Marine

2019 Nephrops norvegicus UWTV Survey – Weblog No. 2


2019 Nephrops norvegicus UWTV Survey 

CV19022

twenty first – twenty eighth August 

Determine 1. Nephrops norvegicus from UWTV footage.
Hey once more!

I’m reporting from on board the RV Celtic Voyager with updates from days 5 and 6 of the Nephrops norvegicus UWTV Survey. The survey is in full swing and at current the crew have managed to cowl greater than half the variety of deliberate stations, making good progress. The climate situations, to this point have been glorious, permitting us to finish, on common one station per hour. For every station it could possibly take roughly half-hour to get the digital camera sledge down onto the seafloor, stabilise it and report footage for 10 minutes earlier than retrieving it. Steam time varies between stations, however on common has been round half-hour for many.

Day 5 began off easy with our first station accomplished by 8:20 am, having began simply earlier than 8 am. After station one, we got here into some technical points with the UWTV sledge, however this was mounted promptly, and we have been quickly off once more, to proceed recording (Determine 2). For many of at this time the crew continued to work by burrow counting (Determine 3a and 3b) and recording UWTV footage (Determine 4a and 4b). 

Determine 2. Jonathan on deck with P&O crew doing UWTV sledge upkeep.

Determine 3a. Mikel and John (controlling sledge) working the midnight to 4 am shift 

Determine 3b. Jonathan and I (controlling sledge) on the 8 am – 12 pm shift

Determine 4a. Marcin counting Nephrops burrows from UWTV footage 

Determine 4b. Dermot updating the checklist of accomplished stations.

Determine 5. Frequent skate from UWTV footage.

Determine 6. Fish resting in burrow.

Determine 7. Monkfish camouflaged on the ocean flooring.

Determine 8. Octopus swimming alongside the ocean flooring.

Determine. 9 Dawn on the Celtic Sea
Day 6, and what a gorgeous morning to get up to. Solar is shining and air is crisp. As we speak, as we transfer from station to station, we’ll take some seize samples (Determine 10).  Seize samples take a sediment pattern from the ocean flooring, which is taken again to the lab and analysed at a later stage. 

Determine 10. P&O crew retrieving sediment seize
This afternoon, I’m spending extra time reviewing UWTV footage, with a deal with growing my burrow identification expertise. With the assistance of the skilled scientists, I’ve managed to place collectively a montage of some Nephropsburrow varieties (Determine 12, 13, 14). Nephrops burrow identification is kind of a ability, and could be complicated for the novice, because it does take a while to get conversant in totally different burrow varieties and to accurately distinguish and determine Nephrops burrows, from these of different burrow forming fauna.

Nephrops begin growing their burrows roughly 6 – 8 weeks after hatching. They choose the seafloor, in places the place sediments are beneficial, having the correct amount of silt and clay. The principle figuring out characteristic of the grownup Nephrops burrow, is the distinct crescent formed entrance (Determine 11). Different burrowing species in the identical surroundings have usually round entrances, from burrowing vertically. When viewing the footage, I discovered this to be the troublesome half. It could take a while to determine if all of the defining options are current, to say that it’s actually a Nephrops burrow that you’re . 

Determine 11. Nephrops burrow from UWTV footage, crescent formed entrance.


Nephrops preliminary burrow over time is prolonged, with a second entrance developed, mirroring the primary one. Relying on the sediment kind during which the burrows are excavated, these could be discovered a number of centimetres to virtually a meter other than one another. This method is known as a linear burrow system (Determine 12). 

Determine 12. Nephrops linear burrow system from UWTV footage. Apex of every entrance (black line) pointing in the direction of one another.

Nephrops burrow methods can develop additional, including one other tunnel to their authentic linear system. The brand new tunnel added to the system is usually constructed at 90o to the first tunnel and varieties a “T”- formed kind system (Determine 13).

Determine 13. Nephrops “T” – formed burrow system from UWTV footage.

Over time, the tunnels can develop into much more complexed. Inside complicated “T” – formed tunnels, the entrances usually begin to be developed asymmetrically, versus symmetrically within the linear and easy “T” – formed burrow methods. This asymmetry improvement begins to happen normally after the fourth entrance is constructed. Determine 14 exhibits one of many complexed “T” – formed burrow system, that we noticed on this survey.

Determine 14. Nephrops complexed “T” – formed burrow system from UWTV footage.

For the remainder of the crew, it was one other day of getting by burrow counts and recording extra footage, at every of the deliberate stations. We’re making good progress, with lower than 20 stations to finish for the remaining few days. It’s exhausting to imagine that we’re approaching the final days of the survey. The primary few days have been actually superb, and the time has handed by quick.

Preserve a watch out for the closing weblog on this collection, for extra alluring UWTV captions and for updates of the remaining days of the Nephrops survey on board the RV Celtic Voyager.

Weblog by Dean Anthony Notaro



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