The spatio-temporal distribution and population structure of green turtles (Chelonia mydas) in New Zealand

Figures & data

Figure 1. Distribution of green turtle records from New Zealand from 1895 to July 2013 (n = 194). Stranded turtles (○); Sightings (♦); Incidental captures (▴).

Figure 2. Size-class frequency distribution of green turtles in New Zealand recorded from 1895 to 2013. Mean curved carapace length (CCL) = 51.9 cm (SD ± 11.6 cm, n = 86).

Figure 3. Predicted means from a Poisson generalised linear model of the number of sightings and strandings per quarter for 2014, assuming typical temperatures. Error bars represent 95% confidence intervals around the means. A, West coast strandings; B, east coast strandings; C, east coast sightings and captures.

Table 1. Analysis of deviance table for a Poisson generalised linear model of the number of green turtle records.

Predictor	Likelihood ratio χ^2	d.f.	P-value
QTA^a	4.265	1	0.0389
Coast	46.221	1	0.0000
Type	16.418	1	0.0001
Year	106.986	1	0.0000
Qtr^b	5.646	3	0.1302
QTA×Coast	5.852	1	0.0156
Coast×Type	7.079	1	0.0078
Coast×Year	0.01	1	0.9214
Type×Year	0.329	1	0.5665
Coast×Qtr	12.881	3	0.0049

^aQTA: Quarterly Temperature Anomaly.

^bQTR: Quarter (season).

Table 2. One-way ANOVA comparing curved carapace length (CCL) of stranded turtles and the seasons in which they were recorded (Jan–Mar, Apr–Jun, Jul–Sep, Oct–Dec; n = 76).

Source of variation	SS	d.f.	MS	F	P-value	F crit
Between groups	465.708	3	155.236	1.141	0.3384	2.7318
Within groups	9796.206	72	136.058
Total	10261.910	75

Note: SS, sum of squares; MS, mean squares.

Figure 4. Predictions from a Poisson generalised linear model of the mean of the quarterly counts of turtle records between 1983 and 2013. Circles represent the number of counts recorded, the black lines are the predicted means, and the grey areas show the 95% confidence bounds for the means. A, West coast strandings; B, east coast strandings; C, east coast sightings and captures.