Broad-scale surveys for the economically valuable gastropod queen conch in historically important fishing grounds of the Bahamian archipelago provide opportunity to explore the impact of variable fishing intensity on population structures. Visual surveys spanning two decades showed that densities of mature individuals had a significant negative relationship with an index of fishing pressure (FP). Average shell length in a population was not related to FP, but shell lip thickness (an index of conch age) declined significantly with FP. Repeated surveys in three fishing grounds revealed that densities of mature conch have declined in all of those locations and the populations have become younger with time. Densities have also declined significantly in three repeated surveys (over 22 years) conducted in a large no-take fishery reserve. Unlike fished populations, the protected population has aged and appears to be declining for lack of recruitment. In all fishing grounds except those most lightly fished, densities of adult conch are now below that needed for successful mating and reproduction. It is clear that queen conch populations in The Bahamas have undergone serial depletion, nearing fishery collapse, and a wide range of recommendations aimed at stock recovery are offered including a broader network of no-take reserves.
There are three main themes in this self-reflective essay, and I hope they are thought-provoking without being pretentious. The first is the topic of scientific specialization. How do we steer a course between being a dilettante on one hand, dabbling in everything without making major contributions in any field, and on the other hand being a specialist who digs deeply but too narrowly? The second theme is the concept of specialization with respect to place, and the study of natural history. It can be incredibly rewarding, both personally and professionally, to develop a rich ecological understanding of a particular place such as a field station. However, this requires a great commitment of time, and it reduces mobility and experience elsewhere. The third theme is the importance of mentoring and the transfer of encouragement and opportunity from one cohort to the next. I will address these three themes in this order but they are closely linked to each other, making the separation somewhat artificial.
Interactions between fishing vessels and oil and gas infrastructure can result in damage to fishing gear, loss of fishing time/access, and risks to crew health and safety. The spatial and temporal patterns characterizing previous incidents (and subsequent losses) between fishers and oil and gas infrastructure were quantified and used to identify key risk factors associated with fisheries losses. Between the years 1989 and 2016, 1590 incidents that resulted in a financial loss, vessel abandonment, or an injury/fatality for UK commercial fishers were recorded. The annual number of recorded incidents decreased by 98.6% over a 27-year period. The majority of past incidences resulted in financial losses (rather than injuries or fatalities) and were associated with interactions between single otter trawlers and oil and gas production-related debris. The odds of an incidence occurring varied according to substrate type and fishing intensity. A risk-model for pipeline–fishing interactions in the Fladen Ground showed that there was significant spatial heterogeneity in the risk of an incident along a pipeline according to the angle and intensity of fishing. The results highlight the need to include the full spectrum of potential losses in fisheries impact assessments associated with the installation and decommissioning of oil and gas assets.
This study describes the pathologic findings and most probable causes of death (CD) of 224 cetaceans stranded along the coastline of the Canary Islands (Spain) over a 7-year period, 2006–2012. Most probable CD, grouped as pathologic categories (PCs), was identified in 208/224 (92.8%) examined animals. Within natural PCs, those associated with good nutritional status represented 70/208 (33.6%), whereas, those associated with significant loss of nutritional status represented 49/208 (23.5%). Fatal intra- and interspecific traumatic interactions were 37/208 (17.8%). Vessel collisions included 24/208 (11.5%). Neonatal/perinatal pathology involved 13/208 (6.2%). Fatal interaction with fishing activities comprised 10/208 (4.8%). Within anthropogenic PCs, foreign body-associated pathology represented 5/208 (2.4%). A CD could not be determined in 16/208 (7.7%) cases. Natural PCs were dominated by infectious and parasitic disease processes. Herein, our results suggest that between 2006 and 2012, in the Canary Islands, direct human activity appeared responsible for 19% of cetaceans deaths, while natural pathologies accounted for 81%. These results, integrating novel findings and published reports, aid in delineating baseline knowledge on cetacean pathology and may be of value to rehabilitators, caregivers, diagnosticians and future conservation policies.
The Mediterranean Sea is affected by one of the most significant plastic pollution worldwide. This review critically evaluates the most recent literature on the presence of microplastics in sediments, suggested to be long term sinks and have a high potential to accumulate this kind of marine debris. A picture of microplastic levels in coastal environments is given, evidencing information gaps and considering also estuary, lagoons and areas influenced by the contribution of rivers. A wide range of contamination levels has been found, with the highest in lagoon and estuary environments. The lack of homogeneity in the methods of study and the need to harmonize the latter and the expression of the results in addition to the need to obtain data on the contributions of the main tributaries of the Mediterranean and on lagoons, are other important considerations taken.
This paper proposes an ‘exploratory mapping’ approach that can be employed in the early stages of a marine protected area planning process. While stakeholders' involvement in conservation has increased, it often only starts after the decision has been made about where the protected areas will be located. The lack of proper engagement with resource users raises questions about transparency and legitimacy of marine conservation initiatives, hampering their successful implementation. The proposed mapping approach offers a simple way to incorporate in the planning process what small-scale fishers consider to be important to conserve, what they value in their fishing livelihoods, and their perception about the likely impact that multiple uses of the area may cause. Conducted in a small group setting, the exploratory mapping approach is casual and conversational, using paper maps and markers to capture information and stories as they are told. The approach was tested with 14 small-scale fishers living near the Marine National Park of Currais Islands, Southern Brazil. The mapping results, based on the GIS analysis, show a high level of agreement among the study participants with respect to the ecological importance of the area under protection. The participants emphasized that, in addition to its ecological significance, the area is also important in economic and socio-cultural terms, aspects that should be considered in the planning. The study highlights how the exploratory mapping approach can provide decision makers with useful information about small-scale fishers' values and knowledge, which can help identify potential conflicts and enhance support for marine protected areas.
The number of fixed oil and gas platforms are declining in the Gulf of Mexico, there were ∼3674 platforms installed the since 1942 and today there are ∼1320. Eventually, ∼30,000 jobs will be lost in related industries because of platform removals. Retired oil and gas platforms could be redeployed for alternate uses such as CO2 capture and storage, renewable wind energy, and sustainable fisheries and employ citizens in coastal areas. Elsewhere around the world, offshore platforms are used for purposes other than producing oil and gas. U.S. Federal legislation (Energy Policy Act 2005 Section 388 of Public Law [PL] 109-58); 30 CFR 285.1000 Subpart J) authorizes the use of retired oil and gas platforms for alternate uses. If the retired oil and gas structures are preserved, the infrastructure could also be used to recover stranded petroleum using CO2 enhanced oil recovery (CO2-EOR). We examined the socio-economic incentives, environmental impacts, and regulatory issues associated with the alternate uses. We suggest that CO2-EOR is the most economically efficient way to store CO2 offshore and that offshore wind turbines may assist with the energy requirements for oil and gas production and CO2-EOR. Data suggest that in our study area offshore platforms are more successful at producing fish and invertebrates if they are left standing instead of toppled over. The greatest regulatory issue facing the use of retired platforms is the transfer of liability. If the structures are redeployed, the previous oil and gas owner/operators are still responsible for eventual removal and catastrophic events. A variety of future economic activity in the Gulf of Mexico could take advantage of this infrastructure, if it remains in place.
Tropical estuaries are one of the most valuable ecosystems on the planet because of the number of ecosystem services they provide. The increasing anthropogenic pressure to which these estuaries are subject has caused a reduction in their natural capital stock. Therefore, the application of a pragmatic and rational ecosystem-based management approach to sustainably manage the multiple ecosystem services provided by this ecosystem is necessary. The aim of our study is to present an approach that combines prospective scenarios with habitat-based perspective to assess the supply capacity of ecosystem services, plus determine the impact of protected areas in an urbanized tropical estuary. The current situation and two scenarios were generated to evaluate the capacity of habitats to supply ecosystem services. This type of assessment will allow the decision makers to visualize the effect of their choices or the occurrence of events which might produce significant changes in the estuary. Thus, over time, measures can be taken to sustain the supply of ecosystem services. We determined that the establishment of protected areas have a positive impact; however, the effect is not the same for all of them. Consequently, indicating that actions such as community participation, research, education, management planning and infrastructure development must accompany the development of a protected area.
We have observed that marine macroalgae produce sound during photosynthesis. The resultant soundscapes correlate with benthic macroalgal cover across shallow Hawaiian coral reefs during the day, despite the presence of other biological noise. Likely ubiquitous but previously overlooked, this source of ambient biological noise in the coastal ocean is driven by local supersaturation of oxygen near the surface of macroalgal filaments, and the resultant formation and release of oxygen-containing bubbles into the water column. During release, relaxation of the bubble to a spherical shape creates a monopole sound source that ‘rings’ at the Minnaert frequency. Many such bubbles create a large, distributed sound source over the sea floor. Reef soundscapes contain vast quantities of biological information, making passive acoustic ecosystem evaluation a tantalizing prospect if the sources are known. Our observations introduce the possibility of a general, volumetrically integrative, noninvasive, rapid and remote technique for evaluating algal abundance and rates of primary productivity in littoral aquatic communities. Increased algal cover is one of the strongest indicators for coral reef ecosystem stress. Visually determining variations in algal abundance is a time-consuming and expensive process. This technique could therefore provide a valuable tool for ecosystem management but also for industrial monitoring of primary production, such as in algae-based biofuel synthesis.
Anthropogenic marine debris is one of the major worldwide threats to marine ecosystems. The EU Marine Strategy Framework Directive (MSFD) has established a protocol for data collection on marine debris from the gut contents of the loggerhead sea turtle (Caretta caretta), and for determining assessment values of plastics for Good Environmental Status (GES). GES values are calculated as percent turtles having more than average plastic weight per turtle. In the present study, we quantify marine debris ingestion in 155 loggerhead sea turtles collected in the period 1995–2016 in waters of western Mediterranean (North-east Spain). The study aims (1) to update and standardize debris ingestion data available from this area, (2) to analyse this issue over two decades using Zero-altered (hurdle) models and (3) to provide new data to compare the only GES value available (off Italian waters). The composition of marine debris (occurrence and amounts of different categories) was similar to that found in other studies for the western Mediterranean and their amounts seem not to be an important threat to turtle survival in the region. Model results suggest that, in the study area, (a) period of stranding or capture, (b) turtle size and (c) latitude are significant predictors of anthropogenic debris ingestion (occurrence and amount) in turtles. The GES value for late juvenile turtles (CCL>40 cm) has decreased in the last ten years in the study area, and this is very similar to that obtained in Italian waters. We also provide a GES value for early juvenile turtles (CCL≤40 cm) for the first time. Recommendations arising from this study include ensuring use of (1) the standardized protocol proposed by the MSFD for assessing marine debris ingestion by loggerhead sea turtles and (2) the ecology of the turtles (neritic vs oceanic), rather than their size, to obtain GES values.
Ocean acidification and warming is widely reported to affect the ability of marine bivalves to calcify, but little is known about the underlying mechanisms. In particular, the response of their calcifying fluid carbonate chemistry to changing seawater carbonate chemistry remains poorly understood. The present study deciphers sources of the dissolved inorganic carbon (DIC) in the calcifying fluid of the blue mussel (Mytilus edulis) reared at two pH (8.1 and 7.7) and temperature (16 and 22 °C) levels for five weeks. Stable carbon isotopic ratios of seawater DIC, mussel soft tissues and shells were measured to determine the relative contribution of seawater DIC and metabolically generated carbon to the internal calcifying DIC pool. At pH 8.1, the percentage of seawater DIC synthesized into shell carbonate decreases slightly from 83.8% to 80.3% as temperature increases from 16 to 22 °C. Under acidified conditions, estimates of percent seawater DIC incorporation decreases clearly to 65.6% at 16 °C and to 62.3% at 22 °C, respectively. These findings indicate that ongoing ocean acidification and warming may interfere with the calcification physiology of M. edulis through interfering with its ability to efficiently extract seawater DIC to the calcifying front.
Marine debris is pervasive worldwide, and affects biota negatively. We compared the characteristics of debris incorporated within brown booby (Sula leucogaster) nests throughout their pantropical distribution by assessing the type, colour and mass of debris items within nests and in beach transects at 18 sites, to determine if nests are indicators of the amount of debris in local marine environments. Debris was present in 14.4% of nests surveyed, with the proportion of nests with debris varying among sites (range: 0–100%). There was minimal overlap between the type or colour of debris found in nests and on adjacent beaches at individual sites. This suggests that brown boobies do not select debris uniformly across their distribution. We propose that the nests of brown boobies can be used as a sentinel of marine debris pollution of their local environment.
Single-use plastics, or SUPs (plastic bags, microbeads, cutlery, straws and polystyrene) are substantial sources of plastic marine pollution, yet preventable via legislative and non-legislative interventions. Various international legislative strategies have been reported to address plastic marine pollution from plastic bags and microbeads, but these have since been accompanied by recent increasing public awareness triggered by international agencies and organizations. The Sixth International Marine Debris Conference highlighted increasing intervention strategies to mitigate SUP pollution. This study presents new multi-jurisdictional legislative interventions to reduce SUPs since 2017 and incorporates emergence of new non-legislative interventions to mitigate other types of SUPs at individual and private-sector levels that complement or influence legislative interventions. Further, effectiveness of SUP bag interventions (e.g., bans vs. levies) to help reduce SUP marine pollution are presented and range between 33 and 96% reduction in bag use.
Based on a validated underwater oil spill model and the hydrodynamic background provided by an unstructured grid, finite-volume, coastal ocean model (FVCOM), a series of numerical experiments are conducted to study the impact of error in ocean dynamical background currents on the 3D transport of underwater spilled oil, in terms of three metrics including oil centroid position, sweeping area, and sweeping volume. Numerical result shows that a larger error in ocean dynamical background currents results in a larger model error expectation and uncertainty for all three metrics. As model time increases, the model error mainly increases and the error growth rate varies unevenly. The sensitivity of the oil spill model to background current error can be interpreted as an integrated result of the temporal and spatial variations of the background current and the movement of oil droplets of different sizes.
This paper explores how people adapt to climate shocks, specifically coral bleaching, that have long-lasting impacts on income. Caused mainly by abnormally high sea surface temperature, coral bleaching has significant effects on marine resources. Using panel data from Indonesia and exogenous variations in bleaching, I observe that fishery households in affected areas experienced a decrease in income relative to other households. Although consumption expenditures did not decline significantly in response to these income shocks, these households reduced their protein consumption in the short and long runs. Regarding labor market outcomes, the affected households tended to substantially increase their labor supply and switch industries only in the long run.
The ever-increasing level of marine pollution due to plastic debris is a globally recognized threat that needs effective actions of control and mitigation. Using marine organisms as bioindicators of plastic pollution can provide crucial information that would better integrate the spatial and temporal presence of plastic debris in the sea. Given their long and frequent migrations, numerous marine species that ingest plastics can provide information on the presence of plastic debris but only on large spatial and temporal scales, thus making it difficult to identify quantitative correlations of ingested plastics within well-defined spatio-temporal patterns. Given the complex dynamics of plastics in the sea, the biomonitoring of marine plastic debris should rely on the combination of several bioindicator species with different characteristics that complement each other. Other critical aspects include the standardization of sampling protocols, analytical detection methods and metrics to evaluate the effects of ingested plastics in marine species.
This paper focuses on the relationship of climate change mitigation and human security and its implications for ocean governance. The analysis of the existing maritime climate change mitigation landscape begins with a mapping of the different actors involved and their empowerment in this domain. This is followed by a presentation of the institutional framework for maritime climate change mitigation, moving from the international to the EU level, with a special focus on the Baltic Sea, which is highlighted as an example of a regional sea environmental system that has incorporated climate change mitigation in its objectives and operational actions within the broader aim of securability. Finally, the prevailing and emerging norms in the domain of maritime climate change mitigation efforts at the international and regional levels are being discussed.
The ubiquity and high bioavailability of microplastics have an unknown risk on the marine environment. Biomonitoring should be used to investigate biotic impacts of microplastic exposure. While many studies have used mussels as indicators for marine microplastic pollution, a robust and clear justification for their selection as indicator species is still lacking. Here, we review published literature from field investigations and laboratory experiments on microplastics in mussels and critically discuss the suitability and challenges of mussels as sentinel organisms for microplastic pollution. Mussels are suitable sentinel organisms for microplastic pollution because of their wide distribution, vital ecological niches, susceptibility to microplastic uptake and close connection with marine predators and human health. Field investigations highlight a wide occurrence of microplastics in mussels from all over the world, yet their abundance varies enormously. Problematically, these studies are not comparable due to the lack of a standardized approach, as well as temporal and spatial variability. Interestingly, microplastic abundance in field-collected mussels is closely related to human activity, and there is evidence for a positive and quantitative correlation between microplastics in mussels and surrounding waters. Laboratory studies collectively demonstrate that mussels may be good model organisms in revealing microplastic uptake, accumulation and toxicity. Consequently, we propose the use of mussels as target species to monitor microplastics and call for a uniform, efficient and economical approach that is suitable for a future large-scale monitoring program.
The term Other Effective Conservation Measures (OECMs) refers to areas which are not protected areas and yet significantly contribute to conservation; they were recently defined by the Convention on Biological Diversity. Efforts to address the designation of OECMs include further definition of the term and the development of typologies of OECMs and of screening tools which can be applied to identify potential OECMs. While the designation process of OECMs is still unclear, especially in the marine environment, we suggest a decision process which can be used by planners to identify and designate specific types of OECMs as part of the marine spatial planning (MSP) process. These OECMs are areas where marine communities benefit from access restrictions established due to safety or security concerns. We applied the suggested process on two case studies of the Italian Northern Adriatic and the Israeli Mediterranean seas. When consideration of OECMs comes at the expense of designating marine protected areas, OECMs can become controversial. However, OECM designation can promote achievement of marine conservation goals and of ecosystem-based management of uses. Therefore, we suggest that while spatial targets for conservation should focus mainly on areas dedicated for marine reserves, OECMs, especially of the type for ancillary conservation discussed in this paper, can be achieved through MSP. Using MSP for the designation of recognized OECMs may significantly promote marine conservation goals in unexpected ways and may help realize ecosystem-based management.
There has been a recent shift in global perception of plastics in the environment, resulting in a call for greater action. Science and the popular media have highlighted plastic as an increasing stressor. Efforts have been made to confer protected status to some remote locations, forming some of the world’s largest Marine Protected Areas, including several UK overseas territories. We assessed plastic at these remote Atlantic Marine Protected Areas, surveying the shore, sea surface, water column and seabed, and found drastic changes from 2013–2018. Working from the RRS James Clark Ross at Ascension, St. Helena, Tristan da Cunha, Gough and the Falkland Islands (Figure 1A), we showed that marine debris on beaches has increased more than 10 fold in the past decade. Sea surface plastics have also increased, with in-water plastics occurring at densities of 0.1 items m–3; plastics on seabeds were observed at ≤ 0.01 items m–2. For the first time, beach densities of plastics at remote South Atlantic sites approached those at industrialised North Atlantic sites. This increase even occurs hundreds of meters down on seamounts. We also investigated plastic incidence in 2,243 animals (comprising 26 species) across remote South Atlantic oceanic food webs, ranging from plankton to seabirds. We found that plastics had been ingested by primary consumers (zooplankton) to top predators (seabirds) at high rates. These findings suggest that MPA status will not mitigate the threat of plastic proliferation to this rich, unique and threatened biodiversity.