Depth profiles of <i>Mnemiopsis leidyi</i>.

<p>Vertical distribution and densities (ind. m⁻³) for three size classes (S = Small, M = Medium, L = Large) of <i>M. leidyi</i> and zooplankton at Ven station in the Sound during 24-h, and the single station in the Central Baltic Sea (BY1) together with biophysical variables. Irradiance and zooplankton biomass are plotted on log scale.</p

Density estimates of <i>Mnemiopsis leidyi</i> from video-net and Multinet.

<p>Density estimates of <i>Mnemiopsis leidyi</i> from video-net and Multinet.</p

Observed environmental range.

<p>Distributions of environmental variables at Anholt and at Ven for three separate size classes of <i>Mnemiopsis leidyi</i>. Irradiance was only measured during daytime. The box represents 50% of all observations, with the solid line representing the median, the whiskers 10^th and 90^th percentile, and the dots the 5^th and 95^th percentile. Axes correspond to minimum and maximum of measured variables at the respective location. S = Small, M = Medium, L = Large. Small and medium individuals in Kattegat migrated.</p

Predator and prey overlap.

<p>Weighted mean depth <i>Z_m</i> (error bars <i>Z_s</i>) of three size classes of <i>Mnemiopsis leidyi</i> plotted against the weighted mean depth of their potential zooplankton prey. OC = overlap coefficient (averaged over all stations) where a value of 1 indicates full vertical overlap, and 0 no vertical overlap. <i>M. leidyi</i> mean depth is based on the same maximum depth as the zooplankton.</p

Test of the hypothesis of no migration.

<p>Test of the hypothesis of no migration.</p

Video-net equipment used for video profiles.

<p>1 = open cylindrical cod end, 2 = light frame, 3 = underwater camera house with a Panasonic SD 100 high definition camera, 4 = position of Scanmar (instrument not shown), 5 = weights, and 6 = floaters. For further details, see text.</p

Station and sampling information.

<p>Station and sampling information.</p

Investigated area.

<p>Stations sampled from 13–23 of October 2009 onboard R/V <i>Skagerak</i>. Station 1 and 2 (solid triangles) are the 24-hour stations sampled 5 times during a diel cycle, and the dots next to station 1 are the on-shore stations T1 and T2. Station 1 = Anholt, 2 = Ven, and 3 = BY1.</p

Depth profiles of <i>Mnemiopsis leidyi</i>.

<p>Vertical distribution and densities (ind. m⁻³) for three size classes (S = Small, M = Medium, L = Large) of <i>M. leidyi</i> and zooplankton at Anholt station in Kattegat during 24-h and the on-shore stations Anholt T1 and T2 together with biophysical variables. Station codes are given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0086595#pone-0086595-t001" target="_blank">Table 1</a>. Irradiance and zooplankton biomass are plotted on log scale.</p

<i>Euphausia superba</i>.

<p>Comparison of the size distributions of postlarval krill in the surface layer and the 0–200 m layer in summer (2007/2008), autumn (2004) and winter (2006). <i>p</i>: Kolmogorov-Smirnov test significance.</p