Thursday, January 5, 2023

Ice-fishing, Carp, Siberia...what is not to like

 

13:30 run-time

This video is interesting because it illustrates a low-input, highly-productive (in terms of labor invested) form of aquaculture in a very severe environment.

It is easy to invent a multitude of food production schemes that have negative net energy return on energy invested. This method, as illustrated, is one of those BUT simply changing from motorized vehicles to foot-transport would flip it right-side up.

That cannot be said for most other schemes after you make a rigorous effort to include the energy costs of ALL inputs.

As a simple frame-of-reference, Com-China subsidizes their deep-sea fishing fleet to a tune of twenty cents per pound of edible fish harvested. Twenty cents of oil has the equivalent of 11,000 dietary calories. A pound of fresh fish has about 400 calories. So looking at just the government fuel subsidy, there is at least 27 times more energy invested in deep-sea fishing than is harvested.*

Thumbnail description of fishing method shown in the video:

120 villagers travel to a nearby, shallow "lake" on the taiga. At one end of the lake they use chainsaws to cut two 4'-by-6' holes in the ice and they use spuds to break a series of holes between the two large holes. Then, after lashing poles together, they pass a line from small-hole-to-small hole to join the two large holes. Then they drag a seine between the two large holes.

The seine might be 8' top-to-bottom. The bottom is weighted and the top has floats. The two large holes might be 100 yards apart.

Then the 120 people go to the opposite end of the lake and by various means (sticks thrust through holes in the ice and banging on the ice) herd the fish to the end of the lake with the net.

Count them if you can.
Roughly counting the number of bags, the 120 villagers appear to harvest in the neighborhood of 3600 pounds of fish-on-the-fin. Given the time of year and the latitude, they probably did not invest more than six hours of time per-person. That works out to five pounds of fish per person per hour on-task.

You can attempt to count bags of fish at the 9:50 mark of the video.

Issues:

Looks like it might be a river. You can see three lines of villagers on the left-center of the image
Seines are different than gill-nets. Gill-nets trap fish by size while seines form a purse and then the ends are pulled together. That pre-supposes the seine can be set in some kind of loop. It is unclear how the loop or belly in the net is achieved. Perhaps there is a slight current that causes it to sag? Perhaps they run a line perpendicular to the center of the net run and pull it back? Not clear.

The timing of the venture is critical. The ice needs to be thick enough to hold a hundred people but thin enough to pop many, many holes through it. The ice appears to be about 4" thick. If the ice is on a river it can be very tricky to estimate when the ice is safe.

The water is stained with vegetation (peat) so the fish will have a "boggy" taste. Not a problem if this is what you grew up with.

Range map Crucian Carp
The fish species is Crucian Carp which has a very northern range. Crucian Carp can survive anaerobic water because they have a metabolic mechanism that creates energy by converting reserves to ethanol which is excreted via urine. Goldfish share this mechanism which accounts for their ability to survive in small fishbowls.

Fish-kills on ice-bound ponds is very common when snow blocks the sunlight. Algae is unable to photosynthesis and decaying organic matter consumes all of the oxygen dissolved in the water.

Crucian Carp is considered one of the best carp for table-fare.

Yield

A review of literature suggests that 30 pounds of fish per acre per year is near top-end for low-input aquaculture. Take that number with a large grain of salt because it varies wildly by location.

The Yakutians never harvest a lake more than once every three years. Working backwards, that implies the lake was at least 36 acres. On the video it appears much smaller but if it was a river then the fish could have congregated in the deep holes which would facilitate catching them.

Those numbers seem improbable, given the northern latitude, the low pH and the general hypotrophic water but carp are at the bottom of the food-pyramid and soils washed into the lakes by erosion can increase nutrient loading. So maybe the numbers work out.

Summary

It an interesting video but it leaves me with many questions

  • I like the social nature of harvesting resources in this way
  • Their methods are knocking-on-the-door of being net-positive-energy and it is an efficient way to harvest protein, a nutrient that is often expensive to collect or grow.
  • I admire the ethic of only harvesting once every three years although that may have more to do with fish size than an inherent conservation ethos
  • Tangential to the video, non-sporting methods-of-take are illegal in many places because they are TOO efficient. Fly-fishing looks great on a calendar but is not as efficient as netting or trapping fish. 
 
* $2 Billion fuel subsidy per year and 15 million metric tonnes of catch per year. 1/3 edible fillets per pound of catch. $75 per barrel oil. 32 million BTU per barrel. Please feel free to double-check my work.
 

2 comments:

  1. Humans can't eat oil so comparing the energy of expended oil vs energy of acquired food is disingenuous. When we run out of oil to use to acquire food...either by using it up or by rulers edicts....an enormous number of humans are going to starve.

    ReplyDelete
  2. They get it done as a community effort, and it is ALL human effort. Good on them!

    ReplyDelete

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