Advancing presence and changes in body size of brown shrimp Crangon crangon on intertidal flats in the western Dutch Wadden Sea, 1984–2018

2021 ◽  
Vol 168 (11) ◽  
Author(s):  
Emma Penning ◽  
Laura L. Govers ◽  
Rob Dekker ◽  
Theunis Piersma
Keyword(s):  
Body Size ◽  
Wadden Sea ◽  
Brown Shrimp ◽  
Crangon Crangon ◽  
Intertidal Flats

Emergence rhythms and tidal migrations in the brown shrimp Crangon crangon (L.)

1975 ◽  
Vol 55 (4) ◽  
pp. 801-810 ◽  
Author(s):  
A. H. Y. Adhub-Al ◽  
E. Naylor
Keyword(s):  
Experimental Investigation ◽  
Shallow Water ◽  
Wadden Sea ◽  
Brown Shrimp ◽  
Crangon Crangon ◽  
Severn Estuary

The brown shrimp Crangon crangon (L.) is a burrowing caridean decapod, inhabiting sandy, sandy-mud and muddy substrata down to 90 m, but occurring mainly in shallow water and between tidemarks (Lloyd & Yonge, 1947; Allen, 1966b). The species also exhibits seasonal inshore and offshore migrations, reportedly in relation to salinity, temperature and availability of food (Ehrenbaum, 1890; Havinga, 1929, 1930; Meyer, 1935; Broekema, 1941, Academy Thesis, Groningen; Lloyd & Yonge, 1947; Allen, 1966a, b; Tiews, 1970). In addition Hartsuyker (1966) reported up and downshore migrations on each tidal rise and fall in the Wadden Sea. In contrast, Havinga (1929) stated that the species rests quietly buried in the substratum by day and feeds at night, and nocturnal emergence was confirmed by Lloyd & Yonge (1947) in aquarium observations. However the latter authors found no difference between field catches during day and night tides in the Bristol Channel and Severn Estuary. Tiews (1970) reported greatest activity at dusk and that C. crangon continued to swim during the night even after feeding. So far there is therefore evidence of nocturnal and tidal rhythms of emergence in C. crangon which deserves further experimental investigation.

scholarly journals Fluctuations of brown shrimp Crangon crangon abundance in the western Dutch Wadden Sea

2010 ◽  
Vol 405 ◽  
pp. 203-219 ◽  
Author(s):  
J Campos ◽  
A Bio ◽  
JFMF Cardoso ◽  
R Dapper ◽  
JIJ Witte ◽  
...  
Keyword(s):  
Wadden Sea ◽  
Brown Shrimp ◽  
Crangon Crangon

scholarly journals A Classification Scheme for Sediments and Habitats on Exposed Intertidal Flats with Multi-Frequency Polarimetric SAR

2021 ◽  
Vol 13 (3) ◽  
pp. 360
Author(s):  
Wensheng Wang ◽  
Martin Gade ◽  
Kerstin Stelzer ◽  
Jörn Kohlus ◽  
Xinyu Zhao ◽  
...  
Keyword(s):  
Classification Scheme ◽  
Wadden Sea ◽  
Relative Difference ◽  
Polarimetric Synthetic Aperture Radar ◽  
Intertidal Flats ◽  
Sediment Types ◽  
X Band ◽  
Good Potential ◽  
L Band ◽  
Sar Data

We developed an extension of a previously proposed classification scheme that is based upon Freeman–Durden and Cloude–Pottier decompositions of polarimetric Synthetic Aperture Radar (SAR) data, along with a Double-Bounce Eigenvalue Relative Difference (DERD) parameter, and a Random Forest (RF) classifier. The extension was done, firstly, by using dual-copolarization SAR data acquired at shorter wavelengths (C- and X-band, in addition to the previously used L-band) and, secondly, by adding indicators derived from the (polarimetric) Kennaugh elements. The performance of the newly developed classification scheme, herein abbreviated as FCDK-RF, was tested using SAR data of exposed intertidal flats. We demonstrate that the FCDK-RF scheme is capable of distinguishing between different sediment types, namely mud and sand, at high spatial accuracies. Moreover, the classification scheme shows good potential in the detection of bivalve beds on the exposed flats. Our results show that the developed FCDK-RF scheme can be applied for the mapping of sediments and habitats in the Wadden Sea on the German North Sea coast using multi-frequency and multi-polarization SAR from ALOS-2 (L-band), Radarsat-2 (C-band) and TerraSAR-X (X-band).

scholarly journals Evaluating the efficacy of technical measures: a case study of selection device legislation in the UK Crangon crangon (brown shrimp) fishery

2008 ◽  
Vol 65 (2) ◽  
pp. 267-275 ◽  
Author(s):  
Tom L. Catchpole ◽  
Andrew S. Revill ◽  
James Innes ◽  
Sean Pascoe
Keyword(s):  
Brown Shrimp ◽  
Crangon Crangon ◽  
Shrimp Fishery ◽  
The North ◽  
Ex Post ◽  
Wide Range ◽  
The Uk ◽  
The Impact ◽  
Technical Measures

Abstract Catchpole, T. L., Revill, A. S., Innes, J., and Pascoe, S. 2008. Evaluating the efficacy of technical measures: a case study of selection device legislation in the UK Crangon crangon (brown shrimp) fishery. – ICES Journal of Marine Science, 65: 267–275. Bycatch reduction devices are being introduced into a wide range of fisheries, with shrimp and prawn fisheries particularly targeted owing to the heavy discarding common in these fisheries. Although studies are often undertaken to estimate the impact of a technical measure on the fishery before implementation, rarely have the impacts been assessed ex post. Here, the efficacy of the UK legislation pertaining to the use of sievenets in the North Sea Crangon crangon fishery is assessed. Three impacts were evaluated: on fisher behaviour (social), on the level of bycatch (biological), and on vessel profitability (economic). An apparent high level of compliance by skippers was identified despite a low level of enforcement. The estimated reduction in fleet productivity following the introduction of the legislation was 14%, equalling the mean loss of Crangon landings when using sievenets calculated from catch comparison trawls. Sievenets did reduce the unnecessary capture of unwanted marine organisms, but were least effective at reducing 0-group plaice, which make up the largest component of the bycatch. Clearly the legislation has had an effect in the desired direction, but it does not address sufficiently the bycatch issue in the Crangon fishery.

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