Variations in life-history traits and statolith shape for Sepioteuthis spp. in the waters off southwestern Japan

The accessory nidamental gland (ANG) is part of the reproduction organ in the majority of female cephalopods, including the bigfin reef squid Sepioteuthis lessoniana, an economically important fishery product. Microbes in Alphaproteobacteria, Gammaproteobacteria, and Verrucomicrobia have been suggested to play a role in the maturation of the S. lessoniana ANG and are responsible for its color. However, the bacterial composition and dynamics of the different maturation stages of the ANG remain unclear. In the present study, we surveyed ANG-associated bacterial dynamics in wild-caught S. lessoniana at various developmental stages in different populations over 3 years. The results obtained showed that the ANG bacterial community shifted gradually and decreased in diversity throughout maturation. Verrucomicrobia occupied the ANG during the early stages in large numbers, and was replaced by Bacteroidia, Alphaproteobacteria, and Gammaproteobacteria in the later stages. Flavobacteriales and Alphaproteobacteria both appeared to contribute to pigmentation, while Bacteroidia, Alphaproteobacteria, and Gammaproteobacteria may be involved in enriching the heme biosynthesis pathway in the ANG with the maturation of S. lessoniana. The present results provide an open question of whether S. lessoniana actively selects the bacterial community in the ANG to adjust to its surrounding environment.

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“…2A, and sp. 3 ( Cheng et al , 2014 ; Ching et al , 2021 ). The dominant taxon around northeastern Taiwan is Sepioteuthis sp.…”

Section: Methodsmentioning

confidence: 99%

“…The dominant taxon around northeastern Taiwan is Sepioteuthis sp. 1 ( Cheng et al , 2014 ; Ching et al , 2021 ). To avoid differences in ANG bacterial communities due to lineage-specific selection, we used only one lineage— Sepioteuthis sp.…”

Section: Methodsmentioning

confidence: 99%

Bacterial Dynamics in the Accessory Nidamental Gland of <i>Sepioteuthis lessoniana</i> throughout Maturation

et al. 2021

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Geographical variations in genetic group composition, life-history traits, and statolith shape for

et al. 2022

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Context Sepioteuthis cf. lessoniana is widely distributed in the coastal waters of the Indo-Pacific region and is a crucial fisheries resource along its distributional range. At least four lineages of Sepioteuthis have been identified in the western Pacific region; however, their biological information remains unclear. Aims In this study, the genetic groups of Sepioteuthis spp. in the southwestern Japan and northern Taiwan was examined using molecular markers, and the life-history traits and statolith morphology of the genetic groups were investigated. Methods A total of 137 and 205 squid individuals from Japan and Taiwan, respectively, were examined. Key results Three genetic groups of Sepioteuthis (S. sp. 1, sp. 2, and sp. 2A) were identified based on molecular evidence in both areas, among which Sepioteuthis sp. 2 was dominant in Japan (87%), whereas Sepioteuthis sp. 1 was dominant in Taiwan (70%). For the same genetic group, the mantle length, average growth rate, and size and age at maturity were greater for the squid in Japan than those in Taiwan. The statolith exhibited a wider lateral dome and longer rostrum for the squid in Taiwan than those in Japan. Conclusions This study indicated the variations in the life-history traits and statolith shapes of the squid were greater between geographic populations (Japan and Taiwan) than among the genetic groups, which suggested that environmental effects on life-history traits and statolith shape of squid were greater than genetic effects. Implications The results of this study provide insights into the population structure of Sepioteuthis spp. in the Northwest Pacific region, which is relevant for the sustainable management of the squid fisheries.

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Thermal histories reveal spatiotemporal distribution and population overlapping of Sepioteuthis lessoniana

Chiang,

Chung,

Shiao

et al. 2023

ICES Journal of Marine Science

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Thermal histories describe ambient temperature experienced by cephalopod species from birth to death, reflecting their habitats and distributions. Thermal histories were reconstructed by analyzing ontogenetic oxygen isotopes (δ18O values) in statoliths of adult Sepioteuthis lessoniana collected from northeastern and southwestern Taiwan between 2017 and 2019. The probabilities of occurrence associated with thermal histories in the two populations were modeled using a spatial interpolation approach, ordinary kriging method. The northeastern population exhibited larger ontogenetic variations in experienced temperature (ranging from 9.1 to 10.4°C) than did the southwestern population (ranging from 4.3°C to 6.8°C). The two geographical populations exhibited distinct ontogenetic movement patterns and distribution. The southwestern population demonstrated wide dispersal influenced by seasonal wind directions and tended to remain in 20°C isotherm areas around the Penghu Islands for maturing and spawning. At the seasonal cohort level, the northeastern population exhibited a southward shift during the 2-year study period as a result of the El Niño event. The distribution of the two geographical populations overlapped in the adult stage primarily in the northern Taiwan Strait, supporting an assumption of population connection in Taiwan. This study revealed the thermal histories of S. lessoniana, providing insights into the field observation of distribution patterns and the progress in relating population dynamics to environmental variability, which are essential for the sustainable management of squid fisheries.

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Variations in life-history traits and statolith shape for Sepioteuthis spp. in the waters off southwestern Japan

Cited by 3 publications

References 55 publications

Bacterial Dynamics in the Accessory Nidamental Gland of <i>Sepioteuthis lessoniana</i> throughout Maturation

Bacterial Dynamics in the Accessory Nidamental Gland of <i>Sepioteuthis lessoniana</i> throughout Maturation

Geographical variations in genetic group composition, life-history traits, and statolith shape for

Thermal histories reveal spatiotemporal distribution and population overlapping of Sepioteuthis lessoniana

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