Long-term interannual variations in the benthic community structure are well-known from abyssal plains in the North Atlantic and North Pacific, where rapid responses to changes in the environment by first-order opportunists modify overall species composition. To increase our knowledge of the long-term variations of deep-sea benthic communities in the North-East Atlantic, we studied the response of a second-order opportunist echinoderm, the holothurian Pseudostichopus aemulatus, before, during and after the “Amperima Event” – a four-year episode (1996–1999) where the first-order opportunistic holothurian, Amperima rosea, increased dramatically in density. We use a collection of 14 sampling times of deep-sea community assemblage over a sixteen-year period to understand the temporal variation (i.e., interannual and seasonal) in population structure (i.e., density and individual sizes) and reproduction (i.e., mean oocyte sizes, sex ratios, gonadal indices, and fecundity) in P. aemulatus. Samples were collected from the Porcupine Abyssal Plain (PAP) in the NE Atlantic Ocean at a depth of ca. 4850 m between 1989 and 2005 with a semi-balloon otter trawl (OTSB14) and epibenthic sledge (BN1.5/C) at varying seasons. We measured individual body size, dissected organisms to prepare histological slides of their gonads, and measured the Feret oocyte diameter in females. We found that changes in the life-history biology of P. aemulatus during the “Amperima Event”. Population density increased gradually from September 1997 until April 1999, when P. aemulatus reached a peak in density coinciding with the smallest mean body size observed (1998 and 1999) indicating recruitment of juveniles. In 1997, before this event, mean oocyte sizes were at their largest, suggesting a strong reproductive effort with individuals either preparing to spawn or spawning. This reproductive effort was minimal in the years after 1999, when we found the largest proportions of previtellogenic oocytes in individuals, which were probably allocating their energy into growth rather than reproduction, given their smaller size. The presence of gametes of all sizes across seasons and a broad range of individual sizes in various sampling times suggests no seasonal reproductive patterns. We suggest that feeding guild differences between various holothurian species explain the diverse life-history responses observed among holothurians competing for resources in a food-poor environment.

在北大西洋和北太平洋的深渊平原，底栖动物群落结构的长期年际变化是众所周知的，在那里，一级机会主义者对环境变化的快速反应改变了整个物种的组成。为了增加我们对东北大西洋深海底栖生物群落长期变化的了解，我们研究了“ Amperima事件”之前，之中和之后，二阶机会主义棘皮动物-整翅类Pseudostichopus aemulatus的反应。–四年一集（1996年至1999年），其中一阶机会主义的全军医徒，安珀里玛·罗莎（Amperima rosea），密度急剧增加。我们使用16年内14个采样时间的深海群落集合，以了解人口结构（即密度和个体大小）和繁殖（即平均卵母细胞）的时间变化（即年际和季节）。大小，性别比例，性腺指数，和在繁殖力）P. aemulatus。样品是从东北大西洋东北部的豪猪深渊平原（PAP）采集的，深度约为。1989年至2005年之间的长4850 m，有半气球水獭拖网（OTSB14）和表皮爬犁（BN1.5 / C）在不同的季节。我们测量了个体的体型，解剖了生物以准备其性腺的组织学切片，并测量了雌性的费雷卵母细胞直径。我们发现“ Amperima事件”期间海豹生活史的生物学变化。从1997年9月到1999年4月，种群密度逐渐增加。达到了密度的峰值，这与观察到的最小平均体重（1998年和1999年）相吻合，表明了少年的招募。1997年，在此事件之前，平均卵母细胞大小达到最大，这表明个体准备产卵或产卵的生殖力很强。在1999年之后的几年中，这种生殖工作极少。当时，我们发现个体中前玻璃体形成卵母细胞的比例最大，鉴于它们的体积较小，它们可能将其能量分配给生长而不是繁殖。跨季节存在各种大小的配子，并且在不同的采样时间内存在各种个体大小，这表明没有季节性繁殖方式。