WOBEC SOP Agassiz Trawl

Weddell Sea Observatory of Biodiversity and Ecosystem Change – WOBEC Standard Operating Procedures Technical Documentation December 2025 To be cited as Mark, Felix, Katharina Teschke, Nils Van den Steen, and Anton Van de Putte. ‘WOBEC SOP Agassiz Trawl’. Zenodo, 12 December 2025. https://doi.org/10.5281/zenodo.17912454. Co-funded by the European Union (c) The authors This report is licensed under the Creative Commons Attribution International license Versions Date Comment Responsible Approved First draft F. Mark/K. Teschke 12/12/2025 Formatting N. Van den Steen Table of Contents 1 Description of sampling gear......................................................................................................... 4 1.1 Specifications .......................................................................................................................................... 4 2 Sampling gear deployment............................................................................................................. 4 3 Sample sorting-collection-preservation procedure ............................................................. 5 3.1 Set up ......................................................................................................................................................... 5 3.2 Initial sample collection ..................................................................................................................... 5 3.2.1 Bulk catch handling ........................................................................................................................... 5 3.2.2 Fish handling ....................................................................................................................................... 5 3.3 Sorting, sample processing and preservation ............................................................................ 5 3.3.1 Fish .......................................................................................................................................................... 5 3.3.2 Benthos subsamples ......................................................................................................................... 6 Washing ................................................................................................................................................. 6 (Pre)Sorting ......................................................................................................................................... 6 Sample processing ............................................................................................................................. 6 Fixation & preservation ................................................................................................................... 6 3.3.3 Remaining catch ................................................................................................................................. 7 Washing ................................................................................................................................................. 7 (Pre)Sorting ......................................................................................................................................... 7 Fixation & preservation ................................................................................................................... 7 Clean up ................................................................................................................................................. 7 4 Sample analysis method .................................................................................................................. 8 5 Raw and analyzed data formats ................................................................................................... 8 6 References ............................................................................................................................................ 8 Method responsible: Felix Mark 1 Description of sampling gear Description of the sampling device that is used, required materials, equipment, required/recommended (function and safety) checks. GEAR: Agassiz Trawl (AGT) Schematic illustration 1.1 Specifications Agassiz Trawl: 3m (width) x 1m (height), mesh size: 10 mm Agassiz Trawl small: 1.5m (width) x 1m (height), mesh size: 10 mm • Use net sensor (Typ/Specification) or bottom contact sensor • Any additional positioning system? GPS, Posidonia, GAPS • Specification of net (botton chain/chaising chain, mesh size) • Crow’s foot • Trawling line (Durchmesser/Tragstärke) Reference? Specification in XYZ et al., Link to AWI O2A 2 Sampling gear deployment BOX - Essential Metadata Trawl data needed: latitude / longitude at bottom and off bottom, water depth (from net sensor), water temperature (from net sensor), time at bottom and off bottom, station number, ship speed (available on screens around ship) • How many stations, which stations, replicates per station? 1 haul per station Non-destructive sampling gear (e.g., OFOBS) first, then AGT • Trawl time/bottom time • Trawling speed (1-2 knots) • Wire in / out at 1 m s-1 • Empty on deck / sorting table Met opmerkingen [1]: https://sleds-and-trawls-fieldmanual.github.io/field-procedures Met opmerkingen [2]: will both be used? Met opmerkingen [3]: on WOBEC cruise?preferred method? Met opmerkingen [4]: Wrench? Met opmerkingen [5]: very limited Met opmerkingen [6]: data acquisition from net sensor: real time or afterwards? Met opmerkingen [7]: safety on deck?description of trawling procedure? for vessel/operator dependent parameters, indication of key points? Met opmerkingen [8]: What needs to be determined? go/nogo? Met opmerkingen [9]: to be decided? Met opmerkingen [10]: pick speed between 1 and 2 knots and keep constant? 3 Sample sorting-collection-preservation procedure Once the gear is back how is the sample collected, sorted and preserved (in a sense from deck to jar). 3.1 Set up Before starting the sample collection and sorting process, ensure the following equipment is ready: 1. 2x hoses (for cleaning and washing samples with seawater) 2. Fish baskets (number as needed based on catch size) 3. 2x sieves (with appropriate mesh size) for cleaning and washing samples 4. 4x wet buckets (for water-based sorting) 5. 6x sorting trays (for sorting without water) 6. Photo station (for photographing samples with station labels) 7. Vials and preservation chemicals (for sample storage and preservation) 8. Storage ice (to preserve samples while awaiting sample processing) 3.2 Initial sample collection 3.2.1 Bulk catch handling • Drop the bulk catch on deck for sorting. • Take photograph(s) of the catch with an event label (see SOP for labeling) to ensure later cross-referencing with metadata. 3.2.2 Fish handling • The fish team will handle gross exposed fish. 3.3 Sorting, sample processing and preservation 3.3.1 Fish • Samples are sorted in the lab for further processing. Further information is required here. Met opmerkingen [11]: seawater? Met opmerkingen [12]: which is? Met opmerkingen [13]: @ Felix: Which mesh size did you use onboard PS129? And would you recommend the same mesh size again? Spontaneously I would say 10 mm -> same mesh size as AGT "2x sieves (with a mesh size corresponding to that of the codend mesh of the AGT) for cleaning and washing the samples. Met opmerkingen [14]: which is? Met opmerkingen [15]: undefined Met opmerkingen [16]: rough estimation quantity? Met opmerkingen [17]: @ Felix: I assume the storage ice is for preserve the fish, right? Met opmerkingen [18]: estimation of quantity? or typically? Met opmerkingen [19]: Labeling SOP will be created Met opmerkingen [20]: on deck? 3.3.2 Benthos subsamples • Spade mud cubes (~20x20 cm) from the trawl into two of the fish baskets and bring them to the washing station. REF? Is this representative for AGT hauls? Washing • Use fire hoses with adjusted pressure to create a gentle flow on deck to wash subsamples, placing small sieves underneath to collect any washed materials. • Place buckets underneath the sieves to catch any remaining organisms. (Pre)Sorting • Place cleaned benthic organisms into buckets of (temperature-chilled) seawater (priority given to live specimens) or trays (organisms for preservation). • Ferry buckets and trays to sorting station. See Coggan et al. (2005) for practical advice on setting up a sorting station. • Sort organisms into taxonomic groups based on previous decisions about onboard level of sorting. Progressively sort organisms into finer taxonomic groups as much as time or expertise allows. This may be done up to a predefined operational taxonomic unit or species level. Sample processing • Weigh, count (depending on time?), and photograph each of the final group. Ensure this is done in a way that does not destroy the DNA in the specimens (e.g., pericards need to be kept chilled and moist). See Schiaparelli et al. (2016) for suggestions on specimen photography. • Photographs: (A) Include a unique identifier, such as an event label (preferably: PANGAEA event label = label in ship's log) to avoid confusion when processing several events and to ensure later cross-references with metadata, in the photographs. (B) Include a scale bar in the photographs. See Schiaparelli et al. (2016) for guidelines on photography. Fixation & preservation • Relax and fix specimens according to survey objectives and taxonomists' preferences. For example, for genetic analysis, do not fix in formalin. • Preserve specimens based on methods decided during pre-survey planning and place them into containers for long-term storage. Detailed descriptions of fixatives and preservatives used for marine invertebrates can be found in Rees (2009) and Schiaparelli et al. (2016). Met opmerkingen [21]: collected with trawl? Met opmerkingen [22]: to gentle flow? Met opmerkingen [23]: temperature? Met opmerkingen [24]: did not find it https://citeseerx.ist.psu.edu/document?repid=rep1&type=p df&doi=405bfb89a7b53042cc31504880e4859cd4c7dff2#pag e=189 doesn't deal with sorting Met opmerkingen [25]: You are right. Coggan et al. (2005) do indeed not deal with sorting. I checked it again Met opmerkingen [26]: what about "global"/"total" data? Met opmerkingen [27]: when will this be known? Met opmerkingen [28]: In my opinion, the minimum taxonomic groups for sorting should be defined before the expedition. These groups could then be listed in a table in the appendix of this SOP. This should be discussed with Felix and others Met opmerkingen [29]: mention minimal level? Met opmerkingen [30]: procedures? (reference?) Met opmerkingen [31]: full list of methods/requirements/...? Met opmerkingen [32]: should be specified for WOBEC Met opmerkingen [33]: The challenge here is that we do not have a colleague in WOBEC who focuses on benthic samples from the AGT. The main aim of the AGT is to sample fish. However, there is a significant amount of bycatch, and we would like to try to make at least dual use of the AGT samples. My suggestion would be to preserve the benthic organisms in 70% ethanol without first fixing them in formalin. This has a proven disadvantage for the identification of organisms, but advantage would be: Reduce working steps (from fixation to preservation), do not have to handle the step with carcinogen formalin, samples could also be used for genetic analyses Met opmerkingen [34]: https://repository.oceanbestprac tices.org/handle/11329/665 Met opmerkingen [35]: https://onlinelibrary.wiley.com/d oi/abs/10.1002/9781118332535.ch15 • Ensure (solvent-resistant) labels with a unique identifier are placed with each longterm storage sample. It is not sufficient to label only the outside of the container as this can easily rub off. See further information on labelling of samples in Schiaparelli et al. (2016). 3.3.3 Remaining catch • Spade the rest of the catch into the remaining fish baskets. Washing • Use fire hoses with adjusted pressure on deck to wash the rest of the catch, placing small sieves underneath to collect any washed materials. • Place buckets underneath the sieves to catch any remaining organisms. (Pre)Sorting • Place cleaned benthic organisms into buckets of seawater (priority given to live specimens) or trays (organisms for preservation). • Ferry buckets and trays away for "opportunistic" sample processing (e.g., for taxonomy, isotopes, genetics). • Do we want a rough visual estimate of the frequency of taxonomic groups for the remaining catch (semi-quantitative approach with classes such as rare, regular, common, very common)? • Regardless of the further sample processing ensure every time that labels with a unique identifier are placed to each sample (preferably: PANGAEA event label = label in ship's log). Fixation & preservation • See benthos subsample Clean up • After sample collection and sorting are completed, thoroughly clean all equipment and materials used, as well as the deck area to ensure readiness for the next sampling event. Met opmerkingen [36]: we might create separate SOP for this Met opmerkingen [37]: referring to diameter or mesh ? Met opmerkingen [38]: seawater Met opmerkingen [39]: cleaning with water and brush? or detergents? 4 Sample analysis method What analysis and addition measures are taken from the sample or from live specimen in case there are experiments or additional measures that are performed. Indicate the obtained parameters and units. 5 Raw and analyzed data formats What are the raw and processed data formats? What are the data structures? What are the parameters and units? Recording Data: Record data under a unique identifier in the database (see PANGAEA event label under 3. Sample processing). Ensure that labels with the same unique identifier are placed to each taxon of the same event. 6 References • Rees, H. L. (ed). 2009. Guidelines for the study of the epibenthos of subtidal environments. ICES Techniques in Marine Environmental Sciences NO. 42, 88pp. http://dx.doi.org/10.25607/OBP-222 • Schiaparelli, S., K. Schnabel, B. Richer de Forges, and T.-Y. Chan. 2016. Sorting, recording, presevation and storage of biological samples. Pages 338-367 in M. R. Clark, M. Consalvey, and A. A. Rowden, editors. Biological Sampling in the Deep Sea. Wiley Blackwell, West Sussex.