Coastal bivalve populations are characterized by large temporal fluctuations, driven by recruitment success dependent on environmental conditions. The present study evaluated the relationship of rainfall, chlorophyll-α, sea surface temperature (SST) and wind, with the biomass of four commercial bivalve species (Spisula solida, Donax trunculus, Chamelea gallina and Ensis siliqua) that occur both along the Barlavento (western region), and the Sotavento (eastern region), along the South coast of Portugal, between 1999 and 2011.

Multiple regression models were used to test two hypotheses: a) the association between environmental conditions three months prior to the spawning period and the biomass in the following year (response variable) and b) the association between environmental conditions during the spawning season plus one month and the biomass in the following year. Wind was not included in the model to test a).

The environmental variables considered were not important for E. siliqua. In the period prior to spawning, temperature was significant for S. solida (both study areas), rain for D. trunculus and C. gallina (western area) and chlorophyll-α for C. gallina (western area). All the correlations were positive.

During the spawning period, rain was significant for all three species but with different trends. The correlation with rain in months early in the spawning season was positive for S. solida (both areas) and D. trunculus (western area). The correlation with the rain in months towards the end of the spawning period was negative for D. trunculus, and C. gallina (western area). Chlorophyll-α in months at later stages of spawning was significant and positive for D. trunculus (both areas) and C. gallina (western area). The wind, expressed as an index developed to indicate the overall occurrence of winds blowing parallel to the coast (assumes to favour the retention of larvae in appropriate environments), was negatively correlated with biomass for mid to late spawning season for S. solida (eastern area) and D. trunculus (western area). For C. gallina there was a positive correlation with wind early in the spawning season. The SST was not an important variable during the spawning period with the exception of D. trunculus where the temperature at mid spawning season was significant with a negative correlation in the western coast and positive in the eastern coast.

This study highlighted the annual spatial distribution of four commercially important bivalves and how environmental factors are likely to play an important role on both biomass and location of the fishing beds. Monitoring of the environmental variables could provide information to predict biomasses of bivalve species, an important tool for its management, as well as predict trends and plan strategies in response to global environmental changes.

沿海双壳类种群的特点是时间波动大，这是由依赖于环境条件的招募成功驱动的。本研究评估了降雨量、叶绿素-α、海面温度 (SST) 和风与四种商业双壳类物种（Spisula solida、Donax trunculus、Chamelea gallina和Ensis siliqua）的生物量之间的关系，这些物种在 Barlavento 沿岸（ 1999 年至 2011 年间，西区）和沿葡萄牙南海岸的 Sotavento（东区）。

多元回归模型用于检验两个假设：a) 产卵期前三个月的环境条件与下一年生物量之间的关联（响应变量）和 b) 产卵期加上一个月的环境条件之间的关联以及次年的生物量。模型中不包括风来测试 a)。

考虑的环境变量对E. siliqua并不重要。在产卵前的期间，温度是为显著S.夏贤坤（两个研究区域），雨D. trunculus和C.加伊纳（西部地区）和叶绿素-α为C.加伊纳（西部地区）。所有的相关性都是正的。

在产卵期间，所有三个物种都下雨，但趋势不同。在几个月雨的相关性在产卵季节早期呈阳性S.夏贤坤（两个区域）和D. trunculus（西部地区）。对于D. trunculus和C. gallina（西部地区），与产卵期结束前几个月的降雨量呈负相关。产卵后期数月的叶绿素-α 对D. trunculus（两个区域）和C. gallina显着且呈阳性（西部地区）。风，表示为一个指数，用于指示与海岸平行的风的总体发生（假设有利于将幼虫保留在适当的环境中），与S.solida（东部）产卵期中后期的生物量呈负相关。地区）和D. trunculus（西部地区）。对于C. gallina，在产卵季节早期与风呈正相关。海温在产卵期不是一个重要的变量，除了D. trunculus产卵中期温度显着，西海岸呈负相关，东海岸呈正相关。

这项研究强调了四种具有重要商业价值的双壳类动物的年度空间分布，以及环境因素如何对生物量和渔床位置发挥重要作用。监测环境变量可以提供信息来预测双壳类物种的生物量，这是其管理的重要工具，以及预测趋势和规划应对全球环境变化的策略。