Krill Invasion in Whangateau Harbour

Krill Invasion

Krill Invasion

Millions of krill, tiny crustaceans important in the marine food chain, have appeared washed up along the sandy harbour shore north of the Omaha boat ramp and jetty.

The shrimp-like animals around 10 to 15 mm in length give a slightly pinkish hue to the strand line, and dry out on the beach where they look like thousands of tiny splinters. Close examination reveals a pair of black eyes, and a row of tiny legs along the lower side. Red spots occur along the sides of the whitish or semi-transparent body.

Krill are seasonally abundant in the Hauraki Gulf where they form a major part of the food of schooling fish like kahawai, trevally and pilchards. They are also directly eaten by several seabirds, including the common fluttering shearwater, and of course red billed gulls. There must be plenty in the waters of the outer Gulf and Omaha Bay for them to be washing into the harbour and stranding on the shores.
The krill in our harbour are related to, but a different species from, the larger whale-krill Euphausia superba found in the Southern Ocean and Antarctic waters which provide most of the summer food for large baleen whales like humpbacks and minkes, as well as millions of penguins.

I collected a supermarket bagful of krill off the beach and am using it as fertilizer while potting up coastal native plants and rushes for restoration plantings around the harbour and catchment. I am hoping a spoonful of krill under each plant will give it a boost!

By Roger Grace

Comments

  1. Well done Roger I saw them and wondered what they were Is that what whales eat ?

    Regards

    Jo

    • Roger Grace says:

      Yes whales do eat krill but the whales which migrate to Antarctica feed on a much large krill species about 50mm long. These Hauraki Gulf ones are much smaller but are a very important part of the food chain. Fish such as trevally and kahawai, and birds like fluttering shearwaters, Bullers shearwaters, and even red billed gulls rely on krill at certain times of the year. If you catch a kahawai when krill are around its stomach will be stuffed full of krill!

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