sea snake carried to NZ on warm ocean currents
- Size
- Length: 80–120 cm
- Lifespan
- 5–10 years
- Diet
- Carnivorous - feeds on small fish and eels. A venomous marine snake found in tropical and subtropical waters. Occasionally visits New Zealand waters, carried by warm currents from the Pacific.
- Habitat
- Open ocean and coastal waters of tropical and subtropical regions. Pelagic, rarely coming to land. Occasionally carried to New Zealand waters by warm currents, where it may be found washed up on beaches after storms.
- Range
- Worldwide - found in tropical and subtropical waters of the Indian and Pacific Oceans. Occasionally visits New Zealand waters, particularly in the north, carried by warm currents from the Pacific.
- Endemism
- Native
- Main Threats
- None significant in New Zealand waters - this species is a rare visitor. Global threats include bycatch in fisheries, marine pollution, and climate change affecting ocean temperatures. Not classified in New Zealand.
- Population
- A venomous marine snake occasionally visiting New Zealand waters from the Pacific. Not established in New Zealand - individuals are rare visitors carried by warm currents. No conservation status in New Zealand.
- Conservation Status
- Not Threatened
The Yellow-Bellied Sea Snake is the ultimate "uninvited guest" of the New Zealand summer. If you find one on a beach in Northland or the Bay of Plenty, it is not there for a holiday; it is likely hypothermic, exhausted, and wondering why the "warm" current it was following suddenly turned into a fridge. They are strikingly beautiful, with a jet-black back and a vibrant lemon-yellow underside, separated by a sharp, clean line. Their tail is flattened into a paddle, shaped exactly like an oar, making them incredibly efficient swimmers in the open ocean but leaving them almost entirely helpless and "floppy" if they wash up on the sand.
Biologically, these are highly specialised predators of the "blue water". They spend their entire lives at sea, never needing to touch land to breed or drink. They have evolved a "salt gland" under their tongue to excrete excess salt from the seawater, and they give birth to live young while floating in the open ocean. They are "sit-and-wait" hunters, often found drifting among mats of floating seaweed, where they wait for small fish to seek shelter beneath them. When a fish gets close, the snake strikes with lightning speed. While they are technically highly venomous - possessing a potent neurotoxin designed to paralyse fish - they are generally very docile towards humans. Most "bites" only occur when a well-meaning person tries to pick one up to "save" it.
In New Zealand, the Yellow-Bellied Sea Snake is a victim of its own curiosity. As our ocean temperatures rise due to climate change, we are seeing more of these tropical drifters reaching our shores. However, they cannot survive a New Zealand winter; once the water drops below 18°C, their metabolism slows to a crawl, and they eventually perish. If you find one, the official advice is: Do not touch. Not because they are aggressive, but because they are legally protected, highly venomous, and likely in a state of extreme stress. Call the Department of Conservation and let the professionals handle the "tourist" who took a very wrong turn at Fiji.