AbstractDrifting Fish Aggregating Devices (dFADs) are a major fishing mode for tropical tuna purse seine fisheries worldwide. However, the extent of dFAD use remains poorly understood. We present novel approaches for estimating annual dFAD deployments and number of dFADs monitored by individual vessels, using empirical data and robust estimation procedures. We leveraged observer and logbook data, combined

Efforts to manage living marine resources (LMRs) under climate change need projections of future ocean conditions, yet most global climate models (GCMs) poorly represent critical coastal habitats. GCM utility for LMR applications will increase with higher spatial resolution but obstacles including computational and data storage costs, obstinate regional biases, and formulations prioritizing global

AbstractDeclines in wild Atlantic salmon (Salmo salar) abundance throughout the north Atlantic are primarily attributed to decreases in survival at sea. However, comparing trends in marine survival among populations is challenging as data on both migrating smolts and returning adults are sparse and models are difficult to parameterize due to their varied life histories. We fit a hierarchical Bayesian

Hearing, as defined by numerous investigators of vertebrate hearing, involves not only detection of a sound, but the ability to respond to the sound behaviourally. Thus, in order to understand what a fish (or any animal) hears, it is important to use behavioural methods that allow an animal to “tell the investigator” which sounds are detected and which are not. However, since the 1980’s, most studies

AbstractThe silky shark Carcharhinus falciformis regularly associates with floating objects in the open ocean, resulting in relatively high levels of bycatch in industrial tuna purse seine fisheries using drifting fish aggregating devices (FADs). This bycatch has contributed to concerns regarding the sustainability of this fishery and its impact on silky shark populations. To investigate fishery interactions

Fisheries are currently under pressure to provide increasing amounts of seafood, causing a growing number of marine stocks to be harvested at unsustainable levels. To ensure marine resources remain sustainable, careful management of biological stocks and their genetic integrity is required. The Eastern Rock Lobster, Sagmariasus verreauxi, is commercially harvested along the New South Wales (NSW) coast

The Siberian Arctic is one of the regions, where the ongoing climate change is the most evident. There is limited knowledge available on the distribution of macrobenthic communities in the Siberian Arctic, their stability and functional structure. We used data from two latitudinal transects from the East Siberian Sea shelf to describe the distribution of macrobenthic communities as well as to identify

In the Mediterranean Sea, shallow rocky reefs and the associated three-dimensional (3D) structure support rich and abundant communities; they are therefore of functional importance, in particular for the renewal of fish stocks. However, these habitats and their functions are likely to be altered by anthropogenic pressures inducing habitat transformations. It is therefore necessary to assess their 3D

The mesozooplankton community was analyzed over a six-year period (2013-2018) during the post-eruptive stage of the submarine volcano Tagoro, located south of the island of El Hierro (Canary Archipelago, Spain). Nine cruises from March 2013 to March 2018 were carried out in two different seasons, spring (March-April) and autumn (October). A high-resolution study was carried out across the main cones

N2O is progressively known as a powerful greenhouse gas and can contribute to the exhaustion of the ozone sphere. Hypoxia and ocean acidification are becoming more intense as a result of climate change. Hypoxia stimulates N2O emissions, while acidification tends to have different effects on N2O emissions in different oceans. Hypoxia and ocean acidification may play a critical role in the evolution

Toothed whales (suborder Odontoceti) are highly social, large brained mammals with diverse social systems. In recent decades, a large body of work has begun investigating these dynamic, complex societies using a common set of analytical tools: social network analysis. The application of social network theory to toothed whales enables insight into the factors that underlie variation in social structure

Networks of no-take marine protected areas (MPAs), where all extractive activities are prohibited, are the most effective tool to directly protect marine ecosystems from destructive and unsustainable human activities. No-take MPAs and MPA networks have been globally implemented in coastal seas, and their success has been significantly enhanced where science-based biophysical guidelines have informed

Ship strikes have been documented around the world and frequently figure as a top human cause of large whale mortality. The shipping lanes in the Santa Barbara Channel, California and nearby waters have some of the highest predicted whale mortality from vessel strikes in the U.S. waters of the eastern Pacific. Beginning in 2007, NOAA requested voluntary vessel speed reductions (VSR) for vessels greater

Sexual dimorphism is generally obvious in brachyurans and sexual dimorphism between species is of higher degree to allow separation of trophic niches compared to the lower intraspecific variations between sexes. Mud crab genus Scylla are distributed along Indo-West Pacific region, and species within this genus often exhibit overlapping niches and similar external morphologies. This study compared the

Marine sponges have been successful in their expansion across diverse ecological niches around the globe. Pioneering work attributed this success to both a well-developed aquiferous system that allowed for efficient filter feeding on suspended organic matter and the presence of microbial symbionts that can supplement host heterotrophic feeding with photosynthate or dissolved organic carbon. We now

Due to the remoteness and difficulty of sampling, the 210Po and 210Pb data are scarce in the Southern Ocean. Here, the activity concentrations of 210Po and 210Pb around Prydz Bay in austral summer were determined to understand their spatial variation and evaluate the dynamics of particle organic matter (POM). The activity concentrations of dissolved 210Po (D210Po) and 210Pb (D210Pb) range from 0.47

The blue swimming crab, Portunus segnis (Forskål, 1775), formerly known as P. pelagicus (Linnaeus, 1758) has become a major fishery resource in the Gulf. Yet, there are no regional studies on the stock population dynamics and life history processes of this species. Considering the extreme oceanographic features of the Gulf (high salinity and high temperature variations), which is hypothesized to cause

The grooved carpet shell clam Ruditapes decussatus is an economically important bivalve species in Morocco. Assessment of genetic diversity and genetic structure is essential for sustainable exploitation and effective management of this bivalve. Ten microsatellite loci were examined at seven localities along the Moroccan coast to determine the genetic diversity and population structure of the natural

Arctic rivers are sensitive to climate and environmental change, but the biogeochemical response remains poorly understood. Monthly size-fractionated dissolved organic matter (DOM) samples from the lower Yukon River were characterized using UV–visible, fluorescence, and Fourier transform-infrared (FT-IR) spectroscopy techniques. The EEM-PARAFAC analysis revealed three major fluorescent DOM components

Temporal Secchi depth trends are used in lake assessment to evaluate lake condition and possible shifts in trophic state. For accurate lake assessments, it is important to differentiate regional trends from lake-specific trends, but this can be confounded by interacting factors. We present a divergent trend analysis which uses temporal patterns of Secchi depth water clarity from 1999 to 2018 for five

The speckled shrimp Metapenaeus monoceros is a commercially important penaeid shrimp in the Indo-West Pacific region including Bangladesh. Phylogenetics of penaeid shrimps is still a debatable issue, and molecular variation within the species is large. This study focused on the phylogeography of M. monoceros, including an assessment of the phylogenetic relationships among seven other Metapenaeus species

The rate of turbulent kinetic energy dissipation and diapycnal diffusivity are estimated along 10 hydrographic sections across the Indian Ocean from a depth of 500 m to the seabed. Six sections were occupied twice. On the meridional section, which is nominally along 95°E, spatial patterns were observed to persist throughout the three occupations. Since the variability in diffusivity exceeds the variability

The East China Sea (ECS) is a complex marginal sea with potential sources and sinks of trace metals. In this study, we investigated the distributions of dissolved Cd, Cu, Zn, and Cu-binding organic ligands in the ECS. Concentrations of Cd and macronutrients were below detection limit in the surface Kuroshio waters. Surface Zn concentrations increased along the Kuroshio Current, which may be attributed

Understanding a tsunami source and its impact is vital to assess a tsunami hazard. Thanks to the efforts of the tsunami survey teams, high-quality tsunami run-up data exist for contemporary events. Still, it has not been widely used to infer a tsunami source and its impact mainly due to the computational burden of the tsunami forward model. In this study, we propose a TRRF-INV (Tsunami Run-up Response

The eddy-resolving (1/12°) global ocean reanalysis GLORYS12 is assessed against 14 years (2002–2015) of independent hydrographic observations collected at 59.5°N in the North Atlantic. Two multi-observations statistical analyses, ISAS-15 and ARMOR-3D, and an eddy-permitting (1/4°) reanalysis, GLORYS025, also contribute to this comparison. The mean thermohaline structure along the 59.5°N section revealed

Primary production (PP) is fundamental to ocean biogeochemistry, but challengingly variable. Satellite models are unique tools for investigating PP, but are difficult to compare and validate because of the scale separation between in situ and remote measurements, which also are rarely coincident. Here, I argue that satellite estimates should be log-skew-normally distributed, because of this scale separation

The implicit equal-weights variational particle smoother (IEWVPS) is a combination of the particle filter (PF) and weak-constraint 4-dimensional variational (4D-Var) method, that inherits the merits of both. The IEWVPS avoids the filter degeneracy of particle filters through an implicit equal-weights scheme and reduces the root mean square deviations (RMSDs) by introducing the 4D-Var method. This method

Maritime Autonomous Surface Ships (MASS) receive enormous attention in recent years. Compared to an individual MASS, greater efficiency and operational capability can be realized by cooperative MASS. An increasing number of researches propose different methods for cooperative multiple ships, such as cooperative collision avoidance, formation control, etc. However, in existing research, hydrodynamic

Earthquakes are considered as the major trigger of submarine landslides. This study analyzes the large-scale seismic seafloor stability in the South China Sea (SCS), taking into consideration the earthquake probability and spatial distribution of seismicity and seafloor soil properties. For this cause, the geographical, seismic, and seafloor soil characteristics are first determined. The digital elevation

The influence of forward speed on stochastic free-surface crossing, in a Gaussian wave field, is investigated. The case of a material point moving with a constant forward speed is considered; the wave field is assumed stationary in time, and homogeneous in space. The focus is on up-crossing events, which are defined as the material point crossing the free surface, into the water domain. The effect

Three-dimensional direct numerical simulation is carried out to investigate the effects of the yaw angle and spanning length on the vortex structures and hydrodynamics of flow crossing a near-wall cylindrical structure. Two yaw angles (α = 0°, 45°), and three spanning length ratios (L* = 25, 50, 100) are investigated at Re = 500. Under the normal cylinder condition (α = 0°), a parallel vortex shedding

Coastal fishing communities rely on goods and services provided by marine ecosystems to satisfy their social and economic needs; however, continued exploitation of these ecosystems has degraded and threatened them making it imperative to implement conservation and management strategies. Management strategy impacts on local communities lifestyle is a function of dependence on the resource targeted by

1 INTRODUCTION The global threat to biodiversity is one of the central challenges of our time (Sala et al., 2000). In addition to climate change (Comte et al., 2013), habitat loss and structural changes, alien species are among the main causes that alter species communities in freshwaters (Jeschke et al., 2014). However, this threat with its long-term consequences can only be properly assessed if we

The Sickle Darter Percina williamsi (Page and Near, 2007) is a species of fish endemic to the upper Tennessee River basin in eastern Tennessee, southwestern Virginia, and western North Carolina. Because of its narrow range and presumed decline in occupied sites over the last half century, it is being proposed for federal listing under the Endangered Species Act. We analyzed the current distribution

Abstract This study investigates the effect of porewater salinity on the compression behaviors of soft marine clay with multi-mineral compositions. A series of one-dimension compression tests were conducted with clays at different porewater salinity. The results indicate that the compression index decreases with increasing porewater salinity and can be described by a second-order polynomial equation

Abstract Acoustic models are effective methods for inverting the geo-acoustic properties of seafloor sediments. To investigate the main sediment types in the northern South China Sea, 221 sediment core samples containing three sediment types (clayey silt, silty clay, muddy sand) were collected, and the geo-acoustic properties of the sediments were measured and analyzed. The results show that the same

Abstract To automate extraction of bathymetric soundings from lidar point clouds, two machine learning (ML1) techniques were combined with a more conventional density-based algorithm. The study area was four data “tiles” near the Florida Keys. The density-based algorithm determined the most likely depth (MLD) for a grid of “estimation nodes” (ENs). Unsupervised k-means clustering determined which EN’s

Abstract Currently, integrated navigation systems with the inertial navigation system (INS)/geomagnetic navigation system (GNS) have been widely used in underwater navigation of autonomous underwater vehicle (AUV). Restricting AUV to navigate in the geomagnetic suitability areas (GSA) as far as possible can effectively improve the accuracy of integrated navigation systems. In order to improve the classification

Abstract The scale dependence of benthic terrain attributes is well-accepted, and multi-scale methods are increasingly applied for benthic habitat mapping. There are, however, multiple ways to calculate terrain attributes at multiple scales, and the suitability of these approaches depends on the purpose of the analysis and data characteristics. There are currently few guidelines establishing the appropriateness

Numerical models have been used extensively in the design process of the TetraSpar floating offshore wind turbine (FOWT) foundation to optimize and investigate the influence from a number of structural and environmental conditions. In traditional offshore design, either the Morison approach or a linear boundary element method (BEM) is applied to investigate the hydrodynamic loads on a structure. The

Extensive electrification of ship power systems appears to be a promising measure to meet stringent environmental requirements. The concept is to enable ship power management to allocate loads in response to load variations in an optimal manner. From a broader design perspective, the reliability of machinery operation is also of importance, especially with regard to the failure cost from power outages

Passive acoustic monitoring (PAM) is a noninvasive technique to supervise wildlife. Acoustic surveillance is preferable in some situations such as in the case of marine mammals, when the animals spend most of their time underwater, making it hard to obtain their images. Machine learning is very useful for PAM, for example to identify species based on audio recordings. However, some care should be taken

Baited lander represents a low impact technique, an alternative to the traditional trawl sampling for collecting data on fish diversity and abundance, especially for threatened species such as Chondrichthyes living in sensitive habitats. In this study, distribution and abundance of cartilaginous fish were compared between two geographic areas, the southern Adriatic Sea and the north-western Ionian

Fish mucosal surface is a significant interface for pathogens to infect from an aqueous environment. In addition to mucosal innate and adaptive immune factors, epithelial cells are considered as a significant physical barrier against microbial invasion. Previously, we identified a mammalian CD46-like complement regulatory protein (Tecrem) in teleost and detected its expression on epithelial cells derived

Marine risers transporting unsteady multiphase flows may experience internal flow-induced vibrations depending on several flow-structure parameters. This study presents an experimental investigation of large-amplitude intermittent vibrations of an inclined bendable riser transporting an air-water flow that exhibits an unsteady slug flow pattern. The riser has an initial catenary profile with a length

Nearly every known exceedance probability distribution applied to rogue waves has shown disagreement with its peers, suggesting that the underlying phenomenon may be too complex to grasp within a single distribution. In recent studies, this view has been supported by the realisation that there is no distribution suitable for wide ranges of sea states, even though distributions can perform well in a

The ability to avoid shorelines, reefs and moving ships or obstacles is the premise of automatic navigation. For achieving the goal, conventional A star algorithm is improved to plan route globally. The safety distance is set between planning route and obstacles. Additionally, the planning route is further optimized to remove unnecessary waypoints, and only vital waypoints are retained for conforming

ABSTRACT Condition-based maintenance is a maintenance strategy that implements Industrial Internet of Things to monitor the assets’ condition. Despite its undeniable benefits, several challenges are encountered, such as the incompleteness of sensor data. Hence, while data imputation is an important practise, there is a lack of analysis and formalisation of data imputation in the maritime industry.

Phosphorus (P) is one of the key nutrient compounds for phytoplankton grow. In the conducted work, eutrophication indexes were used for the assessment of eutrophication level of water course (Służewiecki Stream) and the waters of nearby lakes (Bottom Berensewicz’s Pond, Wyścigi Pond, Wilanowskie Lake). Calculating eutrophication indexes were based on the most important indicators which is crucial for

Groundwater vulnerability assessment has become a crucial step in successfully protecting groundwater against pollution. An attempt of this study has been made to evaluate groundwater contamination risk using intrinsic vulnerability and land-uses in Vanathavillu, Kalpitiya and Katana area in Sri Lanka, using coupled DRASTIC with GIS as feasible methodology. The findings reveal that the groundwater

Banana, orange and potato peels (BP, OP and PP, respectively) were immobilised to produce biosorbent beads that were employed for the biosorption of heavy metals from a cocktail solution containing As(V), Cd(II), Cr(VI), Cu(II), Hg(II) and Ni(II) ions. Drinking water conditions were maintained with neutral initial pH and low concentration of the ions. Batch experiments were performed for evaluating

While tourists contribute to and suffer the consequences of beach litter, studies on beach clean-up exercises have mostly neglected them and overly focused on resident beach goers. Based on a sample of 685 international tourists in Ghana, this paper examines the perception of international tourists on beach litter and the determinants of their willingness to participate in beach clean-up as an experiential

This study analyzed the seasonal variation of sedimentary reservoirs in sandy beaches located at the insular margin of a tidal inlet (Itamaracá Island, Pernambuco, Brazil). We measured the sedimentary budget and identified the dominant coastal processes (accretion or erosion) from Dec/2017 to Dec/2018. In six field campaigns by a Remotely Piloted Aircraft System, digital terrain models and extracted

Human interventions and climate change can heavily influence the large-scale morphological development of tidal basins. This has implications on sediment management strategies, as well as ecological and recreational purposes. Examples of heavily impacted tidal basins are those in the Western Dutch Wadden Sea. The closure of a large sub-basin in 1932 triggered a shift in the sediment budgets of the

67 Ocean Drilling Program and Deep Sea Drilling Project sites were investigated to determine the relationship between temperature and time for silica diagenesis. The selected sites cover a variety of settings where the opal-A to opal-CT transition zone lies in Cenozoic sediments. The opal-A to opal-CT transition leads to abrupt changes in the sediment petrophysics which are used to identify the diagenetic

Overfishing is a key stressor in many coral reefs, affecting their function and ecosystem services. In the Gulf of California, 50 years of artisanal and recreational fishing have removed most of the largest and most vulnerable fish species, the Espiritu Santo Archipelago (ESA) is a marine protected area (MPA) where artisanal and recreational fishing are allowed in most of the natural reefs, while the

Considerable progress in our understanding of long-distance migration has been achieved thanks to the use of small geolocator devices (GLS). The tracking of resident or short-distance migrant animals remains however challenging because geolocation errors are substantial and difficult to estimate. This study aims to examine the sex-specific marine space uses of a resident tropical seabird, the masked

The mangroves of Puerto Rico occupy a gradient of urbanization that offers a chance to test hypotheses on urban faunal communities. These hypotheses state that urban avifaunal communities have greater representation by generalists and that certain mangrove specialists can utilize urban landscapes. Much of this is said to be driven by food resources, with frugivores and nectarivores benefiting from