scholarly journals Modelling demersal fishing effort based on landings and days absence from port, to generate indicators of “activity”

2009 ◽  
Vol 66 (5) ◽  
pp. 886-901 ◽  
Author(s):  
S. P. R. Greenstreet ◽  
G. J. Holland ◽  
T. W. K. Fraser ◽  
V. J. Allen
Keyword(s):  
Spatial Patterns ◽  
Temporal Trends ◽  
Ecosystem Approach ◽  
Fishing Effort ◽  
Anthropogenic Activity ◽  
Activity Levels ◽  
Fishing Activity ◽  
State Response ◽  
General Terms ◽  
Pressure State

Abstract Greenstreet, S. P. R., Holland, G. J., Fraser, T. W. K., and Allen, V. J. 2009. Modelling demersal fishing effort based on landings and days absence from port, to generate indicators of “activity”. – ICES Journal of Marine Science, 66: 886–901. For many components of marine ecosystems, the derivation of biologically significant, operational “pressure” indicators will rely on modelling fishing mortality from indicators of anthropogenic “activity”. This essentially expands the well established Pressure–State–Response framework to one of Activity–Pressure–State–Response. Within the Common Fisheries Policy, the reporting of fishing effort data, the basic indicator of activity, is not mandatory. A modelling approach is therefore developed that utilizes the data that fishers are obliged to report (days absence from port, landings from each rectangle fished, and the gear used) to provide modelled estimates of fishing effort. The model is parameterized for the Scottish demersal fishing fleet using data collected through the Scottish discards observer scheme, and fishing effort over the period 1997–2004 is modelled. Reported effort data for the period 1960–1998 allowed validation of the model through direct comparison of modelled with reported data in 1997 and 1998. Combining the modelled and reported datasets revealed that Scottish fishing activity levels, remarkably constant over four decades, had declined markedly since 2000. Temporal trends in UK quotas for the main targeted demersal species are considered to assess the effectiveness of catch limitation management as a means of regulating fishing activity. Spatial patterns in effort by the four main gear types used by the Scottish demersal fleet are described, and in general terms, these have changed little over the period 1960–2004. However, distinct spatial patterns emerged in the temporal trends in each ICES rectangle, associated with the recent overall decline in Scottish demersal fishing activity. These patterns were not intuitive, and the implications of this for an ecosystem approach to management are discussed.

scholarly journals Highly mixed fisheries: fine-scale spatial patterns in retained catches of French fisheries in the Celtic Sea

2016 ◽  
Vol 74 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Maria Mateo ◽  
Lionel Pawlowski ◽  
Marianne Robert
Keyword(s):  
Spatial Patterns ◽  
Fisheries Management ◽  
Principal Component ◽  
Ecosystem Approach ◽  
Fine Scale ◽  
Biological Interactions ◽  
Management Options ◽  
Fishing Activity ◽  
Fisheries Policy ◽  
Celtic Sea

Efficiency of mixed-fisheries management and operational implementation of the ecosystem approach to fisheries management rely on the ability to understand and describe the technical and biological interactions between fleets, gears and species. The present study aims to describe fine-scale spatial patterns of the French demersal mixed fisheries in the Celtic Sea and discusses their implications in terms of management. Analysis was made by integrating vessel monitoring systems and logbook data collected between 2010 and 2012 at a 3′*3′ spatial scale through the use of principal component analysis followed by hierarchical clustering. It revealed spatial regions defined by a distinct homogeneous composition of retained catches. Each cluster was also described in terms of the fishing activity: vessel length, effort, power and gear used. The analysis revealed a complex spatial structure in the species assemblage caught and suggests that a single situation cannot describe the mixed fisheries of the Celtic Sea, but rather that there are several distinct cases of mixed fisheries. Our results also highlight the limitations of using the current level of data aggregation commonly requested in international data calls to model these fisheries and suggest that improvements should be made to ensure efficient evaluation of management options. Analyses of spatially resolved fisheries data such as the one presented here open a range of potential applications. In the context of the Common Fisheries Policy reform and the landing obligation, comparison of our results with applications of the same methodology to a subset of vulnerable species or to catches of fish below the minimum conservation reference size would help to identify the geographical areas to avoid and assess potential effort reallocation strategies based on groups of target species.

scholarly journals Watershed Sustainability Index for Langat UNESCO HELP River Basin, Malaysia

2018 ◽  
Vol 7 (3.14) ◽  
pp. 187
Author(s):  
Rahmah Elfithri ◽  
Mazlin Mokhtar ◽  
Mat Pauzi Abdullah ◽  
Mohd Raihan Taha ◽  
Mohd Ekhwan Toriman ◽  
...  
Keyword(s):  
River Basin ◽  
Catchment Area ◽  
Economic Conditions ◽  
Environmental Condition ◽  
Sustainability Index ◽  
State Response ◽  
Maximum Value ◽  
Langat River ◽  
Basin Hydrology ◽  
Pressure State

The study on Watershed Sustainability Index (WSI) has been conducted to analyst the environmental condition in the area incorporating ecological baseline and socio-economic conditions. WSI is an integrated indicator based on basin Hydrology, Environment, Life and Policy (HELP) state condition. It is suitable to be applied in the Langat River Basin in Malaysia which has similar catchment area (up to 2,350 km2) and is one of the UNESCO HELP River Basin since 2004. The WSI analysis which uses a pressure–state–response function based on basin HELP Indicator was done for Langat River Basin by using relevant available 5 years data for the period of 2009 to 2013. It is found that Langat River Basin is having WSI value of 0.68 which falls under the category of medium sustainability (between 0.5-0.8). Based on the maximum value (i.e. 1) or high sustainability (i.e. WSI value more than 0.8) it can be said that Langat is in the good side in term of sustainability. Few management aspects need to be improved and maintained well to be more sustainable. The assessment provides Langat River Basin with more information that is crucial in managing the basin through the adoption of UNESCO’s HELP Framework.   

Spatial patterns and temporal trends of daily precipitation indices in Iran

2014 ◽  
Vol 124 (1-2) ◽  
pp. 239-253 ◽  
Author(s):  
Tayeb Raziei ◽  
Jamal Daryabari ◽  
Isabella Bordi ◽  
Reza Modarres ◽  
Luis S. Pereira
Keyword(s):  
Spatial Patterns ◽  
Daily Precipitation ◽  
Temporal Trends ◽  
Precipitation Indices

Mosses as biomonitors of atmospheric heavy metal deposition: Spatial patterns and temporal trends in Europe

2010 ◽  
Vol 158 (10) ◽  
pp. 3144-3156 ◽  
Author(s):  
H. Harmens ◽  
D.A. Norris ◽  
E. Steinnes ◽  
E. Kubin ◽  
J. Piispanen ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Spatial Patterns ◽  
Temporal Trends ◽  
Metal Deposition ◽  
Heavy Metal Deposition

scholarly journals The risk to fishery performance associated with spatially resolved management of Antarctic krill (Euphausia superba) harvesting

2009 ◽  
Vol 66 (10) ◽  
pp. 2148-2154 ◽  
Author(s):  
Simeon L. Hill ◽  
Philip N. Trathan ◽  
David J. Agnew
Keyword(s):  
Antarctic Krill ◽  
Euphausia Superba ◽  
Ecosystem Approach ◽  
Fishing Effort ◽  
Target Species ◽  
Ecosystem Models ◽  
Spatially Resolved ◽  
Management Actions ◽  
Antarctic Krill Euphausia Superba

Abstract Hill, S. L., Trathan, P. N., and Agnew, D. J. 2009. The risk to fishery performance associated with spatially resolved management of Antarctic krill (Euphausia superba) harvesting. – ICES Journal of Marine Science, 66: 2148–2154. The ecosystem approach to fisheries attempts to define objectives for target species, the wider ecosystem, and critically, the fishery itself. Proposals for implementing the approach often include spatial restrictions on harvesting, so it is important to understand how these will affect fishery performance. One metric of potential performance is the probability of encountering exploitable densities of a target species at the scale of fishing operations. The probability of encountering exploitable densities of Antarctic krill, Euphausia superba, at the scale of 1 nautical mile during an acoustic survey was predicted by bathymetry and the mean krill density at the larger scale at which the fishery is managed. This suggests that the risk to fishery performance will increase if management actions relocate the fishery into deeper water. The results also suggest that ecosystem models resolved to the spatial scale of management units could usefully predict effects at the scale of fishing operations. However, correct parameterization of these models will require better characterization of threshold densities for efficient exploitation. Finally, the distribution of catch and fishing effort over an entire fishing season reflected the distribution of krill density observed during the survey.

scholarly journals A fishing ground benthic ecosystem improved during the economic crisis

2018 ◽  
Vol 76 (2) ◽  
pp. 402-409
Author(s):  
Irini Tsikopoulou ◽  
Chris J Smith ◽  
Nadia K Papadopoulou ◽  
Elena Eleftheriadou ◽  
Ioannis Karakassis
Keyword(s):  
Economic Crisis ◽  
Eastern Mediterranean ◽  
Ecological Status ◽  
Ecosystem Approach ◽  
Fishing Effort ◽  
Fishing Ground ◽  
Ecological Studies ◽  
Ecological Quality Status ◽  
Traditional Fishing

AbstractFisheries have global socioeconomic and ecological effects. Long-term ecological studies could be beneficial to ecosystem approach management and biodiversity conservation, however, they are rare. In this study, the impacts of bottom trawling on a traditional fishing ground in the Eastern Mediterranean were addressed and an improvement in diversity metrics and ecological quality status were detected and ascribed to the Greek economic crisis. After 18 years, there was a modest increase in species richness, total abundance, and ecological status in the unaffected zone and more pronounced improvement in the trawled zone pointing at a possible link to a decrease in fishing effort. This upturn emphasized the strong link between financial activities and ecology. The present study underlines the multiple and variable effects of economy not only on countries and citizens but also on the environment and ecosystem conservation and management.

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