Can I use fish for shore lunch?

At most waters you may do so. However, at waters with minimum size restrictions on a particular species, you may not remove more than gills, entrails, and scales from fish of that species. In these cases, you may do so only after transporting it to your personal, permanent residence. See Fish Size Restrictions in the fishing guide. It's important to note, any fish consumed during the course of a day's fishing count in the individual daily limit.