Reconstructing the History of Ocean Life Around Ascension Island
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The Old Man and the Sea: Reconstructing the History of Ocean Life around Ascension Island Polly Rose Burns MSc by Research University of York Environment April 2018 Abstract In 2016, the UK government announced plans for a large-scale Marine Protected Area (MPA) around Ascension Island, a UK Overseas Territory in the South Atlantic. Legal designation is expected in 2019 and research is underway to inform its management. To establish accurate baselines of marine life and assess change over time, extensive historical sources were examined. One hundred and thirty-nine interviews were also conducted to identify perceptions of change in the marine environment by past and present Ascension Island inhabitants. Historical sources indicate seabird and turtle populations declined substantially following human settlement, and despite recent population recoveries, pre-settlement abundance has not been reached. Reported fish abundance was high and remained relatively consistent throughout the historical references, but residents have noticed recent changes, notably in fishing effort, declines in yellowfin tuna (Thunnus albacares), and increases of Galapagos sharks (Carcharhinus galapagensis). Two shark attacks occurred in 2017, with their increased aggression completely new to most interviewees. However, previous periods of high shark abundance with threatening behaviour were noted, including a likely shark attack in 1879. Overall, Ascension appears to have largely avoided depletion of fish stocks from commercial fishing pressure, but recent changes highlight the need for precautionary management with strong protection to safeguard the island’s extraordinary assets. 2 Table of Contents Abstract ...................................................................................................................... 2 List of Tables............................................................................................................. 5 List of Figures ........................................................................................................... 6 List of Accompanying Material (on accompanying CD) .......................... 9 Acknowledgements .............................................................................................. 10 Declaration ............................................................................................................. 10 Introduction ............................................................................................................ 11 The Value of Historical Baselines and Informal Knowledge: A Review ................................................................................................................................. 11 Previous studies on Ascension Island and its Relevance ........................ 14 Aims ....................................................................................................................... 16 Methods .................................................................................................................... 17 Study Site .............................................................................................................. 17 Literature and Archival Research.................................................................. 18 Local Ecological Knowledge (LEK) from Interviews................................. 19 Analysis of Results ............................................................................................. 25 Results ....................................................................................................................... 27 History of Exploitation...................................................................................... 27 Fishing ........................................................................................................................................... 27 Turtles ........................................................................................................................................... 37 Seabirds ........................................................................................................................................ 42 Other wildlife exploitation ..................................................................................................... 45 Historical Timeline ............................................................................................ 47 The Forgotten Island: Post-discovery years of Ascension Island 1501-1814 ...... 47 The H.M.S. Ascension: 1815 – 1922 .................................................................................... 56 Ascension, the Island of Communication: 1923 – 1983 ............................................... 76 Modern Ascension Island: 1984 – 2017 ............................................................................ 93 History of sharks, shark attacks and details of other ‘problematic’ fish ................. 97 Historical photographic sources and images of Ascension’s marine environment ......................................................................................................112 Early views ............................................................................................................................... 112 Seabirds ..................................................................................................................................... 115 Pollution on Ascension Island ............................................................................................ 118 Questionnaire Results ....................................................................................120 Respondent characteristics ................................................................................................. 120 Fishing effort ............................................................................................................................ 120 Attitudes to Sharks................................................................................................................. 125 Perceptions of fishing productivity .................................................................................. 134 Perceived changes in fishing locations............................................................................ 134 Perceptions of species decline or increase .................................................................... 140 General Observations ............................................................................................................ 143 Discussion ............................................................................................................. 144 Fish .......................................................................................................................144 3 Sharks ..................................................................................................................149 Seabirds ..............................................................................................................153 Turtles .................................................................................................................156 Other marine life ..............................................................................................157 Reliability of early accounts ..........................................................................159 Reliability of respondent answers ..............................................................162 Importance of local people’s opinions in designation of a marine protected area ...................................................................................................165 Small-scale fishery impact .............................................................................166 Returning to the past ......................................................................................167 Conclusion ............................................................................................................ 169 Appendix 1 ............................................................................................................ 170 Appendix 2 ............................................................................................................ 175 Appendix 3 ............................................................................................................ 176 References ............................................................................................................ 177 4 List of Tables Table 1: Criteria used to select and reject items related to Ascension Island in online search results based on their titles and description. ................... 18 Table 2: Minor changes made to the questionnaire to make meanings of questions clearer to interviewees. ............................................................ 22 Table 3: References for specific mentions to fish around Ascension during 19th century, with years of the observations in chronological order for each species ............................................................................................. 29 Table 4: Catch statistics from Argentine fishing vessel S.S. Sentinel include species and amounts caught around Ascension in 4-week period of 1938, adapted from Mason, 1939b. ................................................................... 31 Table 5: Timeline of key quotes or events from Ascension’s history and observations of the marine environment from 1501-1814 (References from Osbeck, 1765 translated from German). Additions I added to