# Lake Ellesmere / Te Waihora

Lake Ellesmere / Te Waihora is a shallow coastal lake or waituna, in the Canterbury region of the South Island of New Zealand. It is directly to the west of Banks Peninsula, separated from the Pacific Ocean by the long, narrow, sandy Kaitorete Spit. It lies partially in extreme southeastern Selwyn District and partially in the city of Christchurch's district. The lake holds high historical and cultural significance to the indigenous Māori population and the traditional Māori name Te Waihora means spreading waters. It has officially had a dual English/Māori name since at least 1938.

## Geography and hydrology

Lake Ellesmere / Te Waihora is a brackish bar-type water body, commonly called a lake or lagoon. It covers an area of 198 square kilometres (76 sq mi), and is New Zealand's fifth largest lake.

## Nature

Southern elephant seals have been observed here, spending short periods in the lake. Basking sharks have occasionally entered the lake.
Lake Ellesmere is also home to a wide variety of birds, with over 200 species (if extinct species are also included) having been recorded at the lake and its direct surroundings. Lake Ellesmere has become a well-known bird watching location for certain rare species, such as the Australasian Bittern, Marsh Crake and Kotuku. Wading birds of various species frequent the lake and its surroundings, including native species such as the Pied Stilt, South Island Pied Oystercatcher, Banded Dotterel and Wrybill, and also Arctic migrants such as the Bar-Tailed Godwit, Red-Necked Stint, Sharp-Tailed Sandpiper and Pacific Golden Plover, among others. Waterfowl are also prominent residents on the lake, with native species including Paradise Shelduck, New Zealand Scaup, Australasian Shoveler and Grey Teal. Grey Teal are actually considered one of the most abundant bird species on the lake. Introduced waterfowl species include Mallards, feral Greylag Geese, Canada Geese, Mute Swan and Black Swan, with the latter being another one of the lake's most abundant birds. Cormorants such as the Black Shag, Pied Shag and Little Shag are commonly seen in the lake. Black-Backed Gull, Red-Billed Gull and Black-Billed Gull can be seen in and around the lake, as can some tern species such as the Caspian Tern, White-Fronted Tern and Black-Fronted Tern, and the rarer White-Winged Tern. A wide variety of other birds can also be seen in and around the lake, including White-Faced Heron, Eastern Cattle Egret, Royal Spoonbill, Australasian Harrier, Pukeko, Spotless Crake, Sacred Kingfisher, as well as various introduced Galliforms and both native and introduced Passerines. A variety of rare vagrant birds have also appeared at Lake Ellesmere over the years, with some of these including Little Stint, Long-Toed Stint, Stilt Sandpiper, and Cox's Sandpiper. Australian Terns are also rare visitors to the lake.

## History

The lake has been up to twice its present depth and area in the past, and it has progressed through various stages as it has developed into the current brackish bar-type lagoon. In chronological order these stages began with the lake as part of Canterbury plains, which were then flooded, forming a bay, then an estuary and finally a lake.

## Cultural significance

Lake Ellesmere / Te Waihora has been a revered mahinga kai (site of traditional significance for food and other natural resources) for Māori since ancient times and remains central to the lives of many Māori who now live in the area. Under the Ngāi Tahu Claims Settlement 1998, ownership of the lake bed of Lake Ellesmere / Te Waihora was returned to Te Rūnanga O Ngāi Tahu, who are now able to reassert their rangatiratanga (ownership) over this significant site through direct control of its management.
The traditional name for the lake was Te Kete Ika o Rākaihautū meaning "the fish basket of Rākaihautū". The food sources of Lake Ellesmere / Te Waihora were once abundant and included tuna (eels), pātiki (flounder) and aua (mullet). Lake Ellesmere / Te Waihora was a famed mahinga manu wai māori (place for taking waterfowl). However, today the richness of Lake Ellesmere / Te Waihora as a mahinga kai has been largely lost to farmland. While it remains a mahinga kai, its yields have been significantly reduced due to the periodic drainage of the lake in order to maintain reclaimed land and pasture. Before European settlement in New Zealand, the control of the lake's level was retained at an optimum water level for the birdlife that lived there and provided kai (food) for many people. The lake was only drained when its level exceeded the normal maximum. Kōrari (flax stalks) were dragged across the sand to make the initial opening of the water to the sea. Such carefully monitored drainage of the lake took place for several hundred years, consistently maintaining Lake Ellesmere / Te Waihora's abundant supply of kai.
In 2007 an assessment of the cultural health of Lake Ellesmere / Te Waihora was undertaken as a combined effort by Ngai Tahu and the National Institute of Water and Atmospheric Research (NIWA).

### Recreation

As well as holding high cultural significance to the indigenous population, Lake Ellesmere / Te Waihora is also rated as a nationally significant site for recreation. The lake is currently used for a wide range of water and land based activities.
Many of these activities are reliant on a healthy natural ecosystem, especially fish and wildlife habitat, and a decrease in the number of people participating in trout fishing and other activities has been recorded since 1996.

## State of the lake and future management

In a 2010 report on lake water quality, Lake Ellesmere / Te Waihora was deemed the second most polluted lake in New Zealand in terms of nutrient content and algal growth. Algal blooms are a regular summer occurrence and toxic algae bloomed in the lake in 2009.
Results for E. coli levels are also poor with 42% of sites associated with the lake failing national recreational guide standards for water quality. No sites achieved the shellfish/food gathering standard or were fit for drinking.