Let class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0021782415001610&_mathId=si165.gif&_user=111111111&_pii=S0021782415001610&_rdoc=1&_issn=00217824&md5=ed03601f02145f8f1cbc198b3aaf0458" title="Click to view the MathML source">f:X→P1class="mathContainer hidden">class="mathCode"> be a non-isotrivial family of semi-stable curves of genus class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0021782415001610&_mathId=si10.gif&_user=111111111&_pii=S0021782415001610&_rdoc=1&_issn=00217824&md5=bd6755f44950840e85e2f8f3f9f833eb" title="Click to view the MathML source">g≥1class="mathContainer hidden">class="mathCode"> defined over an algebraically closed field k . Denote by class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0021782415001610&_mathId=si4.gif&_user=111111111&_pii=S0021782415001610&_rdoc=1&_issn=00217824&md5=1397761aa0d749377c61cf7ff0053d5e" title="Click to view the MathML source">sncclass="mathContainer hidden">class="mathCode"> the number of the singular fibers whose Jacobians are non-compact. We prove that class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0021782415001610&_mathId=si22.gif&_user=111111111&_pii=S0021782415001610&_rdoc=1&_issn=00217824&md5=9f39adc813fe7211d10edb464c4439bb" title="Click to view the MathML source">snc≥5class="mathContainer hidden">class="mathCode"> if class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0021782415001610&_mathId=si6.gif&_user=111111111&_pii=S0021782415001610&_rdoc=1&_issn=00217824&md5=e97402407aa0465aebc0d13497d98cf3" title="Click to view the MathML source">k=Cclass="mathContainer hidden">class="mathCode"> and class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0021782415001610&_mathId=si25.gif&_user=111111111&_pii=S0021782415001610&_rdoc=1&_issn=00217824&md5=ab3515f8046d8d5c38efad6cc0f72812" title="Click to view the MathML source">g≥5class="mathContainer hidden">class="mathCode">; we also prove that class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0021782415001610&_mathId=si31.gif&_user=111111111&_pii=S0021782415001610&_rdoc=1&_issn=00217824&md5=c6a259c092ed883d296cc526b8a2d00e" title="Click to view the MathML source">snc≥4class="mathContainer hidden">class="mathCode"> if class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0021782415001610&_mathId=si9.gif&_user=111111111&_pii=S0021782415001610&_rdoc=1&_issn=00217824&md5=db7a3d137d95b52f33772364335e694b" title="Click to view the MathML source">char(k)>0class="mathContainer hidden">class="mathCode"> and the relative Jacobian of f is non-smooth.