Records of turtles and sea snakes in New Zealand, 1837–1996

Abstract

Seven species of turtles and sea snakes have reached New Zealand waters. Analysis of 207 records since 1837 shows that the two main species were Dermochelys coriacea and Pelamis platurus, followed by Chelonia mydas. Many marine reptiles probably came from Australian populations and were assisted or carried to New Zealand by the East Australian Current. A peak of records in 1989 coincided with an influx of tropical and subtropical fishes in north‐eastern New Zealand. Nearly 70% of all marine reptile records were between January and May, with few records in winter and spring. Records for D. coriacea declined throughout the year, and the same was true for Ch. mydas except for a secondary peak in October. The summer‐autumn peak in records for these two species may reflect an increased presence or activity during warmer weather. P. platurus occurred mainly from March to May and was absent from August to December, perhaps because no individuals survive after July. Marine reptiles were mostly recorded in the north of the North Island at 34–38°S latitude; only D. coriacea was widely reported further south. None of the turtles measured had carapaces below 375 mm long, except for Caretta caretta for which juveniles as small as 80 mm were recorded. These juveniles may have hatched at the C. caretta breeding grounds in south‐east Queensland. All P. platurus were adults (>500 mm total length) but the smallest Laticauda colubrina was 295 mm. Nearly 70% of turtles, and some 80% of P. platurus, were alive when found. About 45% of turtles were washed ashore when found, and 41% were entangled in nets or lines, whereas 95% of P. platurus were found washed ashore.