Morphometric relationships, relative growth and roe yield of the sea urchin (Paracentrotus lividus) from the Portuguese coast

Abstract

Sea urchin (Paracentrotus lividus) populations from the northwestern (Carreço) and southwestern (Aljezur) coasts of Portugal were surveyed to analyse and compare their morphometric relationships, relative growth (isometry vs. allometry) and roe yield. Specimens were hand-collected from intertidal rock pools and sampled monthly during two consecutive years (November 2010–November​ 2012). Overall, 1220 P. lividus larger than 40 mm in test diameter (542 from Carreço and 678 from Aljezur) were analysed during the study period. Morphometric relationships established between specimen size (test diameter, height and volume) and weight (total and gonad weight) were statistically significant and displayed high correlation coefficients (r = 0.484 – 0.974), with allometric coefficients ranging from b = 0.962 to 1.239 (linear variables) and from b = 2.541 to 3.437 (linear and ponderal variables). Sea urchins mean roe yield was significantly higher in Carreço (7.5 ± 3.1%) than in Aljezur (6.8 ± 3.5%) and varied depending on the sampling month. The present data on morphometric relationships, relative growth and roe yield was duly compared with previous studies available on these topics, through an exhaustive review covering the distributional range of P. lividus along the Atlantic Ocean and Mediterranean Sea.