Is A quaternary consumer species would be expected to have a smaller population than a secondary consumer species.?

Yes, a quaternary consumer species typically has a smaller population than a secondary consumer species. This is due to the energy transfer inefficiency in trophic levels, where only about 10% of energy is passed from one level to the next. As a result, fewer individuals can be supported at higher trophic levels, leading to lower population sizes among quaternary consumers compared to secondary consumers.