I found this post concerning wild fish ID on another site. This subject was discussed a few months ago on the board. The poster is a Central / Eastern PA fisherman who recently published a book - "Fly fishing Pressured Waters". By chance I just purchased the book a few weeks ago. It has great patterns and instructions on tying realistic flies. He seems to know his subject concerning wild vs. stocked trout ID. Note the "blue halo" observation.
"OK, you asked for it, so I'll give it a go. In order to identify wild browns (especially in a fingerling-stocking situation), it is useful to understand why they can be distinguished. So bear with me, and knowing my own tendency to over-explain, I'll try to pare this down to the bare minimum. Please feel free to ask questions if there's something you don't understand.
The common wisdom, even among the best biologists, is that the brown trout in America is a highly variable fish of mixed heritage, and that trying to distinguish between strains or races (or even between wild and stocked fish in some instances) is nearly impossible in the field. This is generally quite true, but it is not universally true. And it is not true in specific instances (in our case, a specific instance as large as PA).
As you wander PA in search of wild browns, sooner or later you will recognize that they are nearly all of a consistent type with common morphological characteristics. By and large, they did not descend from the domesticated stock produced by the state for more than half a century. To understand this, ask yourself this question: If stocking of this domesticated type of brown trout was making any significant contribution to wild populations, then why aren't the wild trout streams populated by fish that largely resemble their domesticated parents? Or, at least, why don't the wild fish show a much higher degree of variability in their appearance?
The answer is that the overwhelming majority of wild browns in the state descend primarily from one type of highly successful, stream-adapted trout. That fish is the Von Behr, or (more accurately) the common European stream trout. These fish are no longer genetically pure (though in some isolated headwaters, they may be), but they are unquestionably of that morphological type.
Enough of the background for now. (I'd be happy to explain further, if you have questions.) Let me describe the characteristics of the two main types of brown trout you will find in most all of PA. (A third type--a lake-adapted strain called the Loch Leven--was introduced, but survives now only in some of the characteristics of the domesticated stock.)
Domestic stock: A large-headed, somewhat slender trout, usually dark brown on dorsal surfaces and silvery to pale brown with heavy black spotting on sides and dorsal fin, often with slightly paler spots on the upper half (and sometimes the lower half) of the tail. The spots are often of an irregular shape (and may even be connected toward the tail). As these fish "color-up" in streams, the sides become a bit more yellow and spots below the lateral line develop an orange or orange-brown color. As fall approaches, the fish darken (especially males) and the entire lower half of the body may be washed in deep orange-brown. These fish rarely develop any true red or crimson anywhere on the body and their fins are usually dark.
PA wild brown: (Basically, a European stream trout or Von Behr) A smaller-headed, oval-shaped trout, usually olive or olive-brown on dorsal surfaces and yellow or brownish-yellow with large round black or brown spots on sides and dorsal fin. (These spots are often sparser in distribution and have more conspicuous pale halos.) Spotting on the upper tail is either extremely faint or absent. Brilliant red or crimson spots with light halos are concentrated primarily along the lateral line, often with some scattered above and below. Red also stains the adipose fin and may border the top and/or bottom edges of the tail. On a few populations, round red spots may also be found on the dorsal fin, but this is rare and you have to look carefully to notice it. One of the most important distinguishing characteristics is the presence of a blue "eye-spot" on the upper cheek behind the fish's eye. This spot is larger than the other spots and varies from a pale iridescent blue to nearly black. PA domestic stock rarely, if ever, display this mark. As fall approaches, these fish darken and their color intensifies, with the fins often becoming bright(er) orange or orange-brown. Another trait of these fish is their ability to adjust their color somewhat to match their surroundings (a trait of most browns, but pronounced in these fish, particularly in headwater streams). The fish will be darker or lighter overall according to the light conditions where they hold, and in brilliant sun-dappled places the fish will often display a "sun-and-shade" pattern on their sides.
In streams where "catchables" are stocked, fin condition (or size, in the case of "sublegals") is often the easiest way for most anglers to distinguish between wild and stocked fish. But learning the morphological (actually phenotypical) characteristics will allow you to be reasonably sure of this distinction almost anywhere in PA.
To be sure, some mixing does occur, but not nearly as much as you'd think. The main reason is that the domestics are wickedly ineffective spawners. (Watch the stocked browns attempting to spawn in the Little Lehigh sometime. They spawn in stupid, random places and contribute next to nothing to the wild/streambred population.) On the rare occasion when a domestic spawns successfully, it is usually by "piggy-backing" on the spawning of wild fish. This can produce a wild fish with mixed characteristics and probably dilutes the wild gene pool in ways that may not be positive. Fortunately, very little of this mixing occurs in most places (though fall stocking may exacerbate the situation).
Unfortunately (or fortunately, depending on your point of view), when domestic fingerlings are stocked, their spawning success rate is not much better than "catchables." In fact, on a fish-by-fish basis, it is much worse because fewer attain spawning age.
Sorry, I told you this was going to be a lengthy explanation, and there's much more to discuss about the topic. For now, however, I've probably said more than enough to get me in trouble in some circles!"
Best wishes for wild fishes!
Gonzo
_________________
Lloyd Gonzales
author of Fly-Fishing Pressured Water
"OK, you asked for it, so I'll give it a go. In order to identify wild browns (especially in a fingerling-stocking situation), it is useful to understand why they can be distinguished. So bear with me, and knowing my own tendency to over-explain, I'll try to pare this down to the bare minimum. Please feel free to ask questions if there's something you don't understand.
The common wisdom, even among the best biologists, is that the brown trout in America is a highly variable fish of mixed heritage, and that trying to distinguish between strains or races (or even between wild and stocked fish in some instances) is nearly impossible in the field. This is generally quite true, but it is not universally true. And it is not true in specific instances (in our case, a specific instance as large as PA).
As you wander PA in search of wild browns, sooner or later you will recognize that they are nearly all of a consistent type with common morphological characteristics. By and large, they did not descend from the domesticated stock produced by the state for more than half a century. To understand this, ask yourself this question: If stocking of this domesticated type of brown trout was making any significant contribution to wild populations, then why aren't the wild trout streams populated by fish that largely resemble their domesticated parents? Or, at least, why don't the wild fish show a much higher degree of variability in their appearance?
The answer is that the overwhelming majority of wild browns in the state descend primarily from one type of highly successful, stream-adapted trout. That fish is the Von Behr, or (more accurately) the common European stream trout. These fish are no longer genetically pure (though in some isolated headwaters, they may be), but they are unquestionably of that morphological type.
Enough of the background for now. (I'd be happy to explain further, if you have questions.) Let me describe the characteristics of the two main types of brown trout you will find in most all of PA. (A third type--a lake-adapted strain called the Loch Leven--was introduced, but survives now only in some of the characteristics of the domesticated stock.)
Domestic stock: A large-headed, somewhat slender trout, usually dark brown on dorsal surfaces and silvery to pale brown with heavy black spotting on sides and dorsal fin, often with slightly paler spots on the upper half (and sometimes the lower half) of the tail. The spots are often of an irregular shape (and may even be connected toward the tail). As these fish "color-up" in streams, the sides become a bit more yellow and spots below the lateral line develop an orange or orange-brown color. As fall approaches, the fish darken (especially males) and the entire lower half of the body may be washed in deep orange-brown. These fish rarely develop any true red or crimson anywhere on the body and their fins are usually dark.
PA wild brown: (Basically, a European stream trout or Von Behr) A smaller-headed, oval-shaped trout, usually olive or olive-brown on dorsal surfaces and yellow or brownish-yellow with large round black or brown spots on sides and dorsal fin. (These spots are often sparser in distribution and have more conspicuous pale halos.) Spotting on the upper tail is either extremely faint or absent. Brilliant red or crimson spots with light halos are concentrated primarily along the lateral line, often with some scattered above and below. Red also stains the adipose fin and may border the top and/or bottom edges of the tail. On a few populations, round red spots may also be found on the dorsal fin, but this is rare and you have to look carefully to notice it. One of the most important distinguishing characteristics is the presence of a blue "eye-spot" on the upper cheek behind the fish's eye. This spot is larger than the other spots and varies from a pale iridescent blue to nearly black. PA domestic stock rarely, if ever, display this mark. As fall approaches, these fish darken and their color intensifies, with the fins often becoming bright(er) orange or orange-brown. Another trait of these fish is their ability to adjust their color somewhat to match their surroundings (a trait of most browns, but pronounced in these fish, particularly in headwater streams). The fish will be darker or lighter overall according to the light conditions where they hold, and in brilliant sun-dappled places the fish will often display a "sun-and-shade" pattern on their sides.
In streams where "catchables" are stocked, fin condition (or size, in the case of "sublegals") is often the easiest way for most anglers to distinguish between wild and stocked fish. But learning the morphological (actually phenotypical) characteristics will allow you to be reasonably sure of this distinction almost anywhere in PA.
To be sure, some mixing does occur, but not nearly as much as you'd think. The main reason is that the domestics are wickedly ineffective spawners. (Watch the stocked browns attempting to spawn in the Little Lehigh sometime. They spawn in stupid, random places and contribute next to nothing to the wild/streambred population.) On the rare occasion when a domestic spawns successfully, it is usually by "piggy-backing" on the spawning of wild fish. This can produce a wild fish with mixed characteristics and probably dilutes the wild gene pool in ways that may not be positive. Fortunately, very little of this mixing occurs in most places (though fall stocking may exacerbate the situation).
Unfortunately (or fortunately, depending on your point of view), when domestic fingerlings are stocked, their spawning success rate is not much better than "catchables." In fact, on a fish-by-fish basis, it is much worse because fewer attain spawning age.
Sorry, I told you this was going to be a lengthy explanation, and there's much more to discuss about the topic. For now, however, I've probably said more than enough to get me in trouble in some circles!"
Best wishes for wild fishes!
Gonzo
_________________
Lloyd Gonzales
author of Fly-Fishing Pressured Water
