RRS Discovery DY159
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS Discovery (74EQ) |
| Cruise identifier | DY159 |
| Cruise period | 2022-10-27 — 2022-12-18 |
| Status | Completed |
| Port of departure | Southampton, United Kingdom |
| Port of return | Montevideo, Uruguay |
| Purpose | Research |
| Objectives | RRS Discovery expedition 159 (DY159) set sail from Southampton, UK in November 2022, headed for the UK Overseas Territories (UKOTs) of Ascension and St Helena. DY159 is the latest in the ongoing series of surveys in the waters of several UKOTs, the third of its kind to St Helena (following JR-17004 and DY100 in 2018 and 2019 respectively) and the first to Ascension. In recent years, both UKOTs have created very large marine protected areas in their exclusive economic zones, collectively totalling almost 900,000 km2 but about which little is known, particularly beyond the narrow island shelf areas. Over 95% of the waters of each MPA is deeper than 200m, but most of the historic research effort has focussed only on inshore habitats. The Discovery expedition 159 aimed to fill some of the data gaps identified as most urgent by marine fisheries and conservation professionals based in each of Ascension and St Helena, by bringing a multidisciplinary team of UK marine scientists to work directly with local staff.
DY159 deployed a wide range of equipment in both UKOTs, principally with the goal of studying the ecology of commercially important species, or habitats and species that occur in previously unexplored areas. In Ascension, the main focus was upon the biodiversity and physical environment of different topographic features of the deep-sea and adjacent near surface habitats in its MPA, notably seamounts and abyssal plains. In St Helena, the priority areas of work were around species of current or prospective commercial importance, such as the small pelagic scads and mackerels that are consumed locally or used as bait in the tuna fishery. The DY159 scientific crew would like to extend our thanks to Captain Mackay and the Discovery's crew for their hard work and inclusive approach that made the survey such a success. The survey team would also like to acknowledge the vital support of the Governments of the UKOTs, and the Foreign, Commonwealth and Development Office 'Blue Belt' Programme, without which this expedition and all its associated work would not be possible. |
| Chief scientist | Paul Whormersley (Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory) |
| Project | Blue Belt Programme |
| Coordinating body | UK Foreign, Commonwealth and Development Office |
| Cruise report |  (15.96 MB) |
| Ocean/sea areas | |
| General | South Atlantic Ocean |
| Specific | St Helena & Ascension Island |
| Track charts | (0.46 MB) (0.29 MB) |
| Measurements | |
| Physical oceanography | |
| CTD stations | Quantity: number of profiles = 13 Description: CTD profiles and water samples for plastics, nutrients, chlorophyll, eDNA |
| Biology and fisheries | |
| Zooplankton | Quantity: number of hauls = 14 Description: Bongo nets (100 and 200 uM) for zooplankton diversity and stable isotopic analysis. 200m to surface hauls. |
| Zoobenthos | Quantity: number of hauls = 18 Description: Towed camera deployments (depth range 200-1850m) to characterise benthic habitats |
| Pelagic fish | Quantity: number of hauls = 14 Description: Tows of rectangular mid-water opening-closing net (depth range 50-1000m). Samples for taxonomic ID, genetics, stable isotopes |
| Acoustic reflection on marine organisms. | Quantity: activity duration in days = 35 Description: Underway recording using SIMRAD EK80 multiband echosounders, including specific periods of dedicated survey around both Ascension and St Helena |
| Exploratory fishing | Quantity: number of hauls = 2 Description: Targeted fishing by local fishers for small pelagic fishes, samples to validate acoustic survey |
| Geology and geophysics | |
| Core - soft bottom | Quantity: number of cores = 3 Description: Box cores taken at abyssal sites round Ascension to be analysed for isotopes, carbon sequestration, eDNA, faunal diversity (depths 3500-3800m) |
| Multi-beam echosounding | Quantity: activity duration in days = 35 Description: Underway recording using EM122, including specific periods of dedicated survey around both Ascension and St Helena |
| Moorings, landers, buoys | |
| Physical oceanography | |
| Surface drifters/drifting buoys | 20° 22' 47" S 21° 0' 0" W — SOFAR Ocean spotter buoy 30345R [not recovered] |
| Surface drifters/drifting buoys | 19° 16' 11" S 16° 0' 0" W — SOFAR Ocean spotter buoy 1875 [not recovered] |
| Surface drifters/drifting buoys | 21° 8' 59" S 25° 0' 0" W — SOFAR Ocean spotter buoy 1877 [not recovered] |
| Surface drifters/drifting buoys | 20° 58' 48" S 23° 59' 23" W — SOFAR Ocean spotter buoy 1869 [not recovered] |
| Surface drifters/drifting buoys | 4° 59' 24" N 19° 47' 23" W — SOFAR Ocean spotter buoy (id not recorded) [not recovered] |
| Surface drifters/drifting buoys | 22° 38' 59" S 35° 0' 0" W — Argo float 8983 [not recovered] |
| Surface drifters/drifting buoys | 19° 1' 11" S 14° 59' 24" W — Argo float 9472 [not recovered] |
| Surface drifters/drifting buoys | 18° 49' 47" S 14° 13' 12" W — Argo float 9471 [not recovered] |
| Surface drifters/drifting buoys | 12° 24' 36" S 8° 41' 23" W — Argo float 8582 [not recovered] |
| Surface drifters/drifting buoys | 22° 31' 48" S 34° 0' 0" W — SOFAR Ocean spotter buoy 1867 [not recovered] |
| Surface drifters/drifting buoys | 20° 46' 48" S 23° 0' 0" W — SOFAR Ocean spotter buoy 1882 [not recovered] |
| Surface drifters/drifting buoys | 20° 35' 23" S 22° 0' 0" W — SOFAR Ocean spotter buoy 30343R [not recovered] |
| Surface drifters/drifting buoys | 20° 10' 47" S 20° 0' 0" W — SOFAR Ocean spotter buoy 300342R [not recovered] |
| Surface drifters/drifting buoys | 19° 56' 59" S 18° 59' 23" W — SOFAR Ocean spotter buoy 30023R [not recovered] |
| Surface drifters/drifting buoys | 19° 43' 48" S 18° 0' 0" W — SOFAR Ocean spotter buoy 30344 [not recovered] |
| Surface drifters/drifting buoys | 19° 30' 0" S 17° 0' 0" W — SOFAR Ocean spotter buoy 1876 [not recovered] |
| Surface drifters/drifting buoys | 18° 46' 48" S 14° 0' 0" W — SOFAR Ocean spotter buoy 1831 [not recovered] |
| Surface drifters/drifting buoys | 2° 0' 0" S 17° 16' 48" W — SOFAR Ocean spotter buoy (id not recorded) [not recovered] |
| Surface drifters/drifting buoys | 4° 9' 36" N 19° 26' 59" W — SOFAR Ocean spotter buoy (id not recorded) [not recovered] |
| Surface drifters/drifting buoys | 22° 59' 23" N 20° 22' 47" W — SOFAR Ocean spotter buoy 2001 [not recovered] |
| Surface drifters/drifting buoys | 19° 1' 11" S 14° 59' 24" W — SOFAR Ocean spotter buoy 1878 [not recovered] |
| Surface drifters/drifting buoys | 19° 30' 0" S 17° 0' 0" W — Argo float 8984 [not recovered] |
| Surface drifters/drifting buoys | 21° 59' 23" N 21° 10' 12" W — SOFAR Ocean spotter buoy 1829 [not recovered] |
| Surface drifters/drifting buoys | 21° 0' 36" N 22° 0' 36" W — SOFAR Ocean spotter buoy 1985 [not recovered] |
| Surface drifters/drifting buoys | 7° 8' 23" N 19° 47' 23" W — SOFAR Ocean spotter buoy 2000 [not recovered] |
| Contamination | |
| Other contaminant measurements | 15° 54' 36" S 5° 47' 59" W — Hydrophone lander [recovered] |
| Other contaminant measurements | 15° 58' 12" S 5° 43' 11" W — Hydrophone lander [recovered] |
| Biology and fisheries | |
| Zoobenthos | 15° 58' 48" S 5° 48' 36" W — Crustacean pots [recovered] |
| Zoobenthos | 5° 45' 0" S 15° 58' 48" W — Benthic scavenger lander |
| Zoobenthos | 9° 41' 59" S 12° 9' 36" W — Benthic scavenger lander [recovered] |
| Zoobenthos | 9° 49' 12" S 12° 45' 35" W — Benthic scavenger lander [not recovered] |
| Zoobenthos | 13° 2' 23" S 6° 2' 24" W — Crustacean pots [recovered] |
| Pelagic fish | 13° 1' 47" S 6° 2' 59" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 16° 5' 23" S 5° 43' 48" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 15° 55' 11" S 5° 46' 11" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 12° 55' 47" S 5° 42' 35" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 12° 58' 12" S 6° 2' 24" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 9° 44' 24" S 12° 49' 12" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 16° 1' 11" S 5° 50' 23" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 5° 33' 36" S 16° 4' 47" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 9° 44' 24" S 12° 5' 23" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 8° 59' 24" S 12° 49' 12" W — Baited Remote Underwater Video System [recovered] |
| Pelagic fish | 13° 46' 11" S 7° 30' 35" W — Baited Remote Underwater Video System [recovered] |
| Acoustic reflection on marine organisms. | 15° 55' 11" S 5° 43' 11" W — Uncrewed surface vehicle (Autonaut Jura) deployed with SIMRAD echosounder instrumentation [recovered] |
