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Coding early naturalists' accounts into long-term fish community changes in the Adriatic Sea (1800-2000).

Fortibuoni T, Libralato S, Raicevich S, Giovanardi O, Solidoro C - PLoS ONE (2010)

Bottom Line: 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 field-based monitoring programs.

View Article: PubMed Central - PubMed

Affiliation: Department of Oceanography, Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Sgonico, Italy. tfortibuoni@ogs.trieste.it

ABSTRACT
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 20(th) 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 field-based monitoring programs.

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Related in: MedlinePlus

Temporal trends of fish community structure indicators in the period 1800–2000 (N = 87 species/groups of species).Grey boxes indicate the naturalists' observations of species' perceived abundance, and orange boxes indicate the observed relative composition transformed into classes of perceived abundance. (a) Chondrichthyes; (b) large demersals; (c) species with a maximum body length between 120 and 250 cm; (d) species that reach sexual maturity between the 4th and 6th years of life.
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pone-0015502-g005: Temporal trends of fish community structure indicators in the period 1800–2000 (N = 87 species/groups of species).Grey boxes indicate the naturalists' observations of species' perceived abundance, and orange boxes indicate the observed relative composition transformed into classes of perceived abundance. (a) Chondrichthyes; (b) large demersals; (c) species with a maximum body length between 120 and 250 cm; (d) species that reach sexual maturity between the 4th and 6th years of life.

Mentions: A significant decline in the proportion of Chondrichthyes in the fish community from 15.9% to 4.6% was observed (β = −1.664, r2 = 0.548, p = 0.036; Figure 5a). Significant declines were also observed for the proportion in the fish community of large demersals from 24.4% to 8.5% (β = −2.898, r2 = 0.611, p = 0.022; Figure 5b), mid-sized species (maximum body length between 55 and 120 cm) from 31.8% to 17.3% (β = −3.901, r2 = 0.517, p = 0.044), large-sized species (maximum body length between 120 and 250 cm) from 18.3% to 5.8% (β = −1.793, r2 = 0.506, p = 0.048; Figure 5c) and late-maturing species (species that reach sexual maturity between 4 and 6 years of life) from 11.4% to 4.6% (β = −0.979, r2 = 0.398, p = 0.093; Figure 5d). The mean trophic level declined from 3.56 to 3.16, even though this decline was not significant (p = 0.155, Table S9).


Coding early naturalists' accounts into long-term fish community changes in the Adriatic Sea (1800-2000).

Fortibuoni T, Libralato S, Raicevich S, Giovanardi O, Solidoro C - PLoS ONE (2010)

Temporal trends of fish community structure indicators in the period 1800–2000 (N = 87 species/groups of species).Grey boxes indicate the naturalists' observations of species' perceived abundance, and orange boxes indicate the observed relative composition transformed into classes of perceived abundance. (a) Chondrichthyes; (b) large demersals; (c) species with a maximum body length between 120 and 250 cm; (d) species that reach sexual maturity between the 4th and 6th years of life.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2984504&req=5

pone-0015502-g005: Temporal trends of fish community structure indicators in the period 1800–2000 (N = 87 species/groups of species).Grey boxes indicate the naturalists' observations of species' perceived abundance, and orange boxes indicate the observed relative composition transformed into classes of perceived abundance. (a) Chondrichthyes; (b) large demersals; (c) species with a maximum body length between 120 and 250 cm; (d) species that reach sexual maturity between the 4th and 6th years of life.
Mentions: A significant decline in the proportion of Chondrichthyes in the fish community from 15.9% to 4.6% was observed (β = −1.664, r2 = 0.548, p = 0.036; Figure 5a). Significant declines were also observed for the proportion in the fish community of large demersals from 24.4% to 8.5% (β = −2.898, r2 = 0.611, p = 0.022; Figure 5b), mid-sized species (maximum body length between 55 and 120 cm) from 31.8% to 17.3% (β = −3.901, r2 = 0.517, p = 0.044), large-sized species (maximum body length between 120 and 250 cm) from 18.3% to 5.8% (β = −1.793, r2 = 0.506, p = 0.048; Figure 5c) and late-maturing species (species that reach sexual maturity between 4 and 6 years of life) from 11.4% to 4.6% (β = −0.979, r2 = 0.398, p = 0.093; Figure 5d). The mean trophic level declined from 3.56 to 3.16, even though this decline was not significant (p = 0.155, Table S9).

Bottom Line: 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 field-based monitoring programs.

View Article: PubMed Central - PubMed

Affiliation: Department of Oceanography, Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Sgonico, Italy. tfortibuoni@ogs.trieste.it

ABSTRACT
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 20(th) 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 field-based monitoring programs.

Show MeSH
Related in: MedlinePlus