Ocean power in New Zealand speed. Because the tidal speed doubles, eight times more tidal power can be produced at spring tides than at neap tides. The entrance to Kaipara Harbour, one of the largest harbours in the world, is a channel to the Tasman Sea. It narrows to a width of , and is over deep in parts. On average, Kaipara tides rise and fall . At high tide, nearly 1000 square kilometres are flooded. Spring tidal flows reach 9 km/h (5 knots) in the entrance channel and move 1,990 million cubic metres per tidal movement or 7,960 million cubic meters daily. In 2011,
Threats to sea turtles Fisheries often use large-scale nets and hook systems that are indiscriminate and catch whatever comes along, be it sea turtle, dolphin, or even shark. What is known as “bycatch” is a large contributor to sea turtle deaths, as seen in Baja California. Longline, trawl, and gillnet fishing are three types of fishing with the most sea turtle accidents. Deaths occur often because of drowning, where the sea turtle was ensnared and could not come up for air. Another dangerous aspect of fishing that is common is when sea turtles inadvertently swallow sharp hooks, which can get stuck within the soft