Beak length analysis of arrow squid Nototodarus sloanii (Cephalopoda: Ommastrephidae) in southern new Zealand waters

Beak length analysis was undertaken for the arrow squid Nototodarus sloanii in the New Zealand sector of the Southern Ocean between Stewart Island and the Auckland Islands. N. sloanii has a restricted range and is endemic to the waters around New Zealand and its associated southern islands, where it...

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Bibliographic Details
Published in:Polar Biology
Main Authors: Jackson, George D., McKinnon, Jean F.
Format: Article in Journal/Newspaper
Language:English
Published: Springer 1996
Subjects:
Online Access:https://oceanrep.geomar.de/id/eprint/50858/
https://oceanrep.geomar.de/id/eprint/50858/1/3019.pdf
https://doi.org/10.1007/BF02329211
Description
Summary:Beak length analysis was undertaken for the arrow squid Nototodarus sloanii in the New Zealand sector of the Southern Ocean between Stewart Island and the Auckland Islands. N. sloanii has a restricted range and is endemic to the waters around New Zealand and its associated southern islands, where it supports a fishery and is preyed upon by a number of fishes, marine mammals and birds. Lower rostral length (LRL) and upper rostral length (URL) were analysed to see how these beak measurements related to both mantle lentgh (ML) and wet weight (W). Both lower and upper rostral lengths could be used as useful predictors of ML and W in N. sloanii, as relationships had limited scatter and high correlation coefficients. The relationships between LRL and ML, and URL and ML were only linear after regressing log-transformed values of beak length against ML. However, the relationships between LRL and W, and URL and W were linear without transforming either the x or y values. These results are different from previously published beak length analysis of Nototodarus in New Zealand waters.