Tuesday, March 29, 2016

Whither Goest the Burbot? By Don Orth

Burbot, Lota lota (Linnaeus, 1758) is the only freshwater member of the Gadidae family. It is also one of the most widely distributed freshwater fish species in the world, but that range is contracting.   Burbot is an elongate, cylindrically shaped fish with two dorsal fins, a long anal fin, and pelvic fins in front of the pectoral fins.   Adults are yellow or light brown, with dark brown or black mottled pattern on back, sides and fins.  They have a single, taste-sensitive barbel on the lower jaw that they use when hunting in the darkness for a meal.  Burbot are well-adapted benthic predators that live in either large, cold rivers or deep lakes. They are primarily piscivores as adults, but have been known to eat frogs, snakes, even birds. Burbot are not a very charismatic fish, although they have a small loyal following.
Burbot.  Illustration by Joshua Knuth

The name, Burbot, is derived from the Latin word barba, meaning beard.  Many other names refer to the Burbot, these include the coney-fish, cusk, eelpout, la lotte, lush, loche, ling, lingcod, mariah, methy, mizay,  mudblows, and mud shark. However, my favorite name for the Burbot is lawyers. Here is a great photo from a fish market, the sign in the window advertising “fresh lawyers” for sale.   Most open-water anglers catch Burbot as incidental catch when fishing for Walleye. Fishing exclusively for Burbot often means ice-fishing.  The all-tackle record is over 25 pounds, though the typical Burbot is much smaller.   

A twenty-five pound burbot by Uncut Angling.
There is a visceral reaction the first time you handle a Burbot.  Burbot have fine, embedded scales and they produce mucho mucous.  The body tapers, so finding a handle on the Burbot is nearly impossible.  Hence, everyone struggles making awkward attempts to handle this slimy fish.  The Burbot spawns in the middle of winter and attracts the hardiest of cold-weather ice-fishermen. The Burbot is not popular as a sport or food fish in much of North America.  However, in some localities, Burbot fishermen eat the flesh, roe and liver.  The large liver is rich in vitamin A and D, but seldom used in North America. The liver is delicacy for some indigenous peoples, as well as people in Finland and France. The roe includes millions of small eggs in a large female.  Even the testes are unusually large.   Some fisheries agencies promote the underutilized Burbot and provide fishing tips and recipes

Sergei Aksacov (1997, pp. 142-144), the Russian version of Izaak Walton, described fishing for the Burbot in Russia.  He also described making Burbot soup with the flesh and liver.  Other recipes are available.  Burbot soup was a dish for royalty in Leo Tolstoy's Anna Karenina.  One hundred years ago, the US Department of Commerce, Bureau of Fisheries promoted the Burbot as a food fish.  In a pamphlet from 1917, they wrote “… for the burbot is coming on the markets at a price which will place it within the reach of modest means…. It has long been esteemed a great luxury… its flesh is white and delicate, while its liver is its most delicious morsel.”  It never lived up to its cousin, the cod, due to large-scale preservation issues. 
Looking down into the mouth of a Burbot. Photo by Angelo Viola
Burbot are on the move in winter to shallower waters in search of mates.  They deposit eggs over mixtures of sand to coarse gravel and cobble.    Imagine a large ball of Burbot with a few females in the center, surrounded by many males.  That’s what happens in winter spawning aggregations (Cahn 1936). It is dark under the ice.  Burbot, like other cods, make sound by rapidly contracting drumming mussels associated with their swim bladder.   Peter Cott and associates first recorded vocalizations of the Burbot in Yellowknife Bay, Great Slave Lake, Northwest Territories, Canada.   Burbot vocalizations peaked under-ice at the onset of the spawning period.  Sound signatures were stereotypical of swim-bladder generated calls, almost identical to those of the Haddock (Melanogrammus aeglefinus).  The mating system of the cods and haddock involves large aggregations; spawning calls assist in formation of the spawning aggregation.  Naturalist Sigurd F. Olson observed spawning and wrote:
It was February and the mercury was down far below zero. We had come in the middle of the night to watch the spawning of the eelpout, those brownish, eel-like deep water fish that thrive in the coldest lakes of the north ... As we neared the upper reaches of the Burntside River, we could hear the rapids murmuring through the dark. It was at this spot we would see them for they need shallow water, gravel and sand for their breeding. Not until we were within ten feet of the bank did we shine our lights, and then saw such a sight as few have ever seen—a struggling, squirming mass of fish, the long brownish snaky bodies twisted around each other, the entire contorted mass turning over and over beating the water into foam ... I had seen that night a primitive picture that I could never forget, a picture of what might have taken place in some cold primeval pool millions of years ago. There was life in the raw obeying the great urge to reproduce, the one implacable law of creation."

Natural movements of Burbot are disrupted by human efforts to change natural waterways. In particular, hydropower developments, warm discharges, blocked migration, and reservoir fluctuation have caused declines in some Burbot populations around the world (Stepanian et al. 2009).  Burbot populations collapsed in Lakes Michigan, Huron and Ontario concurrently with Sea Lamprey (Petromyzon marinus) population increases in the 1940s to 1960s.  Burbot populations have since recovered in all but Lake Ontario, where the introduced Alewife is still too abundant. 
Harrison et al. (2016) reviewed the many threats of hydropower facilities to Burbot populations.  High winter discharges may delay migration and spawning of Burbot.  Often reservoirs release warmer water in winter, which may reduce hatching or survival of Burbot eggs. Some dams release hypolimnetic waters, which are cold and may benefit Burbot populations. Burbot are not strong swimmers and are incapable of passing through large fishways with high current velocities.  The larval and juveniles passively drift and are vulnerable to entrainment into hydro turbines, though few entrainments studies have been done on Burbot.   Dams disrupt migrations of riverine Burbot populations. Despite these potential influences, Burbot populations are not consistently monitored.  The Kootenai River Burbot population collapsed after increased temperatures and high winter discharges commenced below Libby Dam in Idaho (Hardy and Paragamian 2013).  Many other Burbot populations are in need of monitoring and assessment. 
Once a popular food fish in Great Britain, the Burbot disappeared from British waters in the 1960s. Today there are no British champions for the Burbot.  Burbot declines may be occurring in other northern waters influenced by climate warming.  Burbot in Oneida Lake, near the southern edge of the Burbot’s range, have declined significantly since the 1960s (Jackson et al. 2008). 
Burbot caught at the International Eelpout Festival.
If you want to catch Burbot, then you should consider the attending the International Eelpout Festival.   Every year over 10,000 Burbot catchers gather sometime in February on Leech Lake, Minnesota, to celebrate this coldwater specialist.  

Whither goest the Burbot?   Burbot goest to many fewer places than in the past!

References
Aksacov S.  1997.  Notes on fishing and selective fishing prose and poetry. Northwestern University Press, Evanston, Illinois. 232 pp.
Cahn, A.R. 1936. Observations on the breeding of the lawyer, Lota maculosa.  Copeia 1936:163–165
Cott, P.A. et al.  2014.  Song of the burbot: under-ice acoustic signaling by a freshwater gadoid fish.  Journal of Great Lakes Research 40(2):435-440.
Hardy, R., and V.L. Paragamian. 2013. A synthesis of Kootenai River Burbot stock history and future management goals.  Transactions of the American Fisheries Society 142:1662-1670.
Harrison, P.M., L.F.G. Gutowsky, E.G. Martins, D.A. Pattterson, S.J. Cooke, and M. Power.  2016.  Burbot and large hydropower in North America: benefits, threats and research needs for mitigation.  Fisheries Management and Ecology  doi: 10.1111/fme.12178
Jackson, J.R., A.J. VanDeValk, J.L. Forney, B.F. Lantry, T.E. Brooking, and L.R. Rudstam. 2008.  Long-term trends in burbot abundance in Oneida Lake, New York: life at the southern edge of the range in an era of climate change.  Pages 131-152 in V.L. Paragamian and D.H. Bennett, editors.  Burbot: ecology, management, and culture.  American Fisheries Society, Symposium 59, Bethesda, Maryland.
Paragamian, V.L., and D.H. Bennett, editors. 2008.  Burbot: Ecology, management and culture.  American Fisheries Society Symposium 59.  Bethesda, Maryland. 270 pp.
Paragamian, V.L., B.J. Pyper, M.J. Daigneault, R.P. Beamesderfer, and S.C. Ireland. 2008. Population dynamics and extinction risk of burbot in the Kootenai River, Idaho, USA and British Columbia, Canada. Pages 213-234 in V.L. Paragamian and D.H. Bennett, Editors.  Burbot: Ecology, Management, and Culture. American Fisheries Society, Symposium 59, Bethesda, Maryland.
Stepanian, M.A. et al. 2009. Worldwide status of burbot and conservation measures.  Fish and Fisheries.  DOI: 10.1111/j.1467-2979.2009.00340.x
U.S. Department of Commerce, Bureau of Fisheries.  1917.  The Burbot: A freshwater cousin to the cod.  Economic Circular No. 25. 

1 comment:

  1. And listen to the Burbot's Revenge....http://youtu.be/L3hTCebbHQo

    ReplyDelete