The morphology of Zschokkella mugilis Sitjà-Bobadilla and Alvarez-Pellitero, 1993 (Myxosporea, Bivalvulida) in Nereis diversicolor O. F. Müller, 1776 is described for the first time. The molecular data show that the actinospore has 100% similarity to the myxospore of Z. mugilis. Fully mature actinospores are tri-radiate, the spore body has a small process, and the sporoplasm has 2 inner daughter cells. In the polychaete, the spores of the parasite develop in groups of 8 inside pansporocysts. The schizogony phase takes place in the intestinal epithelium, while gametogony and sporogony occur in the coelom of the polychaete. Observations indicate that mature spores are released only during the polychaete reproductive season. Infection was detected only in the winter and spring. In the Aveiro estuary (Portugal), the overall prevalence of infection of the polychaete was 0.5%.

Eradicating or controlling invasive alien species has frequently had unintended consequences, such as proliferation of other invasive species or loss of ecosystem function. We explore this problem using a case study of a highly invasive floating aquatic macrophyte, water hyacinth (Eichhornia crassipes), in the Sacramento-San Joaquin Delta of California. We used 5 years of remote sensing data to perform change detection analysis to study plant community dynamics contemporaneous with changes in water hyacinth cover. Our results show that as water hyacinth cover decreased, submerged aquatic plant (SAP) cover increased and vice versa. This effect was strongest in large patches of water hyacinth. We found no evidence that the native floating aquatic species, pennywort (Hydrocotyle umbellata), benefitted from reducing cover of water hyacinth. In most years, pennywort cover either showed no trend or followed the same trajectory as water hyacinth cover. In this study a decrease in cover of water hyacinth most often resulted in colonization by SAP species with some habitat returning to open water.

The severe loss or degradation of riparian habitats has led to their impoverishment and impaired function, which may have severe consequences on both the riparian habitats themselves and their associated biota, including mammalian carnivores. We selected 70 riparian habitat reaches to evaluate the condition of the riparian habitats in southern Portugal and their use by carnivores. These sites were assessed for riparian condition using the stream visual assessment protocol (SVAP) and surveyed for carnivore presence along the riparian zones and across the surrounding matrix landscape, both in the wet (winter) and the dry (summer) season. Results show that carnivore surveys adjacent to riparian habitats consistently had significantly higher species richness than the matrix habitats, in both sampling seasons. Carnivore relative abundance and relative abundance of stone marten, common genet and Egyptian mongoose also showed higher values in riparian habitats, with significant differences in at least one season. The Eurasian badger, on the other hand, showed higher relative abundance values in the landscape matrix, though differences were not significant. The SVAP index ranked about 83% riparian reaches as poor or fair condition, and species richness was significantly higher in fair condition reaches during the wet season. These results reflect the importance of riparian habitats in Mediterranean ecosystems for mammalian carnivores. However, the generalized poor condition of these habitats suggests that direct measures for riparian restoration could be appropriate. The preservation or improvement of riparian habitats would certainly benefit the mammalian carnivore populations and consequently their conservation.

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A total of eight species of furcocercous cercariae of four families (Strigeidae, Diplostomidae, Schistosomatidae and Sanguinicolidae), were found in 2005 in Lake Konnevesi in Central Finland in four snail species (Valvata macrostoma, Lymnaea stagnalis, Bathyomphalus contortus and Planorbarius corneus). Australapatemon burti (Miller, 1923), Australapatemon sp., Cotylurus brevis Dubois et Rausch, 1950, Cercaria spinulosa Ginetsinskaya, 1959 and Sanguinicola sp. are new species records for Finland. Ichthyocotylurus variegatus (Creplin, 1825) and Bilharziella polonica (Kowalewski, 1895) were first recorded as cercariae in Finland. The most common cercariae were A. burti (prevalence 13.3%) and Diplostomum pseudospathaceum Niewiadomska, 1984 (10.0%). Our study represents the first host record of Valvata macrostoma for larval stages of Australapatemon sp. and Sanguinicola sp.

Ten new types of sphaeractinomyxon actinospores are morphologically and molecularly described from the coelomic cavity of two marine oligochaete hosts, Hrabě, 1967 and Tubificoides pseudogaster (Dahl, 1960), from Aveiro 2 estuary, Portugal. The smallest sphaeractinomyxon type measured 17 µm (length) × 19 µm (width) × 19 µm (apical diameter), whereas the largest type measured 61 µm × 76 µm × 80 µm. While considering the ten types of sphaeractinomyxon, it was found that the number of spores developing inside pansporocysts varied between one, two, four and eight. The total prevalence of infection was of 19% for the two host species, with a maximum recorded for spring and summer (25-26%). While considering each type of sphaeractinomyxon individually, it was found that the prevalence values ranged between 0.3 and 1.7%. All described sphaeractinomyxons were most similar to mugilids infecting Myxobolus species. Limnodriloides agnesThe validity of the tetraspora and endocapsa collective group names is discussed.

Seasonal occurrence of metazoan ectoparasites is described for the first time in marine European flounder, Platichthys flesus (L.). The parasitofauna, in this study monitored during 1 year, was found to be similar to that previously recorded for flounder. Moreover, specimens of Caligus sp. Mü ller, 1785 and Lepeophtheirus pectoralis (Copepoda : Caligidae), Acanthochondria cornuta (Copepoda : Chondracanthidae), Holobomolochus confusus (Copepoda : Bomolochidae) and Nerocila orbignyi (Isopoda : Cymothoidae), and also, a praniza larva (Isopoda : Gnathiidae), were isolated. From these, L. pectoralis and A. cornuta were the dominant parasites in all samples of flounder, while Caligus sp., H. confusus, N. orbignyi and the gnathiid praniza seemed to infect the flounder only occasionally. As far as the seasonality of infections is concerned, it differed considerably from that described for estuarine environments. Indeed, both prevalence and abundance of L. pectoralis and A. cornuta reached significant peaks in the summer, whereas the literature identifies the autumn as the season of maximum infection on estuarine flounder. Thus, the former period seems more favourable for the occurrence of epizooties of L. pectoralis and A. cornuta in flounder culturing systems running on seawater and operated in the studied or similar environments.

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