BE TROUT

fish eat snake

2011-08-11T11:54:00.001-05:00

small thing and pressured trout

2011-07-28T15:26:00.002-05:00

how many times you see trout rise everywhere on the surface and yet deliberately and carefully ignore the fly you have eagerly offered? many many times here! trout said "sorry, wrong fly again!" usually a very small thing and very often is almost invisible to the frustrated angler: that a blunt big meaty offer often put the feeding activities off. They only want to eat certain thing, and focus on this very image. It has been called "search image" feeding strategy in trout. why? if you have better food items (bigger and meatier) why ignore them? Most of the books will tell you that if fish are "lock in" some pre-request image, it will reduce the research effort even though ignore the nutritional rich item could be even more "costly". Search image strategy has been applied successfully in many predator and prey interaction. see LINK http://en.wikipedia.org/wiki/Prey_detection.

However, for trout feeding specifically on certain insect type or certain stage of life cycle in insects(larva, pupa, emerger etc...). Should we call this behavior is the exercise of the search image feeding behavior? or this is just another alternative feeding behavior that "looks like" search image strategy? Base on the fundamental definition, my answer is a NO, if save energy is the main goal (which is the center of the optimal feeding strategy), trout should NOT avoid big meaty item when it appear in front of them. This feeding behavior will not yield a net extra gain in feeding specifically on certain thing, as we all know trout are opportunitiest general feeder. Trout should pick up everything that looks edible. Even during the peak hatch. But why trout lock them self in feeding certain thing and ignore big flies? predation avoidance behavior is my guess. I argue this is conditioned behavior which is responding to high angling pressure. Only keen on certain thing will ensure their feeding won't be disturbed by angler. This is a evolved alternative feeding strategy that responded to high pressure from angling. How to test it in a scientific way? First, if feeding specifically on certain food items is conditioned we can make some predictions and test it. 1) trout live in the high angling pressure area will more likely to feed specifically compare to the area lacking of angling pressure. 2) In the evolutionary perspective, young trout should also have develop this "search image" behavior to get a higher yield in feed activities. Young trout should have being as selective as old trout (as optimize foraging energy purposed by searching image)... well... I am eager to test this hypothesis, stay tuned, let see if I have gain more information from literature search or field observation..

The breeding cycle of Astatotilapia burtoni

2011-03-23T11:54:00.000-05:00

trout Forellen Quintett

2011-03-20T08:24:00.002-05:00

2011-03-06T19:21:00.001-06:00

Behind the bubble curtain: The Underwater World of Coastal Cutthroat Trout from David Saiget on Vimeo.

amazing!

2011-02-13T16:02:00.001-06:00

flies for anadromous fish

2011-02-13T14:50:00.003-06:00

I enjoy tying flies and fish them. There is nothing more fun than "made up" a fly and use them to catch a fish. You might ask, if the fly is not resemble a regular food item, why fish eat them? Currently, the "field theory" from those steelhead and salmon fishermen says, it might be other motivation than food acquisition. It could be aggressions that provoked by mimic mate stealer? it could be aggressions that toward the egg stealer? or it might be just curiosity? As a behavior ecologist myself, I believe it is all possible. Some fisherman examined the stomach content have found that a lot of steelhead did not have anything in their stomach. This confirmed the previous thoughts that anadromous fish did not eat after enter the freshwater. However, some samples did recover some food items in the steelhead stomach. Some eggs, feathers and some aquatic insects... so they do eat, or at least they do "swallow" something, if we tend to call "eat" is a kind of behavior which is actively seeking food items and consume it in order to extract energy from it. So, good news to us, as soon as they swallow something, then there is still hope for fisherman to catch them, in the form of hook and line. Noted, the high percentage of empty stomachs is interesting. Those fish does not eat, or does not eat recently before they got caught. This totally make sense to me, why would you eat in the place that was poor of food item? the reason you original leave the river for... (seeking food items in the ocean is one of the explanation that some steelhead become anadromous fish species, while some steelhead remain in the poor nutrient river and remain small (trout life form)). So no eating interest, low food abundant...made up high percentage of empty stomach. However, here is question, if they happen to see some food items in front of them. do they eat it? the scenario is you are enter a class and happen to find out it is a surprising b-day party prepared. Do you going to eat the cake, even it is no where near the eating time? I don't know... maybe yes, maybe no? But will you touch it or smell it just to exam how good is this cake, if it worth a bit? What I think this later scenario is more likely in steelhead... the touch and feel it bit light bite "short strike". I have seen a lot of bass doing this short strike when examing the potential food items. That is the place olfactory cue and textile cue come together... I am guess steelhead and other salmonids are doing the same... ever wonder the experienced steelheader tell you to put the trailing hook all the way to the tail of the fly? because there are going to have a lot of short strike if you don't do so. (to be continue...)

2011-02-02T11:21:00.001-06:00

A Letter from Alexandra Morton

2009-05-27T13:01:00.000-05:00

I have been in Norway for 10 days because 92% of fish farming in British Columbia is Norwegian owned. I have met with many Norwegian scientists, members of the Mainstream and Marine Harvest boards, been to their AGMs, toured the area with fishermen, examined a closed-containment facility, met the Norwegians fighting for their fish and joined a scientific cruise.

I thought Norway had this industry handled and I expected to learn how marine salmon farming could work, but this has not been the case. My eyes have really been opened. This industry still has major issues that are growing and has no business expanding throughout the temperate coastlines of the world. The way they have been treating sea lice in Norway has caused high drug resistance. The only solution in sight is increasingly toxic chemicals. In the past two years (2007, 8) sea lice levels have actually increased on both the farm and wild fish. The scientists I met with are holding their breath to see if drug-resistant sea lice populations will explode and attack the last wild salmon and sea trout. The same treatment methods have been used in BC and we can expect this to occur as well.

I am not hearing how the industry can possibly safeguard British Columbia from contamination with their ISA virus. Infectious Salmon Anemia is a salmon virus that is spreading worldwide, wherever there are salmon farms. In Chile, the Norwegian strain of ISA has destroyed 60% of the industry, 17,000 jobs and unmeasured environmental damage. The industry is pushing into new territory. If this gets to BC no one can predict what it will do to the Pacific salmon and steelhead, it will be unleashed into new habitat and we know this is a very serious threat to life.

Professor Are Nylund head of the Fish Diseases Group at the University of Bergen, Norway, reports that, “based on 20 years of experience, I can guarantee that if British Columbia continues to import salmon eggs from the eastern Atlantic infectious salmon diseases, such as ISA, will arrive in Western Canada. Here in Hardangerfjord we have sacrificed our wild salmon stocks in exchange for farm salmon. With all your 5 species of wild salmon, BC is the last place you should have salmon farms.”

New diseases and parasites are being identified. The most serious is a sea lice parasite that attacks the salmon immune system. There is concern that this new parasite is responsible for accelerating wild salmon declines. The Norwegian scientists agree with many of us in BC. If you want wild salmon you must reduce the number of farm salmon. There are three options.

The future for salmon farming will have to include:

permanently reduction of not just the number of sea lice, but also the number of farm salmon per fjord,
removing farm salmon for periods of time to delouse the fjords and not restocking until after the out-migration of the wild salmon and sea trout.
But where wild salmon are considered essential they say the only certain measure is to remove the farms completely.

There are many people here like me. I met a man who has devoted his life to the science of restoring the Voss River, where the largest Atlantic salmon in the world, a national treasure, have vanished due to sea lice from salmon farms. Interestingly he is using the method I was not allowed to use last spring... Towing the fish past the farms out to sea. Another man is working with scientists and communities to keep the sea trout of the Hardangerfjord alive. There are so many tragic stories familiar to British Columbia.

The corporate fish farmers are unrelenting in their push to expand. With Chile so highly contaminated with the Norwegian strain of ISA all fish farmed coasts including Norway are threatened with expansion. I made the best case I could to Mainstream and Marine Harvest for removing the salmon feedlots from our wild salmon migration routes, but they will not accept that they are harming wild salmon. They say they want to improve, but they don’t say how. Norway has different social policies which include encouraging people to populate the remote areas and so fish farming seemed a good opportunity to these people. BC has the opposite policy, but the line that fish farms are good for small coastal communities has been used in BC anyway. I have not seen any evidence that it has even replaced the jobs it has impacted in wild fisheries and tourism.

It is becoming increasingly clear to protect wild Pacific salmon from the virus ISA the BC border absolutely has to be closed to importation of salmon eggs immediately and salmon farms MUST be removed from the Fraser River migration routes and any other narrow waterways where wild salmon are considered valuable.

Our letter asking government that the Fisheries Act, which is the law in Canada be applied to protect our salmon from fish farms has been signed by 14,000 people to date at www.adopt-a-fry.org has still not been answered.

Please forward this letter and encourage more people to sign our letter to government as it is building a community of concerned people word wide and we will prevail as there is really no rock for this industry to hide under and longer.

Alexandra Morton

catch and release

2009-05-15T18:36:00.002-05:00

http://www.npr.org/templates/story/story.php?storyId=99458498

There are nothing new about "catch and release", neither does the artificial selection in our agriculture or poultry industry. You want something to grow big, grow fast and produce more eggs? No problem! Combine Darwin's natural selection and Mendelian breeding principle and other modern genetic theories from Dr. Fisher, Dr. Falconer, Dr. Williams etc. The modern genetic and breeding programs in our animal science can do pretty much everything for you. Whiting Farm (dryfly hackles)is the first one put this exercise into our sport - flyfishing.

So how about catch and release? What it to do with the artificial selection? Well... as a hunter, a predator, we are doing the selection when we hunt and fish. The number and the quality of the prey we kill will influence the population dynamic, or the evolution of the population. (Sorry, I will try not to use too many jargons.) This is a simple idea. If we only eliminate the big animal as a trophy hunter does. The individual carries those "big genes" will be eliminate from the population, will be less contribute to the future generation. This will give the little guys advantage to breeding more and ultimately change the size of that population, or that species. This idea seems simple but it is hard to document in the nature. because there is not a single gene to determine the size. Usually, "size" of those morphological characters such as human height, weight... are determined by several genes. or several group of genes. We called it quantitative trait (QTL). Also the environmental factors such as nutritions, habitat quality etc will also influence the morphology of the animals. Back to "catch and release", there are still debating among the fisherman that if catch and release is a moral issue. well... I will get into that in another post. But now, the catch and release means, we are minimizing the artificial selection, so the population should maintain their balance, their original trajectory direction in evolution... (to be continued) Here is the NPR talk! Great talk! LINK

Steelhead Research

2008-10-16T15:58:00.003-05:00

Science paper about negative hatchery breeding impact in hood river steelhead. The power and fine resolution of this research is because they identified every single return individual and their pedigree. A fine research and elegant design, but sad story of the steelhead.
Title: Genetic Effects of Captive Breeding Cause a Rapid, Cumulative Fitness Decline in the Wild by Hitoshi Araki,* Becky Cooper, Michael S. Blouin Science 5 October 2007: Vol. 318. no. 5847, pp. 100 - 103

Captive breeding is used to supplement populations of many species that are declining in the wild. The suitability of and long-term species survival from such programs remain largely untested, however. We measured lifetime reproductive success of the first two generations of steelhead trout that were reared in captivity and bred in the wild after they were released. By reconstructing a three-generation pedigree with microsatellite markers, we show that genetic effects of domestication reduce subsequent reproductive capabilities by ~40% per captive-reared generation when fish are moved to natural environments. These results suggest that even a few generations of domestication may have negative effects on natural reproduction in the wild and that the repeated use of captive-reared parents to supplement wild populations should be carefully reconsidered.

Why Artificial Breeding Is not Good...

2008-10-10T20:32:00.003-05:00

A recent report in Atlantic salmon.
Mate choice play a role in genetic diversity and parasite resistance.

Title: MHC-mediated mate choice increases parasite resistance in salmon
Proceedings of the Royal Society B. Volume 275, Number 1641 / June 22, 2008
Natural (parasite-driven) and sexual selection are thought to maintain high polymorphism in the genes of the major histocompatibility complex (MHC), but support for a link between mate choice, MHC variation and increased parasite resistance is circumstantial. We compared MHC diversity and Anisakis loads among anadromous Atlantic salmon (Salmo salar L.) returning to four rivers to spawn, which had originated from natural spawning (parents allowed to mate freely) or artificial crosses (parents deprived from the potential benefits of mate choice). We found that the offspring of artificially bred salmon had higher parasite loads and were almost four times more likely to be infected than free-mating salmon, despite having similar levels of MHC diversity. Moreover, the offspring of wild salmon were more MHC dissimilar than the offspring of artificially crossed salmon, and uninfected fish were more dissimilar for MHC than infected fish. Thus, our results suggest a link between disassortative mating and offspring benefits and indicate that MHC-mediated mate choice and natural (parasite-driven) selection act in combination to maintain MHC diversity, and hence fitness. Therefore, artificial breeding programmes that negate the potential genetic benefits of mate choice may result in inherently inferior offspring, regardless of population size, rearing conditions or genetic diversity.

be salmon

2008-10-04T13:18:00.001-05:00

Masu Salmon in Hokkaido

2008-09-14T14:47:00.001-05:00

Snake river Cutthroat Trout

2008-09-14T13:23:00.004-05:00

It's a self-explaning species...as you can tell the red-orange marking on the throat... the cutthroat trout. What a beautiful trout species... not only the brillient red marking stikes me, but also the redish - translucent fin are extremely attractive. To my knowledge no one has study the read marking to the cutthoat trout, what is the function? what is the pigment? I have no clue. Maybe I should plan a long vacation in the smoky mountain region and observe this species more closely : )

Atlantic Salmon's Feeding Competition

2008-06-04T21:46:00.003-05:00

You don't need to be big, but you need to be there earlier!
From a recent scientific research: The relative influence of prior residency and dominance on the early feeding behaviour of juvenile Atlantic salmon: Animal Behaviour 2003 65 (6) 1141-1149
"In many species where social hierarchy mediates conflict over resources, dominant individuals monopolize food, shelter and reproductive opportunities. The benefits of social dominance, however, can often be offset by a prior residence advantage, whereby individuals arriving first in a new habitat obtain, and subsequently defend, the most profitable sites. We investigated the relative influence of these two factors on the acquisition of feeding territories by juvenile Atlantic salmon,Salmo salar L., by placing groups of six individuals of known dominance rank sequentially into an experimental arena with feeding sites of varying quality. Dominants had an advantage over subordinates in the percentage of time spent in a good-quality feeding site and individual feeding rate. There was also a significant time of arrival effect: those individuals that arrived first in a habitat monopolized the resource. The two effects were of approximately equal strength, so that late-arriving dominant fish had similar success as prior resident subordinates..."

Brook Trout in the Western US Rivers

2008-05-27T17:26:00.004-05:00

This brook trout was caught in the western united state, Wyoming. Although this beautiful little trout is gorgeous in their coloration and is a perfect match for a small fly rod. The appearance of him is not a good sign for the local ecosystem, regard to the preservation of biodiversity. Invasive species is what a conservationist call them - brook trout in the west, as well as the brown trout in the whole US, whole south hemisphere (no native trout in the south). Historically, the brook trout only distributed in the eastern part of the US. Started from the south of Appalachia range of Northern Georgia all the way through Great smoky mountain, Maine into Canada. There are also another sea run form of brook trout still thriving in the upper northeast....(to be continued...)

A LITTLE WHITE FISH

2008-02-19T10:01:00.004-06:00

Is the little mountain white fish a trout... OH YEAH... no doubt... despite lot's of people look down on them... They are close related to trout, they are sharing the same ancestor. I love them they are such a cute little fish and put you into a great fight too! And most importantly... they are the native! We should look down on those bastard brown trout when fish in the US instead... The invasive species really is detrimental to the environment in different directions... Well... this is hard decision for anglers though... even to me... I could be blind myself sometimes...

Trout and UV vision.

2008-02-01T08:32:00.000-06:00

Should we tie some UV reflectance flies?

Sources: Environmental Biology of Fishes, Volume 63, Number 2, February 2002 , pp. 223-228(6)

"Most research on environmental effects of ultraviolet radiation (UVR) has focused on its potential negative consequences. However, natural UVR can also be beneficial to living organisms (e.g., vitamin D synthesis, UV vision, germicide activity). UV vision has been demonstrated in a variety of animals including several invertebrates and vertebrates. Juvenile rainbow trout, Oncorhynchus mykiss, has a retinal photoreceptor, which is sensitive to UVR between 360 and 370 nm. Among other functions, UV vision has been proposed to contribute to prey detection by enhancing the contrast between the prey and its background. We performed a series of feeding experiments with juvenile rainbow trout and several zooplankters as prey. The fish were allowed to feed either under full solar radiation, or under solar radiation from which the UV component had been removed using a long-pass cut off filter. We found that the removal of UV wavelengths had no effect on the number of prey eaten or on the preference for particular food items. This is contrary to published studies reporting prey detection enhancement mediated by UV vision in rainbow trout. This disparity in the results may be due to our use of natural radiation instead of artificial UV sources, in which the visible component is poorly represented. Although our results do not disproof the presence of UV vision in juvenile rainbow trout, they do cast doubts about its significance in enhancing feeding performance in a natural light environment."

Colorado Cutthroat Trout

2008-01-05T07:56:00.000-06:00

In the breeding season, they turn on the fire on their body and eyes...they are amazing!

Tiger Trout

2008-01-03T15:59:00.000-06:00

A hybrid mutant from brook trout x brown trout. Two different species from different genus created this monster... amazing...

Green Back Cutthroat

2008-01-02T12:53:00.001-06:00

Yuhina Trout

2007-12-29T08:00:00.000-06:00

There are three different characters in there, Brown trout/ Rainbow trout/ Cutthroat trout

Adipose fin

2007-12-22T10:29:00.000-06:00

The adipose fin is a very interesting fin in Salmonids, means all the salmon and trout, grayling, white fish get this little boneless fin. It's located on the lower back in front of tail, like a little finger shape. (Noted, lot's of different group of fish bare this fin too). It is cute and some are very colorful actually. The brown trout have a exaggerater adipose fin refer to size and coloration in male mature brown trout. What is the function of those small/helpless wing/fin? good question. There is one paper published in Europe showed that the female brown trout actually assess the "size" of those adipose fin to make a mate choice decision. I will come back to this mate choice topic again and again... maybe I should look up that paper again before I write any further...

UV coloration

2007-12-21T16:32:00.001-06:00

If you look closely to the brown trout, you will noticed they have a small blue patch just behind their eyes, on the gill plate. Those blue coloration could be very shinny at times. They should have some UV reflection, as the blue coloration always get into the UV section. The UV-blue color are fascinating, more and more literature "discover" this new color are very important for animal communication! The main reason it become a hot topic now is because 1) we "human beings" do not see UV...2) (stay tuned)

Male-male Competition

2007-12-21T16:08:00.000-06:00

Trout are very agressive and territorial species. They occupied certain spot for feeding, just like fisherman occupy certain spot/honey hole for fishing! Same thing! Because it is easier to obtain food/fish and save energy to maintain their position. Eddies, obstacles that break the currents, all good spots for holding trout.
Bigger trout have first choice to occupied the better spots. Like your elder lab mates always got the window seat first.
Trout compete for food, also compete for mates in the breeding season. The testosterone fire them up. They can fight all day without eating anything... see salmon spawning. These two guys are guarding the same female in the spawning bed. Of course there is not room for the 3 fish...ever once of a while these two guys will dare into the pool just in front of the spawning bed and start the fight...very interesting to see them display/fight...

JUMPING FOR FOOD

2007-12-21T09:03:00.001-06:00

some fish always look down, some fish always look up, and some fish do both. One of the character that make trout fishing so fantastic is they do both and they switch back and forth in a single morning... lot's of poeple love trout fishing because you can expect a 20 inchers to come up and "sip" your #20 (3mm hook) midge pattern. Amazing!

Small Creek Trout

2007-12-18T18:33:00.001-06:00

Catch big trout from big water give you a thrill fight, however, catch a small trout from a small creek could give you a lot of sweet memory as well. This little trout was caught in the 4 feet wide mountian creek... no cast, you are absolutely "high sticking" in a pocket water. Sometimes might over sicking and have to hold the middle part of the rod to control the tip motion. Absolutely fun!
These rainbow are amazing creature! Put them into bigger lake, they will explode to 20 lb monster. But in this tiny creek, it would be just fine/or even better to be small. Environment shape trout's life history, Dr. Behnke say...

SPOTS PLAY A ROLE

2007-12-16T12:35:00.000-06:00

COLOR BELOW THE SURFACE

2007-12-16T10:56:00.001-06:00

I made this trout more colorful...

BLUE SUNDAY / HAVING FUN

2007-12-16T09:27:00.000-06:00

WHY BROWN TROUT GET SOME BLUE?

WHY COLORFUL?

2007-12-15T16:06:00.000-06:00

why trout are always colorful?

Think about it and I will give you more questions later...

WHAT IS BE TROUT

2007-12-15T15:38:00.000-06:00

BE TROUT IS A ONLINE DIARY TALK ABOUT EITHER BEHAVIOR ECOLOGY OR TROUT OR BOTH.