Showing papers in "Aquatic Conservation-marine and Freshwater Ecosystems in 2018"

The alliance for freshwater life : a global call to unite efforts for freshwater biodiversity science and conservation

Abstract: 1. Global pressures on freshwater ecosystems are high and rising. Viewed primarily as a resource for humans, current practices of water use have led to catastrophic declines in freshwater species and the degradation of freshwater ecosystems, including their genetic and functional diversity. Approximately three-quarters of the world's inland wetlands have been lost, one-third of the 28 000 freshwater species assessed for the International Union for Conservation of Nature (IUCN) Red List are threatened with extinction, and freshwater vertebrate populations are undergoing declines that are more rapid than those of terrestrial and marine species. This global loss continues unchecked, despite the importance of freshwater ecosystems as a source of clean water, food, livelihoods, recreation, and inspiration. 2. The causes of these declines include hydrological alterations, habitat degradation and loss, overexploitation, invasive species, pollution, and the multiple impacts of climate change. Although there are policy initiatives that aim to protect freshwater life, these are rarely implemented with sufficient conviction and enforcement. Policies that focus on the development and management of fresh waters as a resource for people almost universally neglect the biodiversity that they contain. 3. Here we introduce the Alliance for Freshwater Life, a global initiative, uniting specialists in research, data synthesis, conservation, education and outreach, and policymaking. This expert network aims to provide the critical mass required for the effective representation of freshwater biodiversity at policy meetings, to develop solutions balancing the needs of development and conservation, and to better convey the important role freshwater ecosystems play in human well-being. Through this united effort we hope to reverse this tide of loss and decline in freshwater biodiversity. We introduce several short- and medium-term actions as examples for making positive change, and invite individuals, organizations, authorities, and governments to join the Alliance for Freshwater Life.

Diving back in time: Extending historical baselines for yelloweye rockfish with Indigenous knowledge

Abstract: Ocean systems, and the culturally and commercially important fishes that inhabit them, face growing threats. Increasingly, unconventional data sources are being used to inform fisheries research and management for data-poor species. Listed as a species of special concern in Canada, yelloweye rockfish (Sebastes ruberrimus) are vulnerable to exploitation, and have historical and cultural value to Indigenous people. In this study, Indigenous fishers of British Columbia, Canada, were interviewed and asked about observed changes to the body sizes (length) and abundance of this species over the last ~60 years, and the factors driving these changes. Their current and historical estimates of size and abundance were compared with current biological survey data. Forty-two semi-directed interviews were carried out and 89% of respondents observed a decrease in yelloweye rockfish body sizes since the 1980s. The median historical (1950s–1980s) length was 84 cm, compared with the median modern (2010–2015) length of 46 cm. All but one respondent reported substantial decrease in yelloweye rockfish abundance since their earliest fishing experiences (1950s to1980s, depending on participant's age), with a third suggesting the change was most evident in the early 2000s, followed by the 1980s (21%) and 1990s (17%). Sizes of modern yelloweye rockfish estimated by participants resembled estimates derived from ecological data recorded concurrently at the study region. This study illustrates a repeatable method for using traditional and local knowledge to extend baselines for data-poor species, and highlights the value of integrating Indigenous knowledge into fisheries research and management.

The understorey of gorgonian forests in mesophotic temperate reefs

Abstract: In the Mediterranean Sea, dense populations of the gorgonian Paramuricea clavata shape marine animal forests, characterizing the seascapes of coralligenous habitats. Despite concerns for its health, with several anthropogenic threats and recent mass mortality events, mainly triggered by thermal anomalies, the understorey of its forests and the ecological processes that they promote are still little known. Here, the abundance and composition of epibenthic assemblages inside and outside P. clavata forests were investigated across the central and western Mediterranean Sea, by applying a multifactorial sampling design. In spite of the large variability in the structures of epibenthic assemblages at local and regional scales, the gorgonian understoreys share some common features, such as higher abundances of calcareous builder organisms and reduced invasion by the non‐indigenous alga Caulerpa cylindracea, compared with the adjacent unforested rocky bottoms. Paramuricea clavata showed non‐linear density‐dependent relationships with algal turfs and non‐encrusting algae belonging to the genus Peyssonnelia. Moreover, by entrapping benthic mucilaginous aggregates with their branches, these gorgonians risk topical necrotic lesions, but may reduce the suffocation risks for understorey organisms. Overall, P. clavata forests may enhance bioconstruction processes and increase resistance and resilience of the benthic assemblages in the Mediterranean coralligenous habitats. This species and its forests, together with their understoreys, should be considered as essential elements of the ecology of the Mediterranean Sea, and therefore worthy of specific and effective protection measures. Conservation strategies should reduce the risk of mechanical damage by regulating fishing activities, anchorages, and scuba diving where gorgonian forests are present. Moreover, when evident alterations are documented, restoration actions should be implemented to recover the integrity of gorgonian forests.

Freshwater conservation in a fragmented world: Dealing with barriers in a systematic planning framework

Abstract: 1. Disruption of longitudinal connectivity poses one of the most important threats to the persistence of freshwater biodiversity worldwide. Longitudinal connectivity plays a key role by facilitating ecological processes, such as migrations or energy transfer along river networks. For this reason, effective conservation of freshwater biodiversity is highly dependent on a capacity to maintain all processes associated with connectivity. Freshwater protected areas are commonly affected by disruptions of connectivity due to human activities and recent approaches to addressing connectivity when identifying priority areas have overlooked the limitations that human perturbations pose to connectivity. 2. Here, a novel approach is presented to address this issue by accounting for the spatial distribution of barriers using Marxan, a tool commonly applied in conservation planning. This approach was first tested on a simulated example and then applied to the identification of priority areas for the conservation of freshwater vertebrates in the Iberian Peninsula (Spain and Portugal). 3. When using this new approach, the number of disrupted connections within priority areas can be significantly reduced at no additional cost in terms of area needed, which would help maintain connectivity among populations of species with low–medium migratory needs. 4.Given the widespread occurrence of barriers in the study region, the improvement in connectivity within priority areas also resulted in the selection of river reaches closer to the headwaters and the river mouth. Focusing on both extremes of the longitudinal gradient might compromise the effectiveness of conservation efforts for long-distance migratory species, such as the European eel. This inevitably means that additional management measures, such as barrier removal or construction of fish passages, would be necessary to ensure that these species are able to complete their life cycles. 5. The method demonstrated here could be applied to other regions where connectivity is compromised.

Rapid declines across Australian fishery stocks indicate global sustainability targets will not be achieved without an expanded network of ‘no‐fishing’ reserves

Abstract: 1. A continuing debate between environmental scientists and fisheries biologists on the sustainability of fisheries management practices, and the extent of fishing impacts on marine ecosystems, is unlikely to be resolved without fishery‐independent data spanning large geographic and temporal scales. Here, we compare continental‐ and decadal‐scale trends in fisheries catches with underwater reef monitoring data for 533 sites around Australia, and find matching evidence of rapid fish‐stock declines. 2. Regardless of a high global ranking for fisheries sustainability, catches from Australian wild fisheries decreased by 31% over the past decade. The biomass of large fishes observed on underwater transects decreased significantly over the same period on fished reefs (36% decline) and in marine park zones that allow limited fishing (18% decline), but with a negligible overall change in no‐fishing marine reserves. Populations of exploited fishes generally rose within marine reserves and declined outside the reserves, whereas unexploited species showed little difference in population trends within or outside reserves. 3. Although changing climate and more precautionary fisheries management contribute to declining fish catches, fisheries‐independent transect data suggest that excessive fishing also plays a major role. 4. The large number of fishery stocks that remain unmanaged or have poor data, coupled with continuing declines in the stock biomass of managed fish species, indicate that Aichi Target 6 of the Convention on Biological Diversity (i.e. ‘by 2020, all fish and invertebrate stocks and aquatic plants are managed and harvested sustainably’) will not be achieved in Australia, or elsewhere. 5. In order to maintain some naturally functioning food webs supported by large predators and associated ecosystem services in this era of changing climate, a greatly expanded network of effective, fully protected marine protected areas is needed that encompasses global marine biodiversity. The present globally unbalanced situation, with >98% of seas open to some form of fishing, deserves immediate multinational attention.

Procambarus clarkii (Girard, 1852) and crayfish plague as new threats for biodiversity in Indonesia

Abstract: Numerous freshwater crayfish species are known to become successful invaders when introduced to new territories. One of the most invasive species in this group is the red swamp crayfish, Procambarus clarkii (Girard, 1852). In addition to other characteristics facilitating its invasiveness, it is also a vector of crayfish plague, a disease mostly lethal to crayfish of non‐North American origin. Procambarus clarkii, at present the most widespread crayfish species globally, is popular in many countries both for human consumption and as an ornamental animal. An established population of this species was documented for the first time within Indonesia, representing the first record for maritime Southeast Asia. The species is also common in the local ornamental pet trade. Infection by the crayfish plague pathogen Aphanomyces astaci Schikora was confirmed both in the outdoor population of P. clarkii and in one of the surveyed pet shops. Furthermore, A. astaci was detected in specimens of freshwater crab and shrimp species coexisting with P. clarkii. Local climatic conditions and the species temperature requirements suggest a high probability of the establishment of P. clarkii in Indonesia. Its further spread could irreversibly damage populations of many native endemic crustaceans in the country (as well as elsewhere in the region), and the thriving local aquacultures of the redclaw crayfish Cherax quadricarinatus (von Martens, 1868) may also be threatened. The total ban of P. clarkii and other crayfish species of North American origin in Indonesia is strongly recommended, especially considering that aquaculture and trade with Australasian species is a viable alternative option.

Die‐offs of the endangered pearl mussel Margaritifera margaritifera during an extreme drought

Abstract: Foundation for Science and Technology (FCT), Grant/Award Numbers: PTDC/AGR-FOR/1627/2014, 3599 and SFRH/BD/115728/2016

Settlement of Ostrea edulis is determined by the availability of hard substrata rather than its nature: implications for stock recovery and restoration of the European oyster

Abstract: Since the collapse of the Ostrea edulis stock in the mid‐1800s the oyster has struggled to re‐establish itself in self‐sustaining assemblages in Europe. It is now widely recognized that O. edulis is an integral component of a healthy biologically functional benthic environment and, as such, the restoration of wild stocks has become a matter of urgency. A major limiting factor in O. edulis stock recovery is the availability of suitable substrate material for oyster larvae settlement. This research re‐examined the larval settlement potential of several naturally occurring in‐situ shell materials (e.g. Mytilus edulis, Modiolus modiolus, O. edulis), with the aim of determining which shell material is the most appropriate for large‐scale restoration projects. A positive correlation between available shell material and settlement was determined, and analysis using permanova did not identify an attachment preference by O. edulis to any particular shell type. The findings suggest that if restoration efforts were coordinated with applied hydrodynamic and habitat suitability modelling, in conjunction with naturally occurring shell substrate concentrations, a cost‐effective recovery for O. edulis assemblages in the wild could be achieved.

Human‐induced gradients of reef fish declines in the Hawaiian Archipelago viewed through the lens of traditional management boundaries

Abstract: Large declines in reef fish populations in Hawai‘i have raised concerns about the sustainability of these resources, and the ecosystem as a whole. To help elucidate the reasons behind these declines, a comprehensive examination of reef fish assemblages was conducted across the entire 2500 km Hawaiian Archipelago. Twenty-five datasets were compiled, representing >25 000 individual surveys conducted throughout Hawai‘i since 2000. To account for overall differences in survey methods, conversion factors were created to standardize among methods. Comparisons of major targeted resource species (N = 35) between the densely populated main (MHI) and remote north-western Hawaiian Islands (NWHI) revealed that 40% of these species had biomass in the MHI below 25% of NWHI levels. In total, 54% of the species examined had biomass <50% of NWHI biomass. The moku or district was a basic unit of resource management in pre-contact Hawai‘i and was used as a unit of spatial stratification for comparisons within the MHI. Biomass of resource species was negatively correlated with human population density within moku boundaries, with extremely low biomass in areas with highest human population densities. No such relationship was found for species not targeted by fishing. A number of remote areas with small human populations in the MHI still support high standing stock of fished species, and these areas are likely important refugia for maintaining fisheries production and biodiversity functioning. These results highlight the large gradient of human impacts on fish assemblages across the Hawaiian Archipelago and the potential in using landscape and seascape units, such as those that are watershed and bio-physically-based, when managing in part based on a framework of traditional ecological knowledge.

Cetacean rapid assessment: An approach to fill knowledge gaps and target conservation across large data deficient areas

Abstract: Wildlife Conservation Society Tanzania Program, Tanzania Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife, UK 23 Adamson Terrace, Leven, Fife, UK Department of Biological Sciences, Florida International University, North Miami, FL, USA 5 Institute of Marine Science, University of Dar es Salaam, Tanzania Correspondence Gill T. Braulik, Wildlife Conservation Society Tanzania Program, Zanzibar, Tanzania. Email: gillbraulik@downstream.vg

Catchment zoning to enhance co-benefits and minimize trade-offs between ecosystem services and freshwater biodiversity conservation.

Abstract: 1: Integrating ecosystem services (ESs) in landscape planning can help to identify conservation opportunities by finding co‐benefits between biodiversity conservation and the maintenance of regulating and cultural ecosystem services. The adequate integration of ESs needs careful consideration of potential trade‐offs, however, especially between provisioning services and biodiversity conservation (e.g. the potentially negative consequences of agricultural water extraction within areas important for the maintenance of biodiversity). These trade‐offs have been overlooked in systematic spatial planning to date, especially in freshwater systems. 2: Marxan with Zones was used to identify priority areas for the conservation of freshwater biodiversity (139 species of freshwater fish, turtles, and waterbirds) and the provision of freshwater ESs in the Daly River, northern Australia. Four different surrogates for ESs were mapped, including those potentially incompatible with conservation goals (i.e. groundwater provision for agriculture and recreational fisheries) and those that are more compatible with conservation (i.e. flood regulation by riparian forests; provision of perennial water). The spatial allocation of multiple management zones was prioritized: (i) three conservation zones, aiming to represent freshwater biodiversity and compatible ESs to enhance co‐benefits; and (ii) two production zones, where access to provisioning ESs could be granted. The representation of ESs obtained when using the multi‐zoning approach was compared with that achieved with a single management zone approach. The comparison was performed across different representation targets. 3: Different results were found with low and high targets for ESs. With low targets ( 25% of all ESs), the trade‐offs avoided were more evident, with up to 56% less representation of incompatible ESs within conservation zones. 4: Multi‐zone planning could help decision makers respond better to the increasingly complex catchment management context, caused by an increasing demand for provisioning services and a diminishing availability of resources, as well as manage and plan for challenges in other realms facing similar problems.

Is current floodplain management a cause for concern for fish and bird conservation in Bangladesh's largest wetland?

Abstract: Worldwide, water regulatory structures have impacts on aquatic ecological connectivity. This study determined the effects of current sluice management on the fish community in the Baral River, a major connection to the largest wetland (Chalan Beel) in Bangladesh. It also examines wider problems for biodiversity conservation (particularly waterbirds) in that wetland, which has shrunk to 30% of its former dry-season size in 50 years. During the flood period, the peak breeding time for native floodplain fishes, sluices were in undershot operation (open by 16–60% of water depth). During this time, fish abundance and species richness were 229% and 155% higher respectively at sites upstream of the sluices, despite similar habitat upstream and downstream. Outside this period, when sluices were fully open, abundance and species richness were similar upstream and downstream. Fish samples were dominated by fry, which are susceptible to damage by sluices. Twenty (41.7%) of 48 fish species captured in this study are classed as threatened in Bangladesh and their abundance was significantly lower downstream of the sluices. Two alien species, Aristichthys nobilis and Hypophthalmichthys molitrix, were recorded, probably escapees from local aquaculture activities. Twenty-five species of wetland birds were recorded in the Chalan Beel. From interviews, 64% of these species appear to have decreased in the last 20 years, together with 11 more species that may have become locally extinct over this period. This suggests that widespread ecological disruption is occurring. Improved water management (e.g. gate opening height and duration) or modification (e.g. fish pass) of the Baral sluices is needed, to meet biodiversity and fisheries needs, rather than just for flood control and crop production. Improved hydrological and ecological connectivity and habitat protection are needed, as are a cessation of destructive fishing and seasonal fish ranching practices that currently provide synergistic pressures.

Structural microhabitat use by endemic cyprinids in a Mediterranean‐type river: Implications for restoration practices

Abstract: Endemic freshwater fish from the Mediterranean region are among the most threatened species in the world owing to increasing river degradation. Because of such threats, the number of river restoration projects has greatly increased. However, they are seldom planned with consideration of the species' life history, often resulting in erroneous practices that compromise their success. This study assessed the seasonal and size-related microhabitat use by three endemic cyprinids (Iberian barbel, Luciobarbus bocagei; Iberian straight-mouth nase, Pseudochondrostoma polylepis; and calandino, Squalius alburnoides) using a modified point electrofishing procedure in a Mediterranean river. A multivariate approach was then employed to analyse both structural resource use and availability data. All species showed non-random microhabitat use. The barbel and nase shifted to faster-flowing positions (>25 cm s−1) with a coarser substratum (>150 mm particle size) during spring and to sheltered positions (50–100% instream cover) during autumn. Calandino selected more covered areas in autumn (>60% cover) and shifted to shallower positions from this season (>40 cm) to summer (<35 cm). Significant size-related differences in microhabitat use were consistent for the three species, with smaller individuals occupying on average shallower microhabitats. Significant resource-use overlap between species size classes increased from autumn to summer, occurring mainly between juvenile and small adult barbel and calandino. The present study helped develop recommendations for river restoration practices that may have a wider application, particularly for other Mediterranean-type rivers. Cover was found to be critical for all species, in particular for calandino, which could be classified as a shelter-oriented eurytopic species. Restoration scenarios should therefore consider maintaining cover habitats during unfavourable flow conditions for these species. Lithophilic spawners, which were highly responsive to velocity and substratum, could particularly benefit from the creation of gravel bedforms and artificial riffles to enhance depth and flow variability.

Effects of whale watching on the activity budgets of humpback whales, Megaptera novaeangliae (Borowski, 1781), on a feeding ground

Abstract: Whale watching can affect cetacean behaviour, and can in some cases lead to long-term negative effects on survival and reproduction The waters of Juneau (Alaska) represent a summer feeding ground for the Central North Pacific stock of humpback whales, Megaptera novaeangliae (Borowski, 1781) The recent dramatic expansion of the local whale-watching industry has raised concerns over the potential negative impact of such activity on the whales The aim of this study was to understand the impact of whale-watching vessels on humpback whale behaviour in Juneau From June to September 2015, land-based observations were conducted to record whale behaviour in the presence and absence of vessels Markov chains and model simulations showed that the presence of vessels was not associated with a reduction in the time spent feeding Whales exhibited more surface-active behaviour and travelled less in the presence of vessels The lack of an overt response of feeding whales to whale-watching disturbance could result from the importance of the Southeast Alaska study region as a feeding ground, which could make the whales less apt to interrupt feeding under disturbance; however, The high proportion of travelling observed may indicate that the study area represents a travelling corridor between other, localized feeding areas The increase in surface-active behaviour may represent a response to vessel presence that could potentially lead to energetic consequences The large number of whale-watching vessels operating could lead to the increased tolerance of whales towards whale-watching activities The lack of responses in this study may suggest that the reactions of whales are context specific, depending on their previous experience with vessels and their foraging behaviour, for example Subtler negative effects could still occur, however, and a prolonged monitoring programme is required to assess less overt behavioural responses of whales over time

Towards the identification of ecological management units: A multidisciplinary approach for the effective management of bottlenose dolphins in the southern Iberian Peninsula

Abstract: Determining discrete and demographically independent management units within wildlife populations is critical for their effective management and conservation. However, there is a lack of consensus on the most appropriate criteria to delimit such management units. A multi-disciplinary, multi-scale approach that combines tools informing in the short-term (i.e. photo-identification), with mid-term ecological tracers (stable isotopes –δ13C, δ15N and δ34S– and persistent organic pollutants –POPs–), and mid- to long-term genetic markers (microsatellites and mitochondrial DNA), was used to define management units within bottlenose dolphins (Tursiops truncatus) inhabiting the southern Iberian Peninsula. Although genetically indistinguishable, individuals inhabiting the Strait of Gibraltar and the Gulf of Cadiz showed differences in their isotopic composition and the concentrations of certain POPs. Accordingly, the lack of photographic recaptures between the two sites pointed to the existence of at least two different ecological management units that segregate spatially and may require different conservation strategies. Different time-scale approaches can reveal different management units. The results highlighted the use of medium- and short-term approaches for properly identifying ecologically different units for effective management and conservation. Furthermore, these results have important management implications as European legislation promotes specific management plans for this species.

Re-introduction of structurally complex wood jams promotes channel and habitat recovery from overwidening: Implications for river conservation

Abstract: Copyright © 2017 John Wiley & Sons, Ltd. Large wood is a powerful geomorphic agent in rivers, providing important habitat functions for a range of aquatic organisms, but has been subject to a long history of removal. Internationally, approaches to river restoration are increasingly incorporating large wood features, but generally favour simple flow deflectors (e.g. single logs, stripped of branches and anchored in place) over more complex structures that more accurately mimic natural wood jams. This paper explores channel response to wood-based restoration of an overwidened lowland chalk stream that incorporated whole felled trees. Hydraulics, sediment, topography and vegetation data were assessed for a 3year period for two restored reaches: an upstream reach where pre-restoration baseline data were obtained, and a downstream reach restored before data collection. Where pre-restoration data were available, the introduction of wood jams generated sediment deposition within jams leading to the development of vegetated marginal ‘benches’ and bed scour in adjacent areas of flow convergence. Patterns were less clear in the downstream reach, where restoration design was less ambitious and outcomes may have been affected by subsequent restoration work upstream. The results indicate that reintroduction of large wood (whole trees), can promote channel and habitat recovery from overwidening in lowland rivers, creating important ecological benefits through the provision of structurally complex marginal habitat and associated food resources. Longer-term assessments are required to establish whether the trajectories of change are persistent. The work emphasizes the effectiveness of restoration approaches that aim to ‘work with nature’. The ambitious design, incorporating structurally complex wood jams, was also low-cost, using materials available from the river corridor (existing riparian trees). Furthermore, ecosystem engineering effects were amplified by the colonization of wood jams by aquatic vegetation. The approach should, therefore, be transferable to other lowland rivers, subject to wider catchment constraints.

Dragging the chain: Quantifying continued losses of seagrasses from boat moorings

Abstract: Globally, seagrasses and other estuarine habitats are under threat from a range of human disturbances, including boating-related activities. The fixed, block-and-chain swing moorings used to secure boats in many countries can create visible scars in seagrass meadows and remove other benthic organisms. Losses of seagrasses in two estuaries in New South Wales (NSW), Australia, were quantified using aerial imagery and used to estimate estuarine habitat damage across the remainder of the state. The rate of mooring scar development was approximated and factors influencing the size of mooring scars were identified. Individually mapped mooring scars in meadows of the endangered Posidonia australis ranged from 55 to 706 m2, and were generally larger than those in the more opportunistic seagrass Zostera muelleri subsp. capricorni (22–342 m2). Scar size in both species of seagrass increased significantly with depth and boat length. The rate of increase in the size of mooring scars amongst P. australis was roughly linear over 4.8 years, averaging 6.3 m2/month up to a maximum of 16.7 m2/month for one 16-m yacht. Across all of NSW, it was estimated that currently leased moorings were causing losses of 129 884 m2 of P. australis and 93 940 m2 of Z. capricorni, and disturbing 2 790 907 m2 of non-vegetated soft sediments. NSW seagrass loss estimates relate only to damage from current moorings and could be underestimated by ~41% for P. australis if estuaries contain many old scars that remain after the relocation of moorings (as has occurred in Lake Macquarie). Mandating the use of moorings that do not rely on a chain dragging on the sea bed would greatly reduce future physical damage of benthic habitats and enable some recovery from legacy effects.

Salmonid stocking in five North Atlantic jurisdictions: Identifying drivers and barriers to policy change

Abstract: New knowledge challenges long‐established practices of fish stocking and transfer because of increasing scientific consensus that the release of cultivated fish can pose risks to biodiversity; however, stocking can also improve fisheries, creating difficult decision trade‐offs regarding its use. Accordingly, controversy persists about fish stocking and transfer. No studies, however, have embraced a multinational perspective to understand the important governance dimensions of the success and failure of salmonid stocking and transfer policies. The present study has analysed the historical development and contemporary governance of the stocking and transfer of native and non‐native salmonids of the genera Salmo, Salvelinus, and Oncorhynchus in five legislative units around the North Atlantic Ocean: the Atlantic Provinces of Canada, France, Germany, Norway, and Sweden. The study is based on the analyses of published and unpublished literature, and a survey of experts. Current salmonid stocking policies and practices varied significantly among jurisdictions; the degree of policy change varied, from radical and rapid changes de jure and de facto in Atlantic Canada and Norway to incremental mostly de jure changes in France and Germany. Rapid policy change in Atlantic Canada, Norway, and partly in Sweden can be explained by the socio‐political importance of salmonid fisheries, stocking regulations based on policy objectives to conserve wild Atlantic salmon (Salmo salar), well‐documented examples of the harmful consequences of transfers of non‐native species, and well‐developed vertical governance linkages. The policy changes resemble that of the ‘punctuated equilibrium policy framework’. By contrast, France and Germany place less socio‐political emphasis on salmonids, have stocking regulations less directed at wild salmonids, more local‐level decision making, more species‐rich fish communities, and little evidence of adverse ecological impacts of the transfer and stocking of salmonids. This has led to small, incremental changes in stocking policy de facto that are reflective of the ‘advocacy coalition policy framework’.

A quantitative PCR‐based environmental DNA assay for detecting Atlantic salmon (Salmo salar L.)

Abstract: The Atlantic salmon ( Salmo salar L.) has worldwide ecological, cultural and economic importance. The species has undergone extensive decline across its native range, yet concerns have been raised about its invasive potential in the Pacific. Knowledge on the distribution of this species is vital for addressing conservation goals. This study presents an eDNA assay to detect S. salar in water samples, using quantitative PCR (qPCR) technology. Species-specific primers and a minor groove binding (MGB) probe were designed for the assay, based on the mitochondrial cytochrome oxidase I (COI) gene. The results of this study indicate that eDNA is a highly sensitive tool for detecting S. salar in situ , and could potentially provide an alternative, non-invasive method for determining the distribution of this species.

Bridging the divide: Social-ecological coherence in Marine Protected Area network design

Abstract: 1. Marine Protected Areas (MPAs) and networks of MPAs are being implemented globally as a spatial management tool for achieving conservation objectives. There has been considerable progress in reaching the prescribed 10% protected area target for 2020, outlined in the Convention on Biological Diversity Aichi Target 11 and the United Nations Sustainable Development Goal 14. 2. The application of MPA network design principles (e. g. Representative, ecological connectivity), which underpin ecological coherence, is still lacking or insufficient in many regions. Poor ecological coherence hinders the ecological performance of MPA networks, leading to dysfunction in the flow of ecosystem services and reduced ecosystem benefits, with potentially negative consequences for human well-being. 3. This paper presents four pivotal focus points for future progress that can bridge the gap between ecological and social systems. The aim is to shift the discourse of ` ecological coherence' further into the social sphere, and hence support the alignment of the process of designating ecologically coherent MPA networks with the ` triple bottom line' of economic development, environmental sustainability, and social inclusion, as described in the Sustainable Development Goals (SDGs), to achieve social-ecological coherence in MPA network design.

A comparison of multispectral aerial and satellite imagery for mapping intertidal seaweed communities

Abstract: Habitat‐forming seaweeds are vital components of marine ecosystems, supporting immense diversity and providing ecosystem services. Reports of major changes in the distribution and abundance of large brown seaweeds in the north‐east Atlantic are an increasing cause for concern, but a lack of consistent monitoring over time is a key impediment in obtaining reliable evidence of change. There is an urgent need to recognize change rapidly and efficiently in marine communities, which are increasingly affected by pressures of human population growth, climate change, and ocean acidification. Here, the potential for remote monitoring of seaweed habitats is investigated using freely available, high‐resolution aerial and satellite imagery. Three sources of imagery were used: (i) Channel Coastal Observatory (CCO) aerial imagery; (ii) aerial images from the Bing webmap server; and (iii) RapidEye multispectral satellite data. The study area, the Thanet Coast, is an area of chalk outcrop in south‐east England of high conservation status, and includes three Marine Conservation Zones. Eight habitat classes, including brown, red, and green algal zones, were recognized based on ground‐truthing surveys. A multi‐class classification model was developed to predict habitat classes based on the chromatic signature derived from the aerial images. The model based on the high‐resolution CCO imagery gave the best outcome (with a kappa value of 0.89). Comparing predictions for images in 2001 and 2013 revealed habitat changes, but it is unclear as to what extent these are natural variability or real trends. This study demonstrates the potential value for long‐term monitoring with remote‐sensing data. Repeated, standardized coastal aerial imaging surveys, such as those performed by CCO, permit the rapid assessment and re‐assessment of habitat extent and change. This is of value to the conservation management of protected areas, particularly those defined by the presence or extent of specific habitats.

Vulnerability of Cape Fold Ecoregion freshwater fishes to climate change and other human impacts

Abstract: Native freshwater fish populations throughout South Africa's Cape Fold Ecoregion (CFE) are in decline as a result of human impacts on aquatic habitats, including the introduction of non‐native freshwater fishes. Climate change may be further accelerating declines of many species, although this has not yet been studied in the CFE. This situation presents a major conservation challenge that requires assigning management priorities through assessing species in terms of their vulnerability to climate change. One factor hindering reliable vulnerability assessments and the concurrent development of effective conservation strategies is limited knowledge of the biology and population status of many species. This paper reports on a study employing a rapid assessment method used in the USA, designed to capitalize on available expert knowledge to supplement existing empirical data, to determine the relative vulnerabilities of different species to climate change and other human impacts. Eight local freshwater fish experts conducted vulnerability assessments on 20 native and 17 non‐native freshwater fish species present in the CFE. Results show (1) that native species were generally classified as being more vulnerable to extinction than were non‐native species, (2) that the climate change impacts are expected to increase the vulnerability of most native, and some non‐native, species, (3) that vulnerability hotspots requiring urgent conservation attention occur in the Olifants‐Doring, upper Berg and upper Breede River catchments in the south west of the region, (4) that in addition to providing guidance for prioritizing management interventions, this study highlights the need for reliable data on the biology and distribution of many CFE freshwater fishes, and (5) that identification of priority areas for protection should be based on multiple sources of data.

Genetic structure of Irish freshwater pearl mussels (Margaritifera margaritifera and Margaritifera durrovensis): Validity of subspecies, roles of host fish, and conservation implications

Abstract: European freshwater pearl mussels are among the most critically threatened bivalve molluscs. Margaritifera margaritifera and Margaritifera durrovensis are endangered, and both occur in Ireland and are currently listed separately in Annex II of the European Habitats Directive. This study had the objective of guiding the conservation of freshwater pearl mussels in Ireland based on a genetic characterization of the most important Irish populations of both species using microsatellite and mitochondrial DNA (mtDNA) analyses. Margaritifera durrovensis from the Nore was found to have the highest genetic divergence from all the populations studied; however, there was substantial relatedness between the genetic constitution of the Nore and of central–eastern M. margaritifera populations, placing the Nore pearl mussel within the M. margaritifera taxon (Habitats Directive species code 1029). Two main conservation units of pearl mussel were identified: a mostly salmon‐dependent western cluster and a trout‐dependent central–eastern cluster. The genetic diversity of western Irish freshwater pearl mussels, as expressed by allelic richness and observed heterozygosity, was greater by a factor of two than in central European and central–eastern Irish populations, suggesting a genetic diversity hot spot and low effects of genetic drift and selection. The trout‐dependent central and eastern populations had much lower genetic variability, but had the greatest differentiation and uniqueness. Conservation of freshwater pearl mussels in Ireland should recognize the existence of a minimum of two conservation units (western and central–eastern) that differ in their use of host fish and in geographic isolation. Low levels of genetic drift and inbreeding in western populations should be secured by sustaining optimal habitat conditions favourable for the recruitment of mussels and their migratory salmonid hosts. The small population sizes of central–eastern populations and problems with recruitment require urgent action, e.g. by captive breeding and augmentation, to prevent any further erosion of their genetic variability.