Coding Early Naturalists' Accounts into Long-Term Fish Community Changes in the Adriatic Sea (1800–2000)

Solidoro C (2010) Coding Early Naturalists' Accounts into Long-Term Fish Community Changes in the Adriatic Sea (1800-2000). PLoS ONE 5(11): e15502. doi:10.1371/journal.pone.0015502 Coding Early Naturalists' Accounts into Long-Term Fish Community Changes in the Adriatic Sea (1800-2000) Tomaso Fortibuoni 0 Simone Libralato 0 Sas a Raicevich 0 Otello Giovanardi 0 Cosimo Solidoro 0 Simon Thrush, NIWA, New Zealand 0 1 Department of Oceanography, Istituto Nazionale di Oceanografia e Geofisica Sperimentale , Sgonico, Italy, 2 Istituto Superiore per la Protezione e la Ricerca Ambientale, Chioggia , Italy The understanding of fish communities' changes over the past centuries has important implications for conservation policy and marine resource management. However, reconstructing these changes is difficult because information on marine communities before the second half of the 20th century is, in most cases, anecdotal and merely qualitative. Therefore, historical qualitative records and modern quantitative data are not directly comparable, and their integration for long-term analyses is not straightforward. We developed a methodology that allows the coding of qualitative information provided by early naturalists into semi-quantitative information through an intercalibration with landing proportions. This approach allowed us to reconstruct and quantitatively analyze a 200-year-long time series of fish community structure indicators in the Northern Adriatic Sea (Mediterranean Sea). Our analysis provides evidence of long-term changes in fish community structure, including the decline of Chondrichthyes, large-sized and late-maturing species. This work highlights the importance of broadening the time-frame through which we look at marine ecosystem changes and provides a methodology to exploit, in a quantitative framework, historical qualitative sources. To the purpose, naturalists' eyewitness accounts proved to be useful for extending the analysis on fish community back in the past, well before the onset of fieldbased monitoring programs. - Funding: TF was supported by the Alfred P. Sloan Foundation, History of Marine Animal Populations project(HMAP), the Regione Veneto administration and the Tegnue di Chioggia onlus association in the framework of the project La pesca in Alto Adriatico e Laguna di Venezia dalla caduta della Serenissima ad oggi: unanalisi storica ed ecologica. This work was partially funded by the projects SESAME (EC Contract No. GOCE-036949, funded by the Sixth Framework Programme) and VECTOR (VulnErabilita` delle Coste e degli ecosistemi marini italiani ai cambiamenti climaTici e loro ruolO nel ciclo del caRbonio mediterraneo) and by the Centro Euro-Mediterraneo per i Cambiamenti Climatici and ISPRA (Istituto Superiore per la Protezione e la Ricerca Ambientale, STS Chioggia). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. Natural fluctuations and human-induced modifications have caused long-term changes of marine fauna [1,2]. The full appreciation of these changes and eventually their relation with driving forces, however, need a broadening of the time horizon through which we look quantitatively at ecosystem dynamics. Indeed, without a historical perspective, our perception of the marine environment might be consistently biased by knowledge of its recent status [35]. Therefore, the rescue and analysis of past records, which encompass literary, archival and scientific sources, for reconstructing a picture of what lived in the oceans in the past, is an important task [1,69]. However, while historical quantitative data for some species may be available [5], information on marine communities before the second half of the 20th century is, in most cases, anecdotal and merely qualitative [10,11]. Thus, quantitative analysis of long-term changes at the community level, as well as integration of historical qualitative information with modern data, is not straightforward. An objective intercalibration between qualitative and quantitative information, if possible, may add value to historical sources, allowing for integration of different types of data and reconstruction of long-term temporal trends of fish communities. This approach might be particularly important when analyzing the past century, during which both the dramatic acceleration of marine ecosystem degradation [6] and the transition from qualitative records to quantitative data occurred [9]. In the Mediterranean region the field-based monitoring programs for quantitative assessing the status of marine resources cover at most the last 30 years [12], failing to encompass the population dynamics of long-living species and the time scale of many natural and human-induced phenomena. However, other historical sources, at least for the past two centuries, might be locally abundant. In this context, the Northern Adriatic Sea (Mediterranean Sea) represents a valuable case-study due to the richness of both qualitative and quantitative historical sources on a large number of fish species, which allow performing the intercalibration between different kinds of information on fish communities. In particular, early naturalists accounts of marine species were abundant since the beginning of the 19th century, as a consequence of the ascendancy of the Linnaean system [13]. These documents, primarily based on observations of landings at fish markets and ports and on interviews with fishermen [14], typically consist of catalogues of species (Figure, 1) whose perceived abundance is described, along with insights into their main ecological features and notes on fishing gears and activities targeting them. We exploited these historical sources referred to the Northern Adriatic Sea to derive a coding of qualitative information provided by early naturalists into semi-quantitative one through an intercalibration with landing proportions. This allowed us to reconstruct a two centuries-long time series (18002000) of perceived abundance for many fish species. Long-term changes in the fish community structure were analyzed by applying a set of indicators based on taxon-specific properties. Results are discussed in the light of historical changes of fishery exploitation and other pressures in the basin. Materials and Methods Archival survey and data collection We carried out an extensive survey of local archives, libraries and museums in Venice, Padua, Rome, Trieste, Chioggia (Italy) and Split (Croatia) to collect naturalists descriptions of Adriatic marine fauna (first dataset) and landing statistics (second dataset) from the beginning of the 19th century onwards. The first dataset contained information on fish species reported in 36 naturalists books published between 1818 and 1956 (Table S1). We updated species synonymies according to modern nomenclature, and species (...truncated)