RV Cefas Endeavour 09/19

Cruise summary report

Cruise Info. 
Ship name (ship code)RV Cefas Endeavour (74E9)
Cruise identifier09/19
Cruise period2019-06-24 — 2019-07-01
Port of departureLowestoft, United Kingdom
Port of returnLowestoft, United Kingdom

1. To conduct a standard underwater TV survey of Nephrops burrow densities on the Farn Deeps grounds, 55 o 35' - 54 o 45' N and 1 o 30' - 0 o 40' W, and to evaluate Nephrops abundance (110 stations).
2. To conduct a standard underwater TV survey of 20 additional stations on the Farn Deeps grounds (as per objective 1). These stations are surveyed by NEIFCA as part of their annual autumn TV survey of inshore grounds. By surveying the same stations during the early Summer, we will be able to estimate seasonal variations in burrow densities.
3. Collect chlorophyll samples to test for nutrients from the surface water for ASMIAC project.


This report summarises the main results and findings of the 23rd annual underwater television survey on the 'Farn Deeps grounds' ICES assessment area, Functional Unit 6. The survey was multi-disciplinary in nature collecting UWTV video transects and ecosystem data. The survey design consists of a randomised fixed grid of 110 stations where at each station a sledge-mounted TV camera is deployed, and a visually clear 10-minute tow is recorded digitally. In June 2019, 90 stations (TVID) were successfully surveyed in the Farn Deeps area with the TV sledge, from 24th June to 30th June. This year, the survey was half a day shorter than previously and with unanticipated downtime, 19 stations had to be dropped. Downtime was due to weather conditions, technical issues with the camera sledge and to enable H&S improvements to sledge deployment and recovery operations. This resulted in a prioritised grid aimed to maximise station coverage. Of the stations surveyed, 1 was dropped due to technical issues with the camera system and 3 had to be repeated due to stability issues caused by loss of the drogue. Water clarity was good to excellent throughout the footage recorded, 2 stations required repeats due poor visibility. A new reference set of calibration videos was used from the 2018 survey footage. All burrow counters completed calibration training to a required concordance to ensure competence and calibration for burrow recounts prior to the survey. Standard protocol for burrows recounts was followed. Counts were recorded in 1-minute blocks for a total of 8 minutes comprising of 1 calibration minute, followed by 7 clear minutes of recorded counting. The counting concordance of the 2019 counters was generally high (average Linn's concordance correlation coefficient, CCC = 0.66). Preliminary results indicate an increased abundance when compared to last year, and at its highest level since 2006 with abundance above the Btrigger threshold as determined by ICES. As with previous years the highest abundance of burrows were recorded on the west side of the ground especially in the central west region of the grid.
Chief scientistChristopher Firmin (Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory)
Cruise programmeRV Cefas Endeavour 09/19 cruise programme endeavour09_19.pdf  (0.37 MB) 
Cruise reportRV Cefas Endeavour 09/19 cruise report endeavour09_19.pdf (0.48 MB) 
Ocean/sea areas 
GeneralNorth Sea
SpecificFarn Deeps fishing grounds