Fig. 4. Changes in (A) protein, (B) lipid and (C) carbohydrate concentrations in the pouch fluid of Syngnathus fuscus (gray squares; solid line) and Syngnathus floridae (white diamonds; broken line) across the progression of embryonic development. For both species, nutrient levels significantly decline in pouch fluid over the seven stages of development (P<0.05). The decrease in protein occurs at a steeper rate for Syngnathus floridae, whereas lipid concentrations drop more quickly in Syngnathus fuscus (both P<0.05).