Open TideMark, go to Compete, and tap Delete account. It happens straight away.
Email altonphotography@gmail.com with the subject Delete my TideMark account, from the email address linked to your Apple or Google sign-in. Tell us your TideMark display name if you know it. We'll confirm it's your account and delete it within 30 days, usually much sooner, and reply to confirm.
What gets deleted: your account, display name, profile photo, every catch synced to our server, the photos attached to them, your competition entries and reactions, and any competitions you organise.
What isn't: catches stored only on your phone stay there until you delete them or remove the app. Reports other people made about content are kept with your name removed, for moderation records.