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Abstract

This study presents the results of inducing spermiation and ovulation of dace (Leuciscus leuciscus L.) spawners collected from different parts in of Poland. Artificial reproduction was performed using carp pituitary homogenate (CPH), human chorionic gonadotropin (hCG), agents containing a GnRHa with a dopamine inhibitor supplement (Ovopel and Ovaprim, GnRHa combined with metoclopramide) and GnRHa alone conducted during the spawning season. Males from the control group produced similar volumes of semen and sperm motility as fish after hormonal preparation application. Stimulation of ovulation by manipulation of environmental factors as well as by GnRHa alone did not trigger ovulation within 70 hrs following administration of a resolving injection, but did cause GV migration. Applying GnRHa with the dopamine inhibitors or CPH produced 80-100 % ovulation in females. The differences in reproduction between fish populations were reflected in ovulation synchronization, which was highly variable among populations or embryo survival. The fish stimulated with CPH ovulated several hours earlier than those injected with GnRHa combined with a dopamine inhibitor. The data obtained in the present paper could be applied to the production of the rheophilic cyprinid stocking process and, consequently, could form an important tool in the conservation of endangered or over-exploited finfish populations.

Influence of temperature and stocking density during rearing on larval blue bream, Ballerus ballerus (L.)

“…Researchers in this field are also interested in fish species that are of no economic importance, but are valuable components of aquatic ecosystems and their biodiversity. This was the case for several species of rheophilous cyprinid fishes that are of no economic importance and/or do not have a high conservation status, including: ide, Leuciscus idus (L.) (Cejko et al 2010, Targoñska et al 2011a; chub, Squalius cephalus (L.) (Krejszeff et al 2008; common dace, Leuciscus leuciscus (L.) (Cejko et al, 2012, Nowosad et al 2014, Targoñska et al 2015; barbel, Barbus barbus (L.) (Targoñska et al 2011b, Prusiñska et al 2020; rudd, Scardinius erythrophthalmus (L.) (Kucharczyk et al 1997a); and asp, Leuciscus aspius (L.) (Kujawa et al 1997. For many fish species, variation in individual growth can lead to changes in population productivity since size affects survival, fecundity, and reproduction.…”