pumpkinseed vs bluegill size structure

[mainbutter]

I fished a new lake today with good results. Plenty of bass, bluegills, and pumpkinseeds, almost all on my fly rod.

I made an interesting observation. The bluegills size structure was pretty poor, extremely numerous with very few fish over 6''.

However, the pumpkinseeds were HUGE! Not only did every single 'seed go over 7'', but I even boated one that was 9'' on the nose.

Now I only boated maybe 7 or 8 pumpkinseeds compared to the 50+ bluegill, but I just thought I'd share and get your thoughts on why there is such a drastic difference in size structure, which is particularly odd because bluegill are typically the fastest growing sunfish with the greatest capability for max size.

[Ctrl_Alt_Dlt]

PM sent to your email.

[Scott M]

Exploitation of different trophic niches. The respective diet is somewhat different. One of the ways to separate out sunfish to the species level is to examine gill rakers, gill rakers are the white "combs" behind the red gill filaments. The rakers ensure that prey items do not get blown out of the mouth during suction feeding. Bluegills have long, thin gill rakers, while pumpkinseeds have short, nubby and thick gill rakers. 'Gills and P-seeds can be separated, partially at least, on diets. One diet study found that bluegills consume a greater proportion of Cladocera and Trichoptera larvae while pumpkinseeds ate more molluscs and isopods.

My best guess was there were more molluscs and isopods available to both species or less intraspecific competition for pumpkinseeds. The only way to know definitively for the latter would be age the fish and compare growth.

Bluegill gill rakers

Pumpkinseed gill rakers

Those two photos are from WiscFish.org. They have a great site for identifying fish and using true taxonomic distinguishing characteristics rather than comparative photos or colors.

[mainbutter]

Cool stuff da-chise! That opened my eyes to a few things.

[Spike76]

Where I fish north of Brainerd, the pumpkinseeds are always wormy, so I throw them back. They are bigger though,usually. Thanks 31, very good information. Does their diet make the pumpkinseeds wormy?

[Scott M]

Yes. You are describing yellow grub. A lot of common fish parasites use molluscs as intermediate hosts, including Neascus and Clinostomum. These two parasites would be more likely in pumpkinseeds versus bluegills because of the dietary difference.

[OnAFly]

"One diet study found that bluegills consume a greater proportion of Cladocera and Trichoptera larvae while pumpkinseeds ate more molluscs and isopods. "

I've been playing around with some of my trout flies for ice fishing with positive results. The flies I've been using have been mostly scud flies, which would mimic the Cladocera fairly well and maybe the Trichoptera.

I'll have to try some midge patterns and caddis larvae patterns this year too.