Localization of carbonic anhydrase in swimbladder of European eel (Anguilla anguilla) and perch (Perca fluviatilis)

A small polyhumic lake inhabited by northern pike (Esox lucius), burbot (Lota lota), perch (Perca fluviatilis), roach (Rutilus rutilus), and eel (Anguilla anguilla) was fished intensively during spring 1984 and 1985 to lower the high mercury levels in the top predator, northern pike. A total catch of 29.5 kg∙ha−1 (74% roach) was removed which represented about 50% of the total fish biomass. Mercury concentrations in burbot, large pike, and small roach had decreased by 1987 and 1988, but increased in young pike and some perch. Northern pike had the clearest increase in growth rate, while that of perch and roach levelled off within 3 yr at the prefishing level. Only a small increase in growth rate of burbot occurred. The yearly accumulation of mercury in northern pike remained constant, and the decrease in [Hg] was apparently due to growth dilution. The decrease in [Hg] of burbot and roach is explained by a switch to a diet with lower [Hg] or a decrease in water methylmercury concentrations. The amount of methylmercury removed from the lake by fishing was equivalent to several years of calculated mercury methylation and accumulation in the fish. Overfishing may be a feasible means of lowering methylmercury levels in this type of oligotrophic lake.

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Effects of Exploitation, Introductions, and Eutrophication on Percids in Lake Balaton

Journal of the Fisheries Research Board of Canada ◽

10.1139/f77-232 ◽

1977 ◽

Vol 34 (10) ◽

pp. 1678-1683 ◽

Cited By ~ 25

Author(s):

Péter Biró

Keyword(s):

Perca Fluviatilis ◽

Anguilla Anguilla ◽

Nonnative Species ◽

Lake Balaton ◽

Abramis Brama ◽

Bream Abramis Brama ◽

Perch Perca Fluviatilis ◽

Exploitation Rate ◽

Maximum Sustained Yield ◽

Stizostedion Lucioperca

Percid populations in Lake Balaton have undergone changes which are considered to have been caused by individual or combined effects of overfishing, interspecific competition from nonnative species, and loadings of nutrients and pesticides. Eurasian perch (Perca fluviatilis) has almost disappeared and the ruffe (Gymnocephalus cernua) population is declining, probably as a result of competition from the eel (Anguilla anguilla) and effects of cultural eutrophication. Growth rate of pikeperch (Stizostedion lucioperca) is declining while that of the bream (Abramis brama) is increasing. Production of cyprinids has increased up to 10% in recent years, apparently in response to accelerated eutrophication. The exploitation rate of pikeperch is far in excess of that considered necessary for maximum sustained yield. The environment in the most eutrophic part of the lake is now considered to be unfavourable for pikeperch. Key words: Percidae, Stizostedion, Perca, Gymnocephalus, exploitation, eutrophication, introductions, ruffe, Lake Balaton

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Characteristics of illegal inland fishing according to the opinions of Polish fisheries guards

Fisheries & Aquatic Life ◽

10.2478/aopf-2020-0015 ◽

2020 ◽

Vol 28 (2) ◽

pp. 125-132

Author(s):

Maciej Mickiewicz ◽

Arkadiusz Wołos ◽

Marek Trella

Keyword(s):

Perca Fluviatilis ◽

Anguilla Anguilla ◽

Esox Lucius ◽

Inland Waters ◽

European Eel ◽

Sander Lucioperca ◽

Great Problem ◽

Frequent Type

AbstractPoaching is still a great problem in Poland. Officers of the fisheries guard from three regions in northeast Poland rich in natural inland waters were surveyed. The most frequent type of poaching encountered by the officers was that practised by recreational fishers using rods (ranking of 4.4 points on a scale of 0–5) followed by poaching stemming from poverty or unemployment (3.4 points), and poaching by professional fishermen was ranked the lowest (1.5 points). Organized poaching was identified as the most dangerous for ichthyofauna (42% of responses), followed by poaching by recreational fishers (28%) and poaching stemming from poverty or unemployment (23%). According to the officers surveyed, the species that were targeted by poachers most frequently were the predators: pike, Esox lucius (98% of responses), European eel, Anguilla anguilla, pikeperch, Sander lucioperca and perch, Perca fluviatilis.

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Differences in head shape of the European eel, Anguilla anguilla (L.)

Fisheries Management and Ecology ◽

10.1046/j.1365-2400.2000.00207.x ◽

2000 ◽

Vol 7 (4) ◽

pp. 349

Author(s):

J. M. Proman

Keyword(s):

Anguilla Anguilla ◽

European Eel ◽

Head Shape

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Metazoan Parasites and Health State of European Eel, Anguilla Anguilla (Anguilliformes, Anguillidae), From Tonga Lake and El Mellah Lagoon in the Northeast of Algeria

Vestnik Zoologii ◽

10.2478/vzoo-2018-0029 ◽

2018 ◽

Vol 52 (4) ◽

pp. 279-288 ◽

Cited By ~ 1

Author(s):

F. Bakaria ◽

S. Belhaoues ◽

N. Djebbari ◽

M. Tahri ◽

I. Ladjama ◽

...

Keyword(s):

Brackish Water ◽

Parasite Species ◽

Anguilla Anguilla ◽

European Eel ◽

Health State ◽

Component Community ◽

Metazoan Parasites ◽

Parasite Communities ◽

High Dominance ◽

Argulus Foliaceus

Abstract The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.

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