This is a feeding network or food chain, it shows producers and top predators, it is expected to find bigger populations for base organisms (producers), meanwhile, for apex predators, we would expect less. This difference in populations numbers has a quite simple explanation, the producers are autotrophs, that is to say, they produce their own food and represent the major energy intake of the system, which is why they must be large populations capable of sustaining the rest of the organisms. In the case of a top predator, are called that way because they don´t have any predator, and in turn, they exert control in the population numbers of downstream organisms, so their populations must be small or they would end the whole chain.
Taking into consideration this information we have three apex predators in this net, bobcat, alligator, and anhinga, These organisms as top predators would be expected to have smaller populations.