Fischer, Philipp; Lienkämper, Miriam; Brand, Markus; Weyel, Niklas (2025): Fish counts and species at and around artificially introduced tetrapod fields in the southern North Sea, 2024 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.983964
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Published: 2025-07-25 • DOI registered: 2025-07-25
Abstract:
With increasing global change, coastal protection measures are becoming increasingly important for preserving our coastal features and infrastructure. Coastal protection often comes in the form of artificial structures however, artificial structures can also appear as renewable energy projects, maritime infrastructure and aquaculture installations. The ecological effects of such structures on the natural surroundings remains largely unclear. 36 tetrapod structures (4-footed concrete breakwaters each weighing 2.8 t) in groups of six were added to the MarGate underwater experimental (see figure 1 in metadata description) area to the north of Helgoland, in the Southern North Sea, in 2009 at 5 and 10 m water depth. The 5 m fields TN5 (North), TM5 (Middle) and TS5 (South) have been monitored monthly, since their introduction, with respect to the abundance, species composition and size of the associated biota community. By carrying out this monitoring project, we aim to study the long-term effects of artificial structures on the local biotic community in shallow coastal ecosystems. Line transect based visual fish census conducted by trained scientific divers is used to survey the fish communities in the vicinity of each tetrapod field. Data collection is communicated by the diver via voice communication of the surface and noted directly in the standardized protocol together with metadata on algae coverage other environmental parameters. Further details regarding the sampling design can be found in the metadata section "Survey Design and Sampling Methodology".
Survey Design and Sampling Methodology
At each tetrapod field (TN5, TM5, and TS5), four permanent 20-meter transect lines were established in the cardinal directions (figure 1): North (N), East (O), South (S), and West (W). Each transect was marked at intervals of 0, 5, 10, 15, and 20 meters from the respective outer edge of the tetrapod field.
At each of these five counting stations along the transects, fish were surveyed within a 2 m² area — 1 m² to the left and 1 m² to the right of the transect line — totaling 10 m² per transect and 40 m² per field. For each observation, the following data were recorded:
• Species identity,
• Total number of individuals (abundance),
• Individual total length (in cm).
This standardized method resulted in a total surveyed area of 120 m² per counting event:
• 3 tetrapod fields × 4 transect lines × 5 stations × 2 m² per station = 120 m².
Keyword(s):
Related to:
Fischer, Philipp; Lienkämper, Miriam; Brand, Markus (2025): Fish counts and species at and around artificially introduced tetrapod fields in the southern North Sea, 2022 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.983844
Fischer, Philipp; Lienkämper, Miriam; Brand, Markus; Mccrea, Cameron; Hoffmann, Henning; Schaeper, Hans; Pogson, Katie; Nader, Lola (2025): Fish counts and species at and around artificially introduced tetrapod fields in the southern North Sea, 2023 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.974110
Wehkamp, Stephanie; Fischer, Philipp (2013): Crustaceans and fish abundances and species at and around artificially introduced tetrapod fields in the southern North Sea, 2009 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.821909
Wehkamp, Stephanie; Fischer, Philipp (2013): Crustaceans and fish abundances and species at and around artificially introduced tetrapod fields in the southern North Sea, 2010-2011 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.821915
Wehkamp, Stephanie; Fischer, Philipp (2013): Crustaceans and fish abundances and species at and around artificially introduced tetrapod fields in the southern North Sea, 2013 [dataset]. Alfred Wegener Institute - Biological Institute Helgoland, PANGAEA, https://doi.org/10.1594/PANGAEA.821916
Further details:
Fischer, Philipp; Lienkämper, Miriam; Brand, Markus; Bussmann, Ingeborg; Brix, Holger (2025): Hydrographical time series data of Helgoland, Southern North Sea, 2024 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.986331
Project(s):
Coastal Ecology @ AWI (AWI_Coast)
MarGate (MarGate)
Coverage:
Median Latitude: 54.193125 * Median Longitude: 7.878254 * South-bound Latitude: 54.192530 * West-bound Longitude: 7.877530 * North-bound Latitude: 54.193700 * East-bound Longitude: 7.879000
Date/Time Start: 2024-03-13T11:21:00 * Date/Time End: 2024-12-13T12:55:00
Minimum DEPTH, water: 5 m * Maximum DEPTH, water: 5 m
Event(s):
MarGate_TM5 (Helgoland_TMI, TM5) * Latitude: 54.192970 * Longitude: 7.878450 * Elevation: -5.0 m * Location: German Bight, North Sea * Campaign: Helgoland * Basis: Marine Station Helgoland * Method/Device: Sampling by diver (DIVER)
MarGate_TN5 (Helgoland_TN, TN5) * Latitude: 54.193700 * Longitude: 7.877530 * Elevation: -5.0 m * Location: German Bight, North Sea * Campaign: Helgoland * Basis: Marine Station Helgoland * Method/Device: Sampling by diver (DIVER)
MarGate_TS5 (Helgoland_TS, TS5) * Latitude: 54.192530 * Longitude: 7.879000 * Elevation: -5.0 m * Location: German Bight, North Sea * Campaign: Helgoland * Basis: Marine Station Helgoland * Method/Device: Sampling by diver (DIVER)
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | Event label | Event | Fischer, Philipp | |||
| 2 | DATE/TIME | Date/Time | Fischer, Philipp | Geocode | ||
| 3 | DEPTH, water | Depth water | m | Fischer, Philipp | Geocode | |
| 4 | Name | Name | Fischer, Philipp | Diver initials | ||
| 5 | LATITUDE | Latitude | Fischer, Philipp | Geocode | ||
| 6 | LONGITUDE | Longitude | Fischer, Philipp | Geocode | ||
| 7 | Direction | Direction | Fischer, Philipp | Compass direction | ||
| 8 | Distance | Distance | m | Fischer, Philipp | ||
| 9 | Kelp, percentage, range | Kelp percent | Fischer, Philipp | |||
| 10 | Red algae, percentage, range | Red algae percent | Fischer, Philipp | |||
| 11 | Species, unique identification | Species UID | Fischer, Philipp | |||
| 12 | Species, unique identification (Semantic URI) | Species UID (Semantic URI) | Fischer, Philipp | |||
| 13 | Species, unique identification (URI) | Species UID (URI) | Fischer, Philipp | |||
| 14 | Length class | Length class | Fischer, Philipp | cm | ||
| 15 | Number of individuals | Ind No | # | Fischer, Philipp |
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Status:
Curation Level: Enhanced curation (CurationLevelC)
Size:
7781 data points
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