Marine invasion ecology and management have progressed significantly over the last 30 years although many knowledge gaps and challenges remain. The kelp Undaria pinnatifida, or “Wakame,” has a global non‐native range and is considered one of the world's “worst” invasive species. Since its first recorded introduction in 1971, numerous studies have been conducted on its ecology, invasive characteristics, and impacts, yet a general consensus on the best approach to its management has not yet been reached. Here, we synthesize current understanding of this highly invasive species and adopt Undaria as a case study to highlight challenges in wider marine invasion ecology and management. Invasive species such as Undariaare likely to continue to spread and become conspicuous, prominent components of coastal marine communities. While in many cases, marine invasive species have detectable deleterious impacts on recipient communities, in many others their influence is often limited and location specific. Although not yet conclusive, Undaria may cause some ecological impact, but it does not appear to drive ecosystem change in most invaded regions. Targeted management actions have also had minimal success. Further research is needed before well‐considered, evidence‐based management decisions can be made. However, if Undaria was to become officially unmanaged in parts of its non‐native range, the presence of a highly productive, habitat former with commercial value and a broad ecological niche, could have significant economic and even environmental benefit. How science and policy reacts to the continued invasion of Undaria may influence how similar marine invasive species are handled in the future.
The existence and magnitude of the recently suggested global warming hiatus, or slowdown, have been strongly debated. Although various physical processes have been examined to elucidate this phenomenon, the accuracy and completeness of observational data that comprise global average surface air temperature (SAT) datasets is a concern. In particular, these datasets lack either complete geographic coverage or in situ observations over the Arctic, owing to the sparse observational network in this area. As a consequence, the contribution of Arctic warming to global SAT changes may have been underestimated, leading to an uncertainty in the hiatus debate. Here, we constructed a new Arctic SAT dataset using the most recently updated global SATs and a drifting buoys based Arctic SAT dataset through employing the ‘data interpolating empirical orthogonal functions’ method. Our estimate of global SAT rate of increase is around 0.112 °C per decade, instead of 0.05 °C per decade from IPCC AR5, for 1998–2012. Analysis of this dataset shows that the amplified Arctic warming over the past decade has significantly contributed to a continual global warming trend, rather than a hiatus or slowdown.
Anthropogenic threats to natural systems can be exacerbated due to connectivity between marine, freshwater, and terrestrial ecosystems, complicating the already daunting task of governance across the land-sea interface. Globalization, including new access to markets, can change social-ecological, land-sea linkages via livelihood responses and adaptations by local people. As a first step in understanding these trans-ecosystem effects, we examined exit and entry decisions of artisanal fishers and smallholder farmers on the rapidly globalizing Caribbean coast of Nicaragua. We found that exit and entry decisions demonstrated clear temporal and spatial patterns and that these decisions differed by livelihood. In addition to household characteristics, livelihood exit and entry decisions were strongly affected by new access to regional and global markets. The natural resource implications of these livelihood decisions are potentially profound as they provide novel linkages and spatially-explicit feedbacks between terrestrial and marine ecosystems. Our findings support the need for more scientific inquiry in understanding trans-ecosystem tradeoffs due to linked-livelihood transitions as well as the need for a trans-ecosystem approach to natural resource management and development policy in rapidly changing coastal regions.
Marine Recreational Fishing (MRF) is an important activity in Europe, with 9 million fishers and generating annually € 6 billion in direct expenditures. However, there is a lack of data and understanding of MRF in Europe, particularly in Southern countries, which prevents a number of fish stocks from being effectively assessed and managed. In November 2016, a participatory workshop on MRF was held in Vigo (Spain) to identify challenges and opportunities for data collection, and to diagnose key research gaps and management issues for MRF in the Southern European Atlantic. Experts from a wide range of disciplines (researchers, policy makers, fisheries managers and commercial and recreational fishers) highlighted that the management of MRF is a challenge due to complex and dispersed legal frameworks, with multiple administrations involved, and overlapping uses of space with commercial fishing, aquaculture, navigation and tourism, among others. The lack of strong and representative fishing associations hampers research and management initiatives. Effective communication between recreational fishers, researchers and fisheries managers is also lacking. Despite the ecological, social and economic relevance of MRF, there is no systematic and comprehensive collection of information on fishing effort, recreational catches, expenses, social profile and access conditions of European recreational fishers. These data would be useful to avoid biases in the assessment of recreational fisheries due to the great diversity of ecosystems, species and typologies of users. Strategic recommendations and research priorities were also identified to address knowledge gaps and are discussed in the context of the management of MRF across Europe.
Spatial fishing closures are typically implemented for conservation and fisheries benefits, but the effects of such initiatives are often not tested. This study examined whether the densities and size compositions of beach clams differed between commercially fished and non-fished zones on beaches. Sampling of clams was stratified across two habitats (swash and dry sand) on two commercially fished beaches, before and during (early and late) the 6-month harvesting period. Two beaches that had no commercial fishing were also sampled the same way and acted as external controls. Differences in densities, but not size compositions, of clams were evident between zones on the commercially fished and control beaches, but they were mostly apparent only across short (day and week) periods before, early and late harvesting, and thus were most likely pulse responses of clams to stochastic, non-fishing related events that acted independently across the different zones on each beach. The potential movements of clams along and across beaches as well as current restrictions on commercial fishing probably dampened detection of longer-term fishing-related impacts and demographic differences in clams between commercially fished and non-fished zones. Direct fishing-related impacts on clams may only be discernable in the immediate vicinity of, and persist for a short period following, an actual fishing event on a beach. Nevertheless, the zones closed to commercial fishing may provide valuable protection to a portion of clams on each beach and alleviate beach-wide harvesting impacts. The broader value of these closed fishing zones requires knowledge of the impacts of fishing on other beach organisms and ecosystem functioning. Further experimentation that tests other aspects of management arrangements of beach clams may help determine their global applicability for sustainable harvesting, and contribute to the overall conservation management of sandy beach ecosystems.
Predicting how species will respond to climate change is a growing field in marine ecology, yet knowledge of how to incorporate the uncertainty from future climate data into these predictions remains a significant challenge. To help overcome it, this review separates climate uncertainty into its three components (scenario uncertainty, model uncertainty, and internal model variability) and identifies four criteria that constitute a thorough interpretation of an ecological response to climate change in relation to these parts (awareness, access, incorporation, communication). Through a literature review, the extent to which the marine ecology community has addressed these criteria in their predictions was assessed. Despite a high awareness of climate uncertainty, articles favoured the most severe emission scenario, and only a subset of climate models were used as input into ecological analyses. In the case of sea surface temperature, these models can have projections unrepresentative against a larger ensemble mean. Moreover, 91% of studies failed to incorporate the internal variability of a climate model into results. We explored the influence that the choice of emission scenario, climate model, and model realisation can have when predicting the future distribution of the pelagic fish, Electrona antarctica. Future distributions were highly influenced by the choice of climate model, and in some cases, internal variability was important in determining the direction and severity of the distribution change. Increased clarity and availability of processed climate data would facilitate more comprehensive explorations of climate uncertainty, and increase in the quality and standard of marine prediction studies.
There is global consensus that marine protected areas offer a plethora of benefits to the biodiversity within and around them. Nevertheless, many organisms threatened by human impacts also find shelter in unexpected or informally protected places. For coral reef organisms, refuges can be tourist resorts implementing local environment-friendly bottom-up management strategies. We used the coral reef ecosystem as a model to test whether such practices have positive effects on the biodiversity associated with de facto protected areas.
North Ari Atoll, Maldives.
We modelled the effects of the environment and three human management regimes (tourist resorts, uninhabited and local community islands) on the abundance and diversity of echinoderms and commercially important fish species, the per cent cover of reef benthic organisms (corals, calcareous coralline algae, turf and macroalgae) and the proportion of coral disease. We used multivariate techniques to assess the differences between reef components among the management regimes.
Reefs varied between the management regimes. A positive “resort effect” was found on sessile benthic organisms, with good coral cover and significantly less algae at resort islands. Corals were larger and had fewer diseases in uninhabited islands. Minor “resort effect” was detected on motile species represented by commercial fish and echinoderms.
In countries where natural biodiversity strongly sustains the tourist sector and where local populations rely on natural resources, a balance between tourism development, local extraction practices and biodiversity conservation is necessary. The presence of eco-friendly managed resorts, which practices would need to be certified on the long term, is beneficial to protect certain organisms. House reefs around resorts could therefore provide areas adding to existing marine protected areas, while marine protection efforts in local community islands should focus on improving fishing management.
Data scarcity in small-scale fisheries hinders the effective management of marine resources. This is particularly true within small island developing states that often have limited capacity for monitoring activities that could inform policy decisions. This study estimates the spatial distribution of fishing activity in the data-poor nearshore reef fisheries of Barbados using low cost interview surveys of fishers combined with a geospatial platform. With data from over 150 fishers in the island's major reef fisheries, the estimated total annual yield ranged from 272.6 to 409.0 mt, with seine fishing accounting for 65% of landings. This estimate is substantially higher than the recorded landings in official databases. Fishing activity is concentrated on the sheltered and heavily populated West Coast of the island. Reef fishing effort decreases markedly during the months associated with the offshore pelagic fishery season, as many fishers switch fisheries during this time and rough sea conditions restrict access to the nearshore windward reefs. The high levels of fishing intensity and low yields per unit of reef area appear to validate anecdotal evidence that the nearshore reefs of Barbados are heavily overexploited. The qualitative nature of interview data and other data gaps hinder the precise estimation of fishing effort and yield, where relative values are likely to be more accurate than absolute values. Nonetheless, the spatially and temporally explicit data generated here demonstrates how simple cost-effective methods can be used to fill important information gaps for marine resource management and spatial planning.
1.Marine protected areas (MPAs) are increasingly integrated into fishery management for coastal systems. Size and spacing rules (SSRs) have been proposed as simple MPA design guidelines, especially in regions where population connectivity data are limited.
2.We assessed whether SSRs allow managers to design effective MPA networks under spatiotemporally varying dispersal patterns using a spatially realistic population model parameterized for a commercially-exploited fish species on the Great Barrier Reef.
3.SSRs are used to design MPA networks, and population simulations are used to measure the mean and variance of the resulting population size and fishery catch.
4.We show that SSR performance is contingent on the extent of the MPA network, and whether species’ connectivity data can be used to target areas for protection. For example, in the absence of connectivity data, a ‘many small’ MPAs rule provides the least variable management outcome.
5.Synthesis and applications. We demonstrate that the performance and usefulness of size and spacing rules (SSRs) as guidelines for marine protected areas (MPAs) depend on the level of knowledge about larval dispersal, as well as the level of current exploitation in the fishery. These context-dependent results offer particularly relevant guidance to future MPA design projects in regions with limited connectivity data.
Anthropogenic carbon (Cant) concentration is determined according to the TrOCA method, from carbonate system data and hydrographic parameters collected during two consecutive spring cruises (2007 and 2008) in the Argentinean Patagonian shelf-break zone between 36°S and 50°S. Cant has intruded the water column until intermediate depths, with no Cant below 1000 m, in the deeper waters (i.e., North Atlantic Deep Water and Antarctic Bottom Water) of the Northern sector of the study area (i.e., North of 38°S). The higher Cant concentration is observed in Subantarctic Shelf Water in the Southern region, whereas in the Northern sector both Tropical Water and South Atlantic Central Water are equally affected by Cant intrusion. The Antarctic Intermediate Water represents the depth-limit achieved by Cant penetration, reinforcing the role that this water mass plays as an important vehicle to transport Cant to the oceans interior. The estimated Cantaverage (± method precision) is 46.6 ± 5.3 μmol kg− 1, considering the full depth of the water column. The ocean acidification state (ΔpH) shows an average (± standard deviation) of − 0.11 ± 0.05, thus, indicating an annual pH reduction of − 0.0010 yr− 1 since the Industrial Revolution (c.a. 1750). The degree of aragonite saturation is lowered towards undersaturation levels of calcite. The Patagonian shelf and shelf-break zones—a strong CO2 sink region in the global ocean—are likely a key area for Cant intrusion in the southwestern South Atlantic Ocean.