Historical landed values were obtained from combining a reconstructed marine fisheries catch database (13) with a complementary ex-vessel fish price database (37). Reconstructed catches begin with reported FAO catches but include additional details from different fishing sectors (i.e., recreational, artisanal, and subsistence) and fisheries catch composition (e.g., discards and species breakdown). The reconstruction of fisheries catch records involves compiling data from multiple sources including primary and gray literature, government and nongovernment agencies, and direct contact with partners located around the world for region-specific data. Other records of marine fisheries catch are known to be largely underestimated and exclude large quantities of biomass that have been removed from marine environments (13).

Ex-vessel fish prices were obtained from a reconstructed version of a global ex-vessel fish price database developed to complement the reconstructed SAU (Sea Around Us) catch database (37). In other words, each unique species-country-year catch record has a corresponding price, which was either a direct match from price data collection or derived from an estimation model. Ex-vessel fish prices are the prices received directly by a fisher for their catch or at the first point of sale when the fish first enters the supply chain. For catch records with no direct price match, prices were estimated using a country-product-dummy model where reported prices were matched on the basis of taxonomic classification and converted using purchasing power parities (37). Ex-vessel prices used are an average weighted by the landed values for the proportion of landings destined for various fisheries end products: direct human consumption, fishmeal and fish oil production, and other purposes.

Catches, prices, and landed values were averaged from 2001 to 2010 as a baseline to quantify the potential changes in the years that the two target warming temperatures (+1.5° and +3.5°C) are reached. Projected changes in future catches were estimated by combining historical catch numbers with outputs from the climate-marine ecosystem modelsEmbedded Imagewhere CtargetΔ°C is the projected catch in the year that the target temperature is reached, C2001–2010 is the historical catch, and ΔMCPtargetΔ°C is the projected percent change in MCP in the year that the target temperature is reached relative to the 2001–2010 period (Fig. 1, indicator ii).

Future ex-vessel prices were calculated using supply-demand models based on historical prices and the relative change in supply. We applied price flexibilities reported in table S4 that define a given percent change in price as a result of a 1% change in supply (i.e., MCP), such thatEmbedded Imagewhere PtargetΔ°C is the projected price in the year when atmospheric temperature reaches target temperature, P2001–2010 is the historical ex-vessel fish price, and Flex is the species-region–specific price flexibility.

Thus, projected landed values are a product of the relationship between the price and catch quantity and the interplay of that catch (or supply) on price. Changes to landed values may then be minimized as a result of a change in price. For example, a decrease in supply (MCP) will directly decrease FR (which is catch × price), but an increase in price due to a decrease in supply will offset the decrease in landed values, with the magnitude dependent on the price flexibility of the product. Changes in landed values in the year the target warming temperature is reached relative to 2001–2010 as a result of a change in supply and price were calculated for each warming scenario (+1.5° and +3.5°C). Changes to MCP (Fig. 1, indicator ii) and FRs (Fig. 1, indicator iii) due to meeting the Paris Agreement warming target were estimated by taking the difference in the changes in MCP and FR between scenariosEmbedded Imagewhere 1.5° and 3.5°C are the warming scenarios for the expected change in MCP and FR.

Note: The content above has been extracted from a research article, so it may not display correctly.



Q&A
Please log in to submit your questions online.
Your question will be posted on the Bio-101 website. We will send your questions to the authors of this protocol and Bio-protocol community members who are experienced with this method. you will be informed using the email address associated with your Bio-protocol account.



We use cookies on this site to enhance your user experience. By using our website, you are agreeing to allow the storage of cookies on your computer.