Structure in a sea of sand: fish abundance in relation to man-made structures in the North Sea

Abstract

Artificial structures in the marine environment may have direct and/or indirect impact on the behaviour and space use of mobile foragers. This study explores whether environmental and physical features in the North Sea—including artificial structures (wrecks, wind turbines, cables, and oil and gas structures) were associated with local abundance of three fish species: cod (Gadus morhua), plaice (Pleuronectes platessa), and thornback ray (Raja clavata). Generalized additive models (GAMs) were used to compare distributions between data collected by fisheries surveys and electronic tags. Distributions of cod, plaice, and ray were correlated with environmental variables including temperature, depth, and substrate, matching findings from previous studies. All species showed seasonal increases in their abundance in areas with high densities of artificial structures, including oil and gas platforms and wrecks. Independent of whether fish purposefully associate with these features or whether structures happen to coincide with locations frequented by these populations, the strong association suggests that greater consideration needs to be given to regulation of habitat alterations, including decommissioning.

Echolocation activity of harbour porpoises, Phocoena phocoena, shows seasonal artificial reef attraction despite elevated noise levels close to oil and gas platforms

“…Based on connectivity modelling, Tidbury et al (2019) estimated that up to 60% of North Sea marine species connectivity could be broken if all O&G structures were removed. Abundance of North Sea fish species like cod (Gadus morhua) and plaice (Pleuronectes platessa) have been found to correlate with offshore structures including O&G platforms (Wright et al, 2020). There are indications that, ultimately, O&G structures attract North Sea top predators such as sharks and marine mammals (Todd et al, 2016), including harbour porpoises (Delefosse et al, 2017).…”

Combining ecosystem modeling with serious gaming in support of transboundary maritime spatial planning

“…Pressure categories such as noise, surface disturbance, and bottom disturbance are broad generalizations of much finer disturbances that could have wide ranges of impacts on marine animals if properly included in accordance with recent studies (Williams et al 2015, Hawkins and Popper 2017, Platteeuw et al 2017, Spence et al 2018. Similarly, there are many types of artificial substrate that offer different benefits across ecosystems (e.g., Wright et al 2020), and variety in marine protection schemes is broadly studied (Katsanevakis et al 2011, Horta e Costa et al 2016, Stelzenmüller et al 2018. Because of limitations in computational power, we opted to include only the most iconic stressors into the EwE-MSP modeling approach, using generic environmental responses to evoke intuitive first-order responses of the ecosystem to these stressors that then mechanistically cascade through the food web.…”

Mapping silver eel migration routes in the North Sea

“…In addition to bathymetry and tidal amplitude with phase, the model was developed to include sea surface temperature (SST), which can provide additional validation when fish are swimming at or near the surface (i.e. depth ≤ 20 m) 59 , 60 , and temperature at depth, which can provide additional validation when fish remain at depths well below the sea surface 61 , 62 .…”

“…The model was run in three different configurations for each recovered dataset: (i) using the tidal location model only (as for Pedersen et al 57 ), hereafter termed TLM geolocation; (ii) using the TLM plus sea surface temperature (as for Wright et al 60 ), hereafter termed SST geolocation, and (iii) using temperature at the surface and sub-surface, hereafter termed 3D geolocation (Supplemental Fig. S3 ).…”