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Web End = Fish Sci (2015) 81:443452DOI 10.1007/s12562-015-0857-8
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Web End = Beak growth pattern of purpleback ying squid Sthenoteuthis oualaniensis in the eastern tropical Pacic equatorial waters
Zhou Fang Luoliang Xu Xinjun Chen Bilin Liu Jianhua Li Yong Chen
Received: 29 August 2014 / Accepted: 13 December 2014 / Published online: 4 March 2015 Japanese Society of Fisheries Science 2015
length, and lower lateral wall length, which showed linear relationships with ML. The relationships between BW and the six beak variables were best tted with power functions, and these functions can be used to estimate squid biomass from beak variable values. All of the beak morphological variables varied according to the maturity stage of the squid. Results of a post hoc comparison suggested that the values of beak morphological variables for immature squids (maturity stages I and II) showed signi-cant differences from the corresponding values for mature squids (maturity stages IIIV). These differences may result from changes in diet that occur during maturation, which affect the relevant mandibular muscle strength. The most common pigmentation stages (PS) encountered were IIV. The relationships of PS to ULWL and lower wing length were best described by exponential functions. Beak morphology and pigmentation of S. oualaniensis tended to change markedly with ontogenetic stage. It is easy to separate mature and immature squids based on their PS.This study provides important biological information on S. oualaniensis.
Keywords Sthenoteuthis oualaniensis Beak
Morphology Growth pattern Pigmentation Eastern Tropical Pacic
Introduction
The purpleback ying squid Sthenoteuthis oualaniensis is an oceanic species that belongs to the family Ommastrephidae and is distributed in a broad band around the equator from approximately 40N to 40S. Its range stretches predominately throughout the tropical and subtropical open waters of the Indo-Pacic region [1, 2]. Purpleback ying
Abstract Cephalopod beaks maintain a stable morphology, implying that they can be used to explore ecological inuences on squid life history. Understanding the beak growth pattern can help us to improve knowledge of the trophic characteristics of squids and to estimate squid biomass. Sthenoteuthis oualaniensis is widely distributed in eastern...