{"id":1167,"date":"2023-10-03T17:44:11","date_gmt":"2023-10-03T21:44:11","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/?post_type=chapter&#038;p=1167"},"modified":"2026-03-27T16:21:50","modified_gmt":"2026-03-27T20:21:50","slug":"tutorial-adding-multi-stanza-groups","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/chapter\/tutorial-adding-multi-stanza-groups\/","title":{"raw":"Tutorial: Adding multi-stanza groups","rendered":"Tutorial: Adding multi-stanza groups"},"content":{"raw":"<p style=\"font-weight: 400\">The purpose of this exercise is to demonstrate how to add multi-stanza groups to an EwE model. \u00a0You can do this with an existing version of the Anchovy Bay model, which likely would have these functional groups:<\/p>\r\n<p style=\"font-weight: 400\">Whales, seals, cod, whiting, mackerel, anchovy, shrimp, benthos, zooplankton, phytoplankton, detritus.<\/p>\r\nOn <em>Ecopath &gt; Input &gt; Basic input <\/em>select <em>Define groups<\/em> (also available from the menu on top: <em>Ecopath &gt; Define groups<\/em>). Place your cursor at the Mackerel, then click <em>Edit &gt; Insert<\/em> on the right side of the form that pops up. We will make mackerel an age-structured (\u2018multi-stanza\u2019) group, therefore enter \"Mackerel juv\" as name for the new group, and enter \u201cMackerel\u201d under the \u201cMulti-stanza group name\u201d. \u00a0Then perhaps change the name of the mackerel group to \"Mackerel ad\" and use the down arrow in the multi-stanza column at the row for Mackerel ad. and select \u201cMackerel\u201d from the drop-down menu (this is to make sure that the stanza name is spelled the same way). Also set the Stanza age to 0 months for the juveniles, and 3 months for the older stanza. On the right panel, you may also want to click the <em>Colours &gt; Alternate all<\/em>, to change the group colours from the default to some darker that will work better on Ecosim plots. Click OK.\r\n\r\nNext, click the baby pram \/ Edit multi-stanza <em>Ecopath &gt; input &gt; Basic input<\/em>\u00a0form. Set the growth curvature parameter to 0.3 year<sup>-1<\/sup> for mackerel (= the average k value from FishBase); total mortality for Mackerel juv. should be 4 year<sup>-1<\/sup>, and \u201cleading\u201d should be checked for Mackerel ad. for both biomass and consumption\/biomass. Click <em>Calculate<\/em>, and the model should parameterize the age structured model.\r\n\r\nYou will also have to add diets for juvenile mackerel (maybe zooplankton) and consider which of the predators that may be preying on juvenile mackerel. \u00a0Do what you find reasonable and check if you can get the model to balance.\r\n\r\nThat's really all that's required to change a group from biomass dynamics to using an age-structured population dynamics model.","rendered":"<p style=\"font-weight: 400\">The purpose of this exercise is to demonstrate how to add multi-stanza groups to an EwE model. \u00a0You can do this with an existing version of the Anchovy Bay model, which likely would have these functional groups:<\/p>\n<p style=\"font-weight: 400\">Whales, seals, cod, whiting, mackerel, anchovy, shrimp, benthos, zooplankton, phytoplankton, detritus.<\/p>\n<p>On <em>Ecopath &gt; Input &gt; Basic input <\/em>select <em>Define groups<\/em> (also available from the menu on top: <em>Ecopath &gt; Define groups<\/em>). Place your cursor at the Mackerel, then click <em>Edit &gt; Insert<\/em> on the right side of the form that pops up. We will make mackerel an age-structured (\u2018multi-stanza\u2019) group, therefore enter &#8220;Mackerel juv&#8221; as name for the new group, and enter \u201cMackerel\u201d under the \u201cMulti-stanza group name\u201d. \u00a0Then perhaps change the name of the mackerel group to &#8220;Mackerel ad&#8221; and use the down arrow in the multi-stanza column at the row for Mackerel ad. and select \u201cMackerel\u201d from the drop-down menu (this is to make sure that the stanza name is spelled the same way). Also set the Stanza age to 0 months for the juveniles, and 3 months for the older stanza. On the right panel, you may also want to click the <em>Colours &gt; Alternate all<\/em>, to change the group colours from the default to some darker that will work better on Ecosim plots. Click OK.<\/p>\n<p>Next, click the baby pram \/ Edit multi-stanza <em>Ecopath &gt; input &gt; Basic input<\/em>\u00a0form. Set the growth curvature parameter to 0.3 year<sup>-1<\/sup> for mackerel (= the average k value from FishBase); total mortality for Mackerel juv. should be 4 year<sup>-1<\/sup>, and \u201cleading\u201d should be checked for Mackerel ad. for both biomass and consumption\/biomass. Click <em>Calculate<\/em>, and the model should parameterize the age structured model.<\/p>\n<p>You will also have to add diets for juvenile mackerel (maybe zooplankton) and consider which of the predators that may be preying on juvenile mackerel. \u00a0Do what you find reasonable and check if you can get the model to balance.<\/p>\n<p>That&#8217;s really all that&#8217;s required to change a group from biomass dynamics to using an age-structured population dynamics model.<\/p>\n","protected":false},"author":1909,"menu_order":11,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[49],"contributor":[],"license":[],"class_list":["post-1167","chapter","type-chapter","status-publish","hentry","chapter-type-numberless"],"part":404,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/pressbooks\/v2\/chapters\/1167","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/wp\/v2\/users\/1909"}],"version-history":[{"count":7,"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/pressbooks\/v2\/chapters\/1167\/revisions"}],"predecessor-version":[{"id":4411,"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/pressbooks\/v2\/chapters\/1167\/revisions\/4411"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/pressbooks\/v2\/parts\/404"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/pressbooks\/v2\/chapters\/1167\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/wp\/v2\/media?parent=1167"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/pressbooks\/v2\/chapter-type?post=1167"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/wp\/v2\/contributor?post=1167"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/ewemodel\/wp-json\/wp\/v2\/license?post=1167"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}