Citation:

j.seares.2013.06.004

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Abstract:

Groundfish survey data from the German Bight from 1902-08, 1919-23, and 1930-1932 and ICES International Bottom Trawl Survey (IBTS) quarter 3 data from 1991 to 2009 were analysed with respect to species frequencies, maximum length, trends in catch-per-unit-effort, species richness parameters (SNR) and presence of large fish (Phi40), the latter defined as average presence of species per haul with specimens larger than 40 cm given. Four different periods are distinguished: (a) before 1914 with medium commercial CPUE and low landings, Phi40 approx. 2, high abundance in elasmobranchs and SNR conditions indicating highly diverse assemblages, (b) conditions immediately after 1918 with higher commercial CPUE, recovering landings, Phi40 at > 4 in 1919, and SNR conditions indicating highly diverse assemblages, (c) conditions from 1920 to the early 1930's with decreasing commercial CPUE, increased landings, decreasing Phi40, SNR conditions similar to later years indicating less diverse assemblages, and a decrease in elasmobranchs. In the IBTS series (d), Phi40 remains low indicating an increased rarity of large specimens, and SNR characteristics are similar to the third period. Dab, whiting and grey gurnard have increased considerably in the IBTS series as compared to the historic data. Phi40 is suggested an alternative indicator reflecting community functional diversity when weight based indicators cannot be applied.

Coverage:

Latitude: 54.380000 * Longitude: 7.620000

Date/Time Start: 1902-08-01T00:00:00 * Date/Time End: 2009-08-01T00:00:00

Event(s):

German_Bight * Latitude: 54.380000 * Longitude: 7.620000 * Location: German Bight, North Sea * Method/Device: Multiple investigations (MULT)

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Comment
1	DATE/TIME	Date/Time			Geocode
2	Comment	Comment		Fock, Heino O	Time series
3	Eutrigla gurnardus, catch per unit effort	E. gurnardus CPUE	kg/30 min	Fock, Heino O
4	Gadus morhua, catch per unit effort	G. morhua CPUE	kg/30 min	Fock, Heino O
5	Limanda limanda, catch per unit effort	L. limanda CPUE	kg/30 min	Fock, Heino O
6	Melanogrammus aeglefinus, catch per unit effort	M. aeglefinus CPUE	kg/30 min	Fock, Heino O
7	Merluccius merluccius, catch per unit effort	M. merluccius CPUE	kg/30 min	Fock, Heino O
8	Pleuronectes platessa, catch per unit effort	P. platessa CPUE	kg/30 min	Fock, Heino O
9	Raja clavata, catch per unit effort	R. clavata CPUE	kg/30 min	Fock, Heino O
10	Squalus acanthias, catch per unit effort	S. acanthias CPUE	kg/30 min	Fock, Heino O
11	Solea vulgaris, catch per unit effort	S. vulgaris CPUE	kg/30 min	Fock, Heino O
12	Conversion factor	Conv fac		Fock, Heino O	Roundfish
13	Conversion factor	Conv fac		Fock, Heino O	Flatfish
14	Eutrigla gurnardus, catch per unit effort	E. gurnardus CPUE	kg/30 min	Fock, Heino O	corrected
15	Gadus morhua, catch per unit effort	G. morhua CPUE	kg/30 min	Fock, Heino O	corrected
16	Limanda limanda, catch per unit effort	L. limanda CPUE	kg/30 min	Fock, Heino O	corrected
17	Melanogrammus aeglefinus, catch per unit effort	M. aeglefinus CPUE	kg/30 min	Fock, Heino O	corrected
18	Merluccius merluccius, catch per unit effort	M. merluccius CPUE	kg/30 min	Fock, Heino O	corrected
19	Pleuronectes platessa, catch per unit effort	P. platessa CPUE	kg/30 min	Fock, Heino O	corrected
20	Raja clavata, catch per unit effort	R. clavata CPUE	kg/30 min	Fock, Heino O	corrected
21	Squalus acanthias, catch per unit effort	S. acanthias CPUE	kg/30 min	Fock, Heino O	corrected
22	Solea vulgaris, catch per unit effort	S. vulgaris CPUE	kg/30 min	Fock, Heino O	corrected

License:

Creative Commons Attribution 3.0 Unported (CC-BY-3.0)

Size:

693 data points

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