Marine species are facing an increasing number of stressors and some species once thought to be resilient to change are now threatened. It is important to understand how species populations have changed through time so that management can be adjusted accordingly, and so that achievable restoration goals can be set. However, many species lack population data at multidecadal or longer time scales. Using historical data from the...

The tetrasporophytic ‘ Trailliella ’ stage of the red algal genus Bonnemaisonia is reported for the first time from the Southern Hemisphere. Here we describe a bloom of the tetrasporophyte of B. hamifera from the mouth of the Waikouaiti River, Karitāne, South Island, where it occurred as thousands of free‐floating tufts up to 1 cm wide in shallow water, accumulated in windrows on sand banks and beaches, and in the water column...

Taiāpure (local fishery) are Customary fisheries Protection Areas (CPAs) designed to make better provision for rangatiratanga (Māori chieftainship) under Article II of te Tiriti o Waitangi. The East Otago Taiāpure was applied for in 1992 and finally gazetted in 1999. It has been twenty‐six years since the East Otago Taiāpure was applied for and the East Otago Taiāpure Management Committee has incorporated mātauranga‐ā‐hapū (su...

The threat posed by ocean acidification (OA) to the diversity and productivity of New Zealand marine ecosystems is assessed in a synthesis of published trends and impacts. A 20‐year time series in Subantarctic water, and a national coastal monitoring programme, provide insight into pH variability, and context for experimental design, modelling and projections. A review of the potential impact of changes in the carbonate system...