R1/12
Not to be cited without reference to Marine Scotland, Marine Laboratory, Aberdeen FRV Scotia
Cruise 0210S REPORT
27 January – 17 February 2010 Personnel
C G Davis (SIC) M Mathewson K Summerbell D.Bova R Watret M/Leys
P.Copland (part1) L Ritchie (part2)
T. Fujii (Oceanlab – part1) Objectives
1. To take part in the coordinated International Bottom Trawl Survey in the North Sea.
Out-turn days per project: 22 days Narrative
Scotia sailed from Aberdeen at 1000hrs on 27 January and commenced trawling on the station east of Aberdeen with a GOV trawl fitted with Groundgear “B”. The medium term forecast suggested favourable conditions for the week ahead. As such, Scotia worked east and then north covering the offshore stations which required both ground-gear “A” and “B” to be deployed. Methot Net (MIK) sampling was undertaken at a rate of 2 tows per statistical rectangle where trawling events took place. This pattern of operation continued up until 6 February when Scotia docked in Aberdeen for her scheduled half landing. Only a few hours of survey time were lost on the first half of the survey due to adverse weather.
During the half landing the opportunity was taken to change to a new trawl and to strip off gear “A” on the top net drum and to replace this with a second set of “B” gear.
Scotia sailed again from Aberdeen on the morning of 7 February and resumed survey work in the Moray Firth area. The survey progressed up the west of Orkney and Shetland Isles, returning south down the east side of the Shetlands and Fair Isle.
During the second part of the survey, several ‘foul’ hauls were recorded with considerable damage to trawl gear. Although one of these foul hauls was on new ground surveyed, in an attempt to establish an additional station for this survey, the remaining foul hauls were encountered on historically ‘clean’ established trawl positions.
Scotia continued surveying up until the evening of Tuesday 16February when she began making way for Aberdeen.
Scotia docked alongside Aberdeen at 0600 hrs on Wednesday 17 February.
2 Results
Trawling
The GOV was used throughout the cruise with groundgear “A” (152mm rubber disks) being used in the southern part of the survey area and groundgear “B” (305mm bobbins) being used in the northern part. The Scanmar system was used throughout the cruise to monitor headline height, wing spread, door spread and distance covered during each tow. A NOAA bottom contact sensor was attached to the groundgear for each tow and the data downloaded for further analysis in the laboratory
A total of 52 valid hauls were achieved with all allocated stations being sampled other than one located in 43E9, where substantial gear damage was encountered. Chart 1 displays trawl locations.
Table 1 shows the preliminary indices for all vessels participating in this international survey with a total of 383 hauls having been completed. The indices are based on the numbers of fish caught per hour below a pre-defined length selected as a probable delimiter of 1+ fish.
Table1: Preliminary indices for Quarter 1 International Bottom Trawl Survey (All countries)
Final 2009 Preliminary 2010 Mean (average 1980–2009)
Cod 1.2 3.7 8
Haddock 74 607 600
Whiting 259 385 506
Norway pout 5496 4976 2891
Herring 2347 1472 1994
Sprat 3468 4086 1093
Mackerel 0.8 0 106
The survey indices for 1980 – 2010 for the above species are provided in Figure 1.
Methot Net Sampling
A total of 99 MIK hauls were carried out in order to obtain an estimate of the numbers of pre- metamorphosing herring larvae. The circular frame was used to complete 2 hauls in each statistical rectangle of the survey area and the deployment and recovery speeds were adapted in accordance with advice from the Herring Assessment WG.
Location of MIK stations and numbers caught are displayed in Chart 2.
Biological Sampling
Additional biological data were collected from various species in support of EU Data Collection Regulation (EC) No 2008/949.
In addition to above the following biological sampling was also undertaken for the subsequent requests:
1) Collection of 100 common dabs from each location at Orkney and Shetland for MSS.
2) Collection of otoloiths and biological parameter data from 100 three year old Cod, Haddock & Whiting from a possible 12 areas for MSS
3) Collection of a considerable quantity of fish specimens from a diverse selection of species for dissection experiments at Aberdeen University.
4) Collection of a variety of specimens from selected species for DNA analysis by the University of Helsinki
5) Collection of DNA samples from Turbot and Halibut for a Phd Student.
6) Collection of representative samples from all shelled mollusc species caught in each haul, for an established reference collection.
Age determination
Otoliths from cod, haddock, whiting, saithe, norway pout, herring, mackerel and sprat were aged at sea.
Hydrographic Sampling
The ship’s thermosalinigraph was run continuously throughout the cruise. A CTD was deployed at each station (with reverser bottle attached) in order to obtain temperature data as well as water samples for analysis for salinity, nitrate, silicate and phosphate.
Submitted C.G.Davis 24 March 2010
Approved:
I Gibb
12 April 2010.
4 Figure 1
final preliminary MEAN
2009 2010 av 80-09
cod 1.2 3.7 8
haddock 74 607 600
whiting 259 385 506
Norway pout 5496 4976 2891
herring 2347 1472 1994
sprat 3468 4086 1093
mackerel 0.8 9 106
0 10 20 30 40 50
1980 1985 1990 1995 2000 2005 2010
Cod
mean 1980-2009 = 8.2
0 1000 2000 3000 4000
1980 1985 1990 1995 2000 2005 2010
Haddock mean 1980-2009 = 600
0 500 1000 1500 2000
1980 1985 1990 1995 2000 2005 2010
Whiting
mean 1980-2009 = 506
0 2,000 4,000 6,000 8,000 10,000
1980 1985 1990 1995 2000 2005 2010
Norway pout mean 1980-2009 = 2891 0
1000 2000 3000 4000 5000
1980 1985 1990 1995 2000 2005 2010
Herring
mean1980-2009 = 1998
0 1000 2000 3000 4000 5000 6000
1980 1985 1990 1995 2000 2005 2010
Sprat
mean 1980-2009 = 1093
0 200 400 600 800 1000 1200 1400
1980 1985 1990 1995 2000 2005 2010
Mackerel mean 1980-2009= 106
Chart No. 1 Fishing Tow Positions (invalid tows in red)
4 2 0 2 4 6
55 N 56 N 57 N 58 N 59 N 60 N 61 N 62 N
6
Chart No.2. MIK Sampling locations and numbers caught.
-4 -3 -2 -1 0 1 2 3 4 5
Scotia Q1 IBTS 2010 Actual numbers caught
56 57 58 59 60 61 62
16
8
33 7
0 1
2
6 2
6
21
3 47
46 75 3
15 13
15 20
12
9 8 10
54 6 10
12 24
5 21 11 21
11 11
27
16 6 4 2
5 13
12 8 1 0
1 30 23
11 8
8
4
38 15
21 9
9 8
22 16
5 16 17 18 18
2 14 30 18 4
5 3 0
0 9 1 0
1
1 0
1
0
2
1 0 1
0 0
1
2
0 1
1
7 4
0 0
0 14
F0 F1 F2 F3 F4
E8 E9 E7
E6
46
45
44
43
42
41 47 48 49 50 51 52
