scholarly journals Dynamics of European eel landings and stocks in the coastal waters of Estonia

2015 ◽  
Vol 73 (1) ◽  
pp. 84-90 ◽  
Author(s):  
P. Bernotas ◽  
M. Vetemaa ◽  
L. Saks ◽  
R. Eschbaum ◽  
A. Verliin ◽  
...  

Abstract European eel stocks are in a decline all over Europe. In Estonia, we analysed three different dataseries (commercial landings 1969–2014, scientific eel monitoring 1998–2014, and recreational catches 2005–2012). In the commercial fishery, the biggest drop in landings occurred in the 1980s, with a small recovery in the end of the 1990s. We also interviewed fishers to evaluate the quality of the official catch figures. In the monitoring dataseries, gathered by the use of special eel fykenets, the steepest cpue decline occurred in the last 5 years. Finally, recreational eel fishery has almost stopped: in 2012, catches were only 3% of that in 2005. In conclusion, both professional and recreational eel catches have declined in all the coastal areas of Estonia. The number of professional and recreational fishers specialized to eel fishing has decreased and the number of licences for eel-specific fishing gear has been reduced.

Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1291 ◽  
Author(s):  
Imane Bourouhou ◽  
Farida Salmoun ◽  
Yusuf Gedik

Coastal areas play a crucial role in maintaining the ecological balance of ecosystems and developing the social and economic wellbeing of the countries bordering it. However, the pressure on both terrestrial and marine resources, the use of oceans as a wastes deposit, the growth of population and the increasing of urbanization and human activities in coastal areas are all causes for marine and coastal degradation. The present situation constitutes a significant danger in many places. As an example, the pollution of the coastal waters in the Mediterranean has increased in recent years. Industrialization, tourism and ports activities along the coastline of the Mediterranean are the main sources of many pollutants that have effects on human’s health and environment. So that, it is very important to examine seawater quality in order to protect the marine and coastal areas from degradation. Hence, comes the need to consider a physicochemical and bacteriological study to evaluate the quality of Tangier coastal seawater using the Water Quality Index (WQI). A campaign of 25 sampling points was conducted and the results of the WQI calculation have highlighted the Tangier water was between medium and bad.


Author(s):  
Fedor Gippius ◽  
Fedor Gippius ◽  
Stanislav Myslenkov ◽  
Stanislav Myslenkov ◽  
Elena Stoliarova ◽  
...  

This study is focused on the alterations and typical features of the wind wave climate of the Black Sea’s coastal waters since 1979 till nowadays. Wind wave parameters were calculated by means of the 3rd-generation numerical spectral wind wave model SWAN, which is widely used on various spatial scales – both coastal waters and open seas. Data on wind speed and direction from the NCEP CFSR reanalysis were used as forcing. The computations were performed on an unstructured computational grid with cell size depending on the distance from the shoreline. Modeling results were applied to evaluate the main characteristics of the wind wave in various coastal areas of the sea.


1991 ◽  
Vol 23 (1-3) ◽  
pp. 1-10 ◽  
Author(s):  
Takeshi Goda

The management and status of public water bodies in Japan is discussed. The environmental quality standards which have been set and the levels of compliance with these standards are shown. The water quality of Japanese rivers, lakes, reservoirs, wetlands and coastal waters is described, and eutrophication problems are mentioned. The effects of changes in population density and levels of recycling of industrial wastewaters on the quality of water bodies are discussed. Almost 75% of industrial wastewater is now recycled. Per capita availability of freshwater in Japan is comparatively low, and the construction of 530 dams, in addition to the 2393 dams already in operation, is planned. Irrigation effluents from paddy fields are a major factor which influences river water quality in Japan. The improvement of water quality using various methods is discussed.


1993 ◽  
Vol 27 (12) ◽  
pp. 223-226
Author(s):  
J.-F. Guillaud ◽  
M. Pommepuy ◽  
E. Dupray ◽  
J.-C. Salomon ◽  
B. Thouvenin

The aim of this paper is to present some results of bacterial studies which were developed by IFREMER in coastal discharge areas of urban wastewaters; they are focused on the determination of bacterial inputs by wastewater treatment plants, the role of environmental factors on the enteric bacteria survival in the coastal zone, and the modelling of bacteria transport and disappearance in order to provide useful management information for minimizing faecal pollution in the coastal zone.


2010 ◽  
Vol 58 (spe3) ◽  
pp. 29-35 ◽  
Author(s):  
Diego Igawa Martinez ◽  
Ana Júlia Fernandes Cardoso de Oliveira

Urban development in coastal areas is intense and leads to the increase of sewage outfall and other negative impacts as consequences. Thus, stringent regulations establishing limits to the microbiological contamination of water and seafood are needed. The objective of this study is to evaluate the usefulness of Enterococci and Thermotolerant Coliform densities in the flesh of mussels Perna perna as an alternative tool for monitoring the microbiological quality of coastal waters. The study also considers allometric relations applied to clearance rates to understand rates of bacterial concentration. Bacterial loads obtained in mussels' flesh were from 50 to 4,300 times greater than in the water sampled in the vicinity of the mussels and some were considered inappropriate for consumption even when the water presented no restrictions. The mean clearance rate obtained for Enterococci retention was 317.7 ml h-1 and this rate (CR) is related to the mussels' size (L) by the equation CR = 28.3229L1.6421. The results showed that bacterial densities in the mussels' tissues may reflect chronic contamination of the environment and that clearance rates are important for taking the best decision in situations where, for example, it is desired to introduce mussels for aquaculture and the evaluation of the water concerned is required.


2018 ◽  
Author(s):  
Anne Wiese ◽  
Joanna Staneva ◽  
Johannes Schultz-Stellenfleth ◽  
Arno Behrens ◽  
Luciana Fenoglio-Marc ◽  
...  

Abstract. In this study, the quality of wind and wave data provided by the new Sentinel-3A satellite is evaluated. We focus on coastal areas, where altimeter data are of lower quality than those for the open ocean. The satellite data of Sentinel-3A, Jason-2 and CryoSat-2 are assessed in a comparison with in situ measurements and spectral wave model (WAM) simulations. The sensitivity of the wave model to wind forcing is evaluated using data with different temporal and spatial resolution, such as ERA-Interim and ERA5 reanalyses, ECMWF operational analysis and short-range forecasts, German Weather Service (DWD) forecasts and regional atmospheric model simulations -coastDat. Numerical simulations show that both the wave model forced using the ERA5 reanalyses and that forced using the ECMWF operational analysis/forecast demonstrate the best capability over the whole study period, as well as during extreme events. To further estimate the variance of the significant wave height of ensemble members for different wind forcings, especially during extreme events, an empirical orthogonal function (EOF) analysis is performed. Intercomparisons between remote sensing and in situ observations demonstrate that the overall quality of the former is good over the North Sea and Baltic Sea throughout the study period, although the significant wave heights estimated based on satellite data tend to be greater than the in situ measurements by 7 cm to 26 cm. The quality of all satellite data near the coastal area decreases; however, within 10 km off the coast, Sentinel-3A performs better than the other two satellites. Analyses in which data from satellite tracks are separated in terms of onshore and offshore flights have been carried out. No substantial differences are found when comparing the statistics for onshore and offshore flights. Moreover, no substantial differences are found between satellite tracks under various metocean conditions. Furthermore, the satellite data quality does not depend on the wind direction relative to the flight direction. Thus, the quality of the data obtained by the new Sentinel-3A satellite over coastal areas is improved compared to that of older satellites.


A Total of 379 pen shells Atrinapectinata were collected from February 2017 to January 2018 in the coastal waters of Maqueda Bay. Measurement and analysis of length and weight were done using FiSAT software. Population parameters were assessed to evaluate the stock status which includes the asymptotic length (L∞) and growth coefficient (K) to be 34.65 cm, 0.77 year−1 respectively. Specimens of A. pectinata reached a mean length of 20.98 cm. Length-weight relationship resulted to “negative allometric” 0.0462L2.6533 R2 = 0.7823; signifying pen shells growth was faster in length than on weight. The recruitment pattern was continuous over the year with one major peak during rainy season (July). In addition, the highest catch based on collected sampling date catch was during summer, which suggest as the peak season of the species in the area. Furthermore, the average catch annually of hookah diver was 17.69208. Higher condition index was recorded from April to May, September and January, indicating the high quality of pen shell meat and is recommended as the best period to harvest pen shell whereas June to August and October to December can be concluded as the spawning period of the pen shell and the ideal period to institute close season. Further analysis revealed that the pen shell was nearly facing overexploitation with the exploitation rate (E = 0.46) mainly due to lack of a minimum limit size and also due to an increase in the harvesting effort. The estimated total mortality (Z), natural mortality (M) and fishing mortality (F); 1.36 year−1, 1.01year−1 and 0.62 year−1, respectively. Using the mentioned (Z), (M), (F) and (E), the total population resulted to 84725.7 suggesting that half of the population has been exploited due to overfishing


2021 ◽  
Vol 869 (1) ◽  
pp. 012054
Author(s):  
S Sulaiman ◽  
M A Abdullah ◽  
T M Mansur ◽  
N Roesa

Abstract This paper aims to examine how to protect of artisanal fishermen fishing ground and the policies that protect them. Small-scale fisher fishing grounds has to have a special attention due to their limitation. They are using very simple fishing gear, so they can’t sail far away from the coastal waters. The Fishing law give a specific attention for this matter, by limiting fishermen with 5 gross tonnage (GT) are only able to conduct their activities within the coastal waters. This study combines legal documents and the results of interviews with fishermen on 5 GT vessel. this studi of find, then the Law Number 27/2016 changed this regulation by increasing gross tonnage for small-scale fishermen from 5 became 10 GT, and it attract more serious problems for these small-scale fishermen since they have no exclusive fishing ground anymore. It will also affect to changes of fishing lane; fishing ground and vessels authorization procedure. By increasing GT, the 10 GT vessels also have rights to sail in the same fishing ground with 5 GT vessels and it’s created a potential conflict between the fishermen. So, harmonization of law is important task for the government in avoiding the overlapping rules on vessels criteria, by choosing law that prioritize on small-scale GT vessels.


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