The Fish Biologists
FishingCommunity.Org (FCO) established this blog as a venue to interact with professional fisheries biologists to share, learn and discuss any and all things related to fish biology, behavior and aquatic habitats. Conservation of fish and fish habitat is critically important, and this blog is intended to promote a greater interest, awareness and appreciation of our fishing resources and help ensure our fishing heritage is maintained into the future.
Wednesday, August 5, 2015
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Fisheries Program: Sea Squirt Invades BLM Submerged Lands in Alaska
Fisheries Program: Sea Squirt Invades BLM Submerged Lands in Alaska: BLM FISHERIES ALASKA SEA SQUIRT INVADES BLM SUBMERGERED LANDS IN ALASKA An invasive marine invertebrate called "rock vomit,&q...
Fisheries Program: Alaska Town Manages World-Class Trout
Fisheries Program: Alaska Town Manages World-Class Trout: BLM FISHERIES ALASKA ALASKA TOWN MANAGES WORLD-CLASS TROUT You may have heard of the plight of the Village of Kivalina, perched on...
Tuesday, January 6, 2015
Cold Bass Have Bright Lipstick Red Lips
Seriously, they do!
So I was fishing this weekend in the Cool Spring Lake in the Wilderness Presidential Resorts near Spotsylvania, Virginia with my good friends at FishingCommunity.Org. It's early January and the air (and water) is well settled into being cold...but the day was warming up unusually nice so our morning fishing session was on...our early dawn fishing action proved non-existent to slow...but bank fishing for leaves was fair to good...sigh.
Paul and I gave up to go get some coffee and get ready to work. Pete ended up getting a little action as the day warmed up. He mentioned that the largemouth he caught had bright red lips. After the obligatory female fish jokes, I didn't think much more about it.
However, the afternoon fishing proved much different! At least for those using silver blue fox spinners with a quick retrieve. Check this guy out!
I also hooked into several nice smallies and they all were all robust and healthy like that. They were all also noticeably slow in fight and lack of any surface water explosions from being cold.
And...they also all had very bright red upper lips as well as in the gills and back mouth. But they were definitely feeding. Kinda freaky.
Check it out...
So what the heck is going on here?
There are several theories going around:
- some think it is bacterial infections,
- some think it is sores from from rooting around for buried food or making nests,
- some think it from a diet of certain food items such as crawdads,
- some think it is a seasonal hormonal thing, and
- and some think it is from being cold...sort of like a physiological blush reaction.
Here's what I found out:
- no one really knows, but it pretty much happens everywhere,
- it happens to large and smallmouth bass and some other species...but not all...it doesn't happen in lots of other fish
- it happens when the water temperature (and fish) are getting cold and different species mouths turn red starting at different temperatures,
- it doesn't appear to have any effects to the health or feeding of fish,
- it doesn't appear to be any type of wound...just blood closer to the skin, and
- it does appear to make the fish more kissable...(sorry, can't help it)
So, here is my theory:
- the reddening appears to occur distinctly in the fish's toothpad and similar functional mouth (pharyngeal) areas. Those patch lines are pretty distinct and repeated.
- these tooth and mouth areas also happen to contain lots of other taste and nerve receptors used for sensing all kinds of things like whether to keep swallowing a food item (such as a tasty minnow) or spit out a food item that is "not right" (such as Paul's frog lure).
- the red may be increased blood flow to these areas related to the sensing organs...and I think there is something going with that. Perhaps more or less nerve or pain sensitivity, more or less tasting, more of less ability to feel certain prey, or
- something else entirely different and unrelated...and still remains a mystery.
Fish on!
Wednesday, November 5, 2014
Northern Snakehead...to loath or respect?
The northern snakehead (Channa argus) is one of many types of snakehead fish native to China, Russia, North Korea, and South Korea. Here in the United States, we consider the fish to be a highly invasive species.
So what does that mean for us? The snakehead is both feared and respected as "invasive" because: 1) it is not from around here; 2) has an ability to spread; and 3) believed to be causing damage to the environment and native fisheries.
As for snakehead they are destroying our native fisheries by eating every fish, insect and amphibian in sight, physically taking up space and aggressively defending areas, and they are reproducing like crazy and spreading very quickly. Since the aquatic ecosystems around here didn't evolve with anything like this, the snakehead are like an NBA player in a pee wee basketball league...and they can really eat and get big! That just ain't fair!
Now they are throughout the Potomac and several other states:
http://nas.er.usgs.gov/taxgroup/fish/northernsnakeheaddistribution.aspx
So how do we stop 'em?
There is not much we can do other than keep them from spreading. Ensure no new introductions and try to knock them back as we find them. You can report sightings at the link above and until we find a better way we to try to kill em all.
Here the story, back in 2002 (only 13 years ago) a snakehead was found in a pond in Crofton, Maryland. They drained the pond and found (and killed) two adult and a bunch of babies. Someone later admitted they released two adults into the pond (sigh). In 2004, multiple snakehead were found in the Potomac River and breeding was documented (sigh).
Snakehead can live outside water for several days and young can wiggle across land into new waters.
They are still a popular food item in Asia and much respected for their virtue as snakehead parents are known to sacrifice themselves to protect the babies.
They are listed as injurious wildlife under the Federal law making it a crime to transport them...
They like slow backwater areas and they put up a big fight...I hear they taste good. Be sure to kill if you catch em'
Shad fishing and our American cultural legacy
Over here in the Washington DC area, the shad run is coming up in
April/May and I am already getting stoked. Over here in the Potomac the American
shad runs overlap with hickory shad. Last
year's run was intense, albeit brief, but man was that fun.
The
shad run over here is a very important part of history and shad fishing has
been identified as very culturally important to many of our early native people
and presidents.
As
Americans, they are part of our cultural identity! George Washington loved to eat shad and honed
shad fishing into a business and fed his workers and sold the fish in the
market.
Since
then, the shad fisheries on East Coast have really taken a pounding from over
fishing, water pollution, and hundreds of passage barriers. They have to migrate to and from the ocean
and face multiple challenges throughout.
Through
hatchery programs and catch and release fishing, they are slowly recovering
from near rock bottom.
Did
you know that shad are actually a type of herring? Shad have also evolved an
ability to detect ultrasound. This ability is thought to help them avoid
dolphins that find prey using echolocation.
Here
are some more fun facts about American Shad:
•
A.K.A.
“common”, “white”, “Atlantic” shad• Large shoulder spot may be followed by 4-6 fainter spots
• Lower jaw doesn’t extend much more than upper jaw
• Historically recognized regional food fish with high commercial value
• Current world record 11 pounds, 4 ounces
• Average 20-24 inches (up to 30), the largest of all the shads
• Schooling and highly migratory (anadromous)
• Spend 3 to 6 years in the ocean before migrating upstream
• Feed primarily on plankton, but also small crustaceans and small fish and eggs
• Females spawn around age 5 or 6, males at age 4 or 5
• Spawning occurs after sundown in gently sloping gravel or sandy bottom areas
• Females broadcast batches of around 30k eggs into the water, males then fertilize
• Each female can produce up to 600k eggs
• Eggs are semi-buoyant and carried downstream with the current, hatch in 7-10 days
• Start spawning once water temperatures have reached 55-68 degrees Fahrenheit
• Can survive and make several spawning runs per lifetime (around 22-45% in the Potomac are repeat)
• Feeding instinct triggered by factors such as water turbidity and temperature
• Male fish are feisty jumpers and put up a good fight, female (roe) not as much
• Generally stay fairly deep in the water column near the bottom unless water is high
• Generally fished for with shad darts, and small spoons and spinners
• They taste great, generally low in accumulated toxins, and very high in omega 3 but over here are catch and release only!
Here are
some neat facts about Hickory Shad:
•
A.K.A.
“hickory jacks” or “tailor” shad• Smaller cousins to the American shad in the herring family
• Current world record 2 pounds, 14 ounces
• Average 12-20 inches
• Bluish-silver on the sides with a gray-green back
• Dusky shoulder spot may be followed by several faint spots
• Lower jaw extends much further than upper jaw
• Females are larger than males
• Low commercial value, but a popular sport fish
• Feed primarily on small fish, but also will eat small squid and crustaceans
• Schooling and highly migratory (anadromous)
• Spawning run usually precedes that of American shad
• Spawning occurs in a diversity of physical habitats ranging from backwaters to sloughs
• Can survive and make several spawning runs per lifetime (around 30-60% here in the Potomac are repeat)
• Females spawn between age 3 to 9, males at age 2 to 7
• Hickory shad don’t really feed during the spawning run
• It is believed that they hit the lures in aggressive spawning defense
• Generally fished for with shad darts, and small spoons and spinners
• In the Potomac, they are catch and release only!
Monday, October 20, 2014
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