I would say Cutbow. I am not a trout expert but believe the differences can vary from almost looking like pure Rainbow to almost pure Cutthroat. Cutthroat can vary on how much red they have, have brown spots on tail, and do not have white on fin tips like Rainbow. Rainbow has the red line down its center and coloration varies widely in the area of "rainbow" effect. Yours looks to be Rainbow colors with the telltale red gill plate.
Rainbows have pink and red on the gill plate as well. I'm pretty certain that the fish in the picture is a rainbow, since I can't see any markings on the throat.
The only way to tell if it's a cuttbow or not is to look at the throat. Most cuttbows will have a yellow or orange slash under the jaw, sometimes it will be red. Most cuttbows look exactly like a normal rainbow otherwise.
However, some cuttbows with more cutthroat genetics will be more yellowish or look more similar to a cutthroat (more spots towards the tail, less greenish coloration) but will have a stronger pink stripe down the side along with the telltale cuts on the throat.
the deciding factor if it's a rainbow or cutbow is the orange in the cuts under its jaw. Looking at this picture alone is hard to tell. I would say cutbow due to the lack of spots on the bottom portion of this fish's body.
That depends on your definition of cut-bow. In most cases of rainbows in Colorado there's a good chance you can find cutthroat DNA in their genetics from what I've read. That being said they are very hard tell apart a majority of the time.
Reply by: brookieflyfisher Posted: 1/29/2013 11:23:46 AM Points: 6196
^ pretty much untrue. The Hofer-harrison rainbow is a hybrid between two rainbow trout subspecies, the Hofer strain from Scotland and the Harrison strain from the US. Accordingly it has no orange "slashes" under the jaw like a cutthroat.
Reply by: rockymountainoutfitters Posted: 1/29/2013 11:35:16 AM Points: 513
The hofer is from Germany not scotland and we stock and net them while working with the division of wildlife here in Grand lake and most hoffer -harrisons have two orange stripes under there jaws when you push on there tongue. [log in for link] [log in for link]
I have to say, I blame the CPW (and CDOW before) for the problems with fish identification. There are so many different varieties of rainbows and cutthroats stocked, some of them with very different appearances, along with cutbow, which isn't even listed in the brochure. And the picture of the cutthroat in the brochure doesn't look like any I have caught. I've seen the posts complaining about people mistaking tiger trout for brookies, yet no where in the brochure are tiger trout listed.
We could go a long way to educating the general population if the brochure had a better and more complete identification section, as well as sections regarding sterile species and the importance of identifying and releasing them.
My question, since cutbow isn't listed in either the species or in the bag limit, do they count towards the daily bag limit for trout? (Yes, being sarcastic in an effort to make my point)
Trying to tell the difference between different strains of rainbows is almost impossible with out a vast knowledge of the fish and body of water. Also a DNA test helps. These species we're talking about all have been grown in hatcheries and hybridized many times, over and over again. There is a lot of muddling of genetics in many of the rainbow/cutthroat species in Colorado.
A straight Hofer-Harrison cross is pure rainbow and will lack the "cutts".
However, CPW commonly stocks a three way cross, the HHN, which is a Hofer-Harrison crossed with a native cutthroat. That makes it a cuttbow and thus explains why many people see cutts on what they think are pure rainbows.
The attributes of the hefty Hofer rainbows brought over from Germany because of their resistance to whirling disease are combined with the Harrison Lake rainbow in order to reduce the amount of domesticated Hofer genes in the new broodstock. The introduction of "wild" genes theoretically creates a hybrid better adapted to reproduction and survival in natural systems. The Hofer rainbows have been breed over years as a food source for humans not for stocking of lakes and rivers. There for the strains of different stocks where not separated or tested and they developed some characteristics, of hybrid cutthroats. The reason they have a resistance to whirling disease is because the hatcheries were infected and they built a immunity to it over the years due to the lack of testing.
bassin makes a good point there are a # of cross breeds using the hofer harrison rainbow. The stock put in grand lake are not the HHN and still have the orange stripe.
It's easiest to tell the difference by handling fresh fish and knowing the water it was harvested from and being familiar with the phenotypes expressed for the hybrid cutbow and rainbow in a particular water. There are some places that don't stock cutbows or cutthroats, so finding a cutbow would be unlikely. There are other places that stock mostly cutbows.
Deeper pink stripes down the sides lean toward rainbow. Red marking under the gills leans toward cutthroats. In reservoirs where both are present, the mouth of the cutbow will tend to be a little longer at a given length. The mouth of a 13" cutbow usually extends behind the eye whereas the mouth of a 13" rainbow does not usually extend behind the eye in most CO reservoirs.
Depending on the cutthroat in the cross, the spots can be a clue. CDPW likes to use the native snake river cutthroat (SRN) which has fine spots in their cutbow hybrid (RXN), so these cutbows tend to have fine spots also. If the rainbows in the reservoir lack the fine spots, it is easier to tell them apart. However, a lot of different rainbow strains (RBT) have been used over the years, and the spots vary.
In response as to why nobody should care if it's a rainbow or cutbow:
They're so close to each other morphologically and ecologically that it is pointless. If it's your dream (or on your bucket list) to catch a cutbow, then that is fairly lame. They are both stocked everywhere, often together. They both get shipped all over the state to be stocked as catchables for the put-and-take trout fisheries. I'm not going to bash that system, but it is what it is.
A cut-bow is nothing special. Just another batch of trout among the millions stocked in Colorado every year. It's not seeking an elusive and exciting new species. They don't even look special (obviously if there's this much difficulty in telling them apart from rainbows, they aren't very novel). Arguments over cutbow vs rainbow come up all the time, but rarely does anyone on here argue whether something is a pure bluegill or a green sunfish x bluegill hybrid. Why not? Because someone at some point elevated the status of the cutbow to be an exotic and exciting new sport fish, even though it's essentially the same as every other stocker bow dumped into every lake in the state.
Something like a tiger trout (while mostly still concocted in a hatchery when found in western waters) is at least interesting because it has a different and striking color pattern. And they are only stocked in very few waters.
Reply by: MathGeek Posted: 1/30/2013 8:42:46 AM Points: 356
I would disagree with the assertion that the cutbow trout is nothing special. This hybrid displays an impressive level of hybrid vigor and rapid growth in Colorado reservoirs. One study (Eleven Mile Reservoir) shows that cutbows can grow from 13" long and one pound in weight in June to 16" long and nearly two pounds in October. (http://precedings.nature.com/documents/6432/version/1/files/npre20116432-1.pdf) The following year that cohort of trout will be from 4-6 lbs. But the cutbow is probably more of a trout for the common man who wants to bring home excellent fillets rather than for the elitist catch and release purist.
The cutbow trout also occupies a slightly different niche in most reservoirs than pure rainbows, so that a stocking that includes rainbows, cutbows, and cutthroats can make better use of the available forage than only stocking rainbows and cutthroats. The size of the mouth in the cutbows grows faster than rainbows, allowing them to prey on bigger fish and on bigger crawfish at a given live stage. A 14"-15" cutbow will usually have more and bigger crawfish in its belly in August and September at Eleven Mile compared with a 14-15" rainbow. The faster growth also moves them out of pike predation risk sooner.
That one is a tough call. Coloration in streams is different from reservoirs. I doubt it's a hatchery cross with Snake River Cutthroat because the spots would be finer. A cross with a natural cutthroat is possible. Knowing the location always assists identification, because one can look up what was stocked and what is naturally occurring to assess the probabilities. If it is a cutbow, maybe its a cross with a greenback cutthroat. The mouth is kind of on the short side for a cutbow, so maybe it's a 3/4 rainbow and 1/4 greenback, or maybe even a more pure rainbow.
Reply by: MathGeek Posted: 1/31/2013 9:51:13 AM Points: 356
The left pic is a greenback cutthroat with the larger spots becoming more prominent toward the tail. The right pic is a snake river cutthroat with the fine spots. Notice the long mouth on both, extending rearward behind the eye. Cutbows will inherit some of the spotting pattern from their cutthroat parent, but they will also almost always inherit the longer mouth than a similarly sized rainbow. The shorter mouth on the trout a few posts up makes me think that this fish is unlikely to have a cutthroat parent, though the spotting pattern suggests the possibility of a greenback cutthroat grandparent. The prominent red stripe also suggests the likelihood of more than 50% rainbow genetics. The red/pink stripe is usually harder to see in 50/50 cutbow hybrids.
Reply by: tfotrout Posted: 1/31/2013 11:09:04 AM Points: 1474
are you sure math geek? i have a video of me releasing this fish and if you pause at the right time you can see a pretty definite orange Cut on its throat, and i checked it out when i was unhooking it. Caught a rainbow in the pool above that looked a little different and didn't have a cut.
Nope, not sure. Kinda like guessing if a person is 100%, 50%, or 25% hispanic. One assesses features and takes a guess. I've tried to make my reasoning clear for guessing that the fish in the picture is probably 25% cutthroat at the most, but assessing from a single photo is challenging. The case is compelling for both cutthroat and rainbow genetics in that specimen. But most 50% cutbows (1st generation hybrids) that I have seen have longer mouths, and I've seen hundreds of them.