Environmental influence on life-history traits in male squid Uroteuthis edulis with alternative reproductive tactics

Yumeng Pang,Tomohiko Kawamura,Yoko Iwata,Chih-Shin Chen

doi:10.1007/s00227-022-04017-y

Yumeng Pang, Tomohiko Kawamura + Show 2 more

Open Access

https://doi.org/10.1007/s00227-022-04017-y

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Abstract

Squid are characterized by flexible life-history traits (LHTs) that change in response to changing oceanic parameters. Male alternative reproductive tactics (ARTs), characterized by large-sized ‘consorts’ versus small-sized ‘sneakers’, are commonly observed in loliginid species. This study reports on LHTs flexibility in male squids displaying ARTs. LHTs of consorts and sneakers in Uroteuthis edulis, including body size, age, growth rate and gonado-somatic energy allocation, were compared among seasonal and geographical groups from Japan and Taiwan. The ratio of consorts to sneakers was highest in the group spawning in the ‘Japan-warm’ season (June–November), followed by that of the ‘Japan-cold’ season (December–May), and lowest in Taiwan (spring and autumn). LHTs were compared among cohorts separated by hatching season and catch location (Jwarm, Jcold and Taiwan cohorts). Mean body size of consorts showed no difference among cohorts, although Taiwan consorts were relatively younger than Japan consorts. Mean size and age of sneakers decreased with increased water temperature at hatching. Growth rates of consorts and sneakers were slightly different among cohorts, in accordance with differences of statolith increment widths during their early life stage (50–150 days). Growth rates of both consorts and sneakers were highest in the Taiwan cohort, followed by the Jwarm cohort, with the Jcold cohort lowest. Sneakers invested more both in mantle and gonadal weights than consorts in all cohorts. Gonado-somatic energy allocation patterns of consorts and sneakers were consistent at different temperatures. LHTs of U. edulis consorts and sneakers were strongly influenced by temperature, with higher flexibility in sneakers than consorts.

Highlights

Considerable flexibility in squid life-history traits (LHTs) has been assumed to be one of the pivotal factors contributing to the increase of squid stocks worldwide, which appearsResponsible Editor: H.-J
A higher proportion of mature individuals was found in the warmer environments: the TSG had the highest proportion of mature individuals, followed by JWSG, with JCSG the lowest
The occurrence of few consorts among the Jcold cohort led to low numbers of consorts in the JCSG

Summary

Introduction

Considerable flexibility in squid life-history traits (LHTs) has been assumed to be one of the pivotal factors contributing to the increase of squid stocks worldwide, which appearsResponsible Editor: H.-J. There is great variability in LHTs in a wide range of squid species (Pierce et al 2005; Ichii et al 2009; Ching et al 2019), which is considered to be a mixture of intrinsic variability and the influence of environmental factors, especially water temperature and food availability (Vidal et al 2002; Pecl and Jackson 2005; Pierce et al 2008; Yu et al 2015). Many squid species continue to grow after reproductive maturation (Arkhipkin et al 1999; Wang et al 2010), but energy allocation to somatic growth decreases progressively (Forsythe 2004). Reproductive investment varies and could be a function of the environmental conditions experienced, especially during the hatching period (Pecl and Moltschaniwskyj 2006)

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