Timing and Magnitude of Energy Deposition and Loss in the Body, Liver, and Gonads of Northern Pike (Esox lucius)

1979 ◽  
Vol 36 (5) ◽  
pp. 481-487 ◽  
Author(s):  
James S. Diana ◽  
W. C. Mackay

Northern pike (Esox lucius) were sampled periodically from Lac Ste. Anne, Alberta, between March 1976 and September 1978. The yearly cycle of production and depletion was determined for individual 3-yr-old fish. Body growth in length was similar for both sexes, and occurred during the summer. Somatic caloric growth was completed during the summer by females, while male somatic growth continued over winter. Gonad growth began in August; testicular growth was completed by September while ovarian growth occurred mainly during winter. There was no loss of somatic energy during ovary growth. Energy requirements for testicular growth appeared to come from liver stores. Both sexes lost considerable somatic energy between March and May, the spawning period; this loss appeared to be due to spawning activity and not late gonad growth. Young-of-year fish did not mature sexually and all of their energy accumulation went into somatic tissue. Total production in females from May to March was twice as high as production in males. Both sexes had similar yearly somatic production, while females had approximately 15 fold higher gonadal production than males. Key words: calories, growth, liver, gonad, somatic, Esox lucius, production, spawning depletion

1983 ◽  
Vol 40 (12) ◽  
pp. 2241-2250 ◽  
Author(s):  
Michael A. Turner ◽  
Alison L. Swick

Although selenium is a pollutant released by several industries, it is also an essential nutrient that protects mammals against mercury intoxication. When added to aquatic ecosystems, selenium is bioaccumulated readily and can reduce mercury accumulation in some biota. Using a predator–prey experimental model, we investigated both the route of selenium uptake and the mechanism of reduction in mercury accumulation. Young northern pike (Esox lucius) and yellow perch (Perca flavescens) were caged in situ in mercury-contaminated Clay Lake, northwestern Ontario. Pike were held in water containing trace (< 0.2 μg Se/L) or elevated (4.5–6.4 μg Se/L) concentrations of selenium and were able to accumulate 203Hg and 75Se from food (yellow perch) only, water only, or from food and water. Control pike accumulated as much as 20 times more 73Se from food than from water, assimilating ~30% of selenium in food. With increased levels of selenium in water (around 5 μg Se/L), food and water were of similar importance as sources. Waterborne selenium did not alter either the amount of 203Hg accumulated from water or its subsequent partitioning among the pike tissues sampled. When elevated in food, selenium decreased both the body burden of 203Hg in pike and the proportion in muscle. It is inferred that selenium added to aquatic ecosystems, and incorporated subsequently in the food web, would interfere with biomagnification of mercury. Furthermore, future studies of selenium toxicity in fish should emphasize its accumulation from food.


1978 ◽  
Vol 35 (2) ◽  
pp. 213-219 ◽  
Author(s):  
B. A. Medford ◽  
W. C. Mackay

Northern pike (Esox lucius) were sampled at regular intervals from Lac Ste. Anne, Alberta, between May 1973 and July 1974. Gonad weight, liver weight, somatic body weight, and the total protein and total lipid content of gonads and liver were determined for a pike of 50 cm fork length to evaluate the deposition of nutrients into gonads and to assess areas of possible nutrient storage and depletion. Protein, lipid, and water concentrations in muscle, gonad, and liver were also measured. Gonad growth began in July and proceeded at a similar rate between sexes during late summer. Testicular growth was complete in September, whereas ovarian growth continued through fall and winter until April. Mature ovaries contained 14.5 times more protein and 10.5 times more lipid than did mature testes. Ovarian growth before March occurred without any depletion of body nutrients. Liver weight in both sexes increased 2.5-fold between May (after spawning) and March. In March, total liver protein of females was 163% that of males. Female liver size decreased significantly before spawning (March–April) coincident with final gonad growth. Male liver size decreased significantly over spawning (April–June). No fat storage depots were observed in either sex. Muscle and somatic body weight data indicate that a depletion of body energy can occur in spring. Key words: protein, lipid, water, gonad, liver, muscle, northern pike, Esox lucius, spawning


2021 ◽  
Vol 83 (3) ◽  
Author(s):  
Mehdi Moslemi-Aqdam ◽  
George Low ◽  
Mike Low ◽  
Brian A. Branfireun ◽  
Heidi K. Swanson

Chemosphere ◽  
2012 ◽  
Vol 86 (5) ◽  
pp. 439-445 ◽  
Author(s):  
Staffan Åkerblom ◽  
Mats Nilsson ◽  
Jun Yu ◽  
Bo Ranneby ◽  
Kjell Johansson

1988 ◽  
Vol 45 (7) ◽  
pp. 1154-1162 ◽  
Author(s):  
Paul Andersson ◽  
Hans Borg

We studied the cadmium concentrations in water, sediment, suspended particles, a free-swimming insect larva (Chaoborus), a sediment-bound insect larva (Chironomus), and liver of northern pike (Esox lucius) before and after liming operations in Lake Långsjön, Sweden. In accordance with the higher pH levels obtained in the lake water after the limings, cadmium concentration decreased in the water but increased in the sediment. Cadmium concentration in fish liver and Chironomus decreased after the limings whereas the concentration in Chaoborus larvae increased after the first liming. Possible mechanisms are discussed.


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