Commercial trawl effort in the west coast North Island region, New Zealand.

<p>Mean annual trawl effort (number of tows) of the commercial mackerel (<i>Trachurus</i> spp. and <i>Scomber australasicus</i>) fishery between 1 October 1995 and 30 September 2011, including locations of observed common dolphin (<i>Delphinus delphis</i>) captures. Also indicated are the boundaries of the area modelled for estimating common dolphin captures.</p

Summary of the covariate regression coefficients.

<p>Summary of the covariate regression coefficients.</p

Monthly distribution of fishing effort and common dolphin (<i>Delphinus delphis</i>) captures.

<p>Total trawl effort, observed effort and observed dolphin captures in the large-vessel mackerel fishery on the North Island's west coast, New Zealand, across the 16-year study period between 1 October 1995 and 30 September 2011.</p

Distribution of selected covariates for the period between 1 October 1995 and 30 September 2011.

<p><b>A</b> Headline depth, <b>B</b> tow duration, <b>C</b> light condition, and <b>D</b> sub-area. The covariates were identified as explanatory factors of common dolphin (<i>Delphinus delphis</i>) captures in the large-vessel mackerel trawl fishery off the North Island west coast, New Zealand. Total observed common dolphin captures are indicated above the bars.</p

Annual summary of common dolphin <i>Delphinus delphis</i> captures in the west coast North Island region.

<p>Annual summary of common dolphin <i>Delphinus delphis</i> captures in the west coast North Island region.</p

Number of common dolphin <i>Delphinus delphis</i> caught per capture event.

<p><b>A</b> Posterior distribution of the size of the zero-truncated Poisson distribution, , showing the probability density and trace of the two chains. <b>B</b> Comparison of the predicted distribution of the number of common dolphin caught per capture event between the observed captures (solid line) and samples from the model posterior (boxplots indicating the median, quartiles, and 95% confidence interval of the distributions).</p

Annual trends of fishing characteristics (covariates) for each of the seven main mackerel trawl vessels.

<p><b>A</b> Trawl effort, <b>B</b> median headline depth, <b>C</b> tow duration, <b>D</b> proportion of tows in the north, <b>E</b> proportion of tows in dark light conditions, and <b>F</b> proportion of tows in black light conditions, for fishing years between 1 October 1995 and 30 September 2011.</p

Potential covariates considered for inclusion in the model.

<p>Potential covariates considered for inclusion in the model.</p