I think a good approach that uses the exclusion of taxa as mentioned by @thebeachcomber would be:
~ Go to Your observations and use the Project filter with the Worldwide Marine Life project (one caveat is that it will only show Research grade observations, but you can use the Worldwide Marine Lifee Needs ID one for the rest)
~ Then you can exclude fish (Actinopterygii = 47178) or vertebrates (Vertebrata = 355675), adding their corresponding taxon IDs to the URL using &withouth_taxon_id= (or &withouth_taxon_ids= for two or more taxa).
Here, I looked up all of my obs that meet the requirements of the Worldwide Marine Life project and excluded the Actinopterygii.
(You can use the link and just change the user_id by your username: https://www.inaturalist.org/observations?project_id=worldwide-marine-life&user_id=roysh&verifiable=any&without_taxon_id=47178)
You can look up the IDs by searching the group(s) you want to exclude with the Search bar; it will be in the URL.