Marine

Denise O’Sullivan’s TTRS Expertise with the Irish Anglerfish and Megrim Survey


My identify is Denise O’Sullivan and I graduated as a Marine Scientist in NUI Galway in 2015. Since graduating I’ve been working as a benthic ecologist which entails figuring out the invertebrate animals that stay on the seafloor.  This March I spent 9 days aboard the RV Celtic Explorer engaged on the Irish Anglerfish and Megrim Survey as a part of  the Strategic Marine Alliance for Analysis and Coaching’s (SMART) survey placement programme, TTRS. It is a nice technique to get expertise at sea and study new functions and abilities. 

The Irish Anglerfish and Megrim Survey

The Irish Anglerfish and Megrim Survey was launched in 2015  to extend our understanding of anglerfish and megrim shares on the Irish Coast. The survey is split into 4 legs and I used to be onboard for leg 3. Leg 3 known as the Irish Beam Trawl Ecosystem Survey as it’s barely completely different utilizing a beam trawl as a substitute of the Jackson demersal trawl used on the opposite legs. Two 4 metre large beam trawls are lowered onto the seafloor on the similar time to match the outcomes of utilizing  a liner and non liner codend. This beam trawl info can be utilized to attach the Irish Anglerfish and Megrim Survey with the UK beam trawl surveys to get an outline of Anglerfish shares in  the Worldwide Council of Exploration of the Sea’s (ICES) space 7.

Determine 1. Catch being emptied into fish bins

What the Survey Does

The catches are small attributable to utilizing a beam trawl, often one field per internet (Determine 1) and dominated by megrim, anglerfish and different flatfish. The catch is sorted into species, weighed and entered into an digital database (Figures 2 and three). That is linked to five work stations within the moist lab the place the fish are sampled. All knowledge is captured electronically utilizing a pill, measuring board of bar codes and a laser pen to scan these bar codes. 
Determine 2. Catch earlier than sorting on the conveyor belt

Determine 3. Catch being sorted into bins


Otoliths and Ageing

At a piece station ( Determine 4) the person fish are measured and weighed, sexual maturity decided and otoliths extracted. Otoliths are small white calcareous buildings discovered within the interior ear which have a number of helpful capabilities. They supply an perception into the age of the fish as opaque bands symbolize a 12 months of development. The chemical composition of the otoliths can even reveal the surroundings the fish has lived during which supplies info on fish migration. When sampling anglerfish, each the otoliths and illicium are taken. The illicium is the primary antennae on the anglerfish head which they use for predation however can be used for getting old. Figures 5 to 9 present otolithis and illicia being taken and the way otholiths are saved.  The sexual maturity of the fish will be simply recognized by trying on the construction of the ovaries and testes. Sampling their sexual maturity permits us to grasp when sure species reproduce together with at what age, size and time of 12 months.
 

Determine 4. Work station with a John Dory (Zeus faber) on the measuring board

Determine 5. Otolith being extracted from an anglerfish utilizing a forceps

Determine 6.  Illicium being lower from an anglerfish  

Determine 7. The place the megrim is lower to gather otolith
Determine 8. Otolith will be seen to the left contained in the fish

Determine 9. How otoliths are saved

Fascinating Add-ons

On all surveys there are requests to hold out varied duties for varied tasks being performed by the Marine Institute. On this survey it included sampling Dublin Bay prawns (Nephrops norvegicus). All Nephrops need to individually sexed, weighed and measured. Boarfish sampling was additionally carried out. This concerned extracting and preserving gonads from boarfish to be analysed again within the lab.  Opportunistic elasmobranch tagging is carried out on all fisheries surveys. Giant species of sharks and rays had been  put right into a water tank when caught to maintain them alive. They’ll then be tagged utilizing a plastic (typical) tag which is inserted onto their dorsal fin. On this survey we had been fortunate sufficient to tag a clean hound  (Mustelus mustelus) which will be seen beneath (Determine 10).
 

Determine 10. Clean hound with tag connected to dorsal fin

Nice to be concerned

An awesome survey to be on total. A small staff of 5 scientists on every shift meant getting caught in and studying loads on the job. The great climate made work loads smoother and simpler and we even obtained a great view of the Skelligs on the best way dwelling (Determine 11).

Determine 11. Skellig Michael and Skellig Beag
Acknowledgements
I want to thank Chief Scientists on board Hans Gerritsen and Sara Jane Moore and the remainder of the scientists. Due to Captain Dennis Rowan and his crew for ensuring every part went easily, Tony and Kevin for maintaining us fed and completely happy. I’m additionally very grateful to John Boyd and the Strategic Marine Alliance for Analysis and Coaching for giving me the chance to go aboard the RV Celtic Explorer

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