Data from: Distribution of the invasive Caprella mutica Schurin, 1935 and native Caprella linearis (Linnaeus, 1767) on artificial hard substrates in the North Sea: separation by habitat

Studying offshore natural and artificial hard substrates in the southern
North Sea (51ºN–57ºN/1ºW–9ºE), the invasive introduced Japanese skeleton
shrimp Caprella mutica Schurin, 1935 was found to co-exist with the native
Caprella linearis (Linnaeus, 1767) only on near-shore locations that had
an intertidal zone (e.g., wind farm foundations). In contrast, on far
offshore and strictly subtidal locations, such as shipwrecks and rocky
reefs, only C. linearis was found. Based on these exploratory
observations, we hypothesised that artificial structures that are only
subtidal are inhabited exclusively by C. linearis, and never by C. mutica.
To test this hypothesis and understand factors driving each species’
habitat preferences, habitat suitability models were constructed using
generalised additive models, based on samples collected in 2013–2015 from
offshore gas platforms, buoys, shipwrecks, and rocky reefs and combined
with data from other published and unpublished surveys (2001–2014). The
models showed that the presence of C. mutica is explained by the
availability of intertidal and floating hard substrates, suspended
particulate matter density (SPM), mean annual sea surface temperature,
salinity, and current velocity. The C. linearis model included subtidal
hard substrates, SPM, salinity, temperature, and current velocity. The
modelled distributions showed a significant difference, demonstrating that
C. linearis’ habitat preference does not fully overlap with that of C.
mutica. Thus, the native and alien Caprella species are likely to be able
to co-exist in the North Sea.