FRV Scotia 1504S

Cruise summary report

Cruise Info. 
Ship name (ship code)FRV Scotia (748S)
Cruise identifier1504S
Cruise period2004-10-21 — 2004-11-07
Port of departureAberdeen, United Kingdom
Port of returnAberdeen, United Kingdom

1. To conduct an acoustic survey to estimate the abundance and distribution of mackerel in the northern North Sea (ICES division IVa).

2. To obtain samples of mackerel for biological analysis, including age, length, weight, sex and maturity.

3. To determine the species composition and target strength of fish in schools using the autonomous echosounder and video rig.

4. To make video observations of the multi-sampling pelagic trawl with the RCTV.


Scientific staff joined the vessel at 0900 on 21 October and the vessel departed at 1000. A small meeting was held with all scientists and the ship's fishing mates and navigation officers to explain the objectives of the survey and to describe general operating procedures. The vessel proceeded to Scapa Flow to calibrate the acoustic transducers, however, prior to arrival it was evident that poor weather would prevent a successful exercise and so this was abandoned. The survey commenced on 22 October at 1347 at 61°55.5'N 001°00'W. Transects progressed southward along lines of latitude, at spacings of 15 or 7.5 nautical miles (nmi) as planned. Problems with the hydraulic systems on the vessel prevented any fishing operations from 2130 on 22 October until 1500 on 25 October. At 1520 on 27 October, an opportunity was taken to calibrate the echosounders due to a break in the [poor] weather in Wick of Grunting, north of Fetlar, Shetland. The vessel docked into Lerwick harbour on 29 October for 24 hours to enable a change of personnel and to give staff their rest day in line with working time directives. The survey resumed at 1432 on 30 October. The first part of the survey was completed at 0656 on 4 November. The second survey commenced immediately, following a zigzag design of the area of higher mackerel abundance along the 200 m contour: this was interlaced with a complementary survey carried out by the Norwegian FRV GO Sars. FRV Scotia completed its survey at 1320 on 5 November, after which the vessel rendezvoused with the GO Sars to carry out an intercalibration exercise starting at 2040. This lasted for approximately 7 hours (73 nmi) covering four transects with each vessel taking the lead alternately. The intercalibration was completed at 0400 on 6 November. The vessel returned to Aberdeen on the morning of 7 November.
Chief scientistPaul G Fernandes (Fisheries Research Services Aberdeen Marine Laboratory)
Cruise programmeFRV Scotia 1504S cruise programme 1504s.pdf  (0.03 MB) 
Cruise reportFRV Scotia 1504S cruise report 1504s.pdf (0.02 MB) 
Ocean/sea areas 
GeneralNorth Sea
North East Atlantic Ocean (limit 40W)
SpecificOrkneys and Shetlands, northern North Sea
Physical oceanography 
CTD stationsQuantity: number of profiles = 27
Biology and fisheries 
Pelagic fishQuantity: number of hauls = 16
Description: PT160 pelagic trawl hauls with 2042 mackerel length measurements, 624 mackerel sampled for weight, sex, maturity and otoliths, 1513 herring lengths, 155 blue whiting lengths, 13 saithe lengths, silversides, pearlsides, and a variety of small gadoids. No cod were caught
Acoustic reflection on marine organisms.Quantity: data volume in gigabytes = 50
Description: acoustic data recorded using a EK60 echosounder (38, 120 and 200 kHz) to detect mackerel