Freely-available Literature

Currently indexing 3698 freely-available titles

The following titles are freely-available, or include a link to a preprint or postprint.

The Global Flood Protection Benefits of Mangroves

Menéndez P, Losada IJ, Torres-Ortega S, Narayan S, Beck MW. The Global Flood Protection Benefits of Mangroves. Scientific Reports [Internet]. 2020 ;10(1). Available from: https://www.nature.com/articles/s41598-020-61136-6
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Coastal flood risks are rising rapidly. We provide high resolution estimates of the economic value of mangroves forests for flood risk reduction every 20 km worldwide. We develop a probabilistic, process-based valuation of the effects of mangroves on averting damages to people and property. We couple spatially-explicit 2-D hydrodynamic analyses with economic models, and find that mangroves provide flood protection benefits exceeding $US 65 billion per year. If mangroves were lost, 15 million more people would be flooded annually across the world. Some of the nations that receive the greatest economic benefits include the USA, China, India and Mexico. Vietnam, India and Bangladesh receive the greatest benefits in terms of people protected. Many (>45) 20-km coastal stretches particularly those near cities receive more than $US 250 million annually in flood protection benefits from mangroves. These results demonstrate the value of mangroves as natural coastal defenses at global, national and local scales, which can inform incentives for mangrove conservation and restoration in development, climate adaptation, disaster risk reduction and insurance.

Conservation Finance: A Framework

Meyers D, Bohorquez J, Cumming T, Emerton L, van den Heuvel O, Riva M, Victurine R. Conservation Finance: A Framework. Conservation Finance Alliance; 2020. Available from: https://www.conservationfinancealliance.org/cfa-white-paper
Freely available?: 
Yes
Summary available?: 
No
Type: Report

In this white paper, we seek to clarify the definition and role of conservation finance to show how important its mechanisms and strategies are for addressing the underlying causes of nature loss as well as contributing to increasing sustainable funding flows to nature conservation. This white paper is intended to improve understanding of the opportunities and challenges posed by the field of conservation finance. The paper emphasizes a holistic approach to conservation finance and seeks to support a more harmonized comprehension going forward. Secondly, the white paper provides several conceptual frameworks to facilitate an understanding of the various concepts associated with conservation finance.  Finally, the white paper presents a taxonomy of conservation finance strategies and mechanisms.

The white paper defines conservation finance as “mechanisms and strategies that generate, manage, and deploy financial resources and align incentives to achieve nature conservation outcomes.”

Diel, daily, and spatial variation of coral reef seawater microbial communities

Weber L, Apprill A. Diel, daily, and spatial variation of coral reef seawater microbial communities Patterson HM. PLOS ONE [Internet]. 2020 ;15(3):e0229442. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0229442
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Reef organisms influence microorganisms within the surrounding seawater, yet the spatial and temporal dynamics of seawater microbial communities located in proximity to corals are rarely investigated. To better understand reef seawater microbial community dynamics over time and space, we collected small-volume seawater samples during the day and night over a 72 hour period from three locations that differed in spatial distance from 5 Porites astreoides coral colonies on a shallow reef in St. John, U.S. Virgin Islands: near-coral (sampled 5 cm horizontally from each colony), reef-depth (sampled 2 m above each colony) and surface seawater (sampled 1 m from the seawater surface). At all time points and locations, we quantified abundances of microbial cells, sequenced small subunit rRNA genes of bacterial and archaeal communities, and measured inorganic nutrient concentrations. Prochlorococcus and Synechococcus cells were consistently elevated at night compared to day and these abundances changed over time, corresponding with temperature, nitrite, and silicate concentrations. During the day, bacterial and archaeal alpha diversity was significantly higher in reef-depth and near-coral seawater compared to the surface seawater, signifying that the reef influences the diversity of the seawater microorganisms. At night, alpha diversity decreased across all samples, suggesting that photosynthesis may favor a more taxonomically diverse community. While Prochlorococcus exhibited consistent temporal rhythmicity, additional taxa were enriched in reef seawater at night compared to day or in reef-depth compared to surface seawater based on their normalized sequence counts. There were some significant differences in nutrient concentrations and cell abundances between reef-depth and near-coral seawater but no clear trends. This study demonstrates that temporal variation supersedes small-scale spatial variation in proximity to corals in reef seawater microbial communities. As coral reefs continue to change in benthic composition worldwide, monitoring microbial composition in response to temporal changes and environmental fluctuations will help discern normal variability from longer lasting changes attributed to anthropogenic stressors and global climate change.

Ten lessons from the frontlines of science in support of fisheries management

Hare JA. Ten lessons from the frontlines of science in support of fisheries management Browman H. ICES Journal of Marine Science [Internet]. 2020 . Available from: https://academic.oup.com/icesjms/advance-article/doi/10.1093/icesjms/fsaa025/5803784
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

After 20+ years as a research scientist, I recently made a career change to a scientific administrator in NOAA Fisheries. Part of the NOAA Fisheries mission is to provide scientific advice for fisheries using ecosystem based approaches to management. Where I used to see fisheries science as a relatively straightforward discipline, I now recognize fisheries as a complex socio-ecological system that spans natural and social sciences. With this recognition has come an appreciation for the concept of wicked problems and for the incremental approach to policy-making. Here I describe my perspectives before and after this recognition and present 10 lessons for myself as a guide to providing science in support of fisheries management.

Realistic fisheries management reforms could mitigate the impacts of climate change in most countries

Free CM, Mangin T, Molinos JGarcía, Ojea E, Burden M, Costello C, Gaines SD. Realistic fisheries management reforms could mitigate the impacts of climate change in most countries Hewitt J. PLOS ONE [Internet]. 2020 ;15(3):e0224347. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0224347
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Although climate change is altering the productivity and distribution of marine fisheries, climate-adaptive fisheries management could mitigate many of the negative impacts on human society. We forecast global fisheries biomass, catch, and profits to 2100 under three climate scenarios (RCPs 4.5, 6.0, 8.5) and five levels of management reform to (1) determine the impact of climate change on national fisheries and (2) quantify the national-scale benefits of implementing climate-adaptive fisheries reforms. Management reforms accounting for shifting productivity and shifting distributions would yield higher catch and profits in the future relative to today for 60–65% of countries under the two least severe climate scenarios but for only 35% of countries under the most severe scenario. Furthermore, these management reforms would yield higher cumulative catch and profits than business-as-usual management for nearly all countries under the two least severe climate scenarios but would yield lower cumulative catch for 40% of countries under the most severe scenario. Fortunately, perfect fisheries management is not necessary to achieve these benefits: transboundary cooperation with 5-year intervals between adaptive interventions would result in comparable outcomes. However, the ability for realistic management reforms to offset the negative impacts of climate change is bounded by changes in underlying biological productivity. Although realistic reforms could generate higher catch and profits for 23–50% of countries experiencing reductions in productivity, the remaining countries would need to develop, expand, and reform aquaculture and other food production sectors to offset losses in capture fisheries. Still, climate-adaptive management is more profitable than business-as-usual management in all countries and we provide guidance on implementing–and achieving the benefits of–climate-adaptive fisheries reform along a gradient of scientific, management, and enforcement capacities.

Differing marine animal biomass shifts under 21st century climate change between Canada’s three oceans

Bryndum-Buchholz A, Prentice F, Tittensor DP, Blanchard JL, Cheung WWL, Christensen V, Galbraith ED, Maury O, Lotze HK. Differing marine animal biomass shifts under 21st century climate change between Canada’s three oceans Favaro B. FACETS [Internet]. 2020 ;5(1):105 - 122. Available from: https://www.facetsjournal.com/doi/full/10.1139/facets-2019-0035
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Under climate change, species composition and abundances in high-latitude waters are expected to substantially reconfigure with consequences for trophic relationships and ecosystem services. Outcomes are challenging to project at national scales, despite their importance for management decisions. Using an ensemble of six global marine ecosystem models we analyzed marine ecosystem responses to climate change from 1971 to 2099 in Canada’s Exclusive Economic Zone (EEZ) under four standardized emissions scenarios. By 2099, under business-as-usual emissions (RCP8.5) projected marine animal biomass declined by an average of −7.7% (±29.5%) within the Canadian EEZ, dominated by declines in the Pacific (−24% ± 24.5%) and Atlantic (−25.5% ± 9.5%) areas; these were partially compensated by increases in the Canadian Arctic (+26.2% ± 38.4%). Lower emissions scenarios projected successively smaller biomass changes, highlighting the benefits of stronger mitigation targets. Individual model projections were most consistent in the Atlantic and Pacific, but highly variable in the Arctic due to model uncertainties in polar regions. Different trajectories of future marine biomass changes will require regional-specific responses in conservation and management strategies, such as adaptive planning of marine protected areas and species-specific management plans, to enhance resilience and rebuilding of Canada’s marine ecosystems and commercial fish stocks.

Science, Diplomacy, and the Red Sea’s Unique Coral Reef: It’s Time for Action

Kleinhaus K, Al-Sawalmih A, Barshis DJ, Genin A, Grace LN, Hoegh-Guldberg O, Loya Y, Meibom A, Osman EO, Ruch J-D, et al. Science, Diplomacy, and the Red Sea’s Unique Coral Reef: It’s Time for Action. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00090/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1268806_45_Marine_20200312_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Rapid ocean warming due to climate change poses a serious risk to the survival of coral reefs. It is estimated that 70–90 percent of all reefs will be severely degraded by mid-century even if the 1.5°C goal of the Paris Climate Agreement is achieved. However, one coral reef ecosystem seems to be more resilient to rising sea temperatures than most others. The Red Sea’s reef ecosystem is one of the longest continuous living reefs in the world, and its northernmost portion extends into the Gulf of Aqaba. The scleractinian corals in the Gulf have an unusually high tolerance for the rapidly warming seawater in the region. They withstand water temperature anomalies that cause severe bleaching or mortality in most hard corals elsewhere. This uniquely resilient reef employs biological mechanisms which are likely to be important for coral survival as the planet’s oceans warm. The Gulf of Aqaba could potentially be one of the planet’s largest marine refuges from climate change. However, this unique portion of the Red Sea’s reef will only survive and flourish if serious regional environmental challenges are addressed. Localized anthropogenic stressors compound the effects of warming seawater to damage corals and should be mitigated immediately. Reefs in the rest of the Red Sea are already experiencing temperatures above their thermal tolerance and have had significant bleaching, though they too would benefit from fewer local anthropogenic stressors. The countries bordering the entire Red Sea will need to cooperate to enable effective scientific research and conservation. The newly established Transnational Red Sea Center, based at the Ecole Polytechnique Fédérale de Lausanne (EPFL), can serve as the regionally inclusive, neutral organization to foster crucial regional scientific collaboration.

Responding to Climate Change: Participatory Evaluation of Adaptation Options for Key Marine Fisheries in Australia’s South East

Ogier E, Jennings S, Fowler A, Frusher S, Gardner C, Hamer P, Hobday AJ, Linanne A, Mayfield S, Mundy C, et al. Responding to Climate Change: Participatory Evaluation of Adaptation Options for Key Marine Fisheries in Australia’s South East. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00097/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1268806_45_Marine_20200312_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Planned adaptation to climate impacts and subsequent vulnerabilities will necessarily interact with autonomous responses enabled within existing fisheries management processes and initiated by the harvest and post-harvest components of fishing industries. Optimal adaptation options are those which enable negative effects to be mitigated and opportunities that arise to be maximized, both in relation to specific climate-driven changes and the broader fisheries system. We developed a two-step participatory approach to evaluating adaption options for key fisheries in the fast-warming hotspot of south-eastern Australia. Four fisheries (southern rock lobster, abalone, snapper, and blue grenadier) were selected as case studies on the basis of their high to moderate vulnerability to climatic effects on species distribution and abundance. Involved stakeholders undertook a “first pass” screening assessment of options, by characterizing and then evaluating options. In the characterization step potential adaptation options for each fishery, contextualized by prior knowledge of each species’ climate change exposure and sensitivity, were described using a characterization matrix. This matrix included: the specific climate vulnerability/challenges, the implications of each option on the fishery system as a whole, the temporal and spatial scales of implementation processes, and realized benefits and costs. In the evaluation step, semi-quantitative evaluation of options was undertaken by stakeholders scoring the anticipated performance of an option against a pre-determined set of criteria relating to perceived feasibility, risk (inclusive of potential costs), and benefit. Reduction of the total annual commercial catch as well as reductions in both effort and catch through spatial and temporal closures were the options scored as having the highest level of expected benefit and of feasibility and the lowest level of risk of negative outcomes overall. Our screening assessment represents a pragmatic approach to evaluate and compare support for and the effects of alternative adaptation options prior to committing to more detailed formal and resource intensive evaluation or implementation.

Methods for Monitoring for the Population Consequences of Disturbance in Marine Mammals: A Review

Booth CG, Sinclair RR, Harwood J. Methods for Monitoring for the Population Consequences of Disturbance in Marine Mammals: A Review. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00115/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1268806_45_Marine_20200312_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Assessing the non-lethal effects of disturbance and their population-level consequences is a significant ecological and conservation challenge, because it requires extensive baseline knowledge of behavioral patterns, life-history and demography. However, for many marine mammal populations, this knowledge is currently lacking and it may take decades to fill the gaps. During this time, undetected population declines may occur. In this study we identify methods that can be used to monitor populations subject to disturbance and provide insights into the processes through which disturbance may affect them. To identify and address the knowledge gaps highlighted above, we reviewed the literature to identify suitable response variables and methods for monitoring these variables. We also used existing models of the population consequences of disturbance (PCoD) to identify demographic characteristics (e.g., the proportion of immature animals in the population, or the ratio of calves/pups to mature females) that may be strongly correlated with population status and therefore provide early warnings of future changes in abundance. These demographic characteristics can be monitored using established methods such as visual surveys combined with photogrammetry, and capture-recapture analysis. Individual health and physiological variables can also inform PCoD assessment and can be monitored using photogrammetry, remote tissue sampling, hands-on assessment and individual tracking. We then conducted a workshop to establish the relative utility and feasibility of all these approaches for different groups of marine mammal species. We describe how future marine mammal monitoring programs can be designed to inform population-level analysis.

Cultivar Development of Kelps for Commercial Cultivation—Past Lessons and Future Prospects

Goecke F, Klemetsdal G, Ergon Å. Cultivar Development of Kelps for Commercial Cultivation—Past Lessons and Future Prospects. Frontiers in Marine Science [Internet]. 2020 ;8. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00110/full?utm_source=F-AAE&utm_medium=EMLF&utm_campaign=MRK_1268806_45_Marine_20200312_arts_A
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Cultivated kelps and other macroalgae have great potential in future provision of food, feed, bioenergy, fertilizer, and raw material for a range of chemical products including pharmaceuticals, food and feed additives, and cosmetics. Only a few species are currently cultivated, almost exclusively in Asia. There is a range of species that could be utilized in different parts of the world, providing that protocols for reproduction, propagation, and cultivation are developed. Domestication of species involves selection of traits that are desirable in cultivation and in the utilization of the harvested biomass. Genetic improvement of cultivated species through recombination of alleles and selection (breeding) has ensured high productivity and product quality in both agri- and aquaculture and will likely do so for macroalgae cultivation and use as well. According to the published literature, genetic improvement of kelps in Asia has so far largely relied on utilization of heterosis expressed in certain combinations of parental material, sometimes species hybrids. Here, we explore and evaluate the various methods that could be used in kelp breeding and propose an initial simple and low-cost breeding strategy based on recurrent mixed hybridization and phenotypic selection within local populations. We also discuss the genetic diversity in wild populations, and how this diversity can be protected against genetic pollution, either by breeding and cultivating local populations, or by developing cultivars that are not able to establish in, or hybridize with, wild populations.

World Seaborne Trade with Oil: One of Main Cause for Oil Spills?

Galieriková A, Materna M. World Seaborne Trade with Oil: One of Main Cause for Oil Spills?. Transportation Research Procedia [Internet]. 2020 ;44:297 - 304. Available from: https://www.sciencedirect.com/science/article/pii/S2352146520300892
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Oil is a main driver for the growth of modern economies because of its multifaceted use in transport, energy and manufacturing. Due to uneven distribution of petroleum products across the world, maritime transportation of mineral oils has increased. The main objective of the paper is to examine data on oil spills created by oil tankers for the past 50 years and to examine trends in oil trading and oil spill pollution in an effort to analyse the state of pollution in major oil disasters. The paper also considers the key factors of tanker oil spills and summarizes strategies and directions for the global maritime transport industry to prevent oil tanker pollution in the future.

Simulation of Ship Radiated Noise Field in Deep Sea Based on Statistical Characteristics of Sound Source

Zhang L, Meng CXia, Zhang MWei. Simulation of Ship Radiated Noise Field in Deep Sea Based on Statistical Characteristics of Sound Source. Procedia Computer Science [Internet]. 2020 ;166:104 - 110. Available from: https://www.sciencedirect.com/science/article/pii/S1877050920301514
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The radiated noise of a ship is mainly composed of a low-frequency line spectrum and a medium-high frequency broadband continuum spectrum. In the ocean, the low-frequency sound signal decays slowly, so the low-frequency line spectrum of ship radiated noise can be transmitted over long distances. Based on the statistical analysis method, the inherent source characteristics of radiated noise are obtained from the measured data in shallow sea waveguides. Different deep sea sound velocity distribution conditions, such as the northeastern Atlantic Ocean, the Norwegian Sea deep sea, the Norwegian sea surface channel and the polar regions, were selected, and the propagation characteristics of the low-frequency radiation noise field of the ship were simulated at a horizontal distance of 150 km. The effects of different sound velocity distributions on the propagation of low-frequency acoustic signals are obtained. The research results have important practical significance for the utilization of low-frequency radiation noise characteristics of ships in deep sea.

Short-term Estimate of Finfish Bycatch Discards in the Inshore Artisanal Shrimp Fishery of Guyana

Kalicharan L, Oxenford HA. Short-term Estimate of Finfish Bycatch Discards in the Inshore Artisanal Shrimp Fishery of Guyana. Gulf and Caribbean Research [Internet]. 2020 ;31(1):GCFI1 - GCFI9. Available from: https://aquila.usm.edu/gcr/vol31/iss1/1/
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The artisanal shrimp fishery in Guyana is important for livelihood and food security, involving around 300 vessels owned and crewed exclusively by Guyanese nationals. This fishery uses Chinese seines and operates in major river estuaries. It targets penaeid shrimp, but also retains some finfish and is known to discard a significant but undocumented quantity of smaller finfish bycatch. The lack of knowledge regarding the bycatch is a concern for fishery management and biodiversity conservation. In this study, we quantify for the first time the finfish bycatch discards through onboard observations (July—August 2016) of a single typical vessel operating in the Demerara estuary. Wet weights of the total catch, retained catch, and finfish discards were recorded separately for each of 76 seine hauls, and subsequently presented as catch rates per trip, catch rates per seine haul (kg/haul), and catch rates standardized per hour of seine net soak—time (kg/hr). A sub—sample of finfish discards was taken from every haul to determine taxonomic composition and species—specific length frequencies. Examination of 2,012 discarded finfish distributed among 32 species revealed high taxonomic diversity, none of which were considered vulnerable by the IUCN Red List. Most finfish discards were small (modal size class 5—7 cm fork length) and included juveniles of 15 species of importance to other fisheries in Guyana. On average, a standardized total catch rate of 14.8 kg was taken per hour of seine net soak—time, yielding 3.9 kg retained catch (shrimp and a few selected finfish), 10.3 kg of finfish bycatch discards, and 0.6 kg of miscellaneous invertebrate discards. This demonstrates significant wastage (finfish discards represent about 69% of the total catch weight) and potential for negative impact on biodiversity and other commercial fisheries. The information provided here addresses an important knowledge gap in the artisanal fisheries of Guyana.

Public Perceptions of Deep-Sea Environment: Evidence From Scotland and Norway

Ankamah-Yeboah I, Xuan BBich, Hynes S, Armstrong CW. Public Perceptions of Deep-Sea Environment: Evidence From Scotland and Norway. Frontiers in Marine Science [Internet]. 2020 ;7. Available from: https://www.frontiersin.org/articles/10.3389/fmars.2020.00137/full
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Knowledge of people's understanding of environmental problems is vital for the effective implementation of the ecosystem approach to marine management. This is especially relevant when conservation goals are aimed at ecosystems in the deep-sea that are remote to the consciousness of most people. This study explores public perceptions of the deep-sea environment among the Scottish and Norwegian public. It further analyses the relationships between respondents' pro-environmental concerns toward the marine environment and personal characteristics using a multiple indicators multiple causes model. The results show that public knowledge of the deep-sea environment is low for Scottish and moderate for Norwegians. Awareness of cold-water corals was high for the Lofoten case study area amongst the Norwegian public and low for the Mingulay reef complex in the Scottish case. These differences might arise because Norway is known to host the world's largest cold-water corals in the Lofoten area; a fact that has been well-publicized. We find that most people think changes in the deep-sea have at least some effect on them. On average, the public perceive the deep-sea condition to be at most “fairly good” but are dissatisfied with the management of it with approximately only one third or less thinking it is well-managed. Generally, the public perception from both countries show ecocentric attitudes toward the marine environment implying that they recognize the value of ecosystem services, the current ecological crisis and the need for sustainable management.

Marketplace shrimp mislabeling in North Carolina

Korzik ML, Austin HM, Cooper B, Jasperse C, Tan G, Richards E, Spencer ET, Steinwand B, F. Fodrie J, Bruno JF. Marketplace shrimp mislabeling in North Carolina Patterson HM. PLOS ONE [Internet]. 2020 ;15(3):e0229512. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0229512
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Seafood mislabeling occurs in a wide range of seafood products worldwide, resulting in public distrust, economic fraud, and health risks for consumers. We quantified the extent of shrimp mislabeling in coastal and inland North Carolina. We used standard DNA barcoding procedures to determine the species identity of 106 shrimp sold as “local” by 60 vendors across North Carolina. Thirty-four percent of the purchased shrimp was mislabeled, and surprisingly the percentage did not differ significantly between coastal and inland counties. One third of product incorrectly marketed as “local” was in fact whiteleg shrimp: an imported and globally farmed species native to the eastern Pacific, not found in North Carolina waters. In addition to the negative ecosystem consequences of shrimp farming (e.g., the loss of mangrove forests and the coastal buffering they provide), North Carolina fishers—as with local fishers elsewhere—are negatively impacted when vendors label farmed, frozen, and imported shrimp as local, fresh, and wild-caught.

Diving behavior of the reef manta ray (Mobula alfredi) in New Caledonia: More frequent and deeper night-time diving to 672 meters

Lassauce H, Chateau O, Erdmann MV, Wantiez L. Diving behavior of the reef manta ray (Mobula alfredi) in New Caledonia: More frequent and deeper night-time diving to 672 meters Hyrenbach D. PLOS ONE [Internet]. 2020 ;15(3):e0228815. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0228815
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The interest in reef manta rays (Mobula alfredi) from the scientific community is growing in reaction to the major decline of populations around the world. Studies have highlighted the need to further investigate the spatial ecology of this species to inform conservation and management initiatives. Here we briefly report the results from nine SPLASH10-F-321A pop-off satellite archival tags (PSAT-tags) deployed in New Caledonia that recorded the world’s deepest known dives for reef manta rays. All tagged individuals performed dives exceeding 300 m in depth, with a maximum depth recorded of 672 ± 4 m. Diel comparisons revealed that most of the deepest dives occurred during night-time. We hypothesize this deep-diving behaviour is employed to access important food resources at these depths during the night and may also indicate that zooplankton abundance in the surface waters surrounding New Caledonian coral reefs is insufficient to sustain these megafauna. These results add new information on the habitat use of this species in a region where manta behaviour has not previously been studied, and increase the known depth range of Malfredi by more than 200 m.

Natural history matters: Plastics in estuarine fish and sediments at the mouth of an urban watershed

Talley TSinicrope, Venuti N, Whelan R. Natural history matters: Plastics in estuarine fish and sediments at the mouth of an urban watershed Hewitt J. PLOS ONE [Internet]. 2020 ;15(3):e0229777. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0229777
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The extent to which small plastics and potentially associated compounds are entering coastal food webs, especially in estuarine systems, is only beginning to be realized. This study examined an estuarine reach at the mouth of urbanized Chollas Creek in San Diego, California to determine: 1) the extent and magnitude of microplastics pollution in estuarine sediments and fish, 2) the extent and magnitude of SVOC contamination in estuarine fish, and 3) whether fish preferentially ingested certain types of microplastics, when compared with the microplastic composition of creekbed sediments. Surface sediments (0–5 cm depth) contained about 10,000 small plastic pieces per m2, consisting mostly (90%) of fibers, and hard and soft pieces. Nearly 25% of fish contained small plastics, but prevalence varied with size and between species. Of the 25 types of small plastics found in sediment, fish preferred about 10 types (distinct colors and forms). Several SVOCs, both water soluble and sediment-associated compounds, were found in the two species of fish tested. This study revealed that a species’ natural history may influence contamination levels, and warrants further study to better understand the pathways of plastics and associated contaminants into and throughout coastal food webs, and the potential health risks for small and/or low-trophic level organisms.

Description and classification of echolocation clicks of Indian Ocean humpback (Sousa plumbea) and Indo-Pacific bottlenose (Tursiops aduncus) dolphins from Menai Bay, Zanzibar, East Africa

Yang L, Sharpe M, Temple AJ, Jiddawi N, Xu X, Berggren P. Description and classification of echolocation clicks of Indian Ocean humpback (Sousa plumbea) and Indo-Pacific bottlenose (Tursiops aduncus) dolphins from Menai Bay, Zanzibar, East Africa Halliday WDavid. PLOS ONE [Internet]. 2020 ;15(3):e0230319. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0230319
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Passive acoustic monitoring (PAM) is a powerful method to study the occurrence, movement and behavior of echolocating odontocetes (toothed whales) in the wild. However, in areas occupied by more than one species, echolocation clicks need to be classified into species. The present study investigated whether the echolocation clicks produced by small, at-risk, resident sympatric populations of Indian Ocean humpback dolphin (Sousa plumbea) and Indo-Pacific bottlenose dolphin (Tursiops aduncus) in Menai Bay, Zanzibar, East Africa, could be classified to allow species specific monitoring. Underwater sounds of Splumbea and Taduncus groups were recorded using a SoundTrap 202HF in January and June-August 2015. Eight acoustic parameters, i.e. -10 dB duration, peak, centroid, lower -3 and lower -10 dB frequencies, and -3 dB, -10 dB and root-mean-squared bandwidth, were used to describe and compare the two species’ echolocation clicks. Statistical analyses showed that Splumbea clicks had significantly higher peak, centroid, lower -3 and lower -10 dB frequencies compared to Taduncus, whereas duration and bandwidth parameters were similar for the two species. Random Forest (RF) classifiers were applied to determine parameters that could be used to classify the two species from echolocation clicks and achieved 28.6% and 90.2% correct species classification rates for Splumbea and Taduncus, respectively. Both species were classified at a higher rate than expected at random, however the identified classifiers would only be useful for Taduncus monitoring. The frequency and bandwidth parameters provided most power for species classification. Further study is necessary to identify useful classifiers for Splumbea. This study represents a first step in acoustic description and classification of Splumbea and Taduncus in the western Indian Ocean region, with potential application for future acoustic monitoring of species-specific temporal and spatial occurrence in these sympatric species.

Biological effects 26 years after simulated deep-sea mining

Simon-Lledó E, Bett BJ, Huvenne VAI, Köser K, Schoening T, Greinert J, Jones DOB. Biological effects 26 years after simulated deep-sea mining. Scientific Reports [Internet]. 2019 ;9(1). Available from: https://www.nature.com/articles/%20s41598-019-44492-w
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The potential for imminent abyssal polymetallic nodule exploitation has raised considerable scientific attention. The interface between the targeted nodule resource and sediment in this unusual mosaic habitat promotes the development of some of the most biologically diverse communities in the abyss. However, the ecology of these remote ecosystems is still poorly understood, so it is unclear to what extent and timescale these ecosystems will be affected by, and could recover from, mining disturbance. Using data inferred from seafloor photo-mosaics, we show that the effects of simulated mining impacts, induced during the “DISturbance and reCOLonization experiment” (DISCOL) conducted in 1989, were still evident in the megabenthos of the Peru Basin after 26 years. Suspension-feeder presence remained significantly reduced in disturbed areas, while deposit-feeders showed no diminished presence in disturbed areas, for the first time since the experiment began. Nevertheless, we found significantly lower heterogeneity diversity in disturbed areas and markedly distinct faunal compositions along different disturbance levels. If the results of this experiment at DISCOL can be extrapolated to the Clarion-Clipperton Zone, the impacts of polymetallic nodule mining there may be greater than expected, and could potentially lead to an irreversible loss of some ecosystem functions, especially in directly disturbed areas.

Juvenile harbor porpoises in the UK are exposed to a more neurotoxic mixture of polychlorinated biphenyls than adults

Williams RS, Curnick DJ, Barber JL, Brownlow A, Davison NJ, Deaville R, Perkins M, Jobling S, Jepson PD. Juvenile harbor porpoises in the UK are exposed to a more neurotoxic mixture of polychlorinated biphenyls than adults. Science of The Total Environment [Internet]. 2020 ;708:134835. Available from: https://www.sciencedirect.com/science/article/pii/S0048969719348272
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Polychlorinated biphenyls (PCBs) are a group of 209 persistent and bio-accumulative toxic pollutants present as complex mixtures in human and animal tissues. Harbor porpoises accumulate some of the highest levels of PCBs because they are long-lived mammals that feed at a high trophic level. Studies typically use the sum of a suite of individual chlorobiphenyl congeners (CBs) to investigate PCBs in wildlife. However, toxic effects and thresholds of CB congeners differ, therefore population health risks of exposure may be under or over-estimated dependent on the congener profiles present. In this study, we found congener profiles varied with age, sex and location, particularly between adult females and juveniles. We found that adult females had the highest proportions of octa-chlorinated congeners whilst juveniles had the highest proportions of tri- and tetra-chlorinated congeners. This is likely to be a consequence of pollutant offloading between mothers and calves during lactation. Analysis of the individual congener toxicities found that juveniles were exposed to a more neurotoxic CB mixture at a time when they were most vulnerable to its effects. These findings are an important contribution towards our understanding of variation in congener profiles and the potential effects and threats of PCB exposure in cetaceans.

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