Rangia cuneata is a brackish water clam with a broad distribution along western Atlantic coasts and is an important component of estuarine communities. Adult R. cuneata are tolerant of salinities ranging from 0 to 32 but limited experimental studies have indicated that spawning and larval development are constrained to salinities between 2 and 10. In 2003, a permanent saltwater barrier was built in the lower Neches River, Texas, that partitioned a population of R. cuneata that had been surveyed since the 1950s. The barrier prevented salt water intrusions upstream and provided a natural experiment to determine how the regulation of salinity intrusion can influence R. cuneata spawning, recruitment, and establishment. We surveyed a total of 12 historical sites (eight above and four below the barrier) plus one site outside the previous surveys. Above the barrier, five sites had no living R. cuneata and the remaining three sites had very low densities (<0.2 per m⁻²). The large sizes of the few R. cuneata above the barrier (mean = 65.8 mm) suggested no spawning, with energy instead being invested into somatic growth. It also demonstrated the effectiveness of the barrier in preventing the continued recruitment of R. cuneata upstream and supports the hypothesis that non-zero salinity levels are needed for successful reproduction of the species. Populations downstream from the barrier experienced a resurgence in population size since the last survey in 1992, with one site having >86 individuals m⁻². The presence of distinct size cohorts indicated that spawning and recruitment occurs sporadically. Using the results of previous research, we defined the conditions apparently needed for successful reproductive events as warm weather periods with a salinity change (≥4 over a week) to induce spawning and elevated salinity levels (2–10 for 15+ days) for larval development. Using these criteria, we identified three salinity influx events on the lower Neches River in the last eight years that correlate with the presence of the size cohorts observed below the barrier, which support the hypothesis that salinity fluxes and durations are needed to induce spawning and facilitate larval recruitment.

Rangia cuneata是一种咸淡水蛤，在西大西洋沿岸分布广泛，是河口群落的重要组成部分。成年R. cuneata的耐盐度范围是0到32，但是有限的实验研究表明，产卵和幼体发育被限制在2到10之间的盐度。2003年，在得克萨斯州的内奇斯河下游建造了一个永久的盐水屏障。自1950年代以来对R. cuneata种群进行了划分。该屏障可防止盐水入侵上游，并提供了一项自然实验，以确定盐度入侵的调控方式如何影响库纳罗非鱼。产卵，招募和建立。我们总共调查了12个历史遗址（在屏障上方8个，在屏障以下4个），再加上先前调查之外的一个遗址。在障碍物上方，有五个地点没有活的库氏螺菌，其余三个地点的密度非常低（<0.2 per m ^-2）。障碍物上方的少量库纳罗非鱼的大尺寸（平均= 65.8 mm）表明没有产卵，而是将能量投入了体细胞生长。这也证明了隔离墙在防止库恩沙棘持续招募方面的有效性。上游并支持以下假设：成功繁殖该物种需要非零盐度水平。自1992年的上次调查以来，屏障下游的人口规模出现了回升，其中一个地点的> 86人m ^-2。大小不同的队列的存在表明产卵和募集是偶发的。利用以前的研究结果，我们将成功进行生殖活动显然需要的条件定义为盐度变化（一周内≥4）的温暖天气时期，以诱导幼虫产卵和盐度水平升高（15天以上为2-10）发展。使用这些标准，我们确定了过去八年来内奇斯河下游的三处盐度涌入事件，它们与在屏障下方观察到的规模队列的存在相关，这支持了需要盐分通量和持续时间来诱导产卵和促进这一假设的假设。幼体招募。