The screenshot shows that you only have 108 food. With the fact you've got two recent deaths it's highly unlikely that you're meeting the minimum requirements for the amount of food actually needed by your colony. You should be able to observe this better by looking at the graphs section on your town hall screen at food storage over time - it will be very low and constantly hit zero.
With this in mind, you need more food production, whether this be additional fishing or additional fields and more farming, or whatever.
It's worth keeping in mind that certain types of food production yield in different ways - fishing and gathering results in a steady quantity of food incoming while fields and orchards result in a (hopefully) large yearly yield. It's no point going all in with farming unless your food supply is already stable as it will be a full year before you get any food out of it.
The bottom line, though, is: your people are starving to death because you're not producing enough food.