The evolution of cetaceans is one of the best examples of macroevolution documented from the fossil record. While ecological transitions dominate each phase of cetacean history, this context is rarely stated explicitly. The first major ecological phase involves a transition from riverine and deltaic environments to marine ones, concomitant with dramatic evolutionary transformations documented in their early fossil record. The second major phase involves ecological shifts associated with evolutionary innovations: echolocation (facilitating hunting prey at depth) and filter-feeding (enhancing foraging efficiency on small prey). This latter phase involves body size shifts, attributable to changes in foraging depth and environmental forcing, as well as re-invasions of freshwater systems on continental basins by multiple lineages. Modern phenomena driving cetacean ecology, such as trophic dynamics and arms races, have an evolutionary basis that remains mostly unexamined. The fossil record of cetaceans provides an historical basis for understanding current ecological mechanisms and consequences, especially as global climate change rapidly alters ocean and river ecosystems at rates and scales comparable to those over geologic time.
This paper reviews the use of acoustic telemetry as a tool for addressing issues in fisheries management, and serves as the lead to the special Feature Issue of Ecological Applications titled Acoustic Telemetry and Fisheries Management. Specifically, we provide an overview of the ways in which acoustic telemetry can be used to inform issues central to the ecology, conservation, and management of exploited and/or imperiled fish species. Despite great strides in this area in recent years, there are comparatively few examples where data have been applied directly to influence fisheries management and policy. We review the literature on this issue, identify the strengths and weaknesses of work done to date, and highlight knowledge gaps and difficulties in applying empirical fish telemetry studies to fisheries policy and practice. We then highlight the key areas of management and policy addressed, as well as the challenges that needed to be overcome to do this. We conclude with a set of recommendations about how researchers can, in consultation with stock assessment scientists and managers, formulate testable scientific questions to address and design future studies to generate data that can be used in a meaningful way by fisheries management and conservation practitioners. We also urge the involvement of relevant stakeholders (managers, fishers, conservation societies, etc.) early on in the process (i.e., in the co-creation of research projects), so that all priority questions and issues can be addressed effectively.
Identifying the most sensitive indicators to changes in fishing pressure is important for accurately detecting impacts. Biomass is thought to be more sensitive than abundance and length, while the wariness of fishes is emerging as a new metric. Periodically harvested closures (PHCs) that involve the opening and closing of an area to fishing are the most common form of fisheries management in the western Pacific. The opening of PHCs to fishing provides a unique opportunity to compare the sensitivity of metrics, such as abundance, length, biomass and wariness, to changes in fishing pressure. Diver-operated stereo video (stereo-DOV) provides data on fish behavior (using a proxy for wariness, minimum approach distance) simultaneous to abundance and length estimates. We assessed the impact of PHC protection and harvesting on the abundance, length, biomass, and wariness of target species using stereo-DOVs. This allowed a comparison of the sensitivity of these metrics to changes in fishing pressure across four PHCs in Fiji, where spearfishing and fish drives are common. Before PHCs were opened to fishing they consistently decreased the wariness of targeted species but were less likely to increase abundance, length, or biomass. Pulse harvesting of PHCs resulted in a rapid increase in the wariness of fishes but inconsistent impacts across the other metrics. Our results suggest that fish wariness is the most sensitive indicator of fishing pressure, followed by biomass, length, and abundance. The collection of behavioral data simultaneously with abundance, length, and biomass estimates using stereo-DOVs offers a cost-effective indicator of protection or rapid increases in fishing pressure. Stereo-DOVs can rapidly provide large amounts of behavioral data from monitoring programs historically focused on estimating abundance and length of fishes, which is not feasible with visual methods.
In several Pacific Island countries and territories (PICTs), rapid population growth and inadequate management of coastal fish habitats and stocks is causing a gap to emerge between the amount of fish recommended for good nutrition and sustainable harvests from coastal fisheries. The effects of ocean warming and acidification on coral reefs, and the effects of climate change on mangrove and seagrass habitats, are expected to widen this gap. To optimise the contributions of small-scale fisheries to food security in PICTs, adaptations are needed to minimise and fill the gap. Key measures to minimise the gap include community-based approaches to: manage catchment vegetation to reduce sedimentation; maintain the structural complexity of fish habitats; allow landward migration of mangroves as sea level rises; sustain recruitment and production of demersal fish by managing ‘source’ populations; and diversify fishing methods to increase catches of species favoured by climate change. The main adaptions to help fill the gap in fish supply include: transferring some fishing effort from coral reefs to tuna and other large pelagic fish by scaling-up the use of nearshore fish aggregating devices; developing fisheries for small pelagic species; and extending the shelf life of catches by improving post-harvest methods. Modelling the effects of climate change on the distribution of yellowfin tuna, skipjack tuna, wahoo and mahi mahi, indicates that these species are likely to remain abundant enough to implement these adaptations in most PICTs until 2050. We conclude by outlining the policies needed to support the recommended adaptations.
Effective management of coastal and marine resources requires knowledge of how community sensitivity varies spatially. With this in mind, we developed a benthic sensitivity index (SI), based on the distribution and abundance of five ecological groups that can be used to assess community tolerance to organic enrichment and other disturbances. The index, projected as a high-resolution map, ranks communities from those dominated by sensitive and ecologically important species (i.e. low SI values) to those composed mainly of tolerant and/or opportunistic species (i.e., high SI values). Applying our model to a multiple-use case study in southeast Brazil, we were able to show considerable variability in the sensitivity of communities across the study area that was relatively stable over time. This allowed us to evaluate the possible direct (i.e., spatially overlapping) and indirect effects (i.e., cumulative changes to the physical environment) of a range of activities on sensitive and ecologically diverse benthic communities. Our approach and the resulting high-resolution maps hold promise for a range of spatial planning applications, including the development of coastal infrastructure, assessments of the representativeness of marine protected areas and other activities such as the selection of appropriate locations for dredge spoil dumping. Overall, we present a novel and transparent way of extrapolating limited survey data to provide spatial and temporal information on the sensitivity of benthic communities in multiple-use coastal and marine areas.
Shark fin has long been one of the most highly demanded 'luxury seafood' in the Chinese market. From the latest available data (1998–2013), 130 countries/territories around the world were recorded as exporting shark fin to Hong Kong. Spain, Taiwan, Indonesia, UAE, Singapore and Japan made up over 50% of all of Hong Kong's shark fin imports. Comparison of Hong Kong's import data with the exporting countries/territories' FAO declarations indicates that some countries/territories are potentially consistently underreporting shark fin exports. Since 2009 Vietnam had overtaken China as the most important destination of Hong Kong's shark fin re-exports, a change that warrants further investigation. Ocean transportation was also identified as the most important transportation mode for shark fin imports into and re-exports from Hong Kong. Given the importance of Hong Kong and based on findings from this study, suggestions are made for the Hong Kong Government to tighten controls to reduce illegal trades, and eliminate loopholes so that a more comprehensive statistical representation of the shark fin trade may be captured for future analysis.
The biodiversity of East to Southeast (E–SE) Asian waters is rapidly declining because of anthropogenic effects ranging from local environmental pressures to global warming. To improve marine biodiversity, the Aichi Biodiversity Targets were adopted in 2010. The recommendation of the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA), encourages application of the ecologically or biologically significant area (EBSA) process to identify areas for conservation. However, there are few examples of the use of EBSA criteria to evaluate entire oceans. In this article, seven criteria are numerically evaluated to identify important marine areas (EBSA candidates) in the E–SE Asia region. The discussion includes 1) the possibility of EBSA criteria quantification throughout the E–SE Asia oceans and the suitability of the indices selected; 2) optimal integration methods for criteria, and the relationships between the criteria and data robustness and completeness; and; 3) a comparison of the EBSA candidates identified and existing registered areas for the purpose of conservation, such as marine protected areas (MPAs). Most of the EBSA criteria could be quantitatively evaluated throughout the Asia-Pacific region. However, three criteria in particular showed a substantial lack of data. Our methodological comparison showed that complementarity analysis performed better than summation because it considered criteria that were evaluated only in limited areas. Most of the difference between present-day registered areas and our results for EBSAs resulted from a lack of data and differences in philosophy for the selection of indices.
The Topical Collection on Invasive Species includes 50 articles addressing many tenets of marine invasion ecology. The collection covers important topics relating to propagule pressure associated with transport vectors, species characteristics, attributes of recipient ecosystems, invasion genetics, biotic interactions, testing of invasion hypotheses, invasion dynamics and spread, and impacts of nonindigenous species. This article summarizes some of the collection’s highlights.
The oceans appear ideal for biodiversity — they have unlimited water, a large area, are well connected, have less extreme temperatures than on land, and contain more phyla and classes than land and fresh waters. Yet only 16% of all named species on Earth are marine. Species richness decreases with depth in the ocean, reflecting wider geographic ranges of deep sea than coastal species. Here, we assess how many marine species are named and estimated to exist, paying particular regard to whether discoveries of deep-sea organisms, microbes and parasites will change the proportion of terrestrial to marine species. We then review what factors have led to species diversification, and how this knowledge informs conservation priorities. The implications of this understanding for marine conservation are that the species most vulnerable to extinction will be large and endemic. Unfortunately, these species are also the most threatened by human impacts. Such threats now extend globally, and thus the only refuges for these species will be large, permanent, fully protected marine reserves.
Using long-term data from government, non-government, academic, and industry sources, we developed species distribution models (SDMs) to predict priority areas in which to target and enhance blue whale Balaenoptera musculus and northern bottlenose whale Hyperoodon ampullatus monitoring efforts in eastern Canada. Priority areas for blue whales were located primarily on the Scotian Shelf and along the south shelf break in waters off Newfoundland. Priority areas for northern bottlenose whales were identified primarily in areas along the edges of the eastern Scotian Shelf and the Newfoundland and Labrador Shelves, in submarine canyons, and deep basins. The SDM results and the tools presented in this study indicate that there are few conservation areas in eastern Canada that currently protect whales at risk, and that priority areas for blue and northern bottlenose whales overlap with regions where noise-producing activities (shipping and seismic exploration) occur. This study also highlighted large gaps in the cetacean data related to human activities (e.g. seismic survey lines are outdated and recent information from the past 5 to 10 yr is not available). The SDM approach developed in this study can be used as an iterative, adaptive process by including updated data as it becomes available, further refining and validating the SDM results and thereby improve our understanding of the distribution of cetaceans and noise-producing activities in eastern Canada.
Wrasse (Labridae) fisheries have increased markedly in Norway since 2010. Wrasse are being used as cleaner fish in salmonid aquaculture to control sea-lice infestations. However, fundamental knowledge on the demography and abundance of the targeted wrasse populations in Norwegian waters is lacking, and the consequences of harvesting at the current intensity have not been assessed. Here, we compared catch per unit effort (CPUE), size, age and sex ratio of goldsinny wrasse (Ctenolabrus rupestris) and corkwing wrasse (Symphodus melops) between marine protected areas (MPAs) and control areas open for fishing at four localities on the Skagerrak coast in Southern Norway. The CPUE of goldsinny larger than the minimum size limit was 33–65% higher within MPAs, while for corkwing three of four MPAs had higher CPUE with the relative difference between MPAs and control areas ranging from −16% to 92%. Moreover, corkwing, but not goldsinny, was significantly older and larger within MPAs than in control areas. Sex ratios did not differ between MPAs and control areas for either species. Our study suggests that despite its short history, the wrasse fisheries have considerable impacts on the target populations and, further, that small MPAs hold promise as a management tool for maintaining natural population sizes and size structure. Goldsinny, being a smaller-sized species, also seems to benefit from the traditional minimum size limit management tool, which applies outside MPAs.
The coastal seagrass meadows in the Townsville region of the Great Barrier Reef are crucial seagrass foraging habitat for endangered dugong populations. Deteriorating coastal water quality and in situ light levels reduce the extent of these meadows, particularly in years with significant terrestrial runoff from the nearby Burdekin River catchment. However, uncertainty surrounds the impact of variable seagrass abundance on dugong carrying capacity. Here, I demonstrate that a power-law relationship with exponent value of − 1 (R2 ~ 0.87) links mortality data with predicted changes in annual above ground seagrass biomass. This relationship indicates that the dugong carrying capacity of the region is tightly coupled to the biomass of seagrass available for metabolism. Thus, mortality rates increase precipitously following large flood events with a response lag of < 12-months. The management implications of this result are discussed in terms of climate scenarios that indicate an increased future likelihood of extreme flood events.
Artificial reefs (ARs) are the most common man-made constructions adopted to prevent coastal erosion from wave actions and currents. Despite their worldwide application in coastal management and the documented chemical and physical alterations on surrounding seabeds that they may cause, few studies have been carried out on their impact upon meiofauna. The aim of this survey was to evaluate the potential effects of ARs on the seabed using various meiofaunal descriptors such as the structure of the entire assemblage and of rare taxa, the richness, the diversity indices and the Nematode:Copepod (Ne:Co) ratio. We investigated meiofaunal assemblages of some exposed areas on the Adriatic coast that are protected by ARs and subject to different levels of anthropogenic impact. This last issue was fundamental to examining possible interactions between AR presence and riverine discharges. The results of this study showed that the most efficient meiofaunal descriptors were diversity indices and the Ne:Co ratio, and suggested that the existence of ARs along with uncontrolled riverine discharges may increase anthropogenic impacts upon coastlines. This point is crucial for the conservation and monitoring of beaches because coastal management should be focused on preventing not only coastal erosion, but also possible impacts on marine ecosystem and human health.
The impact of anthropogenic ocean acidification (OA) on marine ecosystems is a vital concern facing marine scientists and managers of ocean resources. Euthecosomatous pteropods (holoplanktonic gastropods) represent an excellent sentinel for indicating exposure to anthropogenic OA because of the sensitivity of their aragonite shells to the OA conditions less favorable for calcification. However, an integration of observations, experiments and modelling efforts is needed to make accurate predictions of how these organisms will respond to future changes to their environment. Our understanding of the underlying organismal biology and life history is far from complete and must be improved if we are to comprehend fully the responses of these organisms to the multitude of stressors in their environment beyond OA. This review considers the present state of research and understanding of euthecosomatous pteropod biology and ecology of these organisms and considers promising new laboratory methods, advances in instrumentation (such as molecular, trace elements, stable isotopes, palaeobiology alongside autonomous sampling platforms, CT scanning and high-quality video recording) and novel field-based approaches (i.e. studies of upwelling and CO2 vent regions) that may allow us to improve our predictive capacity of their vulnerability and/or resilience. In addition to playing a critical ecological and biogeochemical role, pteropods can offer a significant value as an early-indicator of anthropogenic OA. This role as a sentinel species should be developed further to consolidate their potential use within marine environmental management policy making.
The purpose of this paper is to investigate students’ understandings of ocean sustainability and the pedagogical influence of higher education on those conceptions.
The conceptions of ocean sustainability of 54 university students of various academic disciplines enrolled in the 2014/2015 semester course “Sustainable Oceans” were assessed through use of auto-photography. Data were collected at the beginning and end of the course. Inter-rater reliability was measured by percentage of identical coding outcomes by two coders.
Auto-photography is effective in assessing notions of sustainability. Social and economic dimensions were captured less frequently than environmental aspects in the students’ photographs. Overall, students demonstrated vague perceptual awareness about who should take responsibility concerning lifeworld-related issues. Also, their perceptions were affected by their choice of academic discipline. Engaging students in inter-/transdisciplinary learning, integrating the arts, science and community, helped develop a more balanced, action-motivated conception of sustainability. Post-test patterns of change in students’ vision and action were observed.
Implementing sustainability education in a university’s coordinating bodies is effective in constructing a campus-based learning network, and participation in local community empowerment promotes a substantial and multidimensional concept of sustainability, and teaching material that includes content from the fine arts, literature or music stimulates students’ awareness of, and sensitivity to, lifeworld issues.
This paper provides an innovative, auto-photography-based methodology, including an operational procedure, coding book and method of analysis, for assessing students’ conceptions of sustainability. It also develops an interdisciplinary course that serves a “threshold” intervention role in ocean sustainability education.
Seafood is the world's most internationally traded food commodity. Approximately three out of every seven people globally rely on seafood as a primary source of animal protein (1). Revelations about slavery and labor rights abuses in fisheries have sparked outrage and shifted the conversation (2, 3), placing social issues at the forefront of a sector that has spent decades working to improve environmental sustainability. In response, businesses are seeking to reduce unethical practices and reputational risks in their supply chains. Governments are formulating policy responses, and nonprofit and philanthropic organizations are deploying resources and expertise to address critical social issues. Yet the scientific community has not kept pace with concerns for social issues in the sector. As the United Nations Ocean Conference convenes in New York (5 to 9 June), we propose a framework for social responsibility and identify key steps the scientific community must take to inform policy and practice for this global challenge.
This paper examines the issue of climate change pedagogy and social action in tourism, with particular interest in globally-significant destinations under threat from climate change. Little is understood of the role and responsibility of visitors as key stakeholders in climate change-related action or the potential of such sites to foster environmental learning, as well as social and political action on climate change. Drawing on insights from Aldo Leopold and John Dewey, it is argued here that destinations that are valued intrinsically for their ecological and cultural importance are (or ought to be) sites of enjoyment and pedagogy, facilitating experiential learning, care, responsibility and civic action towards their conservation. An exploratory case study of visitors to the Great Barrier Reef offers corroborative insights for such a “reef ethic” as described in this paper, related to visitor experience, learning and action in this World Heritage Area. The results of this paper support the need for a stronger pedagogic role to be adopted by tourism experience providers and site managers to facilitate climate change literacy and responsible action (hence facilitating global environmental citizenship). Their responsibility and that of reef visitors is discussed further.
Increasing interest in offshore development has motivated intensified efforts to map the seafloor for marine spatial planning. However, surficial geologic maps do not accurately represent habitats for various species groups of concern. This study used a bottom-up approach to integrate macrofaunal densities and benthic conditions on the Pacific Northwest shelf to identify macrofaunal assemblages and associated habitat features. Benthic cores and water-column profiles were collected from 137 stations from 50 to 110 m depth. Analyses grouping stations based on both similar species abundances and benthic conditions resulted in six broad habitats. Within the sampled depth and latitudinal range, sediment characteristics were the primary structuring variable. A major break in assemblages was detected between sediment that had less than 1% silt/clay and those containing more than 1% silt/clay. Assemblages differed primarily in the bivalve species present and secondarily in polychaete species. Within the greater than and less than 1% silt/clay habitats, further discretization of assemblages was based mostly on differing abundances of characteristic bivalves and polychaetes associated with differing median grain sizes, which did not correspond to traditional definitions of fine or medium sand. These data show that a bottom-up methodology is necessary to discern habitats for macrofauna and that site-specific physical sampling is necessary to predict macrofaunal assemblage composition. However, if detailed sediment characteristics are known, macrofaunal assemblages may be predicted without time-intensive biological sampling and processing. These results also indicate that seemingly small sedimentary changes due to offshore installations may have measureable effects on the relative abundances and even the species composition of macrofauna.
Over the coming century humanity may need to find reservoirs to store several trillions of tons of carbon dioxide (CO2) emitted from fossil fuel combustion, which would otherwise cause dangerous climate change if it were left in the atmosphere. Carbon storage in the ocean as bicarbonate ions (by increasing ocean alkalinity) has received very little attention. Yet, recent work suggests sufficient capacity to sequester copious quantities of CO2. It may be possible to sequester hundreds of billions to trillions of tonnes of C without surpassing post-industrial average carbonate saturation states in the surface ocean. When globally distributed, the impact of elevated alkalinity is potentially small, and may help ameliorate the effects of ocean acidification. However, the local impact around addition sites may be more acute but is specific to the mineral and technology.
The alkalinity of the ocean increases naturally because of rock weathering in which > 1.5 moles of carbon are removed from the atmosphere for every mole of magnesium or calcium dissolved from silicate minerals (e.g., wollastonite, olivine, anorthite), and 0.5 moles for carbonate minerals (e.g., calcite, dolomite). These processes are responsible for naturally sequestering 0.5 billion of CO2 tons per year. Alkalinity is reduced in the ocean through carbonate mineral precipitation, which is almost exclusively formed from biological activity. Most of the previous work on the biological response to changes in carbonate chemistry have focused on acidifying conditions. More research is required to understand carbonate precipitation at elevated alkalinity to constrain the longevity of carbon storage.
A range of technologies have been proposed to increase ocean alkalinity (accelerated weathering of limestone, enhanced weathering, electrochemical promoted weathering, ocean liming), the cost of which may be comparable to alternative carbon sequestration proposals (e.g., $20 - 100 tCO2-1). There are still many unanswered technical, environmental, social, and ethical questions, but the scale of the carbon sequestration challenge warrants research to address these.
Ocean warming and acidification have the potential to impact the quality of seafood with flow on effects for future food security and ecosystem stability. Here, we used a 35-day experiment to evaluate how ocean warming and acidification may impact the nutritional qualities and physiological health of Dicathais orbita, a predatory muricid whelk common on the east coast of Australia, and discuss the broader ecological implications. Using an orthogonal experimental design with four treatments (current conditions [~ 23 °C and ~ 380 ppm of pCO2], ocean warming treatment [~ 25 and ~ 380 ppm of pCO2], ocean acidification treatment [CO2 ~ 23 °C and ~ 750 ppm of pCO2], and ocean warming and acidification treatment [CO2, ~ 25 °C and ~ 750 ppm of pCO2]), we showed that changes in moisture and protein content were driven by significant interactions between ocean warming and acidification. Elevated ocean temperature significantly decreased protein in the whelk flesh and resulted in concurrent increases in moisture. Lipid, glycogen, potassium, sulfur, and phosphorus content also decreased under elevated temperature conditions, whereas sodium, boron and copper increased. Furthermore, elevated pCO2significantly decreased lipid, protein and lead content. Whelks from control conditions had levels of lead in excess of that considered safe for human consumption, although lead uptake appears to be lowered under future ocean conditions and will be site specific. In conclusion, while D. orbita has received research attention as a potential food product with nutritious value, ocean climate change may compromise its nutritional qualities and reduce sustainable harvests in the future. Furthermore, ocean climate change may have deleterious impacts on the longevity and reproductive potential of this important rocky shore predator.