Red sea urchins ( Strongylocentrotus franciscanus ) can live over 100 years : confirmation with A - bomb 14 carbon

Red sea urchins (Strongylocentrotus Walters, 1992; Congdon et al., 1994; franciscanus) along the west coast of Ebert, 1998). There is also the need to North America, like most large sea understand the evolution of life histourchins in temperate waters worldries of species where long life tends to wide, are the focus of a commercially be an indicator of uncertainty in indiimportant fishery. In a review of biovidual reproductive success (Murphy, logical data for purposes of fishery 1968; Roff, 1992; Stearns, 1992). management, the life span of red sea Enhanced radiocarbon in the oceans urchins was suggested to be 7–10 due to atmospheric testing of nuclear years (Sloan, 1986) and they have weapons that began in the 1950s (Nybeen included with much shorter-lived dal and Lovseth, 1983; Broecker et species for illustrating complex populaal., 1985, Duffy et al., 1995) provides tion dynamics (Hastings and Higgins, a permanent marker in carbonate1994). Recent work with tetracycline based skeletal elements that are not and calcein tagging (Ebert, 1998; Ebert reworked by resorption and deposition et al., 1999), however, has shown that during growth and hence has a long individuals continue to grow throughtime period between mark and recovout life, although at a very slow rate, ery. The enhanced radiocarbon marker and large individuals are estimated to has been used in various studies to be in excess of 100 years old. A potenvalidate the periodic (usually annual) tial problem with the studies using nature of growth zones in fish (Kalish, tetracycline and calcein is that one1993, 1995; Campana, 1997; Campana year time intervals were used between et al., 2002) and invertebrates (Turekitagging and recapture and therefore it an et al., 1982; Witbaard et al., 1994; is possible that occasionally there may Peck and Brey, 1996) where validation have been very good years for growth by chemical tags such as tetracycline that were missed. If occasional growth has been impractical. Red sea urchins spurts occurred, largest sizes would lack interpretable growth zones (Breen have been attained in much less than and Adkins, 1976) and therefore there 100 years. The potential problem of is no natural feature to serve as a cross missed good years for growth could be check for studies using chemical tags. resolved with a marker that captures In the present study we present a test a longer period of time. The accuracy and confirmation of age in red sea of age estimates has consequences urchins estimated from tetracycline for resource management where size tagging using an enhanced 14C signal limits may need adjustment in order to in the ocean from nuclear weapons protect older individuals (Hilborn and testing. Materials and methods