iiinova — where your digital self keeps evolving

Replies

Andy McKay @korimakoecology.bsky.social · 23/08/2026

"Back then, the bones found in penguin spew showed the birds ate a varied diet of squid and small fish, including red cod, blue cod, āhuru, and opalfish. The new study showed the hoiho diet is now dominated by blue cod, and that many of those other fish, once common, are now gone."

nzgeo.com

Hoiho need to eat better

A study of penguin poo suggests Otago’s declining hoiho population are struggling to find food in their hunting grounds off the South Island coast. University of Otago PhD student Melanie Young colle...

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Andy McKay @korimakoecology.bsky.social · 23/08/2026

"A major change in diet has occurred over the last 30 years. In the 1980s hoiho fed largely on small oily fish species such as sprat, immature red cod and āhuru. Now, on the mainland, blue cod seems to make up the majority of their diet." yellow-eyedpenguin.org.nz/collections/...

yellow-eyedpenguin.org.nz

Yellow-eyed Penguin Trust - Dunedin, New Zealand

The Yellow-eyed Penguin Trust is a New Zealand authority on yellow-eyed penguins / hoiho and their conservation across their geographic range.

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Chris Miller @thelittlepakeha.net · 23/08/2026

big problem for babies :(

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Andy McKay @korimakoecology.bsky.social · 23/08/2026

Warmer spring/summers mean juvenile red cod have much higher mortality and don't go on to be caught as 2/3 year olds in the commercial fishery. This also means they are less available as prey for hōiho fs.fish.govt.nz/Doc/22595/RC...

The relationship between red cod recruitment
and environmental variables
Michael P. Beentjes & James A. Ren wick
Final Research Report for
Ministry of Fisheries Research Project RCO9801
Objective 3
National Institute of Water and Atmospheric Research
July 2000 Final Research Report

Consistently, the strongest correlations between commercial catch and explanatory
variables were with SST, over a wide range of time lags, for both RC03 and RC07.
Following SST, the next best "predictors" of catch variability were the frequencies of
southwest and northeast flow patterns. The correlations generally operate in the sense
that "colder is better": negative correlations (~ -0.75) with SST, positive with
southwest weather types (stronger southwesterlies are cooler over New Zealand),
negative with northeast weather types, and so on.
The maximum magnitude of the correlation occurs at 14-month lag for both fisheries,
corresponding to the period August-January of the year prior to the catch year. There
were often secondary maxima in the magnitude of the correlations two or three years
prior to the catch year. The commercial fishery is made up largely of two and three-
year-old fish, implying that juvenile fish (age ~ one year) are most sensitive to
environmental conditions.
The analyses suggest that enhanced catches since 1990 were largely due to a decrease
in SST, partly as a result of the dominance of El Nino conditions since that time.
Based upon SST values for August-January 1998/1999 and 1999/2000, catches in
both RC03 ,and RC07 fisheries for the current fishing year (1999/2000 and
2000/2001) are predicted to be very low, at levels not seen since the low years of the
mid-1980's.

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