euryhaline Bullshark (Carcharhinus leucas). This sequence data has since been utilized to identify four further aquaporin homologues from the dogfish (Cutler,2007; Squalus acanthias). Affinity purified polyclonal antibodies were then generated against the C-terminal end of each dogfish aquaporin protein. Immunohistochemical localization studies were initiated to determine the cellular localiza- tion of these aquaporin isoforms in osmoregulatory tissues of the dogfish, including rectal gland, kidney, gill, oesophagus and intestine/ rectum.Results from these studies will be presented as time allows. Cutler,C.P.(2007) Cloning and identification offour aquaporin genes in the dogfish shark (Squalus acanthias). Bull. Mt. Des.Isl. Biol. Lab.46: 19–20. Cutler,C.P.,Meischke,L. and Cramb,G. (2005) Evolutionary and comparative analysis of aquaporin water channel genes in fish. Bull. Mt. Des. Isl. Biol. Lab. 44: 55. Meischke, L., Cramb, G. and Cutler, C.P. (2007) Cloning and expression of aquaporin water channels in the euryhaline bull shark, Carcharhinus leucas. Comp Biochem. Physiol. 146: S93. C.P. Cutler would like to thank the Mount Desert Island Biological Laboratory,Maine, USA, for the receipt of four New Investigator Award Fellowships (2004–2007). Email Address for correspondence: ccutler@georgiasouthern.edu doi:10.1016/j.cbpa.2009.04.009 A1.8 12:00 Wednesday 1st July 2009 Seasonal residency and migration of mature lemon sharks (Negaprion brevirostris) off the southeast Florida Coast Steven T.Kessel(Cardiff University,Bimini BiologicalField Station), SamuelH. Gruber (Bimini BiologicalField Station),Todd Gedamke (NOAA), Rupert G.Perkins (Cardiff University) In 2001 aggregations, of ∼ 75,mature lemon sharks (Negaprion brevirostris) were discovered off the Jupiter coast, FL. The presence of concentrated groups presented the first opportunity to study wild lemon sharks of mature life stage. Feasibility studies were conducted from 2003 to 2005 revealing that these sharks could be caught for further study.During the subsequent winter seasons of January to March 2006–2008, sharks were caught on hooks using polyball drop- lines. Captured individuals were secured to the boat, measured, sampled for DNA and tagged (NOAA M-type dart tag and PIT tag). All mature lemon sharks received a Vemco V16H transmitter implanted in their coelom. These, in concert with an array of 18 VR2 monitors along the putative aggregation migration route were used to describe local movements,forming part of the Florida Atlantic Coast Telemetry (FACT) VR2 array consisting of approximately 123 monitoring stations, with 26 to date receiving hits from our study population.A male previously caught off Long Key, FL,and another previously caught in Winyah Bay, NC, were originally tagged under the NMFS co-operative shark tagging program. This demonstrated that mature lemons will undertake long migrations to join this aggregation. Results from the monitors showed that males left the array area around March/April 2007 then returned between December 2007 and January 2008. In contrast,the females produced hits on the array year round.The further deployment of two wildlife computer MK10 PAT tags (3 and 6 months release) should further reveal the longer-term movements. Email Address for correspondence: steven_kessel@hotmail.com doi:10.1016/j.cbpa.2009.04.010 A1.9 13:20 Wednesday 1st July 2009 The unusual energy metabolism of elasmobranchs Ben Speers-Roesch (University of British Columbia) Elasmobranchs possess an unusual energy metabolism character- ized by an increased reliance on ketone bodies rather than lipids as oxidative substrates. It was thought previously that elasmobranchs lacked extrahepatic fatty acid oxidation (FAO). Recently, however, we showed that the capacity for FAO, as measured by carnitine palmitoyltransferase (CPT) activity, is substantialin some extrahe- patic tissues of elasmobranchs.We proposed a revised model of tissue-specific FAO in elasmobranchs with high capacity in the liver, kidney and rectal gland, and low or absent capacity in heart and skeletal muscle. Ketone body oxidation appears to be important in all tissues.We showed that holocephalans possess the same metabolic organization and thus so too did the common ancestor of chon- drichthyan fishes,which lived ~400 Mya. A major challenge is to identify the proximate and ultimate causes of this metabolic organization. One hypothesis is that the high level of urea in chondrichthyans adversely affects the ability of lipid carriers such as albumin to transport fatty acids. Elasmobranchs lack albumin and have low levels of circulating free fatty acids. We tested this hypothesis by comparing the capacity forFAO in freshwater and marine elasmobranchs that vary in the amount of urea accumulated. There were no major differences between the species suggesting no role of urea in explaining the metabolic organization of elasmo- branchs.Currently,we are investigating the determinants of the tissue specific expression of CPT in elasmobranchs. Surprisingly,we found that mRNA of CPT1 is expressed in dogfish heart despite the apparent absence of CPT activity or FAO. Email Address for correspondence: bensr@zoology.ubc.ca doi:10.1016/j.cbpa.2009.04.011 A1.10 13:50 Wednesday 1st July 2009 The influence of feeding and fasting on plasma metabolites in the dogfish shark (Squalus acanthias) Chris M. Wood (McMaster University), Patrick J. Walsh (University of Ottawa,University of Miami), Makiko Kajimura (McMaster Univer- sity, Wakayama University), Grant McClelland (McMaster University), Shit Fun Chew (Nanyang Technological University) Dogfish sharks are opportunistic predators, eating large meals at irregular intervals. We will synthesize data, from both published and unpublished studies, on responses in plasma metabolites after natural feeding (at ration levels of 2.6% and 5.5%) and during prolonged fasting (56 days).Most responses were more pronounced at the higher ration level. These included increases in urea and TMAO concentrations at 20 h, followed by stability through to 56 days of fasting. Ammonia levels were low, exhibited little short-term response to feeding, but declined to very low values during the extended fast. Glucose and β-hydroxybutyrate both fell after feeding, the latter to a greater extent (up to 60 h), whereas acetoacetate did not change. During prolonged fasting, glucose concen- trations were well regulated, but β-hydroxybutyrate increased to 2–3- fold control levels. Total plasma amino acid concentrations increased in a biphasic fashion, with peaks at 6–20 h,and 48–60 h after the meal, followed by homeostasis during the extended fast. Essential and non- essential amino acids generally followed this same pattern, though some exhibited differenttrends which will be high-lighted.Plasma non- Abstracts / Comparative Biochemistry and Physiology, Part A 153 (2009) S64–S70 S66