Alaska Fisheries Science Center, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, 7600 Sand Point Way NE, Seattle, WA 98115, USA.
J Fish Biol. 2009 Jan;74(1):250-69. doi: 10.1111/j.1095-8649.2008.02137.x.
Predation on skate eggs by snails was examined for three skate species at seven nursery sites in three regions (north, middle and south) of the eastern Bering Sea. Mean predation levels were 6.46% for the Alaska skate Bathyraja parmifera, 2.65% for the Aleutian skate Bathyraja aleutica and 22.25% for the Bering skate Bathyraja interrupta. Predation levels were significantly higher at the middle and north sites than the south sites for all species combined. Predation levels decreased with increasing egg-case densities at all nursery sites, and the highest predation levels occurred where egg-case densities were very low. Predated egg-case density increased with increasing snail densities across all nursery sites examined. The Oregon triton Fusitriton oregonensis was the most abundant snail species at all nursery sites and displayed ability to drill holes in the egg case of B. parmifera. Holes left by predatory snails in egg cases of B. parmifera were significantly larger, and of different shape at the middle site compared to the south site. Holes in B. parmifera were also significantly larger than those in egg cases of B. interrupta across all sites examined. Egg cases of B. aleutica possess surface spines that cover the egg case and may inhibit predation by snails at a greater rate than that of the B. parmifera and B. interrupta, which have a smoother egg-case surface.
在白令海东部的三个地区（北部、中部和南部）的七个托儿所，研究了三种鳐鱼的卵被蜗牛捕食的情况。阿拉斯加鳐鱼 Bathyraja parmifera 的平均捕食率为 6.46%，阿留申鳐鱼 Bathyraja aleutica 的平均捕食率为 2.65%，白令鳐鱼 Bathyraja interrupta 的平均捕食率为 22.25%。所有三种鳐鱼的中部和北部地区的捕食率明显高于南部地区。在所有托儿所，随着卵壳密度的增加，捕食率呈下降趋势，在卵壳密度非常低的地方，捕食率最高。在所有检查过的托儿所，被捕食的卵壳密度随着蜗牛密度的增加而增加。俄勒冈蝾螈 Fusitriton oregonensis 是所有托儿所最丰富的蜗牛物种，能够在 B. parmifera 的卵壳上钻孔。在中部地区，与南部地区相比，捕食性蜗牛在 B. parmifera 的卵壳上留下的孔明显更大，形状也不同。在所有检查过的地点，B. parmifera 的卵壳上的孔也明显大于 B. interrupta 的卵壳上的孔。B. aleutica 的卵壳表面有刺，覆盖着卵壳，可能比 B. parmifera 和 B. interrupta 受到蜗牛捕食的速度更快，因为 B. parmifera 和 B. interrupta 的卵壳表面更光滑。
