How Does it Work<\/h1>\r\nDedicated models of Marine Protected Areas (MPAs) can only be used to adequately represent the local effects of MPAs, as these models are created at sufficient spatial scales to allow species to thrive and disperse within the MPA. Coarser models do not have the cell resolution needed to reflect these dynamics, which has been a limiting factor to deciding on spatial scales of EwE models.\r\n\r\nThe Biomass Emitter is a lightweight plug\u2010in to the Ecopath with Ecosim food web modelling desktop software, intended to incorporate MPA biomass effects into models with insufficient spatial resolution to properly calculate the workings of the MPAs.\r\n\r\nThe Biomass Emitter's plug\u2010in provides two pathways to incorporate fine\u2010scale dynamics into larger models:\r\n\r\n \t
from finer\u2010scaled models where MPAs are explicitly modelled, or<\/li>\r\n \t
from empirical rules that emulate the workings of the MPAs in absence of detailed MPA models.<\/li>\r\n<\/ol>\r\nWe describe each of these options in the following.\r\n
Using Detailed Models<\/h2>\r\n[caption id=\"attachment_815\" align=\"aligncenter\" width=\"906\"]Figure 1 <\/strong>- The Biomass Emitter plug\u2010in transfers biomass trends from regions in fine\u2010scaled models to those same regions in coarse\u2010scaled models. This enables regional models to integrate local predictions. The emitter can apply relative biomass trends (as depicted above) or absolute biomass trends.[\/caption]\r\n\r\nTo the transfer biomass effects of local features, obtained from dedicated fine\u2010scale spatial models, the emitter uses time series of biomass effects for selected functional groups (Figure 1). These time series capture either relative or absolute change in biomass within the area of an MPA as computed by a dedicated MPA model:\r\n\r\n \t
Relative biomass trends for use in the Biomass Emitter are calculated as follows,<\/li>\r\n<\/ol>\r\n[latex]\\Delta B_t = {\\bar{B}_t^1}\/{\\bar{B}_t^o} \\tag{1} \\label{eq1}[\/latex]\r\n\r\nwhere \u2206\ud835\udc35t is the relative change in biomass within an MPA area at time step t; [latex]\\bar{B}_t^1[\/latex] is the mean biomass of this group within the same MPA area at time step t extracted from an Ecospace where the MPA was active; and [latex]\\bar{B}_t^o[\/latex] is the mean biomass of the same group within the same MPA area at time step t extracted where the MPA was not enforcing any fishing limitations.\r\n\r\n \t
Absolute biomass trends can be obtained directly from regional average\u2010saved data.<\/li>\r\n<\/ol>\r\nThe biomass trends needed to parameterize the Biomass Emitter can be calculated from Region Averaged CSV files, a data format natively produced by the EwE software, through a utility included with the Biomass Emitter plug\u2010in (see below). Emission files have the following layout:\r\n
\r\n\r\n
\r\n
group<\/td>\r\n
1<\/td>\r\n
1<\/td>\r\n
1<\/td>\r\n
\u2026<\/td>\r\n<\/tr>\r\n
\r\n
target<\/td>\r\n
1<\/td>\r\n
2<\/td>\r\n
3<\/td>\r\n
\u2026<\/td>\r\n<\/tr>\r\n
\r\n
2015\u201001<\/td>\r\n
2<\/td>\r\n
<\/td>\r\n
<\/td>\r\n
<\/td>\r\n<\/tr>\r\n
\r\n
2018\u201001<\/td>\r\n
<\/td>\r\n
2<\/td>\r\n
<\/td>\r\n
<\/td>\r\n<\/tr>\r\n
\r\n
2020\u201001<\/td>\r\n
<\/td>\r\n
<\/td>\r\n
2<\/td>\r\n
<\/td>\r\n<\/tr>\r\n
\r\n
\u2026<\/td>\r\n
<\/td>\r\n
<\/td>\r\n
<\/td>\r\n
<\/td>\r\n<\/tr>\r\n
\r\n
Table 1<\/strong>\u00a0\u2010 an example of a biomass emission data file<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\nEach column identifies biomass fluctuations for a single group and target area over time, where the target area can identify either a region number or the sequential index of an MPA in the coarse scale model where the data is applied. Time is entered in absolute terms as \u2018year\u2010month\u2019, and similar to Ecosim time series, emission values are allowed to be missing. When Ecospace runs, for every time step that a biomass emission value is defined, biomasses of the target group in all cells that fall within the target area will be multiplied by (relative), set to (absolute) or increased by (additive) the emission value.\r\n
Using Emission Rules<\/h2>\r\nWhen local MPA models are not available, and biomass trends thus cannot be obtained from localscale dedicated MPA models, the Biomass Emitter offers the ability to include biomass effects of the fine\u2010scaled MPAs as follows:<\/a>\r\n
![\"\"](\"https:\/\/pressbooks.bccampus.ca\/eweguide\/wp-content\/uploads\/sites\/2056\/2023\/10\/Picture1-13.png\")
\r\n![\"\"](\"https:\/\/pressbooks.bccampus.ca\/eweguide\/wp-content\/uploads\/sites\/2056\/2023\/10\/Picture1-14.png\")
Figure 1 <\/strong>- The Biomass Emitter plug\u2010in transfers biomass trends from regions in fine\u2010scaled models to those same regions in coarse\u2010scaled models. This enables regional models to integrate local predictions. The emitter can apply relative biomass trends (as depicted above) or absolute biomass trends.[\/caption]\r\n\r\nTo the transfer biomass effects of local features, obtained from dedicated fine\u2010scale spatial models, the emitter uses time series of biomass effects for selected functional groups (Figure 1). These time series capture either relative or absolute change in biomass within the area of an MPA as computed by a dedicated MPA model:\r\n![\"\"](\"https:\/\/pressbooks.bccampus.ca\/eweguide\/wp-content\/uploads\/sites\/2056\/2023\/10\/Biomass-emitter-guide-1.jpg\")
Figure 2 <\/strong>-\u00a0 Biomass Emitter's main settings interface.[\/caption]\r\n\r\nThe settings page is where the biomass emitter is enabled or disabled, where to check for possible conflicts, and where one can enter custom values of m ![\"\"](\"https:\/\/pressbooks.bccampus.ca\/eweguide\/wp-content\/uploads\/sites\/2056\/2023\/10\/Biomass-emitter-guide-2.jpg\")
Figure 3 <\/strong>- Emission time series configuration page[\/caption]\r\n\r\nFor all loaded time series, the interface shows whether target group and area index are valid for the currently loaded Ecospace scenario, how many emission values fall within the current Ecospace run, and which emission time series are enabled. Emission time series data points are matched by absolute dates. Biomass emissions can be applied per time step, presuming that the Ecospace time step size is left at monthly defaults.\r\n\r\nThe buttons labelled None, All, and Fished are used to quickly enable or disable emission time series. Note that the fished option functions differently depending on the type of area the time series emissions will be applied to. When applying time series to regions or habitats, the fished option will enable all emission time series for fished groups.\r\n![\"\"](\"https:\/\/pressbooks.bccampus.ca\/eweguide\/wp-content\/uploads\/sites\/2056\/2023\/10\/Biomass-emitter-guide-3.jpg\")
Figure 4<\/strong> - Rule\u2010based emission configuration page.[\/caption]\r\n\r\nNote that rule\u2010based emissions are applied to MPA cells only, and within each MPA, only to those species that are being caught or discarded by fleets prohibited from fishing at the specific time step.\r\n![\"\"](\"https:\/\/pressbooks.bccampus.ca\/eweguide\/wp-content\/uploads\/sites\/2056\/2023\/10\/Biomass-emitter-guide-5.jpg\")
Figure 5<\/strong> \u2010 Biomass Emitters time series builder interface for generating relative (left or top) or absolute (right or bottom) time series.[\/caption]\r\n![\"\"](\"https:\/\/pressbooks.bccampus.ca\/eweguide\/wp-content\/uploads\/sites\/2056\/2023\/10\/Picture1-16.png\")
Figure 6 <\/strong>- Biomass emitter time series builder interface, ready to create a relative time series file where source data from region 1 in the original MPA model will be mapped to region or mpa 7 in the target model, and data from region 2 to target region 8.[\/caption]\r\n\r\n