WALK-THROUGH INTRODUCTION: This walkthrough will demonstrate how I go about seeking identifications on my hybrids without submitting a specimen to any DNA analyses.

Considering there are 78 possible combinations of hybrid lepomids with 13 parent species, it’s obviously impractical to be able to provide information on each hybrid combination. Going over one specimen here should give you some good pointers for how to go about your identifications. (I will make a video on this as well.) I also did a very thorough analysis of the greengill hybrid.

I will also reiterate the advice on the “Introduction to Hybrids” page: It’s often impractical to make a confident ID on a hybrid without having fully understood the parent species and/or submitted the specimen in question to a DNA analysis. That doesn’t mean we can’t try!

Essentially, I am just following the “Six Steps of Lepomid Identification” that I created for this guide. The first two steps can be worked on anytime, and ideally, before you have even caught a possible hybrid.

STEP 1: LEARN THE ANATOMICAL DIRECTIONALITIES & BASIC SUNFISH FEATURES

Yup. I know what anterior, posterior, dorsal and ventral mean. I also know my sunfish body parts. (STEP 1 LINKED HERE.)

STEP 2: LEARN THE BASIC FEATURES OF THE SPECIES

Also feeling good on this. I should hope so as I wrote the guide. =) (STEP 2 LINKED HERE.)

STEP 3: GET PHOTOGRAPHS OF THE FISH

In STEP 3 of the sunfish guide I cover what photographs to capture in order to confirm your fish. Always start with a good lateral shot that captures most of the fish and gets the fins splayed as much as possible. For this hybrid specimen, I did not have my tank with me nor my DSLR camera, so all photos were taken with my old smartphone. These photos aren’t the best but they will be adequate for this analysis. (I also forgot to take a shot of the dorsoanterior view—whoops!) CLICKING ON THE BELOW IMAGES WILL ENLARGE THEM.

It’s apparent from the lateral pattern, colors and opercular flap that this fish is likely a hybrid. We’ll cover what to look for in STEP 5.

STEP 4: LIST ALL NEARBY LEPOMIDS

This is a very important step for identifying hybrids. I caught this fish in N. Virginia on a small lake. It’s time to use the resources in STEP 4 and make a list of all possible species in this lake as well as in nearby waters.

The confirmed species in the lake are green sunfish (Lepomis cyanellus), bluegill (Lepomis macrochirus), redear sunfish (Lepomis microlophus), and warmouth (Lepomis gulosus). Other species caught nearby (within a 25 mile/40 km) radius are the redbreast sunfish (Lepomis auritus), pumpkinseed (Lepomis gibbosus) and longear sunfish (Lepomis megalotis).

That’s seven different species nearby!

SHORT LIST: GREEN, BLUEGILL, REDEAR, WARMOUTH, REDBREAST, PUMPKINSEED & LONGEAR.

STEP 5: ANALYZE THE FISH

Hybrids will often display intermediary characteristics between the parent species but that is not always the case. Let’s break down some important characteristics on this specimen.

PECTORAL FIN: It is quite clear that the pectoral fin extends past the anterior edge of the eye if it were to be bent forward. Only three species will have the pectoral fin extending that far: bluegill (L. macrochirus), pumpkinseed (L. gibbosus) and redear sunfish (L. microlophus). And because it still remains so long and so pointy, I believe we can toss out any of the species with short pectoral fins. That would mean the green sunfish (L. cyanellus) and warmouth (L. gulosus) are likely not parents.

MOUTH SIZE: Similarly to the pectoral fin, we can see this fish has a small mouth where the maxillary does not even reach the anterior portion of the eye. The same three species that have the long and pointed pectoral fin also share this small mouth trait: bluegill, pumpkinseed and redear sunfish.

The warmouth and green sunfish both have very large mouths. With the specimen in question showing a very long pectoral fin and a small mouth, it’s safe to say that both the warmouth and green sunfish are not parent species.

ELIMINATED: GREEN & WARMOUTH.
REMAINING: BLUEGILL, REDEAR, PUMPKINSEED, LONGEAR, & REDBREAST.

The redbreast sunfish (L. auritus) does have a fairly large mouth and a fairly short pectoral fin, but as far as hybrids go, I wouldn’t completely eliminate it yet just off these two traits. The same reasoning applies to the longear sunfish in this situation.

Though after examining the pectoral fin and mouth, it is highly likely that the only possible hybrid parents are two of the following: bluegill, pumpkinseed and redear.

OPERCULAR FLAP: This specimen has an odd opercular flap. The flap is very short with a ventral white edging and a dorsal black edging. I also noticed that there was some faint reddish orange that had mostly folded over on the first lateral shot. This is why it’s important to make sure the opercular flap edging isn’t tucked under the flap itself.

As this fish has a very short ear flap, along with the previous examination of the pectoral fin and mouth, it’s probably fine to assume now that the longear and redbreast are not parent species. Both of these species have the longest ear flaps of all the lepomids.

ELIMINATED: GREEN, WARMOUTH, REDBREAST, & LONGEAR.
REMAINING: BLUEGILL, REDEAR, & PUMPKINSEED.

The bluegill is primarily the only mature lepomid to not have color on the opercular flap other than black. Occasionally some white ventral edging may exist for a very short distance on pure specimens. But there is no red or orange on a bluegill’s opercular flap.

Both the redear and pumpkinseed have a bright, solid red/orange spot with white edging both ventrally and dorsally. Based on that knowledge, we would expect a hybrid to have a very pronounced red and white edging on the opercular flap, of which, we do not see on the specimen in question.

So, it is most likely that the diluted colored-edging on the earflap is the result of a bluegill x redear or bluegill x pumpkinseed.

GILL RAKERS: Looking at the gill rakers is absolutely helpful for hybrid identifications. It’s important to keep in mind that raker sizes will vary between specimens of the same species but the general trends hold true. I advise that you start casually checking the gill rakers on the anterior side of the first gill arch on most of your caught fish just so you may gain a familiarity with the varying appearances.

When I looked at the rakers on this specimen, it was quite apparent they were intermediate in size between what is normally seen on a bluegill, redear, and pumpkinseed in my area. (For your reference, I did place all the commonly seen raker sizes for all the species in STEP 5 “Koaw’s Cheat Sheet.”)

I made a video describing how to locate and find these rakers that is hosted on Koaw Nature’s Fishing Smarts YouTube channel.

So although these rakers don’t eliminate a parent species of the remaining three choices, they do tell us, along with the dulled opercular flap color, that a bluegill is one of the parent species. These rakers are just too long to be a pure redear or pumpkinseed but also too short and thick to be a pure bluegill. Now we have to figure out whether the other parent species is a redear or pumpkinseed.

ELIMINATED: GREEN, WARMOUTH, REDBREAST, & LONGEAR.
REMAINING: REDEAR & PUMPKINSEED.
PARENT SPECIES: BLUEGILL

FIN RAY/SPINE COUNTS: The meristic characteristics, or countable features on fishes, often provide insight into species identifications. In this case, the redear, bluegill and pumpkinseed have such similar meristics for fin rays and spines that this may not be too beneficial. Though counting rays and spines is good practice and it may even provide some insight for this specimen.

Counting the dorsal spines and dorsal rays reveals a peculiarity—there are 9 dorsal spines! Most bluegill, redear, and pumpkinseed will have 10 dorsal spines. Occasionally a bluegill or redear will have 9 spines, and less so on pumpkinseed. The 11 dorsal rays is fairly common on all three of those species.

The 14 pectoral rays is curious—most pumpkinseed will only have 12-13 pectoral rays. Bluegill and redear often have either 13-14 pectoral rays.

This specimen appears to have 10 anal rays, of which, doesn’t help too much as the pumpkinseed, bluegill and pumpkinseed often have 10-11 anal rays. You’ll notice my photo wasn’t that great even as I tried to grab the whole anal fin. Ideally, I should have taken a photo grabbing the last two rays completely outstretched. The last two rays typically are the same ray, just branching under the skin; I’m assuming from the distance between the ray insertions that the last two obvious extending rays are indeed different rays and the last ray’s branches are stuck together, not visible from the photo.

After examining these meristics, there’s a bit of evidence now suggesting we have a bluegill x redear cross. It’s not enough but it’s a good start for finalizing the analysis.

COLOR/PATTERNING: This is not the best place to start for hybrid identification but it is the best place to finish once your list has been narrowed down. Hybrids often express colorations and patterns that are different from the parent species. Though dissimilar, the colors and patterns of the parents are usually present in a faded or obscured form. I’ve tossed together a graphic with the hybrid specimen (flipped for ease-of-comparison) and the three possible parent species; all of these fish were caught in the same township in Virginia.

On the hybrid specimen there is a somewhat dark blotch at the base of the posterior interradial membranes of the 2d dorsal fin; this is typical of a bluegill. The overall plainness on the head also suggests a bluegill parent as this species usually does not have any spotting or bright colorations on the head, only light blue on the lower jaw, along the chin and across the lower cheek and operculum. A bit of that light blue is present on this specimen.

The cheek and operculum of redear often have distinct spotting of brown, gray or gold. Looking closer at the headshot of the specimen, it does seem like some light gold spots exist in a faded manner, though nothing as distinct as seen on pure specimens.

Pumpkinseed have very vibrant blue streaks on the snout and across the head. The hybrid specimen in question does not show any type of iridescent blue streaking on the head. If a pumpkinseed parent existed, it would be expected to see at least some of this blue streaking along the head that has the orange/yellow in between. Furthermore, pumpkinseed often have much dark mottling in the median fins—the specimen shows no mottling. Though redear may also have some mottling in the median fins.

The body pattern of the specimen in question most closely resembles a breeding male redear sunfish, with the dark-olive, bronze color above that fades down to cream color on the breast and belly. The faded spot pattern on the side does not to appear to have any of that orange coloration typical of a pumpkinseed.

There is no coloration or pattern on this fish suggesting a pumpkinseed parent.

ELIMINATED: GREEN, WARMOUTH, REDBREAST, LONGEAR, & PUMPKINSEED.
PARENT SPECIES: BLUEGILL & REDEAR.

With our empirical evidence stacked up, all signs are pointing to a bluegill (L. macrochirus) x redear sunfish (L. microlophus) mix. The specimen is most likely an F1 hybrid but there is no way to know if this is second generation or perhaps a backcrossed specimen or even if an introgression happened earlier in the ancestry.

Extra Info: A redear x bluegill cross is also more likely because I have fished this lake on-and-off for almost thirty-years and I’ve never caught a pure pumpkinseed. That does not necessarily mean pumpkinseed do not exist in the lake or lack the ability to get into the lake from the inlet. I have caught pumpkinseed in nearby waters. A stray pumpkinseed would actually have more inclination to hybridize if unable to find a mate of its species.

To summarize the analysis:

1. We gathered our list of all species from the nearby waters that included seven species: GREEN, BLUEGILL, REDEAR, WARMOUTH, REDBREAST, PUMPKINSEED, & LONGEAR.

2. We analyzed the pectoral fin and mouth first, confidently eliminating the green sunfish and warmouth as their pectoral fins and mouths are too short and large, respectively, compared to the hybrid specimen.

3. Keeping in mind our previous analysis, we also used the opercular flap analysis to toss out the longear sunfish and redbreast sunfish. The ear flap on the hybrid specimen is far too short.

4. Examining the gill rakers on the hybrid specimen revealed the rakers are too short and thick to be a pure bluegill but too long to be a pure redear or pumpkinseed. Of the three remaining possible parent species, the bluegill is the only species with long rakers, thus must be a parent.

5. We looked at the meristics, or the fin spine/ray counts. The 9 dorsal spines is an oddity, more suggesting a hybrid than anything else. The 14 pectoral rays suggested more so that a bluegill x redear cross was likely as pumpkinseed usually have 12-13 rays while bluegill and redear have 13-14 rays.

6. We finally looked at the colors and patterns on the hybrid specimen. The hybrid had features of bluegill and redear without anything suggesting a pumpkinseed was a possible parent.

7. We assume from the evidence that we have a bluegill x redear hybrid or some sort of mixed-blood specimen of the two parent species.

Hybrids can be headaches to ID. I encourage you to attempt the challenge of identification but don’t feel bad if you can’t find a confident resolution after your examination. There are still a number of hybrids that I’ve caught that I simply cannot identify without a DNA analysis. Good luck out there! -K

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