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Titolo:
Total length of age-3 brown trout (Salmo trutta L.) in French Pyrenean streams: Relationships with environmental factors and influence of hydroelectric facilities.
Autore:
Lagarrigue, T; Baran, P; Lascaux, JM; Delacoste, M; Abad, N; Lim, P;
Indirizzi:
Ecole Natl Super Agron Toulouse, Lab Environm Aquat, F-31326 Castanet Tolosan, France Ecole Natl Super Agron Toulouse Castanet Tolosan France F-31326 , France
Titolo Testata:
BULLETIN FRANCAIS DE LA PECHE ET DE LA PISCICULTURE
fascicolo: 357-60, , anno: 2001,
pagine: 549 - 571
SICI:
0767-2861(2001):357-60<549:TLOABT>2.0.ZU;2-2
Fonte:
ISI
Lingua:
FRE
Soggetto:
POPULATION-DENSITY; GROWTH-RATE; MODEL; FOOD; TEMPERATURE; HABITAT; FLOW;
Keywords:
growth; brown trout; Salmo trutta; predictive models; reduced flow; legal size of capture; Pyrenees; France;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Lagarrigue, T Cabinet Etud IMAGO, 26 Rue Dels Pibouls,Labastide Falgarde, F-31120 Lacroix Falgarde, France Cabinet Etud IMAGO 26 Rue Dels Pibouls,Labastide Falgarde Lacroix Falgarde France F-31120
Citazione:
T. Lagarrigue et al., "Total length of age-3 brown trout (Salmo trutta L.) in French Pyrenean streams: Relationships with environmental factors and influence of hydroelectric facilities.", B FR PECHE, (357-60), 2001, pp. 549-571

Abstract

The growth of brown trout (Salmo trutta L.) populations has been studied on 84 streams distributed over the whole range of the Pyrenees. Samples of scales were collected in 215 sites located at altitudes ranging between 185 and 2000 m, for width varying from 1,2 to 60 m. The growth of individuals was determined by scale reading. The mean total length of age-3 trout was selected as the biological variable. The mean total length of age-3 trout was strongly structured by altitude, this altitudinal gradient mainly representing a thermal gradient. It is negatively correlated with altitude and total density of brown trout and positively correlated with stream width and summer conductivity. The nature of the flow regime also plays a major role on the growth since at equivalent altitude and equivalent mean summer temperature, the mean total length of age-3 trout is significantly lower in sites below dams with constant reduced flow than in site with natural flow. According to the nature of the flow, two predictive models of the mean total length of age-3 trout (T-3), which take into account altitude (ALT) and width of the river (L), were established by stepwise linear multiple regression analysis :- sites with natural flow : Log (T-3) = 2.457 - 0.007 x root ALT + 0.066 xLog (L)The model explains 65.5 % (p < 0.01) of the variance of the total length of age-3 trout (T-3 in mm): respectively 61.6 % (p < 0.01) by altitude (ALT in m) and 3.9 % (p < 0.01) by stream width (L in m).- sites with constant reduced flow: Log (T-3) = 2.432 - 0.009 x <root>ALT 0.087 x Log (L). The model explains 53.5 % (p < 0.01) of the variance of the total length of age-3 trout (T-3 in mm): respectively 47 % (p < 0.01) by altitude (ALT inm) and 6.5 % (p < 0.05) by stream width (L in m). These two models, tested and validated on a new data set, may help managers to estimate a legal size of capture adapted to the local conditions met in Pyrenean streams. The value of the two models is discussed and improvements are suggested.

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Documento generato il 13/07/20 alle ore 08:05:27