Restoration of a small-sized macroalgal bed through the removal of sea urchins in Kashiyama, Nagasaki Prefecture

Effects of Artificial Light at Night on Fitness-Related Traits of Sea Urchin (Heliocidaris crassispina)

“…Righting behavior, covering behavior, and food consumption of H. crassispina were measured in glass tanks (long × wide × deep = 40 × 30 × 30 cm; 20 cm of aeration water depth). Righting behavior [16,[20][21][22][23]: A sea urchin was placed at the tank's center with its aboral side facing downward, and the time taken for it to reorient itself to the oral side facing downward was measured as the righting response time. If the sea urchin failed to reorient within 10 min, the righting response time was recorded as 600 s. This experimental protocol aligns with previous studies on covering behavior [23][24][25]27]: A sea urchin was carefully positioned at the central point of the tank, with U. Lactuca available ad libitum at the bottom.…”

“…If the individual failed to engage in covering behavior within a 30-min timeframe, its covering response time was recorded as 1800 s (Figure 1b). Food consumption [16,20,21]: Four sea urchins were delicately placed at the center of the tank, with weighted U. Lactuca available ad libitum at the bottom. The sea urchins began to feed about two hours later.…”

“…Sea urchin Heliocidaris crassispina (previously Anthocidaris crassispina) is an echinoderm species found across a wide range, from the intertidal zone to shallow waters in the Western Pacific region. Its habitat spans from the Japan Sea (at 38 • N) to Hainan Island (at 19 • N) [14][15][16][17]. This species holds a crucial role in intertidal ecosystems, acting both as an herbivorous grazer on macroalgal species such as Ulva Lactuca and as prey for crabs and starfish [18,19].…”