The survey extends from Scott Point on Ninety Mile Beach to Mana Island covering a depth range from 10–200 m north of Cape Egmont and 10–100 m to the south. Since 2018, there has been no sampling within 2–4 nautical miles of the coast between Maunganui Bluff and the Waiwhakaiho River, New Plymouth, a no-trawl area established to protect the Māui dolphin.

 

Everything that is caught in the trawl is sorted, identified, and weighed, and length and maturity data are collected for selected species and otoliths (fish ear stones) for ageing the four main species of interest: snapper, red gurnard, John dory, and tarakihi. The trawl survey provides time series of relative biomass estimates and age, length, and maturity stage information used for stock assessments and fisheries management advice for key inshore species.

 

In 2023, 95 phase one stations were successfully completed followed by four phase two stations completed to improve the coefficient of variation for tarakihi.

 

There were 72 species recorded in total, with snapper by far the most abundant. Biomass estimates (in tonnes) for the key species across the whole survey were: snapper, 8396.3 t ; red gurnard, 1160.5 t; tarakihi, 447.6 t ; John dory, 305.3 t.

 

The 2022 snapper biomass estimate was lower than that from the 2019 and 2020 surveys, but still significantly higher than the historical surveys in the 1990s. There were high numbers of juvenile snapper under 5 years old but a lower number of adult fish. The variability in adult snapper biomass in this survey may be due to fish moving inshore into shallow water to spawn, or may reflect the highly patchy distribution of snapper at this time of year.

 

The biomass estimate for adult red gurnard was relatively stable, but the biomass of smaller fish was substantially below historical estimates.

Document date
Monday, 15 April 2024

Document type
V 1.3

File format
Adobe PDF

File size
13.8 MB

Reference number
2024/18

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FAR: 2024/18;
AUTHOR: Jones, E.G.; Underwood, M.J.; Bian, R.; Walsh, C.; O’Driscoll, R.L.;
ISSN: 1179-5352;
ISBN: 978-1-991285-27-0;

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