Meeting Abstract

P2.28  Thursday, Jan. 5  Externally visible polyfluorochrome marking of urchins: growth comparisons between lab-reared and tidepool urchins ASKINS, M.; LONATI, G.*; GUTTENPLAN, K.; FAHEY, A.; JOHNSON, A.; ELLERS, O.; Bowdoin College, Maine

We marked 2200 Strongylocentrotus droebachiensis urchins (5-35 mm in diameter) with six unique combinations of the fluorochromes tetracycline and calcein. These urchins were outplanted into six individual tidepools at Cedar Beach, Bailey Island, Maine. The tidepools were at a variety of tidal heights and all contained urchins prior to the outplant. The outplanted urchins were obtained from a hatchery at University of Maine’s Center for Cooperative Aquaculture. Tidepool oxygen, temperature, pH and salinity were monitored periodically. After one month, 64 urchins were recaptured from the tidepools; of the recovered urchins, 26 were marked, giving a 1.2% recovery rate. Concurrently, 23 urchins from each marking treatment and an additional unmarked control group were grown for a month in lab aquaria at ambient temperatures and ad libitum food. Gonad index was 8 times higher in lab-reared well-fed urchins than in tidepool urchins. Also, 50 urchins from each treatment were assayed for marking success; the results demonstrated >95% externally visible fluorescent marks and <5% false positives. In addition, a size range of urchins are being grown in the lab at a six different temperatures and we will present the results of the effects of temperature on growth at the meeting. We expect to determine an optimal size-dependent temperature for growth rate and gonad accumulation and to detect an effect of temperature on maximum size. The growth rates are expected to size specific and will be analyzed using Tanaka, von Bertalanffy and Gamma functions.