Probability (mean±95% confidence interval) of navigation channel use by acoustic-tagged Lake Sturgeon in the lower Detroit and St. Clair rivers when analyses included and excluded the extrapolated Livingstone Channel passage data.

<p>Upstream and downstream passages were pooled because direction of sturgeon movement for the extrapolated sturgeon passage data was unknown. Expected probabilities of navigation channel use under the null model are shown as dashed horizontal lines.</p

Use of navigation channels by Lake Sturgeon: Does channelization increase vulnerability of fish to ship strikes? - Fig 3

<p>Bathymetry of the lower Detroit River east of Grosse Ile before (A, B) and after (C) channelization (circa 1900 vs. 2012). Black arrows indicate potential pathways for fish movement. Brown-shaded areas show dredge spoil disposal locations. Above-water compensating works are shown in red. Bathymetry data for the lower Detroit River in 2012 was provided by the U.S. Army Corps of Engineers-Detroit District.</p

Path use (% of observed passages) by acoustic-tagged Lake Sturgeon in the lower Detroit (left panel) and St. Clair (right panel) rivers.

<p>Total number of passages was 280 in the lower Detroit River and 404 in the lower St. Clair River. Movement pathways through navigation channels are shown in red. Lake Sturgeon moving upstream at Sugar Island in the lower Detroit River turned eastward and entered the Livingstone navigation channel (solid path) rather than continuing along the expected path (dashed extension) towards Stony Island.</p

Probability (mean±95% confidence interval) of navigation channel use by acoustic-tagged Lake Sturgeon by river (Detroit vs. St. Clair) and direction of movement (upstream vs. downstream).

<p>Expected probabilities of navigation channel use under the null model are shown as dashed horizontal lines.</p

The Detroit-St. Clair River system.

<p>Dashed boxes delineate the extent of the lower Detroit and lower St. Clair rivers. The direction of flow is from Lake Huron to Lake Erie (i.e., from north to south).</p

The lower Detroit River (left panel) and lower St. Clair River (right panel).

<p>Red circles show locations of acoustic receivers. The unfilled circle shows the location of station DRL-02 in 2012. Beginning in 2013, DRL-02 was moved to its current location (filled red circle with text “DRL-02”).</p

Photographs of injured and dead Lake Sturgeon with wounds consistent with vessel propeller strikes.

<p><i>Upper panel</i>: Lake Sturgeon with fractured skull and operculum photographed in the Livingston Channel of the lower Detroit River on 13 May 2014 (photo credit: P.A. Thompson). <i>Lower panel</i>: Decapitated Lake Sturgeon carcass photographed in the South Channel of the lower St. Clair River on 10 June 2010 (photo credit: D.W. Hondorp).</p

Current hydraulic and bathymetric characteristics of navigation channels (shaded) and other main channels in the lower Detroit and St. Clair rivers.

<p>Trent. = Trenton Channel, St.-Sgr. = Sugar I.-to-Stony I. channel, Liv. = Livingstone Channel, Amh. = Amherstburg Channel, <i>Upper panel</i>: mean annual discharge (± 95% confidence interval). Data from Table 3 of Holtschlag and Koschik [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0179791#pone.0179791.ref027" target="_blank">27</a>]. <i>Middle panel</i>: Variation (median and quartiles) in channel depth. Error bars represent the 10th and 90th percentiles. Data provided by the U.S. Army Corps of Engineers-Detroit District. <i>Lower panel</i>: Variation (median and quartiles) in channel depth-averaged current velocity. Data provided by the NOAA-Great Lakes Environmental Research Laboratory. Error bars represent the 10th and 90th percentiles.</p

Path use (% of observed passages) by acoustic-tagged Lake Sturgeon in the lower Detroit River including and excluding the extrapolated Livingstone channel passage data.

<p>Path use (% of observed passages) by acoustic-tagged Lake Sturgeon in the lower Detroit River including and excluding the extrapolated Livingstone channel passage data.</p