Meeting Abstract

16.1  Thursday, Jan. 3  Cutaneous respiration in the Humboldt squid, Dosidicus gigas NYACK, A.C.*; SEIBEL, B.A.; Univ. of Rhode Island; Univ. of Rhode Island alnyack@gmail.com

Cutaneous respiration in squid via the mantle, which is comprised almost entirely of muscle tissue, has been estimated to contribute 40 � 60% of oxygen demand during routine metabolism. The surface area to volume ratio (SA:V) of most organisms decreases during ontogeny, whereas the body design of squid results in an increase in SA:V, yielding more surface area that may contribute to supplemental oxygen uptake. This study compared the mass specific oxygen uptake rates across the inner mantle surface to that of the outer mantle surface (with and without the tunic) from the Humboldt squid, Dosidicus gigas (family: Ommastrephidae). Excised mantle tissue was used to remove the effect of blood supply and changes in mantle volume due to contraction. Rates were measured at 10 �C, a temperature that D. gigas is regularly exposed to at depth. The mass-specific oxygen uptake rate of the outer mantle with the tunic was not significantly different than the rate when the tunic had been removed (p = 0.38). Further, there was no significant difference in the rate of oxygen uptake of inner mantle surface tissue compared to outer mantle with or without the tunic (p = 0.93 and 0.49, respectively). Oxygen uptake that occurred across both mantle surfaces may reflect respiration of the mitochondria-rich tissue of the inner and outer mantle, but was not affected by the collagen tunic of the outer mantle. However, despite a large SA:V, diffusion of oxygen into the mantle, unaided by muscle contractions or respiratory pigments, is likely insufficient to aid metabolic demand.