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!

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Face upstream in surface flow seams to find fish

Wanna find fish that are feeding? Look for seams in surface water flow, especially where stream and river currents meet and form eddies or backwaters. 

 

Fish don't want to waste a lot of energy to stay in a current, but when they are open to feeding they love to be where food washes out of a current and is presented to them for easy pickings.  I would too.  Plunge pools, eddys, backwaters, around logs, and behind boulders are all excellent places to find stream flow seams and pretend your lure is also seeking out a place to take a break from the current.

Here one waiting for a snack...

Wanna avoid spooking fish and present your lure to look like a real fish?
 

Also keep in mind that juvenile fish will move both up and downstream almost always facing upstream.  This makes sense as it gives them an ability to control position as fish don't swim backwards very well.  So when presenting a lure facing and swimming downstream, in the fish world that ain't right. Fish will pick up on that. Only an injured fish would do that.

Guess which way is upstream?

 

 

Small fish almost always stick to the stream margins where there is lower stream veleocity.  Sticking to the banks also provides a measure comfort by providing cover from predators both in terms of water column and as well as have a whole bank side to not worry about...except for maybe getting picked off by herons.

It's a tough life! It's no wonder juvenile fish always have that scared look in their eyes and usally move under cover of night.

Instead of spooking them by dropping lures directly into these spots, try to present them by casting upstream and floating downstream into these seams.

Practice reading the surface flows and you will be rewarded.

Fish On!


(Photos Courtesy of BLM Fisheries Oregon, BLM Fisheries Idaho)

Climate change and the future of fish

Global warming, global cooling, melting glaciers, ozone holes, new weather extremes and mutant frogs...climate change is a formidable concept.  With all the media and political posturing around the concept it is difficult to really grab just what climate means for the future.

Fish like this very nice dolly varden in places like this sweet glacier fed river in Alaska are certain to change:

It is interesting how we tend to thing of climate change as something new, or that things are suddently now going to change with a new and increased awareness.  It is also interesting to see how socially we talk about, posture and paint climate change as an entirely bad thing.  Could it be possible that there are some good things that we might expect to see?

 

Just to be clear, I'm not trying to downplay the importance for considering climate change, but want to philosophize upon it for a bit.

(I am half chinese after all...and consider myself a "part-time" philosopher).
(I'm serious here)

 

It is an interesting challenge to think about how we are supposed to address managing our aquatic resources for climate change.  Just what is it that we are expected to do to address climate change? Is it to stop the environment from changing at all and maintain the exact same weather patterns into a foreseeable future? Perhaps there is a misception that our society has painted where any change in climate is not supposed to happen and things are supposed to stay as we know it forever. 

 

Obviously the middle ground here is that we would want to slow the rate that humans are exasberating the situation and all take ownership and stop trying to point out and blame who is in the wrong...it is easy to get into an ethical debate on climate change.  Whatever the case, projected climate change scenarios run across the board, and let's just say human negligence of our environment is not a good thing and not natural and we want our natural environment to be able to respond and adjust within a reasonable context.

 

 

As for our aquatic resources, here are some situations that we are likely looking at over the near future:

 

In the headwaters: increased warming in many cooler areas will result in more snow melting quicker and earlier, this could lead to less summer base flows and more flashiness and extremes in flood events, more landslides and less sustained precious summer flows coming off of the mountains. 

Here's a debris torrent in Oregon.  While it povides much needed large wood for fish habitat, too much will scour out the river channels and dump some major fish habitat smothering fine sediment loads.

 

If you are cold water fish like a trout, you are not a big fan of the summer low flow and warm water situations and fish that depend on the cold flows higher in the mountains like cutthroat and bull trout will feel the crunch and drying smaller streams will either strand fish or make them move to unfavorably downstream areas or...die (sigh). For extremely cold water species like bull trout and headwater dependent species, or grayling that looks especially bad.

 

In the midde and lower stream reaches: some areas would also experience some cooling trends and with all the water flowing out earlier in the year, they may be in a better place...warm water species like bass and sunfish may end up in a better place and start moving upstream with warming waters. This could be good or bad and invasive species like nonnative minnows, sunfish, carp (snakehead?) may get some big jump start increase their world dominance.

 

As as biologist what will be particularly intersted to me will be to watch how fish adapt and change to all this.  Species like salmon and trout may start to spawn earlier or later, and start spawning in lower reaches.  Juvenile fish may start growing faster, migratory fish will may start residualizing and stop migrating all together. Our trout fishing hole may become the place to catch trophy bass.  Fish may hybridize even more and many will likely get extirpate or go extinct all together and die. 

 

TBD...

 (Photos courtesy of BLM Fisheries Alaska, BLM Fisheries Oregon)
 

 

Invasive aquatic species...increasingly common and increasingly annoying

Ok let's face it, no one likes the taking over of fish habitat by aquatic plants and animals.  Plants like water hyacinth and aquarium plants like elodea can quickly over run and ruin some otherwise great fishing spots.  

 

Invasive animals like the dreded zebra and closely related quagga mussel can not only take out a fishery, but also cost tax payers billions of dollars. In fact, knowingly transporting a living zebra mussel across many state borders will get you a full out APB and police bulletin to stop you.

 

So, just what exactly is the big deal? Ever dump your old aquarium plants or unwanted aquarium pets out in the local pond or creek?

 

Well several people have done just that and now plants like brazilian waterweed (aka elodea) are blanketing spawning grounds like this example in California.  

 

The gravel is overgrown and no longer mobilizes in the river, forcing fish to spawn in the few remaining pockets of clean gravel...likely digging up eggs already in there.  This can make for some very unproductive spawning success.

 

Here is a pond example:

 

 

Or the crawdad that the innocent science teacher ordered online from a scientific supply gets released in good will after the semester ends quickly bullies and pushes out the native daddies and disrupts the whole invertebrate communities...

 

Here is an unique example of several species of cichlid fish released in a pond in Idaho that are now completely self-reproducing.  These guys are native to places in Africa and South America..kind of a funky novelty fishery, but environmentally it just ain't right.  Imagine if these guys were put into an isolated pupfish pond floods and these guys get in to larger river systems such as the Snake River...that flows in the greater Columbia River basin!

 

The risks are very real and very significant...let's all be extra cautious for our aquatic resources!

(photos courtesy of BLM Fisheries Idaho)

 

Water pollution and mutant fish

Would you drink the water that you're catching fish in?

Beyond all kind of natural things like rotting poop and ecoli bacteria, there are all kind of things flowing into (an falling in from the sky!) into our fishing holes besides water that shouldn't.  We're talking water pollution and this is a very big deal.  Dead fish, mutant fish, even transgender fish and we're seeing more and more of them each day.   

 

Just look at how many rivers, streams and lakes are listed by EPA as impaired on the web site:

http://nac.unl.edu/atlas/Map_Html/Clean_Water/National/Percent_impaired_wate_nat/Percent_impaired_water_nat.htm..

Pollution in the forms chemicals, oils, hormones, etc can come from runoff from our homes, gardens, farms, industrial areas, sewage and (sadly) people just dumping all kinds of crap directly into the water.  Sewage can also introduce pathogens and other disease causing agents of yuck for humans, fish, and most any form of life that touches the water.

 

It is interesting how we tend to think of our fisheries as somehow being able to withstand supernormal amounts of invasive species, low flows, warm waters, low oxygen and huge bombardents of nasty toxic chemicals.  It is actually quite impressive of how much of these a fish can actually withstand, at least for a little while, that is before they die a slow and painful death...but anyways...

 

 

 

Pollution affects fish in many different and compounding ways...and combine that increased stress from a changing climate.  First off, fish get stressed...very very stressed and this makes everything worse.  Fish skin loses protecive slime and atibacterial function and rots and wounds form. Liver and gill damage start to form and that's gotta hurt.  Pants that make oxygen start to die and rot consuming even more oxygen, fish growth gets stunted, ability to smell diminishes, insects and other foods bases die off from the pesticides and toxic sediment fills every nook and cranny in your spawning gravels and rearing areas.  

 

In addition, all the phamacueticals that humans are pooping and peeing also affect fish and turning them into and start behaving as transgender.  Sad joke here is that all those antidepressants that we are taking have also been documented to be affecting fish...sigh

 

So what is it that we can do to help this very critical and out of control issue?

 

The way I see it, we can:

- Choose to be aware of the pathways and mechanisms of pollution and recognize the need for forefront communtiy awareness...and carry this into our local government and political leanings and advocacy.  

- I also choose to not spray any toxic chemicals unless absolutely neeccesary (eg yellowjacket nest in the kitchen) and not chemically fertilize my lawn even if it means I have some rough and yellow patches.

- Also, storm water and street drainage is a big contributor to the problem and I always love seeing a parking lot bioswale and settling ponds in urban planning.  By settling out the water and sediments the toxics and such are significantly reduced from entering water bodies. 

- And finally, I am a fan of full and extended prosecution for all knowing violators who choose to illegally dump/discharge chemicals into my fishing waters. 

 

I have to admit that the future of water pollution and quality for current and future generations is not at all looking bright...sigh...