Horseshoe Crab Spawning Activity in Delaware Bay, USA, After Harvest Reduction: A Mixed-Model Analysis

摘要: A Delaware Bay, USA, standardized survey of spawning horseshoe crabs, Limulus polyphemus, was carried out in 1999 − 2013 through a citizen science network. Previous trend analyses the data were at state (DE or NJ) bay-wide levels. Here, an alternative mixed-model regression analysis used to estimate trends female and male densities beach level (n = 26) with objective inferring their causes. For females, there no overall single explanation applies temporal spatial patterns densities. Individual beaches that initially had higher tended experience decrease, while lower increase. As result, females end study period relatively similar among beaches, suggesting redistribution over period. males, positive abundance from 1999 2013, this increase occurred broadly beaches. Moreover, below-average initial density have greatest increases. Possible explanations for these include harvest reduction, sampling artifact, habitat change, density-dependent selection, mate selection. The broad significant density, which after enactment controls, is consistent reduction explanation, but pattern These results highlight continued value citizen-science-based understanding crab ecology conservation.