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Published September 19, 2022 | Version v1
Dataset Open

Reef effect of offshore structures on the occurrence and foraging activity of harbour porpoises

  • 1. University of Aberdeen

Description

With increasing numbers of offshore structures to be decommissioned, a better understanding of their effect on marine predators is timely. There is some evidence that oil and gas platforms may attract marine mammals acting as artificial reefs. However, it is unclear whether different man-made structure designs have similar effects. Further, due to the lack of baseline data prior to installation, it is unknown whether artificial structures modify the diel patterns of occurrence and foraging behaviour of marine mammals. Here, we used passive acoustics to investigate the occurrence and foraging activity of harbour porpoises (Phocoena phocoena) around three artificial structures of different age and complexity. We deployed an array of echolocation click detectors (CPODs) in 2021, along a gradient of distances to these structures and assessed the extent to which porpoises were attracted to them. We also investigated the effect of these structures on the diel patterns of occurrence and foraging activity of porpoises. The probability of porpoise occurrence and foraging activity decreased with distance from offshore structures. A significant increase in porpoise occurrence and foraging was detected during night-time compared to daytime around all three offshore structures (< 200 m). Comparing pre- and post-installation porpoise detections, the daily patterns of occurrence and foraging activity shifted from a weak diel pattern before the structure was installed, to a strong nocturnal pattern when the structure was present. These findings provide evidence that marine mammals are attracted to man-made structures and that porpoises modify their diel patterns of occurrence and foraging activity around them. This research suggests that offshore structures play an important role as foraging areas for marine mammals and provides key information for the decommissioning process.

Notes

Data consist of 20 files and include the datasets and R code required to repeat all the analyses. A full description of the files provided in the OFB_ReefEffect_Readme.txt file:

1.      OFB_ReefEffect_CPODexe_HP-Clickdetails_Aug2021.csv

2.      OFB_ReefEffect_CPODexe_HP-DPH_perDAY_2021.txt

3.      OFB_ReefEffect_CPODexe_HP-PPM_perHOUR_2021.txt

4.      OFB_ReefEffect_CPODexe_MaxClickInfo_perDAY_Aug21.csv

5.      OFB_ReefEffect_TPODexe_HP-ClickTimes_2005.csv

6.      OFB_ReefEffect_TPODexe_HP-PPM_perHOUR_2005.txt

7.      OFB_ReefEffect_HP-DPH-BPH_perDAY.csv

8.      OFB_ReefEffect_HP-DPH-BPH_perDAY_FinalDataset.csv

9.      OFB_ReefEffect_ HP-DPH-BPH_perDAYNIGHT_FinalDataset.csv

10.  OFB_ReefEffect_HP-PPM-BPM_perHOUR_2021.csv

11.  OFB_ReefEffect_HP-PPM-BPM_perHOUR_2005.csv

12.  OFB_ReefEffect_HP-PPM-BPM_Pre-Post-FinalDataset.csv

13.  OFB_ReefEffect_OffshoreStructures_Locations.csv

14.  OFB_ReefEffect_PAMLocations.csv

15.  OFB_ReefEffect - Buzz extraction and summarise perHour and perDay.R

16.  OFB_ReefEffect - Create DPH-BPH perDay - Final dataset.R

17.  OFB_ReefEffect - Create DPH-BPH perDayNight - Final dataset.R

18.  OFB_ReefEffect - Create Pre-Post Structure dataset.R

19.  OFB_ReefEffect - GLM GAM Modeling.R

20.  OFB_ReefEffect - Manuscript Plots

Funding provided by: Department for Business, Energy and Industrial Strategy, UK Government
Crossref Funder Registry ID: http://dx.doi.org/10.13039/100011693
Award Number: OESEA-20-125 and OESEA-21-133

Files

OFB_ReefEffect_CPODexe_HP-Clickdetails_Aug2021.csv

Files (312.7 MB)

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Additional details

Related works

Is cited by
10.3389/fmars.2022.980388 (DOI)
Is derived from
10.5281/zenodo.6772078 (DOI)