The activity of hydrolytic enzymes in the digestive system of Acanthobdellida, Branchiobdellida and Hirudinida (Annelida,Clitellata) – considerations on similarity and phylogeny

Activities of nineteen hydrolases were measured in the digestive systems of predatory and blood-feeding true leeches (Hirudinida) and their closest relatives, Branchiobdellida and Acanthobdellida. Hydrolase activities were analyzed in different parts of the digestive systems: the species-specific anterior part, i.e. jaws, pharynx or proboscis, crop and intestine. The results obtained suggest that food digestion and possible absorption predominate in the intestine of most of the studied Hirudinida and A. peledina, whereas in B. astaci these processes take place in the anterior part of the digestive system and crop. In Erpobdellidae and Piscicola respirans, the activity of acid and alkaline phosphatases, N-acetyl-β-glucosaminidase, leucine and valine arylamidases, and α-fucosidase was also detected in the anterior part of the digestive system. We also detected differences in enzyme occurrence between the studied species, which are probably connected with their different food preferences. Moreover, the presence of the whole spectrum of enzymes in predatory leeches and the absence of trypsin and α-chymotrypsin activity in the crop of all the leeches support the hypothesis that the leech ancestor was a blood-feeder. Our study showed that “Rhynchobdellida” constitute a paraphyletic group which confirms the previous results based on molecular phylogenetics, while Arhynchobdellida appears to be a non-monophyletic group which is not consistent with previous molecular results

REVIEW OF THE NATIONAL RESTOCKING PROGRAMME “ACTIVE PROTECTION OF NATIVE CRAYFISH IN POLAND” 1999-2001

After the first spread of crayfish plague (aphanomycosis) at the end of the nineteenth century, the formerly abundant populations of native crayfish in Poland declined drastically. Analysis of historical data on the occurrence and distribution of crayfish in Poland led to the conclusion that without human intervention the native crayfish species would be at high risk of being made extinct. The largest programme concerning crayfish monitoring and restocking in Poland was “Active protection of native crayfish in Poland” conducted by the Inland Fisheries Institute, the Department of Ecology, University of Szczecin, the Department of Zoology, Warsaw Agricultural University and the University of Warmia and Mazury that was funded by the EkoFundusz Foundation and Inland Fisheries Institute in 1999-2001. One of the main objectives and results of this programme was the determination of indigenous crayfish distribution in Poland (mainly Astacus astacus and Astacus leptodactylus) and the restocking of suitable habitats with indigenous crayfish. The densest populations (> 2 500 adult individuals per hectare) were used as a source of restocking material. Restocking was performed in 54 water bodies using a total of 45 200 individuals of A. astacus and 9 800 of A. leptodactylus. Between 2001-2002, the success of the restocking programme was monitored. According to the results obtained so far, the restocking exercise has been successful in at least 60.8% of the cases

Hydrodynamical Balance as Important Parameter Influencing the Ecological Status of Carpathian Rivers

According to the Water Framework Directive human activities should lead to an improvement or at least stabilizing of water ecosystems. Due to the adaptive nature of living species, reference conditions specified under the WFD for mountain river should be tested after reaching of proper hydromorphological parameters. The hydrodynamical balance of mountain river channel is reflected by it's plan view as well as by vertical and cross-sectional layouts. Mountain river in natural conditions produce a clearly defined riffle and pool system and can create a variety of channels with bars. Fluvial processes occurring in mountain rivers differ much from those that occur in lowland rivers. Beds of mountain rivers and streams, due to the water flow in high bed relative roughness conditions, are sensitive to changes in the bed material composition, size and shape. In these circumstances, bedforms are not created. While low and medium flows, there is no sediment transport, and only minor grain hide, sorting and armoring processes form the top of the bed. Granulometric curve changes depend on variations in several parameters. During the process of creating or removing the armored layer, the variation of fractions describing bed stability and water flow conditions exist. In a changing regime of watercourses functioning with the rough bottom, the standard deviation of the curve correctly reflects the bed material sorting processes. Armored bottom exists for it's values less than 1.6, and in the natural conditions the value does not fall below 1.3. In this case, fine material is almost completely removed from the bottom of the cover. Below the reaches of river sources, which are the steepest sections of mountain streams, riverbeds mostly achieve hydrodynamic balance and this is the optimal condition for the development of the aquatic ecosystem. When the incised channel, with armored bottom in alluvial river is found, it often shows a limited supply of bed material. Many factors can affect the change of the river channel so the stable morphological state occurs after some time, and after many oscillations around the optimal condition. It is a period of a few to tens of years. In any case, one can determine the state and intensity of fluvial processes. This paper presents a proposal for the implementation of the hydrodynamic balance to assess their ecological status as one of the first and basic. The assessment of the alluvial rivers hydrodynamic balance is shown on the example of the Skawa river (section above the mouth of Bystrzanka stream). Hydrodynamic balance of the channel was based on the analysis of interdependencies between riverbed bandwidth, the channel lateral and vertical layout and bed stability for the characteristic flows of the water: (Q75%, Q50% Q25%, Q10% and Q1%, bankfull an dominant flows). Bed stability analysis presented in the paper was performed using the computer program ARMOUR. Calculations were performed by comparing the critical Shields stresses characterizing all fractions of bed material to the bed shear stresses of the flowing water. On the basis of analysis of the riverbed in this section it was classified as natural