Information briefs and risk analyses for species under consideration ...

Social, Economic, Cultural Information
Customary fishery characteristics
18 There is little information of the significance of octopus (wheke) to Maori. They
occur in some Maori legends and there is reference to some species of octopus being
caught by hand and used as bait.
19 The most well-known legend concerning wheke concerns the great explorer Kupe.
While fishing in his homeland, Hawaiki, he was distracted by a giant octopus
belonging to the chief Muturangi. He pursued it and eventually caught it at the
entrance to Cook Strait from Totaranui, in the same journey discovering and naming
New Zealand (Aotearoa).
Commercial fishery characteristics
20 There are over 41 species of octopus in New Zealand however there are only three
generic reporting classifications used to report catch (OCT, DWO and OPI). As the
majority of octopus species are recorded under only one classification, OCT, the
distribution of various species of octopus in the catch effort and/or landing returns is
unknown. It is therefore extremely difficult to assess the commercial fishery
characteristics of individual species.
21 In New Zealand, octopuses have historically been landed mainly as a bycatch of rock
lobster and blue cod potting. Due to increases in bottom trawling in some parts of
New Zealand over the last twenty years, the amount of octopus taken as trawl bycatch
has increased. Some octopuses are also taken in the bottom long lining fisheries.
22 Anecdotal information from fishers and fishery managers suggests that Pinnoctopus
cordiformis is the main contribution to the total catch. This would seem to be
validated by the amount of bycatch of octopus being taken in the rock lobster fisheries
throughout New Zealand (84% of total estimated catch from the past 6 fishing year)
and research conducted that shows Pinnoctopus cordiformis as the main predator of
rock lobster. Of the other species of octopus very little is known.
23 The validity of the information concerning octopus must be questioned due to the high
likelihood of non-reporting of octopus. Anecdotal information suggests that much
octopus is discarded and not reported by rock lobster fishermen as it is considered a
‘pest’ species. Such catch is most likely returned to sea without being recorded. The
survival rate of returned octopus (their ‘pest status’ in the rock lobster fishery means
some are deliberately killed before being returned) is unknown. Thus, the actual catch
of octopus may be much greater than recorded catch levels.
24 Over the last 6 years, total landings of octopus in New Zealand (from catch landing
returns) have fluctuated within a range of 98-112 t with a mean of 102 t. Figure one
below shows the comparison of catch landings and estimated catch data. As can be
seen from the graph there is a reasonable level of correlation between the two,
however there is a significant difference between landings and estimated catch. This
difference can most likely to be attributed to bottom trawling and bottom long lining
as octopus caught may not be recorded on the estimated catch section of catch effort
returns where only the top five species caught are required to be reported.
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