It gives me 3-4 darters at 6 fishing skill.
Data points:
3 x darters
4 x darters
1 x darter + 3 x Seaweeds
2 x darter + 1 x Seaweed
2 x darter + 1 x Seaweed
2 x darter + 1 x Seaweed
2 x darter + 1 x Seaweed + 1 x Freshwater Eel
1 x darter + 3 x Seaweeds
2 x darter + 1 x Seaweed
3 x Seaweeds
1 x darter + 1 x Seaweed + 1 x Freshwater Eel
2 x darter + 1 x Seaweed + 1 x Freshwater Eel
2 x darter + 1 x Seaweed + 1 x Freshwater Eel
3 x Freshwater Eel
3 x darter + 1 x Seaweeds
Got 25 darters in all :)