Changes in biomass and elemental composition during early ontogeny of the Antarctic isopod crustacean Ceratoserolis trilobitoides

• Published in: Polar Biology
• Main Authors: Heilmayer, Olaf, Thatje, Sven, McClelland, Christine, Conlan, Kathleen, Brey, Thomas
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2008
• Subjects: Antarctic; The Antarctic; South Shetland Islands; Antarc*; Polar Biology
• Online Access: https://eprints.soton.ac.uk/51151/; https://eprints.soton.ac.uk/51151/1/Heilmayer_PolarBiol_08.pdf; http://www.springerlink.com/content/0858821r6p315454/?p=ed0cdd079e99446da19fc46158f29b20&pi=3

Changes in biomass and elemental composition (dry mass, DM; carbon, C; hydrogen, H; nitrogen, N) were studied throughout the early ontogeny in the serolid isopod Ceratoserolis trilobitoides from a population off the South Shetland Islands (62°24.35?S, 61°23.77?W). Specimens of C. trilobitoides were sampled using an Agassiz trawl during the expedition ANT XXIII-8 of RV Polarstern in January 2007. Classification of embryos into six developmental stages followed previous studies. No clear size-dependant fecundity relationship was found in ovigerous C. trilobitoides. Egg volume increased by about 160 and 400% from stage I to IV and stage IV to VI, respectively. DM, C, N, and H continuously decreased throughout the early ontogeny from stage I to VI, but DM showed significant increase on reaching the late-V stage and premanca stages. The C:N ratio remained relatively stable throughout stages I to V, followed by a significant drop from about 6.17 to 5.5 in subsequent stages, indicating depletion of lipid resources of maternal origin. The results coincide with previous studies and indicate a shift from a lipid-based metabolism throughout early embryo stages to a protein-based metabolism in the late-V and premanca stage, which requires external energy supply. Given the steep increase in DM in the final phase of embryo development (late-V stage to premanca) and the need for external food supply to exert growth, the possibility of external food supply or cannibalism in early offspring of C. trilobitoides is discussed.