Find answers to common questions about Fishmarks — from offline use and GPS accuracy to billing, privacy, and referrals.
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Usage & Features
Yes! FISHMARKS is a Progressive Web App (PWA) that you can install on your phone or tablet for use on the water with spotty connectivity.
What works offline:
The full app interface loads instantly from cache
Standard (OpenStreetMap), NOAA Bathymetry, and NOAA Chart map tiles are cached as you browse — areas you’ve viewed before will load offline
Your waypoints, lists, and other data are cached locally
You can add, edit, or delete marks — changes queue and sync automatically when you reconnect
What requires a connection:
Google Satellite and Bing Satellite imagery (licensing prevents offline caching)
Weather forecasts, radar, wind overlays, and tide data (real-time data)
List sharing, invitations, and friend requests
To install:
Look for the install banner at the bottom of the screen, or use your browser’s “Add to Home Screen” option. The installed app opens in full-screen mode like a native app.
Tip: Before heading out, browse the map areas you plan to fish so the tiles get cached for offline use.
The crosshair represents the exact GPS coordinates of the center of the map. When you click a mark in the sidebar and the map pans to it, the crosshair sits precisely at that mark’s latitude and longitude. The marker symbols (pins, squares, circles, etc.) are visual references. Each symbol is anchored at its bottom-center point, but due to their size and shape, they serve as a general reference rather than a precision indicator.
For exact positioning:
Enable the crosshair from the map layer controls (Options > Show Crosshair)
Pan or click a mark to center it — the crosshair shows the true coordinate
The coordinates displayed in the bottom bar also reflect the exact crosshair position
Tip: Think of the crosshair as the precision tool and the marker symbol as the visual label.
When a proximity circle is active (via Near Me or Search Near Here), the yellow pill at the top of the map displays a menu with powerful actions scoped to marks within the circle.
Available actions:
Catch Analytics — View charts and statistics for catches logged at marks within the circle. Includes summary cards (total catches, species count, best month), catches over time, species breakdown, method distribution, conditions insights (tide, moon, wind), and personal records. Use the time range buttons (All Time, 5 Yr, 1 Yr, etc.) to narrow the analysis period.
Catch History — Browse individual catches at marks within the circle, grouped by date. Each entry shows species, measurements, fishing method, conditions, and which mark it was logged at.
Add to List — Add all marks inside the circle to an existing list or create a new list on the spot. Quick way to organize marks by geographic area.
Tips:
Change the radius to widen or narrow the area before running an action
Analytics and history update automatically when you adjust the radius
Combine with other filters (tags, icons, depth) to focus on specific types of marks within the area
Note: These actions are available whenever the proximity circle is active, on any paid plan.
Fishmarks Connect is the companion iOS app for Fishmarks. It gives you quick access to your marks on your phone — browse your spots, export to your chartplotter app, and view mark details without opening a browser.
Key Features:
Browse & search all your marks on an interactive map
Share directly to chartplotter companion apps like ActiveCaptain and Simrad App via the iOS share sheet
Open in Fishmarks — tap any mark to jump to it in the full web app with the popup open
Filter by list to focus on specific groups of marks
Fishmarks Connect requires a paid subscription (Angler or Captain) with cloud sync enabled. It syncs with your Fishmarks account so your marks are always up to date.
Tip: Fishmarks Connect is the fastest way to get marks from Fishmarks to your chartplotter — export from your phone, share to the chartplotter app, and sync to the device over Wi-Fi. No SD card or computer needed.
Not yet — but we’d love to make that happen someday. Unfortunately, chartplotter manufacturers like Garmin, Simrad, Lowrance, and Raymarine do not currently offer open APIs that would allow third-party apps to sync data directly with their devices.
What you can do today:
Manage your marks, tracks, and routes in FISHMARKS
Export a GPX file and load it onto your chartplotter via SD card
Import a GPX file from your chartplotter back into FISHMARKS to capture any new points added on the water
FISHMARKS detects duplicates during import, so you won’t end up with double entries
Looking ahead: We hope to be invited to work with the major chartplotter manufacturers to build direct sync integrations.
Tip: See “Which GPS devices and chartplotters are supported?” below for brand-specific export profiles.
FISHMARKS supports import and export for all major marine electronics brands:
Supported Brands:
Garmin — GPSMAP, ECHOMAP, and other Garmin devices
Lowrance — HDS, Elite, and Hook series
Simrad — NSS, NSO, GO, and Cruise series
B&G — Zeus, Vulcan series
Raymarine — Axiom, Element, and other models
Humminbird — Helix, Solix, and Apex series
Furuno — NavNet and TimeZero devices
How It Works:
Import: When you import a GPX file, FISHMARKS automatically detects which device created it and maps its symbols to the correct Fishmarks icons — no setup needed
Export: When you export to GPX, choose a device-compatible profile (Garmin, Navico SD Card, Simrad / C-MAP App, or Universal) so the file is ready for your chartplotter or companion app
Brand-specific data like Garmin depth and temperature extensions are also handled automatically
Tip: Don’t see your device? The Universal export profile uses standard GPX symbols that work with virtually any GPS device or mapping software.
Map Overlays
The NOAA Bathymetry layer is a basemap option that displays compiled best-available bathymetric data as a hillshade terrain view. It uses data from NOAA’s BlueTopo program, combining multiple sonar and depth survey sources into a single, seamless layer.
How to enable it:
Open the Map Controls menu (gear icon on the map)
Select NOAA Bathymetry from the basemap options
Coverage:
Gulf Coast, Atlantic Coast, and US Caribbean
Areas without bathymetric data will show the underlying base map
Note: The NOAA Bathymetry layer is available on the Captain plan.
They serve different purposes:
NOAA Charts — official electronic navigational charts (ENCs) showing aids to navigation, shipping lanes, hazards, and depth soundings — the same charts you’d use for navigation
NOAA Bathymetry — a terrain-style hillshade view of the seafloor compiled from the best available depth surveys, making underwater ridges, channels, and drop-offs visually obvious
Use NOAA Charts for navigation. Use NOAA Bathymetry when you want to read the shape of the bottom at a glance.
The data comes from NOAA’s BlueTopo program, which compiles the best available bathymetric sources — including multibeam sonar surveys, lidar, and historic soundings — into a single compiled dataset. The tiles are served free of charge through NOAA’s nowCOAST service.
The Bottom Hardness overlay is a map layer that visualizes bottom substrate hardness across U.S. coastal waters. It uses NOAA Seabed Type data from over 685,000 USGS/NOAA usSEABED sample points to display a continuous color gradient from soft bottoms (mud) to hard bottoms (rock).
How to enable it:
Open the Map Controls menu (gear icon on the map)
Check Bottom Hardness under the Overlays section
A color legend will appear in the bottom-right corner of the map
Note: The Bottom Hardness overlay is available on the Captain plan.
The color scale represents bottom hardness on a spectrum:
Blue — Soft bottom (mud, silt)
Cyan — Sand
Yellow-Green — Gravel, shell hash
Orange-Red — Hard bottom (rock, reef)
A legend displaying this scale appears in the bottom-right corner of the map whenever the overlay is active.
Bottom composition is one of the strongest predictors of where fish hold. The overlay helps you identify productive areas before you ever leave the dock.
What to look for:
Hard bottom areas (orange/red) — rock, reef, and shell beds attract structure-oriented species like snapper, grouper, and sea bass
Soft-to-hard transitions — edges where the color shifts from blue/cyan to orange/red are especially productive, as baitfish congregate along these boundaries
Isolated hard patches — small areas of hard bottom surrounded by soft substrate often concentrate fish
Tip: Combine the Bottom Hardness overlay with NOAA Charts or the NOAA Bathymetry basemap to cross-reference bottom structure with depth contours and known features.
The data comes from the USGS/NOAA usSEABED database, a compilation of over 685,000 seafloor sediment samples collected across U.S. continental shelves. The raw sample points are processed into a continuous hardness gradient using spatial interpolation (IDW), then rendered as map tiles.
The overlay is available at zoom levels 6 through 10. Zoom in past level 6 to see the data appear. At zoom levels beyond 10, the tiles are upscaled from the highest available resolution.
Coverage includes U.S. coastal and continental shelf waters where usSEABED samples exist. Areas without sufficient sample density may appear transparent.
The HD Sonar overlay displays high-resolution seafloor terrain from NOAA multibeam sonar surveys. It renders a color-shaded hillshade showing underwater topography in striking detail — channels, ledges, drop-offs, and man-made structures are clearly visible.
How to enable it:
Open the Map Controls menu (gear icon on the map)
Check HD Sonar under the Overlays section
Zoom to level 10 or higher to see data appear
Note: The HD Sonar overlay is available on the Captain plan.
They answer different questions about the ocean floor:
Bottom Hardness — shows what the bottom is made of (mud, sand, gravel, rock) using 685K+ NOAA Seabed Type sediment samples
HD Sonar — shows the shape of the bottom (terrain, depth, structure) using high-resolution multibeam sonar
Use them together for the most complete picture — Bottom Hardness to find hard bottom, and HD Sonar to see the structure and terrain around it.
The data comes from NOAA BAG (Bathymetric Attributed Grid) surveys — multibeam sonar collected by NOAA hydrographic survey vessels.
Coverage:
Concentrated along shipping channels, ports, harbor approaches, and heavily surveyed coastal areas
Strong coverage along the East Coast continental shelf, Gulf of Mexico approaches, and major harbors
Not all waters have been surveyed — areas without data appear transparent
Resolution:
0.5–2 meters in shallow water (<20m depth)
2–5 meters nearshore (20–100m depth)
5–25 meters on the continental shelf (100–200m depth)
This is dramatically higher resolution than standard chart data, which is typically derived from older singlebeam soundings.
The high-resolution terrain view reveals underwater structure that doesn’t appear on standard charts.
What to look for:
Ledges and drop-offs — sharp depth transitions where predators ambush baitfish
Holes and depressions — deeper pockets in otherwise flat bottom that concentrate fish
Channel edges — where current flow creates feeding opportunities
Isolated structure — rock piles, wrecks, or artificial reefs rising from flat bottom
Tip: Pair the HD Sonar overlay with the Bottom Hardness overlay to see both terrain shape and bottom composition at the same time.
Dynamic Lists
Dynamic Lists are rule-based collections that automatically populate based on conditions you define — no manual mark assignment needed.
How they differ from regular lists:
Regular lists — you manually add and remove marks
Dynamic lists — marks are included automatically when they match your rules
Examples:
All marks deeper than 30 feet
All marks where you caught Snook
All marks tagged “reef” created in the last year
All marks with 5+ total catches using live bait
Note: Dynamic Lists are available on Angler and Captain plans.
Dynamic Lists support a wide range of conditions across two categories:
Waypoint Rules (evaluated locally):
Name — contains, does not contain, or equals
Notes — contains or does not contain
Symbol / Icon — is or is not a specific icon
Tags — has any of or has all of selected tags
Depth — greater than, less than, or between values
In List — mark belongs to another specific list
Date Created — after, before, or between dates
Catch-Based Rules (evaluated from your catch history):
Species — is or contains a species name
Method — live bait, lure, fly, trolling, spear, etc.
Weight / Length — greater or less than a value
Total Catches — number of catches at the mark
Tide State — low, incoming, high, or outgoing
Moon Phase — new, waxing crescent, full, etc.
Tip: You can combine any number of conditions from both categories using ALL or ANY match mode.
Auto-Update keeps your Dynamic List membership current in real time.
When enabled:
The list re-evaluates its rules automatically when marks or catches change
New matching marks are added to the list
Marks that no longer match are removed
A small bolt icon appears next to the list in the sidebar
When disabled:
The list keeps its current membership as a snapshot
A wand icon appears instead
Re-evaluate manually by editing the list
Tip: Toggle Auto-Update on or off anytime from the list edit modal.
Import & Export
Yes! Your data is always yours and you can export at any time from the Data menu or from a list’s context menu.
Export formats:
GPX — Standard GPS format compatible with chartplotters and mapping software
CSV — Spreadsheet format for Excel, Google Sheets, or data analysis
GPX Device Profiles:
When exporting to GPX, choose a profile optimized for your target device:
Garmin Compatible — symbol names and extensions formatted for Garmin chartplotters and ActiveCaptain app
Navico (Simrad / Lowrance / B&G) SD Card — for importing via SD card to Navico-family chartplotters
Simrad / C-MAP App — for sharing directly to the Simrad App (formerly C-MAP or Embark app) on your mobile device
Universal GPX — standard symbols for maximum compatibility with any device
Fishmarks (Full Data) — includes all metadata, lists, tags, and diary entries
Tip: You can export all marks at once or export individual lists from the sidebar.
Data & Privacy
No, your data is not shared. Free accounts store data locally in the browser, and paid accounts store data in a secure cloud.
Client-side encryption is an optional feature that adds an extra layer of protection to your most sensitive data — your waypoint names, GPS coordinates, and notes.
How it works:
You create a passphrase (minimum 8 characters) that only you know
Your passphrase is used to derive an AES-256-GCM encryption key using PBKDF2 with 600,000 iterations
Waypoint names, coordinates, and notes are encrypted in your browser before being sent to our servers
Data stored in our database is unreadable ciphertext — even we cannot decrypt it
When you open the app, you enter your passphrase to unlock and view your data
What gets encrypted:
Waypoint name
Latitude and longitude
Notes
What is NOT encrypted:
Icon, depth, tags, and dates (needed for filtering and display)
Trips, catches, routes, and tracks
Lists and list memberships
To enable: Go to Settings > Security and toggle encryption on.
Warning: If you forget your passphrase, your encrypted data cannot be recovered. This is by design — only you can decrypt your waypoints.
Encryption and list sharing work together seamlessly. When you share a list with another user:
Waypoints in the shared list are automatically decrypted in the database so the recipient can view them
This happens transparently when you send the invitation — no extra steps needed
New waypoints you add to a shared list are stored as plaintext (not encrypted)
When sharing ends:
If you remove all guests from a list, the waypoints are automatically re-encrypted
Waypoints that are also in another shared list will stay as plaintext until that list is also unshared
Key points:
Only waypoints in the shared list are affected — your other waypoints remain fully encrypted
You remain in full control of who has access
Revoking access and re-encrypting is automatic
Tip: If you want maximum privacy for specific waypoints, keep them out of shared lists.
Changing your passphrase:
You can change your passphrase at any time from Settings > Security.
Click “Change Passphrase” in the Security tab
Enter your current passphrase to verify your identity
Enter and confirm your new passphrase
All waypoints are decrypted with the old key and re-encrypted with the new key automatically
Forgotten passphrase:
There is no recovery mechanism — we do not store your passphrase
If you forget your passphrase, encrypted waypoint data cannot be recovered
You can disable encryption to start fresh, but previously encrypted data will be lost
Tip: We recommend storing your passphrase in a password manager for safekeeping.
Important: Free accounts store all data locally in your web browser. Your data is not backed up to the cloud and exists only on the device and browser you are currently using.
How you can lose your data:
Clearing browser data — “Clear browsing data,” “Clear cache,” or “Clear cookies” will erase your marks
Private / Incognito mode — all data is deleted when the window closes
Switching browsers or devices — data saved in Chrome is not available in Safari, Firefox, or on another phone/computer
Browser storage limits — some browsers may automatically purge local storage when space runs low
Uninstalling or resetting your browser — local data is removed
OS updates or factory resets — may wipe browser storage
How to protect your data:
Export after every session — go to Data > Export GPX or Export CSV
Keep multiple backups — save exports to a cloud drive (Google Drive, iCloud, Dropbox)
Avoid private/incognito windows
Be careful with “Clear Data”
The best protection — upgrade your plan:
Starting at just $16.99/year, an Angler plan stores your data in secure cloud, backed up automatically, synced across all your devices, recoverable through Trash if you accidentally delete something.
Warning: We strongly recommend exporting a backup after each use until you upgrade to a paid plan.
If you are on a paid plan (Angler or Captain), deleted items are moved to Trash instead of being permanently removed. Items remain recoverable for 30 days.
What you can do from Trash:
Restore — put a mark, trip, or route back exactly where it was, including list associations and linked catches
Download — export trashed marks as GPX or CSV before they expire
Permanently delete — remove individual items or empty the entire Trash immediately
To access Trash: Open your Profile (user icon in the menu) and select the Trash tab.
What gets saved:
Marks — full waypoint data including list memberships
Trips — trip details plus all associated catches and catch photos
Routes — complete route with all points and metadata
Note: Free accounts do not have Trash — deletions are permanent. After 30 days, trashed items are automatically and permanently removed.
Billing & Subscriptions
Payments are processed through Stripe, an industry leader and secure payment processor. All major credit/debit cards are supported and we hope the payment process is simple for everyone.
Should you decide to stop using the software, you can cancel your subscription from your Profile page. On this page you’ll see your Subscription Level and a link to manage your subscription. Complete that process and you’re done! You will still have access for the remainder of your annual subscription period.
Not formally, however we will work with you to do what’s right if you are unhappy with the solution. To avoid this need we offer a Free tier with a lot of functionality that allows you to get a feel for the software.
When you upgrade your plan, you are only charged the prorated difference for the time remaining in your current billing period. Your new features activate immediately.
How it works:
Stripe calculates the price difference between your current plan and the new plan
That difference is prorated based on the days remaining in your billing period
The prorated amount is charged to your card on file right away
Your renewal date stays the same — no changes to your billing cycle
On your next renewal (January 1), you pay the full Captain price of $14.99
Note: Downgrades work differently — your current plan stays active until the end of the billing period, then switches to the lower plan at renewal. No additional charges or refunds apply.
When you downgrade, your current plan stays fully active until the end of your billing period. The switch happens automatically at renewal.
How it works:
Your current plan features remain available until the billing period ends
No additional charges and no partial refunds — you keep what you paid for
At renewal, your subscription switches to the lower plan at its regular price
Example:
You are on Captain ($14.99/yr) renewing January 1
On April 1 you downgrade to Angler
You keep all Captain features through December 31
On January 1, your subscription renews as Angler at $9.99/yr
Tip: If your new plan has lower limits (e.g., fewer waypoints or lists), make sure to adjust your data before the switch takes effect.
Each year we will donate a portion of proceeds to Captains for Clean Water, however at this time an exact amount or percentage has not been determined. At a minimum we will donate $1 for every Angler account and $2 for every Captain account, however we may donate more as subscriber count scales.
Referral Program
Our referral program rewards you for sharing FISHMARKS with friends and fellow anglers! Find your unique referral link on your Profile page. When someone signs up using your link, you earn merch credits that can be exchanged for Fishmarks merchandise. The credits you earn depend on the plan your referral signs up for.
You earn merch credits based on the plan your referral signs up for:
Free signup — 1 credit (up to 20 per year)
Angler signup — 2 credits
Captain signup — 5 credits
Credits are tracked on your profile and can be exchanged for Fishmarks merchandise. You can view your credit balance and referral history on your Profile page.
Note: Paid signup credits are only awarded after the referred user’s payment is confirmed.
If someone signs up for free using your referral link and then upgrades to a paid plan within 90 days, you receive additional credits based on their new tier — minus the 1 credit already earned for the free signup.
For example, if your referral signs up free (you earn 1 credit) then upgrades to Captain within 90 days, you earn 4 additional credits — for a total of 5 credits from that single referral.
Note: The 90-day attribution window ensures you get credit for referrals who take time to decide.
Your unique referral link is displayed on your Profile page. Just click the “Copy” button to copy it to your clipboard, then share it via text, email, or social media. Your link never expires and is unique to your account.
Merch credit redemption is coming soon! Your credits are safely tracked on your profile and will be exchangeable for Fishmarks merchandise. Stay tuned for our merch store launch.