Contourf not producing vector files

Hello, I made a contourf plot, but for some reason when I save my figure as an .svg, .pdf or .eps file, the result is not scalable; yet the output files are over 4 MB. My guess is that it has something to do with how complex the data in the plot are, because I had produced contourf .svg files before with no problem. My code is below along with an example of what I'm getting and what I had gotten in the past (both using contourf, although the image on the right had a plot() command too).

figure(2)
contourf(tiempo(inicio:fin), alturas, velEst(inicio:fin, 1:56)', 30, 'LineStyle','none'); 
%set(h, 'EdgeColor','none')
xlabel('Fecha (2006)'); ylabel('Profundidad');
caxis([-15 15]); datetick('x');

[Chad Greene]

Can you provide some sample data so we can replicate the problem?