Bird scaring lines (BSLs) protect longline fishing gear from seabird attacks, save bait, reduce incidental seabird mortality and are the most commonly prescribed seabird bycatch mitigation measure worldwide. We collaborated with fishermen to assess the efficacy of applying BSL regulations from the demersal longline sablefish fishery in Alaska to a similar fishery along the U.S West Coast. In contrast to Alaska, some U.S. West Coast vessels use floats along the line to keep hooks off the seafloor, where scavengers degrade the bait and the target catch. Our results confirmed that BSL regulations from Alaska were sufficient to protect baits from bird attacks on longlines without floats, but not baits on longlines with floats. Longlines with floats sank below the reach of albatrosses (2 m depth) at a distance astern (157.7 m ± 44.8 95% CI) that was 2.3 times farther than longlines without floats (68.8 m ± 37.8 95% CI). The floated longline distance was well beyond the protection afforded by BSLs, which is approximately 40 m of aerial extent. Black-footed albatross attacked floated longlines at rates ten times more (2.7 attacks/1000 hooks, 0.48–4.45 95%CI) than longlines without floats (0.20 attacks/1000 hooks, 0.01–0.36 95% CI). Retrospective analysis of NOAA Fisheries Groundfish Observer Program data suggested that seabird bycatch occurs in a few sablefish longline fishing sectors and a minority of vessels, but is not confined to larger vessels. Analysis also confirmed fishermen testimonials that night setting reduced albatross bycatch by an order of magnitude compared to daytime setting, without reducing target catch. Night setting could be an effective albatross bycatch prevention practice if applied to the U.S. West Coast sablefish longline fishery and provide a practical alternative for vessels that elect to use floated longlines. These results highlight the importance of understanding region-specific longline gear modifications to identify effective bycatch reduction tools and the value of working collaboratively with fishermen to craft solutions.
The Southern Resident killer whale population (Orcinus orca) was listed as endangered in 2005 and shows little sign of recovery. These fish eating whales feed primarily on endangered Chinook salmon. Population growth is constrained by low offspring production for the number of reproductive females in the population. Lack of prey, increased toxins and vessel disturbance have been listed as potential causes of the whale’s decline, but partitioning these pressures has been difficult. We validated and applied temporal measures of progesterone and testosterone metabolites to assess occurrence, stage and health of pregnancy from genotyped killer whale feces collected using detection dogs. Thyroid and glucocorticoid hormone metabolites were measured from these same samples to assess physiological stress. These methods enabled us to assess pregnancy occurrence and failure as well as how pregnancy success was temporally impacted by nutritional and other stressors, between 2008 and 2014. Up to 69% of all detectable pregnancies were unsuccessful; of these, up to 33% failed relatively late in gestation or immediately post-partum, when the cost is especially high. Low availability of Chinook salmon appears to be an important stressor among these fish-eating whales as well as a significant cause of late pregnancy failure, including unobserved perinatal loss. However, release of lipophilic toxicants during fat metabolism in the nutritionally deprived animals may also provide a contributor to these cumulative effects. Results point to the importance of promoting Chinook salmon recovery to enhance population growth of Southern Resident killer whales. The physiological measures used in this study can also be used to monitor the success of actions aimed at promoting adaptive management of this important apex predator to the Pacific Northwest.
Mass changes of ice sheets, glaciers and ice caps, land water hydrology, atmosphere, and ocean cause a nonuniform sea level rise due to the self-attraction and loading effects called sea level fingerprints (SLF). SLF have been previously derived from a combination of modeled and observed mass fluxes from the continents into the ocean. Here we derive improved SLF from time series of time variable gravity data from the Gravity Recovery and Climate Experiment (GRACE) mission for April 2002 to October 2014. We evaluate the GRACE-derived SLF using ocean bottom pressure (OBP) data from stations in the tropics, where OBP errors are the lowest. We detect the annual phase of the SLF in the OBP signal and separate it unambiguously from the barystatic sea level (BSL) at two stations. At the basin scale, the SLF explain a larger fraction of the variance in steric-corrected altimetry than the BSL, which has implications for evaluating mass transport between ocean basins.
Systematic conservation planning (SCP) to design marine protected areas (MPAs) has traditionally focused on species distributions or benthic habitat features that drive the determination of conservation priorities. Pelagic ecosystem protection is usually incidental because these ecosystems are often data-poor and are difficult to visualize in a planning context. Pelagic ecosystems, however, face increasing and cumulative impacts from threats such as overfishing and climate change, and a precautionary approach is required to protect both known and unknown biodiversity patterns and ecosystem processes. Data-driven pelagic habitat classifications are important when planning for habitat protection in the absence of sufficient in-situ data. In this study, we describe a method for creating a bioregional map of the upper-mixed layer of South Africa's pelagic realm. We selected relevant variables and parameters that best reflect key ecosystem properties at broad, meso, and local scales. We conducted a hierarchal cluster analysis using open-access sea surface temperature (SST), chlorophyll-a (chl-a), net primary productivity (NPP), mean sea level anomalies (MSLA), and seabed slope and depth data. The resulting map delineates three bioregions subdivided into seven biozones and sixteen pelagic habitats within South Africa's continental Exclusive Economic Zone (EEZ). This habitat map was incorporated into SCP of a proposed expanded MPA network that includes offshore protected areas and meets National objectives. The proposed network will increase protection of the pelagic realm (>30 m depth) of the EEZ from 0.002% to 6.0%. We contend that bioregional analyses based on publicly available remote-sensing data are useful for identification of offshore habitats, especially when robust biological data are unavailable, as a framework for ecosystem reporting, and for inclusion in a systematic design for a representative offshore MPA network. Further research should focus on modelling and mapping the permanence of pelagic habitats and different spatio-temporal scales of variability, validating habitat boundaries with biological data, and understanding the threats and efficacy of achieving pelagic protection through management mechanisms like MPAs.
A Sustainable Future for Small States: Pacific 2050 is part of the Commonwealth Secretariat’s regional strategic foresight programmes that examines whether current development strategies set a region on a path to achieve sustainable development by 2050. The publication follows a previous study on the Caribbean entitled Achieving a Resilient Future for Small States: Caribbean 2050, which was launched at the Commonwealth Global Biennial Conference on Small States in May 2016.
The study commences with an analysis of whether the Commonwealth Pacific small states (Fiji, Kiribati, Nauru, Papua New Guinea, Samoa, Solomon Islands, Tonga, Tuvalu and Vanuatu) are set to achieve the Sustainable Development Goals (SDGs) (Chapter 2). It then focuses on a number of critical areas impacting on the region’s development:
- Governance, focusing on political governance (Chapter 3), development effectiveness and co-ordination (Chapter 4) and ocean governance (Chapter 5).
- Non-communicable diseases (NCDs) (Chapter 6).
- Information and communications technology (Chapter 7).
- Climate change, focusing on migration and climate change (Chapter 8) and energy issues (Chapter 9).
In each of these areas, possible trajectories to 2050 are explored, gaps in the current policy responses are identified and practical recommendations are offered.
Coastal Social–Ecological Systems (SESs) are subject to several stresses, including climate change, that challenge fisheries and natural resource management. Fishers are front-line observers of changes occurring both on the coast and in the sea and are among the first people to be affected by these changes. In this study, we perform a meta-analysis of observations and adaptations to climate change by subsistence-oriented coastal fishers extracted from a global review of peer-reviewed and grey literature. Fishers' observations compiled from across the globe indicate increased temperatures and changes in weather patterns, as well as coastal erosion, sea level rise and shifts in species range and behaviours. Coastal areas offer a wide array of resources for diversifying livelihoods, but climate change is reducing these options. Specifically, climate change could reduce the resilience of fishers' communities, limiting options for diversification or forcing fishers to abandon their houses or villages.
Species invasions in marine ecosystems pose a threat to native fish communities and can disrupt the food webs that support valuable commercial and recreational fisheries. In the Gulf of Mexico, densities of invasive Indo-Pacific Lionfish, Pterois volitans and P. miles, are among the highest in their invaded range. In a workshop setting held over a 2-week period, we adapted an existing trophic dynamic model of the West Florida Shelf, located in the eastern Gulf of Mexico, to simulate the lionfish (both species) invasion and community effects over a range of harvest scenarios for both lionfish and native predators. Our results suggest small increases in lionfish harvest can reduce peak biomass by up to 25% and also that reduced harvest of native reef fish predators can lead to lower lionfish densities. This model can help managers identify target harvest and benefits of a lionfish fishery and inform the assessment and management of valuable reef fish fisheries.
A major goal of ecosystem-based fisheries management is to prevent fishery-induced shifts in community states. This requires an understanding of ecological resilience: the ability of an ecosystem to return to the same state following a perturbation, which can strongly depend on species interactions across trophic levels. We use a structured model of a temperate rocky reef to explore how multi-trophic level fisheries impact ecological resilience. Increasing fishing mortality of prey (urchins) has a minor effect on equilibrium biomass of kelp, urchins, and spiny lobster predators, but increases resilience by reducing the range of predator harvest rates at which alternative stable states are possible. Size-structured predation on urchins acts as the feedback maintaining each state. Our results demonstrate that the resilience of ecosystems strongly depends on the interactive effects of predator and prey harvest in multi-trophic level fisheries, which are common in marine ecosystems but are unaccounted for by traditional management.
What exactly does “doing conservation” or “incorporating conservation” into ocean science mean? Although today it is often coupled with the sustainable use of natural resources, by definition, conservation traditionally involves the preservation, protection, or restoration of the natural environment or natural ecosystems (Soulé and Wilcox, 1980). In other words, if the conservation intervention is successful then the ecosystem should reflect a better (or perhaps, more commonly, a “less worse”) state as a result. In this context, is simply conducting science conservation? Are outreach and advocacy conservation—whether through old school print and TV/radio broadcasts or through social media such as blogs or building a Twitter following? The field of modern marine conservation is an interdisciplinary one (e.g., van Dyke, 2008; Parsons and MacPherson, 2016) with a landscape that is populated with individuals engaged in science, education, social marketing, economics, resource management, and policy.
But how are we measuring our impact considering this diverse field? How do we know that the ecosystems toward which we direct our conservation efforts are “better” or at least “less worse” than they would be without them? Conservation needs to be more than just “being busy” or “feeling” that we are having an impact. And shouldn't we strive to ensure that conservation is not just conversation? How do we connect our actions to ecosystem responses in meaningful time frames?
This paper summarizes the results of a focus group discussion session on this topic held at the 2016 International Marine Conservation Congress, St John's, Newfoundland. It aims to assess ways to measure positive effects of marine conservation efforts beyond the “feel good” aspect to demonstrable impact.
High-resolution distribution maps can help inform conservation measures for protected species; including where any impacts of proposed commercial developments overlap the range of focal species. Around Orkney, northern Scotland, UK, the harbour seal (Phoca vitulina) population has decreased by 78% over 20 years. Concern for the declining harbour seal population has led to constraints being placed on tidal energy generation developments. For this study area, telemetry data from 54 animals tagged between 2003 and 2015 were used to produce density estimation maps. Predictive habitat models using GAM-GEEs provided robust predictions in areas where telemetry data were absent, and were combined with density estimation maps, and then scaled to population levels using August terrestrial counts between 2008 and 2015, to produce harbour seal usage maps with confidence intervals around Orkney and the North coast of Scotland. The selected habitat model showed that distance from haul out, proportion of sand in seabed sediment, and annual mean power were important predictors of space use. Fine-scale usage maps can be used in consenting and licensing of anthropogenic developments to determine local abundance. When quantifying commercial impacts through changes to species distributions, usage maps can be spatially explicitly linked to individual-based models to inform predicted movement and behaviour.
Researchers have long recognized the importance of ecological differences at the species level in structuring natural communities yet until recently have often overlooked the influence of intraspecific trait variation, which can profoundly alter community dynamics [ 1 ]. Human extraction of living resources can reduce intraspecific trait variation by, for example, causing truncation of age and size structure of populations, where numbers of older individuals decline far more with exploitation than younger individuals. Age truncation can negatively affect population and community stability, increasing variability in population and community biomass [ 2–6 ], reducing productivity [ 7–10 ] and life-history diversity in traits such as the spatial and temporal pattern of reproduction and migration [ 4, 11–16 ]. Here, we quantified the extent of age truncation in 63 fished populations across five ocean regions, as measured by how much the proportions of fish in the oldest age groups declined over time. The proportion of individuals in the oldest age classes decreased significantly in 79% to 97% of populations (compared to historical or unfished values, respectively), and the magnitude of decline was greater than 90% in 32% to 41% of populations. The pervasiveness and intensity of age truncation indicates that fishing is likely reducing the stability of many marine communities. Our findings suggest that more emphasis should be given to management measures that reduce the impact of fishing on age truncation, including no-take areas, slot limits that prohibit fishing on all except a narrow range of fish sizes, and rotational harvesting.
Sea level rise (SLR), a well-documented and urgent aspect of anthropogenic global warming, threatens population and assets located in low-lying coastal regions all around the world. Common flood hazard assessment practices typically account for one driver at a time (e.g., either fluvial flooding only or ocean flooding only), whereas coastal cities vulnerable to SLR are at risk for flooding from multiple drivers (e.g., extreme coastal high tide, storm surge, and river flow). Here, we propose a bivariate flood hazard assessment approach that accounts for compound flooding from river flow and coastal water level, and we show that a univariate approach may not appropriately characterize the flood hazard if there are compounding effects. Using copulas and bivariate dependence analysis, we also quantify the increases in failure probabilities for 2030 and 2050 caused by SLR under representative concentration pathways 4.5 and 8.5. Additionally, the increase in failure probability is shown to be strongly affected by compounding effects. The proposed failure probability method offers an innovative tool for assessing compounding flood hazards in a warming climate.
Calcareous octocorals are ecologically important calcifiers, but little is known about their biomineralization physiology, relative to scleractinian corals. Many marine calcifiers promote calcification by up-regulating pH at calcification sites against the surrounding seawater. Here, we investigated pH in the red octocoral Corallium rubrum which forms sclerites and an axial skeleton. To achieve this, we cultured microcolonies on coverslips facilitating microscopy of calcification sites of sclerites and axial skeleton. Initially we conducted extensive characterisation of the structural arrangement of biominerals and calcifying cells in context with other tissues, and then measured pH by live tissue imaging. Our results reveal that developing sclerites are enveloped by two scleroblasts and an extracellular calcifying medium of pH 7.97 ± 0.15. Similarly, axial skeleton crystals are surrounded by cells and a calcifying medium of pH 7.89 ± 0.09. In both cases, calcifying media are more alkaline compared to calcifying cells and fluids in gastrovascular canals, but importantly they are not pH up-regulated with respect to the surrounding seawater, contrary to what is observed in scleractinians. This points to a potential vulnerability of this species to decrease in seawater pH and is consistent with reports that red coral calcification is sensitive to ocean acidification.
The location and intensity of small-scale fishing is dynamic over time, greatly shaping ecosystems. However, historical information about fishing effort and fishing gear-use are often unavailable. Within a marine biodiversity hotspot in the Philippines, we characterized spatio-temporal dynamics of fishing (1960–2010) using participatory mapping. First, we compared non-spatial and spatial estimates of total fishing effort. Our non-spatial estimate indicated that fishing increased 2.5 fold, reaching 1.3 million fishing days per year in 2010. Yet, spatial estimates showed fishing effort increased >20 fold, with the highest effort in 1990. Second, we evaluated how spatial characteristics of fishing changed over time. We introduced a method to estimate the sample size of fishers needed to accurately map the extent of fishing. By 2000, fishing extent grew 50% and small-scale fisheries affected over 90% of the coastal ocean. The expanded fishing area coincided with a greater spatial overlap among fishing gears and a proliferation of intensive fishing gears (destructive, active, non-selective). The expansion and intensification of fishing shown here emphasize the need for spatial approaches to management that focus on intensive, and often illegal, fishing gears. Such approaches are critical in targeting conservation actions (e.g. gear restrictions) in the most vulnerable areas.
Biological invasions are a substantial threat to Antarctic biodiversity and a priority conservation policy focus for Antarctic Treaty Parties and the sovereign states of surrounding islands. Key to their strategies is prevention, including assessment of establishment risk for alien species. Despite establishment of some of the worst globally invasive species across the Antarctic region, assessments of establishment potential of these species are non-existent. Here, we address this deficit and determine whether these invasive species constitute a significant conservation threat to the broader Antarctic region both now and in response to future regional climate change.
Antarctica and the Southern Ocean islands (45°–90° S).
We used ensemble species distribution models to assess the current and future climate suitability of the Antarctic region for 69 of the worst globally invasive species and 24 insect and plant species that have already established somewhere in the region.
The Antarctic continent is unsuitable for all of the worst globally invasive species under current conditions, but areas of the Antarctic Peninsula are predicted to become climatically suitable for up to six globally invasive species within the next century. By contrast, all Southern Ocean islands are presently climatically suitable for additional non-native species, with the threat increasing in the future.
Our findings demonstrate that climate, which is often cited as a key barrier to alien species establishment, may afford some protection to continental Antarctica, but that this protection is not currently extended to the Southern Ocean islands. Furthermore, existing climatic barriers to alien species establishment will weaken as warming continues across the region. This not only illustrates the value of applying distribution modelling methods to this largely ice-covered region, but demonstrates how these methods can be used to inform targeted surveillance of introduction pathways and sites that have the highest risk of establishment of invasive alien species.
Pots (also known as traps) are baited fishing gears widely used in commercial fisheries, and are being considered as a tool for harvesting Atlantic cod (Gadus morhua) in Newfoundland and Labrador, Canada. Pots produce lower environmental impacts than many other fishing gears, but they will only be a viable fishing strategy if they are efficient and selective at catching their target species. To study the behaviour of cod in and around pots, and how those behaviours affect pot efficiency, we used long-duration underwater video cameras to assess two models of cod pot deployed in the nearshore waters of Fogo Island, NL. We examined the number of cod that approached the pot, the number and proportion that successfully completed entries into the pot openings, and the number that exited, and related these factors to the direction of water movement. We observed very few entry attempts relative to the number of approaches by cod, and only 22% of all entry attempts were successful. We observed that 50% of approaches, 70% of entry attempts, and 73% of successful entrances occurred against the current, and 25% of cod were able to exit the pot following capture. Based on our observations, we suggest that future cod pots should have a greater number of entrances, or a mechanism to ensure that entrances rotate in line with the current, in order to maximize their catch efficiency for cod.
The movement capacity of the crown-of-thorns starfishes (Acanthaster spp.) is a primary determinant of both their distribution and impact on coral assemblages. We quantified individual movement rates for the Pacific crown-of-thorns starfish (Acanthaster solaris) ranging in size from 75–480 mm total diameter, across three different substrates (sand, flat consolidated pavement, and coral rubble) on the northern Great Barrier Reef. The mean (±SE) rate of movement for smaller (<150 mm total diameter) A. solaris was 23.99 ± 1.02 cm/ min and 33.41 ± 1.49 cm/ min for individuals >350 mm total diameter. Mean (±SE) rates of movement varied with substrate type, being much higher on sand (36.53 ± 1.31 cm/ min) compared to consolidated pavement (28.04 ± 1.15 cm/ min) and slowest across coral rubble (17.25 ± 0.63 cm/ min). If average rates of movement measured here can be sustained, in combination with strong directionality, displacement distances of adult A. solaris could range from 250–520 m/ day, depending on the prevailing substrate. Sustained movement of A. solaris is, however, likely to be highly constrained by habitat heterogeneity, energetic constraints, resource availability, and diurnal patterns of activity, thereby limiting their capacity to move between reefs or habitats.
We collected movement data for eight rehabilitated and satellite-tagged green sea turtles Chelonia mydas released off the United Arab Emirates between 2005 and 2013. Rehabilitation periods ranged from 96 to 1353 days (mean = 437 ± 399 days). Seven of the eight tagged turtles survived after release; one turtle was killed by what is thought to be a post-release spear gun wound. The majority of turtles (63%) used shallow-water core habitats and established home ranges between Dubai and Abu Dhabi, the same area in which they had originally washed ashore prior to rescue. Four turtles made movements across international boundaries, highlighting that regional cooperation is necessary for the management of the species. One turtle swam from Fujairah to the Andaman Sea, a total distance of 8283 km, which is the longest published track of a green turtle. This study demonstrates that sea turtles can be successfully reintroduced into the wild after sustaining serious injury and undergoing prolonged periods of intense rehabilitation.
Spatial erosion of stock structure through local overfishing can lead to stock collapse because fish often prefer certain locations, and fisheries tend to focus on those locations. Fishery managers are challenged to maintain the integrity of the entire stock and require scientific approaches that provide them with sound advice. Here we propose a Bayesian hierarchical spatio-temporal modelling framework for fish abundance data to estimate key parameters that define spatial stock structure: persistence (similarity of spatial structure over time), connectivity (coherence of temporal pattern over space), and spatial variance (variation across the seascape). The consideration of these spatial parameters in the stock assessment process can help identify the erosion of structure and assist in preventing local overfishing. We use Atlantic cod (Gadus morhua) in eastern Canada as a case study an examine the behaviour of these parameters from the height of the fishery through its collapse. We identify clear signals in parameter behaviour under circumstances of destructive stock erosion as well as for recovery of spatial structure even when combined with a non-recovery in abundance. Further, our model reveals the spatial pattern of areas of high and low density persists over the 41 years of available data and identifies the remnant patches. Models of this sort are crucial to recovery plans if we are to identify and protect remaining sources of recolonization for Atlantic cod. Our method is immediately applicable to other exploited species.
Climate change indicators are tools to assess, visualize and communicate the impacts of climate change on species and communities. Indicators that can be applied to different taxa are particularly useful because they allow comparative analysis to identify which kinds of species are being more affected. A general prediction, supported by empirical data, is that the abundance of warm-adapted species should increase over time, relative to the cool-adapted ones within communities, under increasing ambient temperatures. The community temperature index (CTI) is a community weighted mean of species’ temperature preferences and has been used as an indicator to summarize this temporal shift. The CTI has the advantages of being a simple and generalizable indicator; however, a core problem is that temporal trends in the CTI may not only reflect changes in temperature. This is because species’ temperature preferences often covary with other species attributes, and these other attributes may affect species response to other environmental drivers. Here, we propose a novel model-based approach that separates the effects of temperature preference from the effects of other species attributes on species’ abundances and subsequently on the CTI. Using long-term population data of breeding birds in Denmark and demersal marine fish in the southeastern North Sea, we find differences in CTI trends with the original approach and our model-based approach, which may affect interpretation of climate change impacts. We suggest that our method can be used to test the robustness of CTI trends to the possible effects of other drivers of change, apart from climate change.