The crustacean cuticle—I. Studies on the composition of the cuticle

Trophic ecology has benefitted from the use of stable isotopes for the last three decades. However, during the last 10 years, there has been a growing awareness of the isotopic biases associated with some pre-analytical procedures that can seriously hamper the interpretation of food webs. We have assessed the extent of such biases by: (1) reviewing the literature on the topic, and (2) compiling C and N isotopic values of marine invertebrates reported in the literature with the associated sample preparation protocols. The factors considered were: acid-washing, distilled water rinsing (DWR), sample type (whole individuals or pieces of soft tissues), lipid content, and gut contents. Two-level ANOVA revealed overall large and highly significant effects of acidification for both delta(13)C values (up to 0.9 per thousand decrease) and delta(15) N values (up to 2.1 per thousand decrease in whole individual samples, and up to 1.1 per thousand increase in tissue samples). DWR showed a weak overall effect with delta(13)C increments of 0.6 per thousand (for the entire data set) or decrements of 0.7 per thousand in delta(15) N values (for tissue samples). Gut contents showed no overall significant effect, whereas lipid extraction resulted in the greatest biases in both isotopic signatures (delta(13)C, up to -2.0 per thousand in whole individuals; delta(15)N, up to +4.3 per thousand in tissue samples). The study analyzed separately the effects of the various factors in different taxonomic groups and revealed a very high diversity in the extent and direction of the effects. Maxillopoda, Gastropoda, and Polychaeta were the classes that showed the largest isotopic shifts associated with sample preparation. Guidelines for the standardization of sample preparation protocols for isotopic analysis are proposed both for large and small marine invertebrates. Broadly, these guidelines recommend: (1) avoiding both acid washing and DWR, and (2) performing lipid extraction and gut evacuation in most cases.

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“…The carapace calcium concentrations (Table 2) were, on average, two-thirds of those recorded for astacid and cambarid species (Welinder 1974(Welinder , 1975Huner et al 1976;France 1987;Lahti 1988;Jussila et al 1995) and were typical of other freshwater crayfish species that occupy low pH environments (water pH 5á4Ð5á6) and have low mineralization (France 1987).…”

Section: Carapace Mineralizationmentioning

confidence: 95%

“…The role of calcium in carapace mineralization has been widely studied (Welinder 1974(Welinder , 1975Huner et al 1976;Vigh and Dendinger 1982;Lahti 1988;Aiken and Waddy 1992); it has a significant role in crayfish growth and population dynamics (Gallagher et al 1978;Lowery 1988;Wheatly and Gannon 1993). Carapace minerals, especially calcium and magnesium, have a complicated derivation from nutrients in feeds and mineral levels in the environment (Jussila et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Carapace mineralization and hepatopancreatic indices in natural and cultured populations of marron (Cherax tenuimanus) in Western Australia

Jussila¹

1997

Mar. Freshwater Res.

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Marron (Cherax tenuimanus) were sampled from three wild populations in south-western Western Australia (Warren River, Donnelly River and Gardner River) and from five farmed populations in south-western, lower-western and central-western Western Australia. Mean calcium concentrations in the carapace were higher in wild populations (from 182320 to 213140 mg kg-1 dry matter) than in farmed populations (from 141960 to 182090 mg kg-1). The average calcium concentrations in the carapace were two-thirds those of other freshwater crayfish species. Mean carapace magnesium concentrations varied from 970 to 1880 mg kg-1 with no evident difference between wild and farmed populations. The proportion of calcium and magnesium in carapace inorganic matter varied from 54% to 78% and from 0·32% to 0·75%, respectively, being higher in the wild than in the farmed populations. With minor exceptions, carapace mineralization parameters correlated positively with calcium, magnesium and hardness of the water, and negatively with water pH. The wet hepatosomatic index, 4·5–6·0%, and the dry hepatosomatic index, 1·3–2·5%, were both higher in the farmed than in the wild populations, indicating better condition in the farmed marron. Hepatopancreas moisture concentration varied inversely with hepatosomatic index, ranging from 56·2% to 71·9%.

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The crustacean cuticle—I. Studies on the composition of the cuticle

Cited by 84 publications

References 2 publications

Fluctuations in Ca, Mg and P levels in the hemolymph, muscle, midgut gland and exoskeleton during the moult cycle of the Indian white prawn, Penaeus indicus (Decapoda: Penaeidae)

Fluctuations in Ca, Mg and P levels in the hemolymph, muscle, midgut gland and exoskeleton during the moult cycle of the Indian white prawn, Penaeus indicus (Decapoda: Penaeidae)

Effects of sample preparation on stable isotope ratios of carbon and nitrogen in marine invertebrates: implications for food web studies using stable isotopes

Carapace mineralization and hepatopancreatic indices in natural and cultured populations of marron (Cherax tenuimanus) in Western Australia

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