Globally, habitat loss in coastal marine systems is a major driver of species decline, and estuaries are particularly susceptible to loss. Along the United States Pacific coast, monospecific eelgrass (Zostera marina) beds form the major estuarine vegetated habitat. In Morro Bay, California, eelgrass experienced an unprecedented decline of > 95%, from 139 ha in 2007 to < 6 ha by 2017. Fish populations were compared before and after the eelgrass decline using trawl surveys. Beach seines surveys were also conducted during the post-decline period to characterize species within and outside of remnant eelgrass beds. While the estuary-wide loss of eelgrass did not result in fewer fish or less biomass, it led to changes in species composition. The post-eelgrass decline period was characterized by increases in flatfish (mainly Citharichthys stigmaeus) and staghorn sculpin (Leptocottus armatus), and decreases in habitat specialists including bay pipefish (Syngnathus leptorhynchus) and shiner perch (Cymatogaster aggregata). There were similar trends inside and outside of remnant eelgrass patches. These findings support evidence across multiple ecosystems suggesting that the predominance of habitat-specialists predicts whether or not habitat loss leads to an overall decline in fish abundance. In addition, loss of critical habitats across seascapes can restrict population connectivity and lead to range contraction. For bay pipefish, the loss of eelgrass in Morro Bay is likely to create a population biogeographic divide. Currently, Morro Bay is dominated by flatfish and sculpins, and the longevity of this new ecosystem state will depend on future eelgrass recovery dynamics supported by ecosystem-based management approaches.

在全球范围内，沿海海洋系统中栖息地的丧失是物种减少的主要驱动力，河口特别容易遭受损失。沿美国太平洋海岸，单种鳗el（Zostera marina）床形成了主要的河口植被栖息地。在加利福尼亚州的莫罗湾，鳗鱼的空前下降幅度超过了95％，从2007年的139公顷下降到2017年的<6公顷。通过拖网调查对鳗鱼下降前后的鱼类种群进行了比较。在下降后的时期内还进行了海滩围网调查，以鉴定鳗e草床内外的物种。虽然河口范围内的鳗草损失并没有导致鱼类减少或生物量减少，但却导致了物种组成的变化。鳗草后衰退期的特征是比目鱼（主要是Cithharichthys stigmaeus）和鹿角tag（Leptocottus armatus）增加，而栖息地专家包括海湾bay鱼（Syngnathus leptorhynchus）的减少）和光泽鲈鱼（Cymatogaster aggregata）。残余鳗草斑块的内部和外部也有类似的趋势。这些发现支持了多个生态系统的证据，这表明栖息地专家的优势可以预测栖息地的丧失是否会导致鱼类丰度的总体下降。此外，跨海景的关键栖息地的丧失会限制人口的连通性并导致范围缩小。对于海湾pipe鱼而言，莫罗湾鳗鱼的损失很可能造成种群生物地理鸿沟。目前，Morro湾以比目鱼和杜鹃为主，而这种新的生态系统状态的寿命将取决于基于生态系统的管理方法支持的未来鳗草恢复动态。