Growth and spatial distribution of Cassidulus mitis (Echinodermata: Echinoidea) on a sandy beach in Southeastern Brazil

Rate of natural mortality in the sea starArchaster angulatus(Echinodermata: Asteroidea)

“…Typifying these two examples in echinoids are the short-lived tropical Tripneustes gratilla with k values of 1.08 to 1.80 and M values of 4.74–5 year −1 (Bacolod & Dy, 1986; Regalado et al ., 2011) and those such as the long lived Antarctic Sterechinus antarcticus with k of 0.017 and M of 0.07 year −1 (Brey, 1991) and the sub-Arctic Strongylocentrotus droebachiensis ( M = 0.04–0.30 year −1 ) which lives commonly in excess of 50 years and may reach 100 years (Russell et al ., 1998). Intermediate among these extremes and comparable to A. angulatus are the subtropical echinoid Cassidulus mitis ( k = 0.39 and M = 0.812 year −1 , Freire et al ., 1992) and the temperate S. franciscanus ( k = 0.51 and M = 0.26–0.34 year −1 , Ebert & Russell, 1993).…”

Use of plate growth measurement for the estimation of skeletal growth of two sand dollars, Astriclypeus manni (Verrill 1867) and Clypeaster japonicus (D^|^ouml;derlein 1885), in Jeju, Korea

“…In particular, computer-based planimetric techniques that analyze digitized images have proven to be prompt and objective in the processing of large quantities of image data (De Pontual et al 1985, Lango-Reynoso et al 2000, Kang et al 2003. Most studies measuring the skeletal growth of sea urchins have used length parameters such as radius and TD (Duineveld & Jenness 1984, David 1987, Freire et al 1992, Hong & Chung 1998, Branchard & Feder 2000. As an alternative, we have measured areas of dark bands on the plate to estimate skeletal growth.…”

A laboratory study of the correlation between texture and the speed of locomotion by the sea urchinHemicentrotus pulcherrimus

“…The restoration of submarine forests must, therefore, be accompanied by a concomitant management and reduction in the number of organisms that prey upon seaweeds (Dadsi 2005). Most sea urchin research has focused on their feeding, growth, genesis, and distribution (Yoo et al 1982;Hur & Yoo 1985;Freire et al 1992;Lee & Baik 1995;Kang & Choi 2002;Kim et al 2007). Those studies concerning the movement of sea urchins have been conducted directly in the sea (Mattison et al 1977;Kang & Choi 2002;Dumont et al 2007).…”