Date of Award


Document Type

Open Access Thesis

Degree Name

Master of Science (MS)


Marine Sciences and Technology

First Advisor

John W. Mandelman

Second Advisor

Jarrett Byrnes

Third Advisor

Owen C. Nichols


The Gulf Stream exerts tremendous influence over oceanographic conditions in the Northwest Atlantic as it transports tropical water to higher latitudes. As the Gulf Stream’s path traverses the east coast of North America, there are implications for the biogeography of marine ecosystems within this range and beyond. While the meandering eddies and warm core rings generated by the Gulf Stream persist year-round, the seasonal warming of New England’s coastal waters afford many tropical species transported by the current temporary residence through the summer and fall. Many aspects that shape this phenomenon and its impact on coastal ecosystems remain a mystery. There is evidence that habitat choice by larval fish affects their distribution within tropical waters. Based on this evidence, tropical species incidence may serve as an indicator of critical nursery habitat and biodiversity hotspots for targeted conservation efforts. From 2015 to 2017, a biodiversity survey of Pleasant Bay, Massachusetts gathered incidence data to estimate species richness at unique sites within the estuary. This survey asserts that sampling species incidence may be a viable and efficient small-scale method to extrapolate native species richness and indicate desirable habitat for non-native tropical species. The distribution of teleost species is the result of many factors. To begin to address the conditions that shape observed richness, characteristics including sediment type and dominant benthic communities were applied as criteria to cluster survey sites for species richness analysis through sample-based rarefaction. The results of this study indicate that small-scale species incidence sampling can be used to highlight critical habitat for conservation protections. The evidence for habitat choice by juvenile fishes highlights the importance of evaluating biodiversity as an indicator for ecosystem health and resiliency. Paired with a broader citizen science network, characteristics including reported species frequency and a review of species life history, are beginning to reveal potential ecosystem impacts that result from the dispersal of expatriated species by the Gulf Stream. As climate change continues to alter marine coastal environments, furthering our understanding of the role expatriated species play in New England waters may improve the allocation of conservation effort and help anticipate future ecosystem changes.