Plastic debris and seabird presence in the Hauraki Gulf, New Zealand

Figures & data

Fig. 1  Map showing the location of trawls conducted within the inner Hauraki Gulf.

Table 1  Mean (±SE) number of seabirds recorded per trawl in three regions of the inner Hauraki Gulf.

Species	Region 1: numbers per trawl	Region 2: numbers per trawl	Region 3: numbers per trawl	Feeding method
Australasian gannet	0.06±0.06	2.25±0.79	20.12±5.46	Plunge diving
Fluttering shearwater	Not recorded	0.32±0.31	10.88±3.51	Pursuit diving
White fronted tern	0.16±0.10	0.13±0.09	0.12±0.12	Plunge diving
Caspian tern	0.16±0.16	Not recorded	Not recorded
Black backed gull	0.19±0.09	0.19±0.10	0.88±0.61	Surface feeding
Red billed gull	0.91±0.27	0.38±0.20	0.12±0.12	Surface feeding
Black shag	0.15±0.09	Not recorded	Not recorded	Pursuit diving
Pied shag	0.41±0.13	0.06±0.06	Not recorded	Pursuit diving
Buller's shearwater	Not recorded	Not recorded	0.76±0.59	Surface feeding
Little blue penguin	Not recorded	0.31±0.15	0.18±0.13	Pursuit diving
Cape pigeon	Not recorded	Not recorded	0.12±0.12	Dipping
Total number of birds recorded per trawl	2.0±0.71	3.41±1.12	33.2±7.82
A total of 32 trawls were conducted in Region 1, 17 in Region 2 and 17 in Region 3. Individual trawls lasted 8 min. Dominant feeding method is indicated.

Fig. 2  Count of number of plastic items recovered during 8-min trawls conduct in and outside natural slicks within three regions of the inner Hauraki Gulf (mean±SE).

Fig. 3  Count of number of plastic items in and outside natural slicks separated by type of plastic (mean±SE).

Fig. 4  Proportion (%) of differently coloured plastic items recovered from the inner Hauraki Gulf.

Fig. 5  Size frequency distribution of plastic items recovered from trawls.