Stylet elemental signatures indicate population structure in a holobenthic octopus species, Octopus pallidus

Abstract

Targeted trace elemental analysis was used to investigate the population structure and dispersal patterns of the holobenthic octopus species Octopus pallidus (Hoyle, 1885). Multi-elemental signatures within the pre-hatch region of the stylet (an internal 'shell') were used to determine the common origins and levels of connectivity of individuals collected from 5 locations in Tasmania. To determine whether hatchling elemental signatures could be used as tags for natal origin, hatchling stylets from 3 of the 5 locations were also analysed. We analyzed 12 elements using laser ablation inductively-coupled plasma-mass spectrometry (LA-ICPMS). Of the 12 elements, 7 were excellent spatial discriminators. There was evidence of high-level structuring with distinct groupings between all sites (the 2 closest being 85 km apart) within the adult O. pallidus population, suggesting that all adults had hatched in or near their respective collection sites. The hatchling signatures showed significant spatial variation, and a high percentage of individuals could successfully be traced back to their collection locations. However, they could not be used to trace adults back to their natal site, due to significant differences in element concentrations in hatchling and adult stylets, which was likely the result of differences in Ca concentration. This study presents the first insights into the population structure of a holobenthic octopus species using stylet elemental signatures, which will have important implications for the sustainable management of O. pallidus.

Elemental uptake via immersion: a mass-marking technique for the early life-history stages of ­cephalopods

“…The successful management of cephalopod fisheries is hindered by an inability to evaluate population structure and connectivity (Doubleday et al 2008a, 2008b, Pecl et al 2010. Whilst significant advances in recent years have improved our understanding of movement and migration patterns of many cephalopod populations globally (Semmens et al 2007), methods to tag and track the poorly understood juvenile stage of cephalopods is recognised as a key priority for marine ecologists, as this is the stage most influenced by environmental fluctuations (Semmens et al 2007).…”

A multilevel approach to examining cephalopod growth usingOctopus pallidusas a model

“…There has been considerable recent research conducted on O. pallidus (e.g. André et al, 2008;Doubleday et al, 2008;Leporati et al, 2008b), and the species serves as a good model to examine detailed aspects of octopus growth in the laboratory. The key aims of our study were to determine: (1) the nature of the growth curve from hatching to 8 months old, (2) the mechanism of muscle growth (hyperplasia versus hypertrophy), and (3) the effect of seasonal temperature on whole-body growth, muscle tissue structure and repro-somatic investment, with the hypothesis that females will be ready to spawn during cooler periods, such that hatching young will be exposed to continually increasing temperatures for the first few months of life when growth is rapid (Forsythe, 1993).…”

Spatial difference in elemental signatures within early ontogenetic statolith for identifying Jumbo flying squid natal origins

“…Understanding the population structure and connectivity of marine organisms is critical for studying their population dynamics and developing effective conservation and sustainable management strategies (Thorrold et al, 2001;Gillanders, 2002). Recently natural geochemical signatures of trace elements and isotopes in the hard structures of marine animals, such as bivalve shells, fish otoliths, octopus styles and squid beaks and statoliths, have been successfully utilized to investigate the population distribution of animals (Campana, 1999;Ikeda et al, 2003;Becker et al, 2005;Cherel and Hobson, 2005;Doubleday et al, 2008). The elemental signature is considered to be a potential complement to more commonly used genetic and morphologic methods for defining cephalopod cohorts and population structures (Arkhipkin, 2005).…”

“…However, these studies focused on Sr, the most abundant element incorporated into the aragonite matrix of statoliths. Recently, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has become increasingly popular for examining lower concentration trace elements such as Ba, Mg and Mn (Zumholz et al, 2006(Zumholz et al, , 2007Doubleday et al, 2008;Warner et al, 2009;Liu et al, 2011).…”