Monday, February 21, 2011

Esox

A well adapted killer

Perhaps my favorite genus of fish is Esox. I have to admit that Amia, Lepisosteus, Moxostoma, Micropterus and others are right up there too, but there is something special about Esox. For those of you not familiar with the Latin, these are the pikes. Current scientific data shows these fish have been around for about 65 million years. A good amount of time to perfect themselves huh? There are only 5 species currently accepted by ichthyologists, there are several subspecies and a few hybrids even. Despite the lack of diversity within the genus, these fish are really successful. How successful you ask? Well the type species, Esox lucius, better known as the Northern Pike is the freshwater fish with the largest natural distribution. It is found all over the northern hemisphere throughout North America, Europe and Asia. It can even be found in brackish water. Not too shabby…
This pick looks like it wants to kill me, would you like to be a baitfish?

What makes these fishes so successful? If I had to make an educated guess (and I will), I would say that they have developed a form that works beautifully for their niche. They are classic ambush predators that will eat almost anything (fish, amphibians, reptiles, mammals,  birds, even toy poodles). Look at that long skinny shape- perfect for an ambush predator. One quick S-curve and they can lunge forward to grab what they want to eat. The head on these fishes has been described as “gator-like” and it isn’t far off. A lot of very well adapted predators have that look: wide mouth, lots of teeth, eyes on top. It works. Ever watch a pike hunt?  Their eyes are constantly on the lookout, especially up. I have seen pike and musky going after stuff on the bottom- mostly crawfish- and it doesn’t quite look right. But something on top… lookout! 

Their mouth is probably one of the best adapted parts of their body. The design is simple- grab something and don’t let it go. Anyone who has had the misfortune of getting their hand stuck in the mouth of an Esox can tell you that first hand. There are teeth to grab prey fast and hard and then there are the teeth on the upper jaw. Several hundred smaller teeth that all point backwards. If you have the chance to check out a pike or musky skull do it. Those upper teeth are pretty impressive. Once something is in there it isn’t coming out easily. Just talk to your buddy “Burger Fingers” about the time he was too slow…
You can see some of the hinging here...

The other cool thing about their mouth is how big it can open up. Really frickin’ big! The mouth of Esox is pretty complex and hinged in several places to allow it to open very wide.  If you have seen a musky flare to grab your fly you know what I am talking about. It is often said that a pike or pickerel can eat something about two thirds their own body length. It is true. I have seen it happen. I used to maintain aquariums for a public aquarium in Vermont and we had two small chain pickerel in the same tank. They were about 8” long. One morning I came in, looked in the tank and there was the slightly larger one looking incredibly fat and with a tail hanging out of his mouth. It survived but if you do a search online you will definitely find pictures of pike that have bitten off more than they can chew and have choked to death on something they tried to eat. Like one another!
That fish will blend in the weeds well...

I think another thing that has lead this genus to success is the cryptic coloration they display. Their markings from the bright patches on a dark background on pike, dark stripes on a lighter background of muskies or the distinctive chain patterning that gives E. niger it’s common name really let these predators blend in with their environment. An ambush predator that can’t be seen is a successful ambush predator! I have been amazed at how well these fish blend in. I am sure that some of their victims are amazed too. For about a millisecond before their demise that is.

We have the greatest species distribution right here in North America with the muskellunge, northern pike, chain pickerel and grass pickerel (and redfin pickerel but the grass and redfin are just subspecies of the same fish).  I have caught 3 of the 4 of these. Well, that is unless they decide to split the muskellunge into the musky and the masquinonge into two different species, but that is a whole other kettle of fish. I am going to try to get a redfin this year in VT which should not be difficult. I have caught a tiger musky- a natural one not a stocked one and I would like to get a pike/pickerel hybrid too (any help from Mr. Capsey on locating one?).

The one Esox that I would absolutely love to get but cannot get in N. America anymore is E. reichertii. They were stocked in a Pennsylvania reservoir but never took hold well. The hatchery they were in lost all their brood stock and eggs in the 1970’s and the program sank after that. Looks like I will have to head to Mongolia after all….

2 comments:

  1. An Informative read Drew. Thanks

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  2. Love the pictures. I always like to see what other vermonters are fishing for. This is a great blog. I will follow. If you like, check out my blog on vermont fishing at www.bassnvt.blogspot.com
    Tight lines

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