterranean Sea. The biomass of alien and native range-expanding fishes was found to be higher in the South and Eastern Mediterranean MPAs than in adjacent unprotected areas. The association of barrens (rocky reefs deprived of vegetation) and invasive herbivores was observed at all eastern sites, regardless of protection status. Currently, the level of fishing pressure exerted on alien and native range-expanding fishes seems to be the most influential factor determining the lower biomass of invasive fishes at unprotected sites compared to MPAs. Our findings suggest that complementary management actions, such as species-targeted removals, should be taken in MPAs to effectively control invasive fish populations.
Large, remote marine protected areas (MPAs) containing both reef and pelagic habitats, have been shown to offer considerable refuge to populations of reef‐associated sharks. Many large MPAs are, ...however, impacted by illegal fishing activity conducted by unlicensed vessels. While enforcement of these reserves is often expensive, it would likely benefit from the integration of ecological data on the mobile animals they are designed to protect. Consequently, shark populations in some protected areas continue to decline, as they remain a prime target for illegal fishers.
To understand shark movements and their vulnerability to illegal fishing, 3 years of acoustic tracking data, from 101 reef‐associated sharks, were analysed as movement networks to explore the predictability of movement patterns and identify key movement corridors within the British Indian Ocean Territory (BIOT) MPA. We examined how space use and connectivity overlap with spatially explicit risk of illegal fishing, through data obtained from the management consultancy enforcing the MPA.
Using individual‐based models, the movement networks of two sympatric shark species were efficiently predicted with distance‐decay functions (>95% movements accurately predicted). Model outliers were used to highlight the locations with unexpectedly high movement rates where MPA enforcement patrols might most efficiently mitigate predator removal.
Activity space estimates and network metrics illustrate that silvertip sharks were more dynamic, less resident and link larger components of the MPA than grey reef sharks. However, we show that this behaviour potentially enhances their exposure to illegal fishing activity.
Synthesis and applications. Marine protected area (MPA) enforcement strategies are often limited by resources. The British Indian Ocean Territory MPA, one of the world's largest ‘no take’ MPAs, has a single patrol vessel to enforce 640,000 km2 of open ocean, atoll and reef ecosystems. We argue that to optimize the patrol vessel search strategy and thus enhance their protective capacity, ecological data on the space use and movements of desirable species, such as large‐bodied reef predators, must be incorporated into management plans. Here, we use electronic tracking data to evaluate how shark movement dynamics influence species mortality trajectories in exploited reef ecosystems. In doing so we discuss how network analyses of such data might be applied for protected area enforcement.
Marine protected area (MPA) enforcement strategies are often limited by resources. The British Indian Ocean Territory MPA, one of the world's largest ‘no take’ MPAs, has a single patrol vessel to enforce 640,000 km2 of open ocean, atoll and reef ecosystems. We argue that to optimize the patrol vessel search strategy and thus enhance their protective capacity, ecological data on the space use and movements of desirable species, such as large‐bodied reef predators, must be incorporated into management plans. Here, we use electronic tracking data to evaluate how shark movement dynamics influence species mortality trajectories in exploited reef ecosystems. In doing so we discuss how network analyses of such data might be applied for protected area enforcement.
This research is the first to assess marine litter and plastic pollution in India's first marine protected area (MPA), the Gulf of Kachchh Marine Protected Area (GOKMPA). We compare it to two ...non‐protected areas, that is, Okha Beach and Beyt Dwarka, known for their high industrial and tourist activity, respectively. Standing‐stock surveys were used to collect primary litter data, while questionnaire surveys were used to learn about people's perception and attitude towards the plastic pollution problem in the study area. We found that plastic was the most common component of the litter at all the sites and that it was primarily of terrestrial origin. Compared to non‐protected sites, GOKMPA had the lowest litter density but the highest proportion of plastic litter. Single‐use plastic bottles were the most counted items at all the sites, regardless of the conservation status of the sites. The majority of people (locals, visitors, and fishers) around these sites expressed concern about waste but were hesitant to take responsibility and discourage or prevent littering. We noted that designating coastal territories as protected areas helps in reducing plastic pollution while also conserving habitat and biodiversity. However, this could change rapidly due to either mishandling of litter within MPAs or neighboring non‐PAs, and also because plastics pose an actual toxicity risk when present even at minimal concentrations in the environment. We recommend combining preventive, mitigating, and curative measures in areas where risk hotspots for plastic litter are identified, and such sites must be constantly monitored. Long‐term solutions could include transitioning from a linear to a circular economy, which would involve goals for reducing plastic waste and instituting more sustainable production and consumption patterns.
Despite promises that ‘healthy’ marine systems show increased resilience, the effects of ecosystem management strategies on invasion success in marine systems is still unclear. We show that ...resistance to the invasive alga, Sargassum horneri, in a temperate reef system occurs through alternate mechanisms in different ecosystem states. In an old marine protected area (MPA), invasion of S. horneri was suppressed, likely due to competitive pressure from native algae, resulting from protection of urchin predators. In a nearby fished urchin barren, invasion of S. horneri was also suppressed, due to herbivory by urchins whose predators are fished. Within newer MPAs with intermediate levels of interacting species, S. horneri was abundant. Here, neither competition from native algae nor herbivory was sufficient to prevent invasion. We confirm that invasion in marine systems is complex and show that multiple mechanisms in single systems must be considered when investigating biotic resistance hypotheses.
Oceanic marine protected areas (MPAs) that are close to the litter accumulation zones in the subtropical gyres receive large amounts of plastic litter, both as micro‐ and as macroplastics.
The ...macro‐litter accumulating on the islands in the Easter Island Ecoregion (Rapa Nui and Salas y Gómez) can be traced back to the high seas industrial fishery operating in the South Pacific.
Seabirds nesting in the MPAs in the South Pacific are affected by both microplastic ingestion and macroplastic in their nests, but there was no evidence of entangled birds.
Conservation of seabirds (and other species) in these oceanic MPAs requires efficient measures to reduce plastic contamination in the ocean.
Observations made in the South Pacific coincide with those from other oceanic MPAs, calling for global actions.
Marine protected areas have been scaling up from small areas located in coastal waters to large‐scale marine protected areas in remote areas, partly in response to the international agenda to ...conserve 10% of marine and coastal areas.
Chile has made considerable progress in the designation of large‐scale marine protected areas in its oceanic islands with varying degrees of top‐down and bottom‐up processes, scientific knowledge and interplay among institutions.
The process of designating the multiple‐uses marine protected area in Rapa Nui (Easter Island) involved interplay among scientific research, capacity building, local knowledge and collaboration between sectors, which contributed to the community transformation toward marine conservation in Rapa Nui.
A recent increase in scientific research on the marine ecosystems was transmitted to stakeholders and the local community via capacity‐building actions. The knowledge‐based empowerment of the Rapanui population (inhabitants of Rapa Nui) involved the definition not only of the objectives, the extension and the conservation goals of the Rapa Nui multiple‐uses marine protected area, but also of the implications beyond the designation, such as issues of governance, management and financing.
The implementation of the Rapa Nui multiple‐uses marine protected area will test local and Rapanui government relationships. The continuous science‐knowledge‐based dialogue in a strengthened relationship between the government and the local community in a ‘process of relating’ might be the pathway to future effective conservation efforts and successes.
The conservation of migratory marine species, including pelagic seabirds, is challenging because their movements span vast distances frequently beyond national jurisdictions. Here, we aim to identify ...important aggregations of seabirds in the North Atlantic to inform ongoing regional conservation efforts. Using tracking, phenology, and population data, we mapped the abundance and diversity of 21 seabird species. This revealed a major hotspot associated with a discrete area of the subpolar frontal zone, used annually by 2.9–5 million seabirds from ≥56 colonies in the Atlantic: the first time this magnitude of seabird concentrations has been documented in the high seas. The hotspot is temporally stable and amenable to site‐based conservation and is under consideration as a marine protected area by the OSPAR Commission. Protection could help mitigate current and future threats facing species in the area. Overall, our approach provides an exemplar data‐driven pathway for future conservation efforts on the high seas.
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