Sturgeon harvesting season still continues

Sturgeon fishers did not fear to experience Sunday chilly weather and cold to catch 297 sturgeons. The number of harvested fish was not enough for the State Department for Natural Resources to end the 2008 season.

Photo: Sturgeon harvesting season still continues

For the time being, spearers have caught the total of 1,103 fish. The majority of them were harvested from Lake Winnebago (888), whereas the rest (215) were taken from lskes Poygan, Butte Des Morts and Winneconne.

Several species of sturgeons are harvested for their roe, which is made into caviar - a luxury good which makes some sturgeons pound for pound the most valuable of all harvested fish. Because they are slow-growing and mature very late in life, they are particularly vulnerable to exploitation and to other threats, including pollution and habitat fragmentation. Most species of sturgeons are currently considered either vulnerable, endangered or critically endangered.

In Russia, sturgeon fisheries are of immense value. Early in summer the fish migrate into the rivers or towards the shores of freshwater lakes in large shoals for breeding purposes. The ova are very small, and so numerous that one female has been calculated to produce about three million in one season. The ova of some species have been observed to hatch within very few days after exclusion. In Sturgeons that have attained maturity their growth appears to be much slower, although continuing for many years. Frederick the Great placed a number of them in the Garder See Lake in Pomerania about 1780; some of these were found to be still alive in 1866. Professor von Baer also states, as the result of direct observations made in Russia, that the Hausen (Acipenser huso) attains an age of 100 years, but can live over 210 years.

In countries like England, where few sturgeons are caught, sturgeon is included as a royal fish in an act of King Edward II, although it probably only rarely graces the royal table of the present period, or even that of the lord mayor of London, who can claim all sturgeons caught in the Thames above London Bridge. Where sturgeons are caught in large quantities, as on the rivers of southern Russia and on the great lakes of North America, their flesh is dried, smoked or salted. The ovaries, which are of large size, are prepared for caviar, for this purpose they are beaten with switches, and then pressed through sieves, leaving the membranous and fibrous tissues in the sieve, whilst the eggs are collected in a tub. The quantity of salt added to them before they are finally packed varies with the season, scarcely any being used at the beginning of winter. Finally, one of the best sorts of isinglass is manufactured from the airbladder. After it has been carefully removed from the body, it is washed in hot water, and cut open in its whole length, to separate the inner membrane, which has a soft consistency, and contains 70% of glutin.

Sturgeon (and, therefore also the caviar trade) are under severe threat from overfishing, poaching and water pollution