Abstract
The properties of the regression of standard length on the length of the exopodit of the uropod of Euphausia superba as a method to estimate the distribution of the standard length from penguin stomach contents samples are explored. The distance between the estimated and observed distributions was measured with the Kolmogorov–Smirnov statistic. Sample variability was determined using resampling techniques. The ability of linear functions (Models I and II), allometric and non-parametric methods to recover the observed distributions was evaluated within samples and exchanging parameters between samples. Linear and allometric models proved inadequate to recover the distribution, while the differences obtained with non-parametric methods fall within the bounds of sample variability, suggesting that a linear equation does not capture the relation between total and exopodit length. The use of a non-parametric regression is recommended to increase the sample size when estimating the distributions of prey lengths in the stomach contents of Antarctic penguins.
Similar content being viewed by others
References
Bargmann HE (1937) The reproductive system of Euphausia superba. Disc Rep IV:325–350
CCAMLR CEMP (2004) Standard methods for monitoring parameters of predators species. CCAMLR ecosystem monitoring program, Hobart
Draper NR, Smith H (1966) Applied regression analysis. Wiley series in probability and mathematical statistics. Wiley, New York, 407 pp
Goebel M, Lipsky D, Reiss CS, Loeb V (2007) Using caparace measurements to determine the sex of Antarctic krill, Euphausia superba. Polar Biol 30:307–315
Härdle W (1989) Applied nonparametric regression. Cambridge University, Cambridge, 333 pp
Hill HJ (1990) A new method for the measurement of Antarctic krill Euphausia superba from predator food samples. Polar Biol 10:317–320
Irvine L (2002) Sex differences in Antarctic krill (Euphausia superba) retrieved from Adelie penguin stomachs: implications for diet anlysis. Polar Biol 25:717–720
Mauchline J (1980) Measurement of body length of Euphausia superba Dana. Biomass Handb 4:9
Miller DGM (1983) Variation in body length measurement of Euphausia superba Dana. Polar Biol 2:17–20
Morris DJ, Watkins JL, Ricketts C, Bucholz F, Priddle J (1988) An assesment of the merits of lenght and weight measurements of Antarctic krill Euphausia superba. Br Antarct Surv Bull 79:27–50
Nicol S (1993) A comparison of Antarctic petrel (Thalassoica antarctica) diets with nets samples of Antarctic krill (Euphausia superba) taken from the Prydz Bay region. Pol Biol 13:399–403
Reid K, Measures J (1998) Determining the sex of Antarctic krill (Euphausia superba) using caparace measurements. Pol Biol 19:145–147
Ricker WE (1973) Linear regressions in fishery research. J Fish Res Bd Can 30(3):409–434
Rombola E, Marschoff E, Coria N (2003) Comparative study of the effects of the late pack-ice break-off on chinstrap and Adélie penguins’ diet and reproductive success at Laurie Island, South Orkney Islands, Antarctica. Pol Biol 26:41–48
Shin H-C, Nicol S (2002) Using the relationship between eye diameter and body length to detect the effects of long-term starvation on Antarctic krill Euphausia superba. Mar Ecol Prog Ser 239:157–167
Siegel V (1982) Relationship of various length measurements of Euphausia superba Dana. Meeresforsch 29:114–117
Thompson RJ, Tapia RA (1990) Non-parametric function estimation, modeling and simulation. Society for industrial and applied mathematics (S.I.A.M.). Philadelphia, 303 pp
Acknowledgments
We thank members of Orcadas and Jubany Stations for their support in the collection of samples. We gratefully acknowledge the professional assistance of rangers of Administración de Parques Nacionales.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Marschoff, E., Rombolá, E. & Coria, N. The uropod as a proxy for total length distribution in Antarctic krill: an assessment of different models. Polar Biol 31, 717–724 (2008). https://doi.org/10.1007/s00300-008-0411-6
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00300-008-0411-6