scholarly journals Implications of using alternative methods of vessel monitoring system (VMS) data analysis to describe fishing activities and impacts

2012 ◽  
Vol 69 (4) ◽  
pp. 682-693 ◽  
Author(s):  
Gwladys I. Lambert ◽  
Simon Jennings ◽  
Jan Geert Hiddink ◽  
Niels T. Hintzen ◽  
Hilmar Hinz ◽  
...  
Keyword(s):  
Data Analysis ◽  
Monitoring System ◽  
Spatial Scales ◽  
Alternative Methods ◽  
Track Reconstruction ◽  
Fishing Activity ◽  
Fishing Impact ◽  
Fishing Vessels ◽  
Epifaunal Communities ◽  
Fishing Impacts

Abstract Lambert, G. I., Hiddink, J. G., Hintzen, N. T., Hinz, H., Kaiser, M. J., Murray, L. G., and Jennings, S. 2012. Implications of using alternative methods of vessel monitoring system (VMS) data analysis to describe fishing activities and impacts. – ICES Journal of Marine Science, 69: 682–693. Understanding the spatial distribution and intensity of fishing activity is a prerequisite for estimating fishing impacts on seabed biota and habitats. Vessel monitoring system data provide information on fishing activity at large spatial scales. However, successive position records can be too infrequent to describe the complex movements fishing vessels make. High-frequency position data were collected to evaluate how polling frequency and the method of analysis influenced the estimates of fishing impact on the seabed and associated epifaunal communities. Comparisons of known positions with predictions from track interpolation revealed that the performance of interpolation depended on fleet behaviour. Descriptions and indicators of fishing intensity were influenced significantly by the analytical methods (track reconstruction, density of position records) and grid-cell resolution used for the analysis. These factors can lead to an underestimation of fishing impact on epifaunal communities. It is necessary to correct for such errors to quantify the effects of fishing on various ecosystem components and hence to inform ecosystem-based management. Polling at intervals of 30 min would provide a desirable compromise between achieving precise estimates of fishing impacts on the seabed and minimizing the cost of data collection and handling.

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 Mapping inshore fishing activity using aerial, land, and vessel-based sighting information

2014 ◽  
Vol 72 (2) ◽  
pp. 467-479 ◽  
Author(s):  
Patricia Breen ◽  
Koen Vanstaen ◽  
Robert W. E. Clark
Keyword(s):  
Monitoring System ◽  
Spatial Planning ◽  
Satellite Monitoring ◽  
Marine Spatial Planning ◽  
Fishing Activity ◽  
Fishing Vessels ◽  
Spatial Differences ◽  
Fisheries Interactions ◽  
Enforcement Activity ◽  
Good Agreement

Abstract Information on the distribution and intensity of inshore fishing activity is needed to inform marine spatial planning and to assess fisheries interactions with the environment and other industries. Although fishing vessels under 15 m (overall length) account for 98.4% (2011 value) by the number of the European fleet, information on inshore fishing activity in Europe is very limited as there is no statutory satellite monitoring of smaller vessels (<15 m length before 2012, <12 m thereafter). Here, we develop, present, and apply a method which uses sightings-per-unit-effort (SPUE) estimates calculated from fisheries enforcement data to describe the distribution and intensity of inshore fishing activity off the coasts of England and Wales. For the larger inshore vessels, the SPUE estimates of activity were validated with vessel monitoring system (VMS) data and showed good agreement at the scale of analysis. Fishing activity estimates from SPUE are presented with an assessment of uncertainty, to account for spatial differences in enforcement activity. Our estimates of the distribution and intensity of inshore fishing activity and will complement estimates of offshore fishing activity based on VMS.

scholarly journals Factors affecting relative abundance of low-mobility fishing resources: spiny lobster in the Galapagos Marine Reserve

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7278 ◽  
Author(s):  
Juan Carlos Murillo-Posada ◽  
Silvia Salas ◽  
Iván Velázquez-Abunader
Keyword(s):  
Monitoring System ◽  
Relative Abundance ◽  
Spatial Scales ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Fishing Effort ◽  
Additive Models ◽  
Catch Per Unit Effort ◽  
Monthly Basis ◽  
Galapagos Marine Reserve

Management of low-mobility or benthic fisheries is a difficult task because variation in the spatial distribution and population dynamics of the resources make the monitoring and assessment of these fisheries challenging. We assumed that environmental, spatial, and temporal factors can contribute to the variability of the relative abundance of such species; we used Generalized Additive Models for Location Scale and Shape (GAMLSS) to test this hypothesis using as a case study the lobster fishery (targeting two species) in the Galapagos Marine Reserve, Ecuador. We gathered data on each of the two species of lobster on a monthly basis over seven years, including: (a) onboard observers’ records of catch data, fishing effort, and ground location by trip, and (b) data from interviews undertaken with fishers at their arrival to port, recording the same type of information as obtained from onboard observers. We use this information to analyze the effect of the measured variables and to standardize the Catch per Unit Effort (CPUE) in each case, using the GAMLSS. For both species, the temperature, region, fishing schedule, month, distance, and the monitoring system were significant variables of the selected models associated with the variability of the catch rate. ForPanulirus penicillatus, CPUE was higher at night than during the day, and forPanulirus gracilisit was higher during the day. Increased temperature resulted in a decrease of CPUE values. It was evident that temporal, spatial scales and monitoring system can influence the variability of this indicator. We contend that the identification of drivers of change of relative abundance in low-mobility species can help to support the development of monitoring and assessment programs for this type of fisheries.

scholarly journals PERBANDINGAN KAPAL MONOHULL, CATAMARAN, TRIMARAN BERDASARKAN TINJAUAN OPERASIONAL PENGGUNAAN BAHAN BAKAR

2021 ◽  
Vol 4 ◽  
pp. 30-36
Author(s):  
Jacobus Tupan ◽  
Richard Benny Luhulima
Keyword(s):  
Data Analysis ◽  
Energy Requirements ◽  
Energy Usage ◽  
Fishing Vessel ◽  
Fishing Vessels ◽  
Initial Stage ◽  
Transverse Stability ◽  
Fishing Fleets

In general, fishing fleets operating in Maluku waters and managed by local entrepreneurs consist of monohull and trimaran fishing vessels with outriggers. Monohull fishing vessels have limited deck space and poor transverse stability, while trimaran-type vessels have better deck space and transverse stability than monohull vessels, but because they are still in the form of outriggers, the space is limited. This study aims to examine the development of the trimaran fishing vessel in terms of energy requirements, safety, and comfort of the crew during fishing operations. The initial stage of this research begins with data analysis and the basic size of monohull fishing vessels operating in Maluku waters, from this data the shape of the trimaran hull is designed. Calculation of resistance using CFD, then analyzed the calculation of resistance and stability, safety, and comfort of the ship using Maxsurf. The drag Trimaran is 8.86% smaller than a monohull and 3.25% smaller than a catamaran. Energy Usage (EHP) is proven by trimaran ships more than other ship modes. The average trimaran period is 10.5 seconds which meets IMO standards and is declared operationally good.

An Optimised Data Analysis for the Balb/c3T3 Cell Transformation Assay and its Application to Metal Compounds

2007 ◽  
Vol 20 (4) ◽  
pp. 673-684 ◽  
Author(s):  
J. Ponti ◽  
B. Munaro ◽  
M. Fischbach ◽  
S. Hoffmann ◽  
E. Sabbioni
Keyword(s):  
Data Analysis ◽  
Cell Transformation ◽  
T Test ◽  
Alternative Methods ◽  
Metal Compounds ◽  
Exact Test ◽  
Fisher's Exact Test ◽  
Transformation Assay ◽  
Carcinogenic Potential ◽  
Fisher’S Exact Test

The Balb/c3T3 cell transformation assay (CTA) is an available in vitro system to detect the carcinogenic potential of chemicals. Currently, the European Centre for the Validation of Alternative Methods (ECVAM) is validating this test, assessing its reliability and relevance. Its endpoint is the formation of type III foci, which is, when using clone A31-1-1, a very rare event that usually does not occur at all for negative controls. The carcinogenic potential of a compound tested is assessed by comparing the number of foci in treated and untreated cells. The objective of the present work is to optimise the data analysis for this endpoint by applying the most commonly used approach by a t-test and the Fisher's exact test as an alternative approach. For this purpose selected metal compounds classified as carcinogenic (NaAsO2, CdCl2 cisPt), as suspected carcinogenic (C6H5)4AsCl, CH3HgCl), or as compounds without evidence of carcinogenic properties in humans ((NH4)2PtCl6, NaVO3) as well as a non-carcinogenic (AgNO3) were analysed. Our evaluation revealed that the t-test approach, which assumes normality of data, is not appropriate. The results demonstrated that the statistical analysis by Fisher's exact test better reflects the data properties and greatly facilitates the interpretation of Balb/c3T3 CTA data regarding carcinogenic potential.

scholarly journals Experimental Validation of Transverse Stability Monitoring System for Fishing Vessels

2019 ◽  
Vol 52 (21) ◽  
pp. 57-63
Author(s):  
Lucía Santiago Caamaño ◽  
Roberto Galeazzi ◽  
Marcos Míguez González ◽  
Vicente Díaz Casás ◽  
Ulrik D. Nielsen
Keyword(s):  
Monitoring System ◽  
Experimental Validation ◽  
Stability Monitoring ◽  
Fishing Vessels ◽  
Transverse Stability
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