Publications

People in New Zealand enjoy the collection of seafood as a recreational and customary activity along the country’s coastline. Two important seafood species in coastal areas are cockles and pipi, which occur in intertidal sediments of beaches, estuaries, and large tidal inlets and harbours. In northern New Zealand, cockles and pipi have been regularly monitored for several decades across different sites in Northland, Auckland, Waikato, and Bay of Plenty. This monitoring aims to ensure the persistence of their populations, providing information of the abundance, density, and population size structure of cockles and pipi. Presented here are the survey findings from the summer of 2024–25, with population information for Pataua Estuary (Northland), Cockle Bay, Kawakawa Bay (West), Mill Bay, Ōkahu and Okoromai bays (Auckland and its wider region), Ōhiwa Harbour, Otūmoetai (Tauranga Harbour), and Waiotahe Estuary (Bay of Plenty), and Whangapoua and Whitianga harbours (Waikato). Both cockle and pipi populations across these northern sites were generally large, consisting of millions of individuals. Their densities varied dependent on the site, but were a minimum of over 140 individuals per square metre for cockles, and over 180 individuals per square metre for pipi, except at one site (Pataua Estuary). At several sites, small-sized individuals made up most of the population, highlighting strong recruitment events that preceded the data collection.

The aim of this project was to estimate the extent of the spatial area that was commercially fished for longfin and shortfin eels in the South Island from 2020 to 2023. For longfin only, this was compared to the previous estimate of all habitat to provide an update of the proportion of longfin habitat that is fished commercially. This provides an indication of the spatial fishing pressure that both longfin and shortfin eel species have experienced and can be used as a tool to assess the status or health of eel stocks.



From 2020 to 2023 there were 1851 eel fishing events of approximately 15 fyke nets set per event, from 21 fishers. About half of the eel fishing events were from lakes and half from rivers. Most fishing on rivers was from the riverbank where the target species was longfin, and most lake fishing was vessel-based where shortfin were targeted. Nearly three-quarters of longfin fishing events and half of shortfin events were in Southland, Otago, and Westland, with most of the remaining shortfin effort focused on Te Waihora (Lake Ellesmere) and Lake Brunner.



A total of 3714 unique river reaches (totalling approximately 2700 km) were fished over the four years. Half the river reaches were fished only once in the four years, with a fifth of the reaches fished more than four times. The total area fished for longfin in the South Island from 2020 to 2023 was 55.4 km2 and for shortfin was 42.7 km2. Of the total current longfin habitat in rivers, and in lakes accessible to longfin in the South Island, about 14% is currently fished. Compared to the previous estimate of the proportion of longfin habitat fished in 2016, the current estimate has declined by about 20% reflecting a substantial drop in fishing effort in recent years.

Presented in this report are standardised catch per unit effort (CPUE) analyses and fishery characterisation for the South Island commercial freshwater shortfin and longfin eel fisheries for the years 1991 to 2023. The fisheries within nine catchments or management areas that are commercially fished are described along with trends in abundance of both eel species, where sufficient data exist, over this 33 years period.

The main South Island longfin commercial fisheries are concentrated along rivers in Otago, Southland and Westland and the main shortfin fisheries are focussed on coastal lakes and river mouths such as Te Waihora (Lake Ellesmere) and Lake Brunner.

Before introduction into the Quota Management System in 2001, shortfin abundance indices showed clear declines for Otago (AV) and Southland (AW), but in Westland (AX) there was an overall increase in abundance. After 2001 there were slight increases in shortfin abundance in AV and AW and a clear increasing trend for AX. Te Waihora (AS1), after 2001, showed a steep increase in abundance before levelling off for a few years, followed by a fast and steep decline after which it was variable with no clear trend.

Shortfin stock status is as follows:
AV and AX - No target has been set for shortfin, but stock status is unlikely (<40%) to be below the soft limit.
AW - No target has been set for shortfin, but stock status is about as likely as not (40–60%) to be below the soft limit.
AS1 - Unlikely to be at or above the target Bmsy for shortfin, but unlikely (<40%) to be below the soft limit.

Longfin abundance showed clear declines before 2001 for AV and AW, but in AX it progressively increased over time. After 2001 abundance for AV and AW was generally stable but with increasing trends in recent years, whereas AX showed an overall trend of increasing abundance.

Longfin stock status is as follows:
AV and AX - No target has been set for longfin, but stock status is unlikely (<40%) to be below the soft limit.
AW - No target has been set for longfin, but stock status is very unlikely (<10%) to be below the soft limit