Submersible Gathered Evidence of a Vulnerable Marine Ecosystem at the Melchior Islands, Western Antarctic Peninsula (Subarea 48.1) - multimedia

Imagery to support a proposed VME based on high abundances of VME indicator taxa that fall within the range of previously registered VMEs. The site is off the east coast of Lambda Island, Melchior Islands, Western Antarctic Peninsula. Video imagery was taken via submersible deployed by Seabourn Venture crewed by scientist and volunteer citizen science pilots. Data on the relative percent cover of all VME indicator taxa was sourced and analysed in the same manner as VMEs added to CCAMLR’s registry in 2018 (SC-CCAMLR-XXXVII) and 2022 (SC-CCAMLR-41) using all data from WG-EMM-18/35, WG-EMM-22/34Rev1 and WG-EMM-22/46Rev1 for a direct comparison. The present site clusters with previously registered VMEs. The site supports many large hexactinellid sponges and small bamboo corals. Notable also, is the presence of the rare and little-known hydroid, Candelabrum sp. – a VME indicator taxa that is particularly vulnerable to fishing gear as they can extend metres into the water column.

Method step description: 

1. DaVinci Resolve 18 was used to combine separate files where necessary and for editing. 

2. Clean-up followed the same methodology as was used for analyzing the submarine footage for the successful nomination of VMEs in WG-EMM-22/46Rev1 to remove unusable sequences. For the Lambda Is footage that meant the removal of any sequences where the submersible was too far from the wall, where the visibility was poor and when the submersible was stationary. Footage from Dive A was the longest resulting video after the completion of this clean-up procedure (Table 1), thus it became the footage that was analysed.

3. Footage was color adjusted within DaVinci Resolve 18.

4. The analysis methodology also followed that which was used in WG-EMM-22/46Rev1. To compare the relative percent abundance of VME indicator taxa to that of non-VME taxa and bare substrate at the Lambda Is site, frames were exported at regular intervals (30 secs) beginning at 0:00.

5. The resulting series of images were then imported into the program PAPARA(ZZ)I (Marcon & Purser,  2017). Within this program images were further enhanced by adjusting brightness, contrast and gamma. As recommended by the authors, the usable area was then defined for each image allowing the exclusion of dark or blurred edges.

6. Once images were prepared in this way, an array of 100 random points was overlayed. Each point in each image was assigned one of three designations: VME indicator taxa, non-VME taxa or bare substrate.

This version contains frames (tif files) with area analyzed by PAPARA(ZZ)I boxed. This version is an updated version of https://doi.org/10.5281/zenodo.12179714