Abundance of invertebrates collected from all sites via four different sampling methods.

<p>Abundances are standardised by the most abundant taxa within a sampling method, but all plots are presented in order of abundance for diet invertebrates. Taxonomic nomenclature presented is not always at same level.</p

Map of Whangarei Harbour.

<p>Intertidal areas and the location of sampling sites indicated by light grey shading and starts respectively. New Zealand and the location of Whangarei Harbour within east-northland inset.</p

Abundance, condition, pelagic feeding frequency and location of post-settlement snapper by site as observed from video deployments and ‘brush and dustpan’ netting in Whangarei Harbour.

<p>(A) Abundance: proportion of two minute video segments where post-settlement snapper were observed. (B) Abundance: number of snapper captured by ‘brush and dustpan’. Kruskal Wallis test did not find any significant differences. (C) Fish condition: Condition of post-settlement snapper captured by ‘brush and dustpan’ netting. (D) Location: average proportion of observations of post-settlement snapper within each position category (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0122137#sec002" target="_blank">methods</a> for category definitions). Statistical test conducted for observations that were categorised as near seagrass. (E) Feeding events: proportion of two minute video segments where post-settlement snapper were present that suspected pelagic feeding events were observed (standardised for snapper abundance). For all plots sites are listed in increasing order of maximum water velocity (from Whangarei Harbour hydrodynamic model), values at each site are averages from four replicate ASUs ±1 standard error. Different lowercase letters denote significant differences between sites at the α = 0.05 level (Student-Newman-Keuls tests).</p

Rapid treatment of vessels fouled with an invasive polychaete, <i>Sabella spallanzanii</i>, using a floating dock and chlorine as a biocide

<p>Chlorine solution was added to the water encapsulated within a proprietary ‘floating dock’ to treat a vessel infested with the invasive polychaete <i>Sabella spallanzanii</i>. The chlorine was added as sodium dichloroisocyanurate (‘dichlor’) at an initial concentration of 200 mg l⁻¹ of free available chlorine (FAC). This concentration killed 99% of <i>S. spallanzanii</i> in their tubes during a 4-h exposure in laboratory tests (EC₉₉ 160 mg FAC l⁻¹). The concentration of FAC in the floating dock declined to ~50 mg l⁻¹ after 4 h and < 10 mg l^–1 after 16 h. Residual FAC was neutralised with thiosulphate at completion of exposure. A sample of 30 <i>S. spallanzanii</i> individuals collected from the hull after treatment all showed morphological damage and 28 showed no response to touch. Re-examination of the hull after 6 d found no live worms or other fouling organisms. This method provides a cost-effective, rapid means of treating hull fouling.</p