Journal archives for July 2019

July 3, 2019

Unicorn discovered in Island Bay

On June 27 @kelvinperrie photographed the beach cast carcass of a large leatherjacket not far from the Island Bay Marine Education Centre (https://www.inaturalist.org/observations/28086555). The somewhat unusual looking fish turned out to be a unicorn or smooth leatherjacket (Aluterus monoceros). Aluterus monoceros is a large species of leatherjacket that attains a maximum total length of at least 76.2 cm and a maximum published weight of 2.7 kg. It is a tropical-subtropical species with a circumglobal distribution. In life adults are coloured pale grey with faint spotting along the back. Juveniles are pelagic and have a complex reticulate colour pattern of pale lines and greyish blotches. The name unicorn leatherjacket refers to the very long, slender dorsal-fin spine located above the eyes. Adult unicorn leatherjackets feed on benthic invertebrates and are usually found on or near deep reefs (to at least 110 m depth). The pelagic juveniles are often found sheltering around flotsam and jellyfishes. At times adults have also been observed in large schools beneath weed-rafts. This species is infrequently recorded from New Zealand waters (North Cape to Golden Bay). The one and only individual I have seen was caught in an inshore trawl in Hawke Bay in the mid 1990s. Recently however there have been several others recorded from the Wellington region. One was speared off Warehou Bay, Makara, in May (https://www.inaturalist.org/observations/25653642), and like the Island Bay specimen two were found washed ashore at Paraparaumu Beach in June (https://www.inaturalist.org/observations/26936301; https://www.inaturalist.org/observations/26936301).

Posted on July 3, 2019 11:08 PM by clinton clinton | 1 comment | Leave a comment