krillgrowth 96jan jan-feb96 Instantaneous growth rate and molting frequency of Antarctic krill from experiments held on board ship at ambient temperatures for short periods. Animal: sex, total length, molt period, telson length of animal and molt if molted Experimental: temperature of seawater, time observed animals for presence ofmolts, dead animals Only krill in good physiological condition were used in IGR experiments, i.e. swimming, no white sections in abdomen. Krill were used from either standard tows or targeted tows. All lively swimming krill were gently placed in a large volume of cold seawater, and then 100 randomly selected krill were gently placed in individual 2-liter vessels in a flowing seawater table at ambient temperature. Temperature was recorded, and animals were checked every 12 hours for molts over the following 4 days. Dead or unhealthy animals were noted. Once an animal molted, both animal and molt were removed from the vessel. The total length of the fresh animal was measured with digital calipers, then molt and animal were preserved together in 10% formalin. The lengths of the telson of the animal and the molt were measured under a binocular microscope at Palmer Station. At the end of the experiment, the total lengths of all non-molters were measured, and the non-molters preserved together. Total length is from the tip of the rostrum to the end of the uropods, not including spines (Standard Length 1, Mauchline 1981). Dead or dying animals were excluded from experimental totals, but their total lengths recorded. Instantaneous growth rate (IGR) experiments were conducted across the grid to observe growth both on and off shore and at the northern and southern area of the sampling region. antarctic krill, growth rates, molting frequency ascii, comma separated variable ~lter/lterdata krill mac and robin's mac Robin M. Ross, Langdon B. Quetin none Robin M. Ross, Langdon B. Quetin Robin M. Ross, C. Tracy Shaw Robin M. Ross, Langdon B. Quetin Langdon B. Quetin May 1998 IGR experiments with this protocol conducted with Antarctic krill wer reported in: Quetin, L. B. and R. M. Ross. 1991. Behavioral and physiological characteristics of the Antarctic krill, Euphausia superba. Amer. Zool. 31: 49-63. Ross, R. M. and L. B. Quetin. 1991. Ecological physiology of larval euphausiids, Euphausia superba (Euphausiacea. Memoirs of the Queensland Museum 31: 321-333. Prior comparisons of the results of live and preserved animals showed that although the average % growth per intermolt period was the same for the two sets of measurements, the variance was decreased when done in a more stable environment and by 1-2 individuals.