ABSTRACT

The reproduction of the sea urchin Pseudechinus magellanicus and the influence of environmental factors were studied during a 27-month period in central Patagonia, Argentina, where this species is among the dominant grazers in kelp forests and tide pools. The monthly variation in the gonad dry weights, gonadal stages and other quantitative reproductive variables (oocyte diameter, density and thickness of spermatogenic columns) indicated a clearly annual gametogenic cycle and revealed a high level of spawning synchrony. A main spawning event occurs between August and September, and a minor and asynchronous spawning event was recorded during the austral summer (January–March). The highest gonadal growth rate occurs between late spring and summer, accompanied by growth and early prematurity gonadal stages, indicating active vitellogenesis. The accumulation of ova begins in autumn and shows a peak during winter. After spawning, the recovery stages are not extended in time and ovaries do not show a complete meshwork of nutritive phagocytes within the acinus, suggesting simultaneous reabsorption and inversion processes. Spermatogenesis shows a higher maturation rate than oogenesis, and a higher temporal prevalence of premature and mature stages. Major spawning coincides with the first rise in seawater temperature, the maximum rate of increase in day length and the maximum peak of chlorophyll a. Results also revealed some temporal differences in the gonadal cycle, vitellogenesis and spawning periods compared with other P. magellanicus populations from different latitudes. This could be attributed to individual differences in the acquisition and allocation of energy for gametogenesis, as well as to local environmental factors.

摘要

海胆Pseudechinus magellanicus的繁殖在阿根廷巴塔哥尼亚中部地区进行了为期27个月的研究，研究了环境因素的影响，该物种是海带森林和潮汐池中的主要食草动物之一。性腺干重，性腺阶段和其他定量生殖变量（卵母细胞直径，密度和生精柱的厚度）的每月变化表明，明显的年度配子形成周期，并显示出较高的产卵同步性。一个主要的产卵事件发生在八月和九月之间，并且在南方夏季（一月至三月）记录了一个较小的异步产卵事件。最高的性腺生长速度发生在春末和夏季之间，并伴有生长和早期的早熟性腺阶段，表明卵黄发生活跃。卵的积累始于秋天，并在冬季出现高峰。产卵后，恢复阶段没有及时延长，卵巢在腺泡内未显示出营养性吞噬细胞的完整网状结构，表明同时发生了重吸收和倒置过程。精子形成的成熟率高于卵子发生，并且早熟和成熟期的时间患病率更高。主要产卵与海水温度的首次升高，日长的最大增加速率和叶绿素的最大峰值相吻合。以及早熟和成熟阶段的较高时间患病率。主要产卵与海水温度的首次升高，日长的最大增加速率以及叶绿素的最大峰值相吻合。以及早熟和成年期的较高的时间患病率。主要产卵与海水温度的首次升高，日长的最大增加速率以及叶绿素的最大峰值相吻合。一个。结果还显示，与不同纬度的其他麦哲伦菌种群相比，性腺周期，卵子发生和产卵期存在一些时间差异。这可能归因于配子发生的能量获取和分配方面的个体差异，以及局部环境因素。