Data from: Estimating sensitivity of seabed habitats to disturbance by bottom trawling based on the longevity of benthic fauna

Bottom fishing such as trawling and dredging may pose serious risks to the
seabed and benthic habitats, calling for a quantitative assessment method
to evaluate the impact and guide management to develop mitigation
measures. We provide a method to estimate the sensitivity of benthic
habitats based on the longevity composition of the invertebrate community.
We hypothesize that long-lived species are more sensitive to trawling
mortality due to their lower pace of life (i.e. slower growth, late
maturation). We analyse data from box-core and grab samples taken from 401
stations in the English Channel and southern North Sea to estimate the
habitat-specific longevity composition of the benthic invertebrate
community and of specific functional groups (i.e. suspension feeders and
bioturbators), and examine how bottom trawling affects the longevity
biomass composition. The longevity biomass composition differed between
habitats governed by differences in sediment composition (gravel and mud
content) and tidal bed-shear stress. The biomass proportion of long-lived
species increased with gravel content and decreased with mud content and
shear stress. Bioturbators had a higher median longevity than suspension
feeders. Trawling, in particular by gears that penetrate the seabed
>2cm, shifted the community towards shorter-lived species. Changes
from bottom trawling were highest in habitats with many long-lived species
(hence increasing with gravel content, decreasing with mud content).
Benthic communities in high shear stress habitats were less affected by
bottom trawling. Using these relationships, we predicted the sensitivity
of the benthic community from bottom trawling impact at large spatial
scale (the North Sea). We derived different benthic sensitivity metrics
that provide a basis to estimate indicators of trawling impact on a
continuous scale for the total community and specific functional groups.
In combination with high resolution data of trawling pressure, our
approach can be used to monitor and assess trawling impact and seabed
status at the scale of the region or broadscale habitat and to compare the
environmental impact of bottom-contacting fishing gears across fisheries.