Ontogenic changes in habitat and trophic ecology in the Antarctic squid Kondakovia longimana derived from isotopic analysis on beaks

Queirós, José P.; Cherel, Yves; Ceia, Filipe R.; Hilario, Ana Belén Ríos; Roberts, Jim; Xavier, José C.

doi:10.1007/s00300-018-2376-4

Cited by 26 publications

(42 citation statements)

References 53 publications

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“…Wings or free lateral corners of lateral walls from lower beaks were cut with scissors. Importantly, all the different sampled parts of lower and upper beaks referred to newly built material, to minimize potential trophic ontogenetic changes (Cherel & Hobson 2005, Queiros et al 2018 and different tissue-related time integration periods between beaks and the metabolically active muscle tissue.…”

Section: Study Sites Dietary Sampling and Analysismentioning

confidence: 99%

Amino acid δ13C and δ15N from sclerotized beaks: a new tool to investigate the foraging ecology of cephalopods, including giant and colossal squids

Cherel¹,

Bustamante²,

Richard³

2019

Mar. Ecol. Prog. Ser.

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Combining the use of predators as biological samplers together with measurements of the stable isotopic ratios (d 13 C Bulk and d 15 N Bulk ) of their sclerotized beaks help investigate foraging ecology of poorly known oceanic cephalopods. However, high chitin content (an amino-sugar macromolecule) lowers beak d 15 N Bulk values, thus precluding direct isotopic comparison with other tissues and organisms. To overcome the chitin effect, compound-specific isotopic analysis of amino acids (CSIA-AA) was performed on squid beaks. The method was applied on beaks and muscle, and the resulting d 13 C AA and d 15 N AA values compared between tissues. The usefulness of CSIA was tested by defining the habitat and trophic position (TP CSIA ) of squids using their d 13 C AA and d 15 N AA values. Beak d 13 C AA values were reliably measured on 12 AA that included 5 essential and 7 non-essential AA, and d 15 N AA values were quantified on at least 7 AA that included 2 source and 4 trophic AA. Importantly, d 13 C AA and d 15 N AA varied little between muscle and lower and upper beaks, and TP CSIA estimates were identical regardless of the tissue considered. Tissue d 13 C AA values of both essential and non-essential AA reflected the latitudinal baseline d 13 C gradient that occurs in the Southern Indian Ocean, while beak d 15 N AA from source and trophic AA allowed the disentangling of the baseline effect from the trophic effect, and thus better calculations of squid TP estimates than from d 15 N Bulk values. Beak d 13 C AA and d 15 N AA defined isotopic niches of colossal and giant squids, the 2 largest living invertebrates. In subantarctic waters, they segregate by having species-specific foraging habitats (using d 13 C Gly or d 15 N Phe ) and TP CSIA (using d 15 N Glx and d 15 N Phe ). TP CSIA is higher in colossal (4.7) than giant (4.3) squids, and both values compare well with those of myctophid-eaters, suggesting very large squids prey primarily upon small zoo plankti vorous fishes. As expected, CSIA-AA overcomes the chitin effect on beaks and it is a powerful tool to investigate trophic interactions of cephalopods. The method has a great potential with arthropods, because chitin is a main component of their exoskeleton but the deleterious effect of chitin is overlooked in isotopic studies focusing on crustaceans and insects.

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Section: Study Sites Dietary Sampling and Analysismentioning

confidence: 99%

Amino acid δ13C and δ15N from sclerotized beaks: a new tool to investigate the foraging ecology of cephalopods, including giant and colossal squids

Cherel¹,

Bustamante²,

Richard³

2019

Mar. Ecol. Prog. Ser.

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“…Yet, as in digestive gland and muscle analyses, mercury determination using whole beaks provide only an average of individuals' levels, while it is known that some species shift their diet and/or habitat with ontogenesis (Chouvelon et al, 2011). Recent studies showed that the analysis of different beak regions provided valuable data on different periods of individuals' lifespans, from juvenile to adult stages (Guerra et al, 2010;Queirós et al, 2018). The evolution of the trophic position revealed by the analysis of different portions of squid beaks, suggests that the mercury exposure of squids evolves during ontogenesis, as shown for soft tissues (Chouvelon et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…longimana (Cherel and Hobson, 2005;Queirós et al, 2018) suggest a change in the mercury exposure because of mercury trophic-magnification (Chouvelon et al, 2011;Jarman et al, 1996) Xavier and Cherel (2009) and preserved in 70% ethanol.…”

Section: Introductionmentioning

confidence: 99%

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Cephalopod beak sections used to trace mercury levels throughout the life of cephalopods: The giant warty squid Moroteuthopsis longimana as a case study

Queirós

Bustamante

Cherel

et al. 2020

Marine Environmental Research

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Cephalopods represent an important pathway for mercury transfer through food-webs. Due to the general difficulties in capturing oceanic squid, beaks found in the diet of top predators can be used to study their life-cycles and ecological role. Using upper beaks of the giant warty squid Moroteuthopsis longimana (major prey in the Southern Ocean), we describe a method to assess mercury concentrations along the life of cephalopods through the segmentary analysis of beak sections (i.e. rostrum's tip and subsections along the hood). Distinct total mercury concentrations in the different subsections support that beaks can be used to study mercury levels in different periods of cephalopods' life-cycle. Mercury values in the anterior (1.3 to 7.9 μg kg-1 dw) and posterior (7.8 to 12.5 μg kg-1 dw) subsections reflect juvenile and adult stages, respectively. Furthermore, these results confirm that mercury bioaccumulates continuously throughout the individuals' life, with adults doubling their mercury concentrations to juveniles.

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“…Significant differences found on upper beak's crest δ 15 N values suggest that A. polymorpha and P. turqueti explore different trophic niches during their adult life stage. Even though no differences were found on δ 15 N values for lower beaks, different isotope signatures have been recorded between individuals' upper and lower beak (Cherel and Hobson, 2005) and a recent study suggests that upper beaks present isotopic signatures more reliable to be used in trophic models, as lower beaks present a slower growing rate which makes harder to study isotopic signatures of specific periods (Queirós et al, 2018). For that reason, we are confident that both species might occupy partially different trophic niches, differing in some prey items available in function of the adaptations that both species present, such as the different physical properties of the beak, buccal mass and posterior salivary gland size.…”

Section: Habitat and Trophic Niche Of A Polymorpha And P Turquetimentioning

confidence: 88%

Show your beaks and we tell you what you eat: Different ecology in sympatric Antarctic benthic octopods under a climate change context

Matias

Gregory

Ceia

et al. 2019

Marine Environmental Research

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Sympatry can lead to higher competition under climate change and other environmental pressures, including in South Georgia, Antarctica, where the two most common octopod species, Adelieledone polymorpha and Pareledone turqueti, occur side by side. Since cephalopods are typically elusive animals, the ecology of both species is poorly known. As beaks of cephalopods are recurrently found in top predator's stomachs, we studied the feeding ecology of both octopods through the evaluation of niche overlapping and specific beak adaptations that both species present. A multidisciplinary approach combining carbon (δ 13 C) and nitrogen (δ 15 N) stable isotope signatures, mercury (Hg) analysis and biomaterials' engineering techniques was applied to investigate the beaks. An isotopic niche overlap of 95.6% was recorded for the juvenile stages of both octopod species, dropping to 19.2% for the adult stages. Both A. polymorpha and P. turqueti inhabit benthic ecosystems around South Georgia throughout their lifecycles (δ 13 C: −19.21 ± 1.87‰, mean ± SD for both species) but explore trophic niches partially different during adult life stages (δ 15 N: 7.01 ± 0.40‰, in A. polymorpha, and 7.84 ± 0.65‰, in P. turqueti). The beaks of A. polymorpha are less dense and significantly less stiff than in P. turqueti. Beaks showed lower mercury concentration relative to muscle (A. polymorpha-beaks: 0.052 ± 0.009 μg g −1 , muscle: 0.322 ± 0.088 μg g −1 ; P. turqueti-beaks: 0.038 ± 0.009 μg g −1 ; muscle: 0.434 ± 0.128 μg g −1). Overall, both octopods exhibit similar habitats but different trophic niches, related to morphology/function of beaks. The high Hg concentrations in both octopods can have negative consequences on their top predators and may increase under the present climate change context.

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Ontogenic changes in habitat and trophic ecology in the Antarctic squid Kondakovia longimana derived from isotopic analysis on beaks

Cited by 26 publications

References 53 publications

Amino acid δ13C and δ15N from sclerotized beaks: a new tool to investigate the foraging ecology of cephalopods, including giant and colossal squids

Amino acid δ13C and δ15N from sclerotized beaks: a new tool to investigate the foraging ecology of cephalopods, including giant and colossal squids

Cephalopod beak sections used to trace mercury levels throughout the life of cephalopods: The giant warty squid Moroteuthopsis longimana as a case study

Show your beaks and we tell you what you eat: Different ecology in sympatric Antarctic benthic octopods under a climate change context

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