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WELCOME ON BOARD OF THE R/V ARQUIPELAGO!
WELCOME ON BOARD OF THE R/V ARQUIPELAGO!
Since 1994 and with few exceptions, the spring bottom longline survey (ARQDAÇO) takes place on board of the research vessel Arquipelago [1].
The aim of the expeditions is to collect:
fishery-independent data on abundance and size composition;
biological information such as growth, parasites, reproduction, migration, and diet;
ecological information on depth range, distribution, and community structure.
STONE AND BUOY GEAR
STONE AND BUOY GEAR
The gear used during the survey is the very similar to the one used by the commercial fleet in the Azores and it is known as the ‘‘stone and buoy’’ longline. Indeed, stones and buoys that are attached to the longline progressively during the deployment. In the “quarter skates” (the wooden box) there is the longline with around 30 hooks already prepared with chopped salted sardine baits [1].
TARGETED SPECIES
TARGETED SPECIES
Here are some of the main targeted species, in particular Pagellus bogaraveo. However, bycatch of other species may occur. When this happens, the adopted procedure depends on the species, for example corals are collected for lab identification and analysis, while alive deep sea sharks are tagged and released.
MARK AND RELEASE WORKSTATION
MARK AND RELEASE WORKSTATION
Tags must be applied following the correct procedure otherwise you may either hurt greatly the animal or the tag may be too loose and thus easily lost. On board, two different types of tags were used:
stainless steel dart tags are used for big teleosts and elasmobranchs [2]
T-bar anchor tags for smaller fish [3].
All the following information were recorded on a sampling sheet:
✔ Species
✔ Stratum (depth)
✔ Length
✔ Tag number
✔ State (high activity, low activity)*
➡After all these steps are done, BACK TO THE WATER!
*The definition of the state depends on the species, for example for Scorpaena scrofa, you must check if it breathes regularly and expands its mouth, instead with sharks you must observe their behavior also right after the release (e.g. if they swim away right after or lay close to the surface).
Watch the procedure below!
(I know the quality of the video is very low, but please, be merciful: I was filling in the sampling sheet at the same time)
Test what you learnt about the mark and release workstation by taking a quiz!
Test what you learnt about the mark and release workstation by taking a quiz!
SAMPLING WORKSTATION
SAMPLING WORKSTATION
All catches are reported specifying species, number, and depth of each individual. This data is essential to obtain abundace indices, and depth range.
For size composition estimation, all individuals were measured to the lowest unit using ichtyometers, and weighted.
TO CUT SHORT... SOME SAMPLES
Otoliths
Otoliths
The otolith are located in in the utricule and must be extracted possibly without breaking them. When the fish was still alive, the otolithic membrane provided a mechanical linkage between the otolith and the cilia of the sensory hair cells [4].
Gonads
Gonads
In order to assess sex and maturity, gonad were inspected and, for some species, collected for histology analyses in lab. First, they must be found. Secondly, species-specific maturation scales were used to assess the stage. and this was the tricky part.
Liver, DNA, ...
Liver, DNA, ...
Depending on the species and the ongoing projects, different cut were performed.
Obviously, before taking samples for genetic studies, all the tools (tweezers, scissors, etc.) were rinsed.
STALKING DEEP-SEA SHARKS WITH A BRUV!
STALKING DEEP-SEA SHARKS WITH A BRUV!
The SOS TubaProf is a project whose general aim is the evaluation of sustainability of deep-sea sharks bycatch. A goal that can't be reached but with the collaboration between researchers and fishers.
The team relies on a Baited Remote Underwater Video (BRUV) to capture deep sharks in their natural habitat, estimate relative abundances, and test an eventual monitoring program.
In the video you can see the deployment of the BRUV system that consists basically of a metal structure with an underwater camera, a lamp, and...the bait, chopped salted sardines!
REFERENCES
REFERENCES
[1] Pinho, Mário, et al. "Azorean demersal longline survey abundance estimates: Procedures and variability." Regional Studies in Marine Science 39 (2020): 101443. https://doi.org/10.1016/j.rsma.2020.101443 [2] Medeiros‐Leal, W., Santos, R., Novoa‐Pabon, A., Silva, H., Pinho, M., 2021. Population structure of the European conger Conger conger from the mid‐North Atlantic Ocean inferred from bathymetric distribution, length composition and movement patterns analyses. Fish. Manag. Ecol. https://doi.org/10.1111/fme.12485[3] Santos, R., Pabon, A., Silva, W., Silva, H., Pinho, M., 2020. Population structure and movement patterns of blackbelly rosefish in the NE Atlantic Ocean (Azores archipelago). Fish. Oceanogr. 29, 227–237. https://doi.org/10.1111/fog.12466 [4] Helfman, Gene, et al. The diversity of fishes: biology, evolution, and ecology. John Wiley & Sons, 2009.
IMAGE CREDITS
IMAGE CREDITS
- Targeted species: © Les Gallagher - Fishpics® & IMAR-DOP, UAç.
- Pagrus pagrus otolith: İşmen, Ali, et al. "Otolith morphometry and population parameters of red porgy, Pagrus pagrus (Linnaeus, 1758) in Saros Bay (North Aegean Sea)." Su Ürünleri Dergisi 30.1 (2013): 31-35.
Unless specified, all the pictures/videos were taken on board by me or other crew members/friends.
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