For the first day that rattletrap lure was used, they captured 28 fish. is this the sample of fish or the population of fish? population sample

This is a sample of the fish population.

Explanation:

There are more than 28 fish in the sea (river, lagoon, or other body of water). The fish population consists of all fish present in the sea. When we put a bait in this sea, we want to attract as many people as possible from this population, but we will not be able to attract the whole population. The individuals we are able to attract with our bait represent a sample of the population.

A population is a set of people, items, or events that you want to make inferences about. A sample is a subset of people, items, or events from a larger population that you collect and analyze to make inferences. To represent the population well, a sample must be randomly collected and appropriately large. This concept can also be used to represent the fish, shown in the question above, so we can say that the 28 fish are the population sample.

this is math not biology xd