We evaluated the relationship of stocking density to survival, growth performance and fin condition of European perch Perca fluviatilis with hand feeding and self-feeders. Hand-fed perch (body weight 19.1 ± 5.1 g and total length 107 ± 9 mm) were reared at 0.5, 1.0, 1.5 and 2.0 fish/L. Self-feeding perch (body weight 25.4 ± 3.9 g and total length 128 ± 7 mm) were reared at stocking densities of 0.6, 1.0 and 1.4 fish/L. Pond-reared perch served as a comparison group for fin damage assessment. We found no differences in survival rate among stocking densities with either feeding method. Hand-fed fish displayed the highest weight gain and SGR at stocking density of 0.5 fish/L. The self-feeding fish showed a non-linear association of weight gain with stocking density with the highest growth at 1.0 fish/L. Fin length was noticeably greater in pond-reared fish compared with RAS-reared fish regardless of feeding method. In both experiments, fin length relative to standard length showed a negative relationship with stocking density, with pectoral fins showing the greatest effect. Fin condition deteriorated with increasing stocking density, and growth was highest at 0.5 and 1.0 fish/L in hand-fed and self-feeding fish, respectively.

• MeSH
• hustota populace MeSH
• metody výživy veterinární   MeSH
• okounovití růst a vývoj   zranění   fyziologie   MeSH
• ploutve zvířat zranění   patologie   MeSH
• rybářství * MeSH
• vodní hospodářství * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

Copepods of the genus Achtheinus Wilson, 1908 (Pandaridae) are parasites of elasmobranchs that attach to their fins, gill slits and around the nostrils. Specimens of Achtheinus pinguis Wilson, 1912 were collected and examined using histology and scanning electron microscopy to determine their way of attachment to the host and the possible effect on the host. They insert their antennae deep into the dermis of the shark's skin, which causes the most damage due to possible tissue compression and/or fibrosis as well as rupture of the connective tissue. Additionally, the presence of the copepod on the skin causes cell erosion of the epidermal cells and thus reduces the number of epidermal layers. The maxillipeds are used to attach to the placoid scales that cover the shark's skin and probably serve to keep the copepod and inserted antennae in position. This is accomplished by the insertion of the placoid scales into the flaccid corpus of the maxillipeds. Observed damage seems to be negligible to the shark apart from the possibility of secondary infection.

• Klíčová slova
• plakoidní šupiny, maxillipeds,
• MeSH
• branchiální krajina parazitologie   MeSH
• Copepoda * anatomie a histologie   klasifikace   ultrastruktura   MeSH
• Elasmobranchii * anatomie a histologie   parazitologie   MeSH
• histologické techniky MeSH
• kůže patologie   MeSH
• mikroskopie elektronová rastrovací MeSH
• ploutve zvířat anatomie a histologie   parazitologie   patologie   ultrastruktura   MeSH
• tkáně patologie   MeSH
• tykadla členovců anatomie a histologie   MeSH
• zvířecí šupiny anatomie a histologie   parazitologie   patologie   ultrastruktura   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH