scholarly journals Maritime Vessel Classification to Monitor Fisheries with SAR: Demonstration in the North Sea

2019 ◽  
Vol 11 (3) ◽  
pp. 353 ◽  
Author(s):  
Boris Snapir ◽  
Toby Waine ◽  
Lauren Biermann
Keyword(s):  
North Sea ◽  
Automatic Identification ◽  
Identification System ◽  
Fishing Vessel ◽  
Fishing Activity ◽  
The North ◽  
Fishing Vessels ◽  
Monitoring Strategies ◽  
The North Sea ◽  
Sar Imagery

Integration of methods based on satellite remote sensing into current maritime monitoring strategies could help tackle the problem of global overfishing. Operational software is now available to perform vessel detection on satellite imagery, but research on vessel classification has mainly focused on bulk carriers, container ships, and oil tankers, using high-resolution commercial Synthetic Aperture Radar (SAR) imagery. Here, we present a method based on Random Forest (RF) to distinguish fishing and non-fishing vessels, and apply it to an area in the North Sea. The RF classifier takes as input the vessel’s length, longitude, and latitude, its distance to the nearest shore, and the time of the measurement (am or pm). The classifier is trained and tested on data from the Automatic Identification System (AIS). The overall classification accuracy is 91%, but the precision for the fishing class is only 58% because of specific regions in the study area where activities of fishing and non-fishing vessels overlap. We then apply the classifier to a collection of vessel detections obtained by applying the Search for Unidentified Maritime Objects (SUMO) vessel detector to the 2017 Sentinel-1 SAR images of the North Sea. The trend in our monthly fishing-vessel count agrees with data from Global Fishing Watch on fishing-vessel presence. These initial results suggest that our approach could help monitor intensification or reduction of fishing activity, which is critical in the context of the global overfishing problem.

scholarly journals Hindcasting Soundscapes before and during the COVID-19 Pandemic in Selected Areas of the North Sea and the Adriatic Sea

2021 ◽  
Vol 9 (7) ◽  
pp. 702
Author(s):  
Hüseyin Özkan Sertlek
Keyword(s):  
North Sea ◽  
Adriatic Sea ◽  
Propagation Model ◽  
The North ◽  
Fishing Vessels ◽  
Water Test ◽  
The North Sea ◽  
Monthly Changes ◽  
Source Level ◽  
Sound Maps

The national measures in several European countries during the COVID-19 pandemic also affected offshore human activities, including shipping. In this work, the temporal and spatial variations of shipping sound are calculated for the years before and during the pandemic in selected shallow water test areas from the Southern North Sea and the Adriatic Sea. First, the monthly sound pressure level maps of ships and wind between 2017 and 2020 are calculated for frequencies between 100 Hz to 10 kHz. Next, the monthly changes in these maps are compared. The asymptotic approximation of the hybrid flux-mode propagation model reduces the computational requirements for sound mapping simulations and facilitates the production of a large number of sound maps for different months, depths, frequencies, and ship categories. After the strictest COVID-19 measures were applied in April 2020, the largest decline was observed for the fishing, passenger and recreational ships. Although the changes in the number of fishing vessels are large, their contribution to the soundscape is minor due to their low source level. In both test areas, the spatial exceedance levels and acoustic energies were decreased in 2020 compared to the average of the previous three years.

An "experiment" on effort allocation of fishing vessels: the role of interference competition and area specialization

2007 ◽  
Vol 64 (2) ◽  
pp. 304-313 ◽  
Author(s):  
Jan-Jaap Poos ◽  
Adriaan D Rijnsdorp
Keyword(s):  
North Sea ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Seasonal Pattern ◽  
Interference Competition ◽  
Catch Rate ◽  
The North ◽  
Closed Area ◽  
Fishing Vessels ◽  
The North Sea

A temporarily closed area established to protect spawning Atlantic cod (Gadus morhua) in the North Sea allowed us to study the response of the Dutch beam trawl fleet exploiting common sole (Solea solea) and plaice (Pleuronectes platessa). A number of vessels left the North Sea 1 month earlier than the normal seasonal pattern. The vessels that continued fishing in the North Sea were concentrated in the remaining open areas. In the first week after the closure, the catch rate decreased by 14%, coinciding with an increase in crowding of 28%. Area specialisation affected the response of individual vessels because vessels without prior experience in the open areas showed a larger decline in catch rate compared with vessels that previously fished in these open areas and were more likely to stop fishing during the closed period. The decrease in catch rate in response to the increase in competitor density allowed us to estimate the strength of the interference competition.

scholarly journals A comparison of VMS and AIS data: the effect of data coverage and vessel position recording frequency on estimates of fishing footprints

2017 ◽  
Vol 75 (3) ◽  
pp. 988-998 ◽  
Author(s):  
Jennifer L Shepperson ◽  
Niels T Hintzen ◽  
Claire L Szostek ◽  
Ewen Bell ◽  
Lee G Murray ◽  
...  
Keyword(s):  
Missing Data ◽  
Monitoring System ◽  
Spline Interpolation ◽  
Automatic Identification ◽  
Identification System ◽  
Fishing Activity ◽  
Fishing Vessels ◽  
Position Data ◽  
Hermite Spline ◽  
Data Coverage

Abstract Understanding the distribution of fishing activity is fundamental to quantifying its impact on the seabed. Vessel monitoring system (VMS) data provides a means to understand the footprint (extent and intensity) of fishing activity. Automatic Identification System (AIS) data could offer a higher resolution alternative to VMS data, but differences in coverage and interpretation need to be better understood. VMS and AIS data were compared for individual scallop fishing vessels. There were substantial gaps in the AIS data coverage; AIS data only captured 26% of the time spent fishing compared to VMS data. The amount of missing data varied substantially between vessels (45–99% of each individuals' AIS data were missing). A cubic Hermite spline interpolation of VMS data provided the greatest similarity between VMS and AIS data. But the scale at which the data were analysed (size of the grid cells) had the greatest influence on estimates of fishing footprints. The present gaps in coverage of AIS may make it inappropriate for absolute estimates of fishing activity. VMS already provides a means of collecting more complete fishing position data, shielded from public view. Hence, there is an incentive to increase the VMS poll frequency to calculate more accurate fishing footprints.

scholarly journals Exit and entry of fishing vessels: an evaluation of factors affecting investment decisions in the North Sea English beam trawl fleet

2011 ◽  
Vol 68 (5) ◽  
pp. 961-971 ◽  
Author(s):  
Alex N. Tidd ◽  
Trevor Hutton ◽  
Laurence T. Kell ◽  
Gurpreet Padda
Keyword(s):  
North Sea ◽  
Choice Model ◽  
Investment Decisions ◽  
Strategic Decision ◽  
Beam Trawl ◽  
Factors Affecting ◽  
The North ◽  
Fishing Vessels ◽  
The North Sea ◽  
The Impact

Abstract Tidd, A. N., Hutton, T., Kell, L. T., and Padda, G. 2011. Exit and entry of fishing vessels: an evaluation of factors affecting investment decisions in the North Sea English beam trawl fleet. – ICES Journal of Marine Science, 68: 961–971. A profitable fishery attracts additional effort (vessels enter), eventually leading to overcapacity and less profit. Similarly, fishing vessels exit depending on their economic viability (or reduced expectations of future benefits) or encouraged by schemes such as decommissioning grants and/or when there is consolidation of fishing effort within a tradable rights-based quota system (e.g. individual transferable quotas). The strategic decision-making behaviour of fishers in entering or exiting the English North Sea beam trawl fishery is analysed using a discrete choice model by integrating data on vessel characteristics with available cost data, decommissioning grant information, and other factors that potentially influence anticipated benefits or future risks. It is then possible to predict whether operators choose to enter, stay, exit, or decommission. Important factors affecting investment include vessel age and size, future revenues, operating costs (e.g. fuel), stock status of the main target species, and the impact of management measures (e.g. total allowable catches) and total fleet size (a proxy for congestion). Based on the results, the predicted marginal effects of each factor are presented and the impact of each is discussed in the context of policies developed to align fleet capacity with fishing opportunities.

Hidden Markov Model(HMM)-Based Fishing Activity Prediction Using V-Pass Data

2021 ◽  
Vol 8 (4) ◽  
pp. 221-227
Author(s):  
Ju-Han Park ◽  
Ho-Kun Jeon ◽  
Chan-Su Yang
Keyword(s):  
Markov Model ◽  
Hidden Markov Model ◽  
Time Series Data ◽  
Hidden Markov ◽  
Series Data ◽  
Automatic Identification ◽  
Identification System ◽  
Research Station ◽  
Fishing Vessel ◽  
Fishing Activity

Illegal fishing has been a serious threat to the conservation of seafood resources and provoked the importance of marine surveillance. There are several types of fishing vessel monitoring systems operated by Republic of Korea, for example, Vessel Monitoring System(VMS), Automatic Identification System (AIS), V-Pass and VHF-DSC. However, those methods are not adaptable directly to fishing activity monitoring. The limitation requires more human resources to determine fishing status. Thus, this study proposes a method of estimating fishing activity from V-Pass, fishing vessel position reporting system, using Hidden Markov Model (HMM). HMM is a model to determine status through probability distribution for a sequence of time-series data. First of all, fishing activity status was labeled on V-Pass data. The distribution of speed on fishing activity was computed from the labeled data and HMM was constructed from the data obtained at Socheongcho Ocean Research Station (SORS). The model was first applied to the data of SORS for a test, and then Busan for validation. The model showed 99.4% and 89.6% as test and validation accuracy, respectively. It is concluded that the HMM can be applicable to predict a fishing activity from vessel tracks.

scholarly journals Do Norway pout (Trisopterus esmarkii) die from spawning stress? Mortality of Norway pout in relation to growth, sexual maturity, and density in the North Sea, Skagerrak, and Kattegat

2012 ◽  
Vol 69 (2) ◽  
pp. 197-207 ◽  
Author(s):  
J. Rasmus Nielsen ◽  
Gwladys Lambert ◽  
Francois Bastardie ◽  
Henrik Sparholt ◽  
Morten Vinther
Keyword(s):  
North Sea ◽  
Sexual Maturity ◽  
Life History Traits ◽  
Trawl Survey ◽  
Older Individuals ◽  
Fishing Activity ◽  
The North ◽  
Spawning Areas ◽  
The North Sea ◽  
New Evidence

Abstract Nielsen, J. R., Lambert, G., Bastardie, F., Sparholt, H., and Vinther, M. 2012. Do Norway pout (Trisopterus esmarkii) die from spawning stress? Mortality of Norway pout in relation to growth, sexual maturity, and density in the North Sea, Skagerrak, and Kattegat. – ICES Journal of Marine Science, 69: 197–207. The mortality patterns of Norway pout (NP) are not well understood. It has been suggested that NP undergo heavy spawning mortality, and this paper summarizes and provides new evidence in support of this hypothesis. The very low–absent fishing activity in recent years provides a unique opportunity to analyse the natural life-history traits of cohorts in the NP stock in the North Sea. Based on the ICES trawl survey abundance indices, cohort mortality is found to significantly increase with age. We argue that this cannot be explained by selectiveness in the fishery, potential size-specific migrations out of the area, higher predation pressure on older individuals, or differences in survey catchability by NP age from before to after spawning and that it is higher in the main spawning areas than outside. We found that natural mortality (M) is significantly correlated with sexual maturity, sex, growth, and intraspecific stock density. All of this is consistent with a greater mortality occurring mainly from the first to the second quarter of the year, i.e. spawning mortality, which is discussed as being a major direct and indirect cause of stock mortality.

Commercial fisheries interactions with oil and gas pipelines in the North Sea: considerations for decommissioning

2017 ◽  
Vol 75 (1) ◽  
pp. 279-286 ◽  
Author(s):  
Sally Rouse ◽  
Andronikos Kafas ◽  
Rui Catarino ◽  
Hayes Peter
Keyword(s):  
North Sea ◽  
Spatial Data ◽  
Oil And Gas ◽  
Commercial Fisheries ◽  
Physical Interaction ◽  
Fishing Gear ◽  
Fishing Activity ◽  
The North ◽  
The North Sea

Abstract Commercial fisheries and oil and gas extraction are both spatially extensive industries in the North Sea (NS), and inevitably there is physical interaction where the two activities coincide. Regular contact between fishing gear and pipelines may risk pipeline integrity and could lead to gear snagging. It is also known, anecdotally, that some vessels target pipelines, potentially benefiting from local artificial reef effects. The impacts of pipeline decommissioning options (removal vs. in situ) on commercial fisheries must be evaluated as part of the consenting process, but the degree of interaction between the two is presently unknown in the NS. Vessel Monitoring System (VMS) data for the Scottish demersal fleet were analysed with spatial data on pipelines. Approximately one-third (36.1%) of trips fished within 200 m of a pipeline over a 5-year period, suggesting that pipelines are subjected to regular interaction with fishing gear. The fishing effort (in hours) associated with pipelines was 2.52% of the total effort, compared to 1.33% in an equivalent area of seabed 1 km away, implying modest aggregation of fishing around pipelines. Only a small percentage (0.93%) of fishing trips actively targeted pipelines as fishing grounds. The highest level of fishing around pipelines occurred in the northeast NS. Pipeline sections with >100 h of fishing were typically larger diameter pipelines. The results suggest that pipeline decommissioning may have both negative (displacement of aggregated effort) and positive (reduced snagging potential) outcomes for commercial fisheries. It is recommended that where there is little or no fishing activity associated with pipelines, receptors other than fishing should be prioritized when selecting decommissioning strategies. Additionally, the intensity of fishing around pipelines should be used to inform the frequency of post-decommissioning integrity monitoring for any pipelines left in situ.

GEOPHYSICAL OPERATIONS IN THE NORTH SEA

Geophysics ◽  
1965 ◽  
Vol 30 (4) ◽  
pp. 495-510 ◽  
Author(s):  
Ernest E. Cook
Keyword(s):  
North Sea ◽  
Eastern Coast ◽  
Identification System ◽  
Quality Of Data ◽  
Multiple Reflections ◽  
Low Velocity ◽  
Lateral Velocity ◽  
Gas Field ◽  
The North ◽  
The North Sea

During the last three years the discovery of the world’s second largest natural gas field at Groningen in the Netherlands has touched off in the North Sea one of the greatest competitive offshore geophysical operations in history. Before 1962, only minor amounts of geophysical work had been done there. Severe weather conditions were expected, but seismic operations have not been as much affected by weather as was originally anticipated. However, strong currents, making cable location uncertain, hampered reflection stacking and refraction operations. Location by radio was also a serious problem due to lack of sufficient available frequencies for a lane identification system. Seismic work was carried out safely in areas mapped as mine fields. Few problems with the fishing industry have so far been encountered. As a preliminary, the geophysics of the Groningen area are discussed. A gravity compilation of the North Sea shows that there are three major basins—the Northwest German Zechstein Basin, the British North Sea Basin, and the Norwegian North Sea Basin. The British Basin which contains Tertiary, Cretaceous, Jurassic, Triassic, Permian, Carboniferous, and older sediments shows considerable salt movement with salt domes, walls, and pillows being in evidence to within 30 miles of the eastern coast of England. Some examples of seismic record sections show the quality of data and the kind of structures encountered. Water reverberations were satisfactorily reduced by means of anti‐ringing procedures. Multiple reflections were frequently observed and often interfered with or obscured simple reflections. Refraction studies indicate that two main refractors, the Upper Cretaceous Chalk and the Upper Magnesian Limestone of the Permian, are present over most of the British Basin. Mapping the key basal Permian reflector is made difficult by deterioration of the reflection under areas of salt growth. Stacking sometimes enhances this reflection. Also intrusions of Permian salt into the Mesozoic beds give rise to large and rapid changes in thickness of the overlying low‐velocity Tertiary and high‐velocity Cretaceous chalk sections. A correction system for these large lateral velocity changes is described.

scholarly journals A comprehensive inventory of ship traffic exhaust emissions in the European sea areas in 2011

2015 ◽  
Vol 15 (5) ◽  
pp. 7459-7491 ◽  
Author(s):  
J.-P. Jalkanen ◽  
L. Johansson ◽  
J. Kukkonen
Keyword(s):  
Assessment Model ◽  
Automatic Identification ◽  
Identification System ◽  
Traffic Emission ◽  
Ship Traffic ◽  
Eu Member States ◽  
The North ◽  
The North Sea ◽  
System Data ◽  
The Mediterranean

Abstract. Emissions originated from ship traffic in European sea areas were modelled using the Ship Traffic Emission Assessment Model (STEAM), which uses Automatic Identification System data to describe ship traffic activity. We have estimated the emissions from ship traffic in the whole of Europe in 2011. We report the emission totals, the seasonal variation, the geographical distribution of emissions, and their disaggregation between various ship types and flag states. The total ship emissions of CO2, NOx, SOx, CO and PM2.5 in Europe for year 2011 were estimated to be 131, 2.9, 1.2, 0.2 and 0.3 million tons, respectively. The emissions of CO2 from Baltic Sea were evaluated to be more than a half (58%) of the emissions of the North Sea shipping; the combined contribution of these two sea regions was almost as high (96%) as the total emissions from ships in the Mediterranean. As expected, the shipping emissions of SOx were significantly lower in the SOx Emission Control Areas, compared with the corresponding values in the Mediterranean. Shipping in the Mediterranean Sea is responsible for 39 and 49% of the European ship emitted CO2 and SOx emissions, respectively. In particular, this study reported significantly smaller emissions of NOx, SOx and CO for shipping in the Mediterranean than the EMEP inventory; however, the reported PM2.5 emissions were in a fairly good agreement with the corresponding values reported by EMEP. The vessels registered to all EU member states are responsible for 55% of the total CO2 emitted by ships in the study area. The vessels under the flags of convenience were responsible for 25% of the total CO2 emissions.

scholarly journals The impact of shipping emissions on air pollution in the greater North Sea region – Part 1: Current emissions and concentrations

2016 ◽  
Vol 16 (2) ◽  
pp. 739-758 ◽  
Author(s):  
A. Aulinger ◽  
V. Matthias ◽  
M. Zeretzke ◽  
J. Bieser ◽  
M. Quante ◽  
...  
Keyword(s):  
Particulate Matter ◽  
North Sea ◽  
Transport Model ◽  
Identification System ◽  
Scientific Publications ◽  
The North ◽  
Relative Contribution ◽  
The North Sea ◽  
The Impact ◽  
Concentration Levels

Abstract. The North Sea is one of the areas with the highest ship traffic densities worldwide. At any time, about 3000 ships are sailing its waterways. Previous scientific publications have shown that ships contribute significantly to atmospheric concentrations of NOx, particulate matter and ozone. Especially in the case of particulate matter and ozone, this influence can even be seen in regions far away from the main shipping routes. In order to quantify the effects of North Sea shipping on air quality in its bordering states, it is essential to determine the emissions from shipping as accurately as possible. Within Interreg IVb project Clean North Sea Shipping (CNSS), a bottom-up approach was developed and used to thoroughly compile such an emission inventory for 2011 that served as the base year for the current emission situation. The innovative aspect of this approach was to use load-dependent functions to calculate emissions from the ships' current activities instead of averaged emission factors for the entire range of the engine loads. These functions were applied to ship activities that were derived from hourly records of Automatic Identification System signals together with a database containing the engine characteristics of the vessels that traveled the North Sea in 2011. The emission model yielded ship emissions among others of NOx and SO2 at high temporal and spatial resolution that were subsequently used in a chemistry transport model in order to simulate the impact of the emissions on pollutant concentration levels. The total emissions of nitrogen reached 540 Gg and those of sulfur oxides 123 Gg within the North Sea – including the adjacent western part of the Baltic Sea until 5° W. This was about twice as much of those of a medium-sized industrialized European state like the Netherlands. The relative contribution of ships to, for example, NO2 concentration levels ashore close to the sea can reach up to 25 % in summer and 15 % in winter. Some hundred kilometers away from the sea, the contribution was about 6 % in summer and 4 % in winter. The relative contribution of the secondary pollutant NO3− was found to reach 20 % in summer and 6 % in winter even far from the shore.

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