Effect of domestication on ide Leuciscus idus L. reproductive parameters

Abstract

Stocking hatchery-reared brown trout in different densities into a wild population -a comparison of growth and movementIn spring 2001 and 2002 a small stream was stocked with tagged hatchery-reared yearling brown trout (Salmo trutta), in order to study their influence on the resident brown trout population. The stream was separated into six sections: two sections without stocking, two sections where stocking doubled the trout population and two sections where the fish population was quadrupled. The working hypothesis was that due to food limitation (competition) growth of the wild fish will be negatively influenced by stocking, and wild fish will be displaced by the (possibly more aggressive) hatchery fish. Surprisingly, growth rate of wild and stocked fish of the same age was similar and independent of stocking density. Two main reasons may be responsible for this finding: only a low percentage of the stocked fish remained in the stream, and food was not limited during summer. Only 12-19% of the stocked fish were recaptured after six months, in contrats to 40-70% of one-year old and up to 100% of older wild trout. The wild fish were not displaced by hatchery-reared fish: During summer the wild fish remained more or less stationary, whereas most of the stocked trout had left their release site. The results indicate that in a natural stream stocking of hatchery reared brown trout does not influence negatively growth and movement of the wild fish independent of stocking density. Baer, J. (Fisheries Research Station of Baden-Wu¨rttemberg, Untere Seestraße 81, 88085 Langenargen, Germany). Swimming activity of seabass: comparing patterns obtained in natural environment and in re-circulating tanks under high density Genetic quality of domesticated African tilapia populations Anecdotal and empirical evidence exists for substantial (up to 40%) declines in growth among Oreochromis populations domesticated in both large and small-scale fish farms in Africa. These declines are at least partly attributable to poor genetic management, including inadvertent selection, inbreeding, bottle-necks and founder effects. Due to restricted cash flow and investment capital, genetic management and selective breeding for the improvement of domesticate populations are difficult for small-scale farmers, but feasible on larger-scale farms. In managing domesticated gene pools, feral populations can serve as a broodstock reservoir, making the use of indigenous species advantageous. A development model of large-scale hatcheries producing selected lines of sex-reversed, indigenous tilapia for sale to smaller-scale farmers is proposed as a solution to the problems of poor genetic management in African aquaculture. Brummett, R. E. & Ponzoni, R. (WorldFish Centre, BP 2008, Yaounde´, Cameroon). Polyculture production of juvenile fishes for survival in natureProduction of seed for stock enhancement projects requires consideration of the behavioural quality of the animals to be released in the wild. Our approach to improving behavioural quality of hat...

The effects of cadmium and copper on embryonic and larval development of ide Leuciscus idus L.

“…According to Hamackova et al ( 2007 ), in some European countries (e.g., Czech Republic), the ide belongs to less frequent and vulnerable species; thus, it is bred in captivity and reared under controlled conditions. Also, in Poland, natural populations of many rheophilic fish including the ide are dwindling due to environment deterioration, and the fish are artificially reproduced and prereared under hatchery conditions (Wolnicki and Górny 1995 ) and cultured in carp farms (Cieśla and Wojda 2004 ; Krejszeff et al 2009 ). L. idus is also used to assess the quality of surface water (Allner et al 1999 ; Fenske et al 2006 ) and for toxicity tests (Braunbeck and Segner 1992 ; Lenyen et al 1998 ).…”

Success of nursing ide (Leuciscus idus, L.) fry related to the period of feeding with live food

“…Maintenance of its original natural distribution in the Czech Republic is possible if the methods of artificial reproduction and nursing of fry in a controlled environment are elaborated. Data gained can be used for rearing this species in ponds and special facilities (Hochman 1959;Ciesla and Wojda 2004). The goal of our work was to determine and assess statistically the values of survival, growth, condition, production and early ontogenesis of larval and juvenile specimens of ide fed for varying periods with Artemia salina nauplii and transferred to a selected starter feed.…”