|Determine 1. Mobilising for IAMs Leg 1 on the docks in Galway|
My identify is Kevin McGookin, I’m a latest graduate of Earth and Ocean Science on the Nationwide College of Eire, Galway and I used to be chosen to participate within the SMART Coaching By Analysis Scheme (TTRS). The primary leg of the survey befell aboard the R.V. Celtic Explorer (Determine 1) from the 1st-Thirteenth of March 2019. The first goal of the IAMS is to acquire distribution and abundance estimates for 2 species of anglerfish (Lophius piscatorius and L. budegassa) and set up an abundance index for megrim (Lepidorhombus whiffiagonis and L. boscii) of the coast of Eire. The secondary aims of the survey had been to gather information on different commercially viable species equivalent to Haddock (Melanogrammus aeglefinus), Hake (Merluccius merluccius) and Plaice (Pleuronectes platessa) whereas additionally amassing information of elasmobranchs (cartilaginous fish together with sharks, rays and skates). Key biometric information collected for industrial species included fish lengths, weights, intercourse and maturity phases.
The survey began in Galway and sadly was delayed by a day by Atlantic storms. As soon as we set of it was an extended steam as much as of the coast of Donegal the place we did our first trawl. Survey operations befell over 24 hours with every day divided into two twelve hour shifts and I used to be allotted the 16:00 to 04:00 shift. Tows had been made on the seabed with every tow lasting one hour at predetermined stations and depths. Station positions, heading and backside depth had been recorded in the mean time the gear settled on the underside and from the second we began to haul it again. As soon as the online was hauled up on the deck the fish had been positioned in a hopper which allowed them to be transported by conveyor belt into the moist lab for separation and sorting into species.
|Fig. 2. The moist lab the place fish had been sorted by species, measuring stations are additionally seen.
Within the moist lab fish moved down the conveyor belt with 4 or 5 scientists positioned at intervals sorting and putting them in their very own containers. As soon as all fish had been moved down the belt and sorted some species had been additional separated by intercourse. All species teams had been then weighed to provide a species pattern weight for every station. The containers had been then taken to the work stations the place they had been measured and weighed with a fundamental dissection carried out to find out intercourse and the stage of sexual maturation. For commercially viable species otoliths had been eliminated to offer estimates of age. Otoliths are onerous calcium carbonate constructions situated straight behind the mind of bony fish which give the fish with a way of orientation and sound detection. Illicia (Determine 3), the trademark lure on high of the pinnacle of the anglerfish had been additionally eliminated as a secondary methodology for getting older the fish. Hauls different in measurement however usually took about an hour and a half to type via and course of and as soon as completed relying on location you may be just a few hours away from the subsequent station or the fish may already be within the hopper ready for you!
|Fig. 3. Anglerfish (Lophius piscatorius) with illicia current|
We began with some deep-sea hauls and had supposed to do as a lot of those as potential to make issues simpler for the next survey legs however opposed climate circumstances pushed us additional south into extra sheltered shallow water stations. The deep-sea trawls pulled up some extraordinary fish which had been thrilling to see and in addition a bit puzzling to establish. A few of these fascinating species are proven under in Figures 4-6.
|Fig. 4. Kevin McGookin with a Straightnose Rabbitfish (Rhinochimaera atlantica)|
|Fig. 5. A Black Scabbard (Aphanopus carbo)|
|Fig. 6. A species of Scorpionfish (Scorpaenidae)|
As soon as away from the deep sea trawls issues grew to become much more routine with related haul sizes and extra acquainted species so there wasn’t a lot to confuse us! On common we sorted and processed 3-4 hauls every shift with downtime being spent within the lounge or combing via Fishbase. There have been additionally alternatives to gather different information equivalent to anglerfish stomachs for dietary evaluation and DNA sampling from elasmobranchs equivalent to cuckoo rays.
One memorable half was mentioning a spawning feminine anglerfish (Lophius piscatorius) which I used to be informed will be fairly uncommon (it solely occurred as soon as on our survey). Anglerfish ovaries differ from different bony fish in that they encompass a really lengthy ribbon of gelatinous materials which comprise the eggs, the feminine releases the ribbon and it’s then fertilized externally nevertheless spawning behaviour has by no means been straight noticed and areas the place spawning happens are poorly documented in Irish waters. This explicit feminine weighed simply over 20kg together with her ovaries weighing 6kg and spanning 7m!
|Fig. 7. A spawning feminine Anglerfish (Lophius piscatorius) with ovaries stretching 7m in size.|
I hope you loved a small glimpse into the method of such a survey like this. I want to take this chance to thank John Boyd from SMART sea faculty and Dr Eoghan Kelly and Dr Leonie O’Dowd of Fishery Ecosystem Advisory Companies on the Marine Institute for the possibility to participate on this survey. I might additionally prefer to thank the scientific crew on the survey who helped me to be taught lots and made it a really worthwhile and memorable expertise. Lastly, I want to thank the Captain and the crew on board the Celtic Explorer who allowed every little thing to run easily for us.
|Gannets following the Celtic Explorer at Sundown|