Date of Award


Document Type

Honors Thesis (Open Access)


Colby College. Environmental Studies Program


Loren McClenachan

Second Advisor

Philip Nyhus

Third Advisor

Manny Gimond


As the degradation of Caribbean coral reefs occurs, memory of past states is lost so the degraded status is used as a standard in management, a phenomenon known as “shifting baselines.” To set restoration targets, marine historical ecology studies are helpful to document baselines of species and understand the past productivity of ecosystems. In this study, I examine the historical ecology of the islands Barbuda, Curaçao, and Montserrat. I analyzed archival materials, including historical maps and other documents from the islands to identify previously abundant or iconic species and understand historical changes. From the archival resources I identified 30 places named after marine species on or near the islands and 22 references to marine species. I interviewed 40 fishermen, divers, and others familiar with the waters of Antigua, Barbuda, and Montserrat about changes in the ecosystem, with an initial focus on species identified as important or iconic from historical materials. My results demonstrate a shifted baseline: interviewees with greater experience in the marine environment view from four to six times as many species, on average, as depleted and were more likely to describe declining species as rare compared to their less-experienced counterparts. I also found disparities between perceptions of abundance, ecological assessments, and the historical material. For example, interviewees described the ecosystem of 20-30 years ago as pristine, when historical documents suggest earlier depletion. Additionally, interviewees perceived key species as more abundant than in-water surveys would suggest and described increases in species that were recently protected by legislation and have not yet had a chance recover, suggesting a “policy placebo” effect. Knowledge of past abundance is critical for policymaking, education and outreach efforts to empower communities to see the potential in the marine environment.


shifting baselines, marine historical ecology, marine restoration, Caribbean