The mean (± SE) number of minutes per day during which harbour porpoises were acoustically detected at each site offshore of Maryland.

<p>There were no data in March at site 4 due to instrument loss.</p

The results of the binomial generalized additive models (GAM) used to relate presence/absence of foraging to hour of the day (EST) and Julian day at sites 1, 2, and 3.

<p>The results of the binomial generalized additive models (GAM) used to relate presence/absence of foraging to hour of the day (EST) and Julian day at sites 1, 2, and 3.</p

Map of the northeastern coast of the United States and study location.

<p>Displayed is the Maryland Wind Energy Area (yellow) and the four C-POD sites (inset). Bar plot shows the mean (± SE) number of hours per day that porpoises were detected throughout the study period.</p

Summary of harbour porpoise foraging behaviour.

<p>The proportion of hours harbour porpoise foraging behaviour was detected in each month (a) and the proportion of days that harbour porpoise foraging was detected in each hour (b).</p

Smoothers from the generalized additive model (GAM) for site 2.

<p>The relationship between the proportion of hours per week that harbour porpoises were detected and (a) sea surface temperature (SST, °C) and (b) the natural logarithm of chlorophyll <i>a</i> concentration (mg m^-3). The predictor is on each x-axis, the centered fitted values are on each y-axis, the dashed lines are error bands. Tick marks on the x-axes—rug plot—show the distribution of the underlying data. Similar smoother patterns occurred for sites 1 and 3.</p

Spearman’s rank correlation coefficients (<i>p</i>-values are in parentheses) for the median porpoise positive hours (PPHs) per day, total PPHs per month, maximum number of PPHs per day and proportion of days harbour porpoises were detected acoustically in each month compared to Roberts et al.’s [25] monthly predictions of porpoise density at each site.

<p>Spearman’s rank correlation coefficients (<i>p</i>-values are in parentheses) for the median porpoise positive hours (PPHs) per day, total PPHs per month, maximum number of PPHs per day and proportion of days harbour porpoises were detected acoustically in each month compared to Roberts et al.’s [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0176653#pone.0176653.ref025" target="_blank">25</a>] monthly predictions of porpoise density at each site.</p

The mean number of minutes in each hour that harbour porpoises were detected at sites 1 and 2, where the hour of the day was a significant factor in the generalized auto-regressive moving average (GARMA) models of hourly porpoise presence.

<p>The shaded polygons represent the standard error.</p

The predicted densities of harbour porpoises per month (red) and the total number of acoustically detected porpoise positive hours (PPHs) per month offshore of Maryland (black).

<p>Predictions (in individuals per 100 km²) are from Roberts et al.’s [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0176653#pone.0176653.ref025" target="_blank">25</a>] model and acoustic data were collected from November 2014 to May 2016. There were no acoustic data for March at site 4.</p

Summary of the harbour porpoise acoustic data collected at each of the four sites offshore of Maryland.

<p>Summary of the harbour porpoise acoustic data collected at each of the four sites offshore of Maryland.</p

The results of the generalized additive models (GAM) used to relate the weekly occurrence of harbour porpoises to sea surface temperature and the natural logarithm of chlorophyll <i>a</i> concentration at sites 1, 2, and 3.

<p>The results of the generalized additive models (GAM) used to relate the weekly occurrence of harbour porpoises to sea surface temperature and the natural logarithm of chlorophyll <i>a</i> concentration at sites 1, 2, and 3.</p