SirMatthew KC,
Marymarcel isn't available at this time,
Currently, there is no way in game for you to see how much of the coin limit you have already earned.
If you had only earned one fish bonus, like cod, you can get an idea of the value of that bonus by the amount of fish in the bonus and the value of the fish, but even then you would still need to count up how many bonuses you had received to get an idea of how much you had earned as the day progressed and more were sent.
Something like cod that has a low coin value would take a quite a lot of bonuses to get you to 15 million IF that was the only bonus you received.
Something like salmon or lobster has a much higher coin value and would take far less bonuses to reach that 15 million IF that was the only bonus received.
Figuring out values of bonuses gets far more complicated if different bonuses were posted and sent as well, which many wouldn't want to try doing.
You can certainly request if that information could be shown somewhere in the the game, in the
Suggestions area where the devs will see it.