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1.
A survey of intestinal helminth communities of Audouin's gulls Larus audouinii, from their breeding colonies in Chafarinas Islands, western Mediterranean, Spain was conducted to determine the abundance and species diversity of intestinal parasites of these birds. The sample of 58 gulls harbored intestinal helminth infracommunities composed of species that are gull generalists, including the digeneans Cardiocephalus longicollis, Knipowitschiatrema nicolai, Condylocotyla pilodora, and Aporchis massiliensis, and the cestode Tetrabothrius cylindraceus. Two nematodes are waterfowl generalists (Cosmocephalus obvelatus and Paracuaria adunca), whereas the digenean Acanthotrema armata is an Audouin's gull specialist. The relative high values of species richness and diversity of the helminth infracommunities are comparable to those of other gulls (Larus philadelphia, Larus canus), probably reflecting the specialized, nonselective fish diet of L. audouinii.  相似文献   

2.
Research over the past decade shows that fish populations on coral reefs can vary enormously, both spatially and temporally. Nonetheless, predictable patterns in structure are present at both small and regional scales. These have usually been interpreted as resulting from processes acting after settlement of fishes from the plankton. However, current research now suggests that planktonic processes could also result in deterministic patterns of community structure.  相似文献   

3.
The morphology of young stages of Eupolymnia nebulosa (Montagu, 1818) is observed using SEM. Significant changes occur at several times after egg laying. The transition from endotrophy to exotrophy takes place when the larvae are about 13–15 days old. At the same time, the primary tentacle appears as a hemispherical bud; the first setae to emerge are transitory and club-shaped. They are shed when the larvae are about 50 days old. Observations on the development of the uncinigerous torus of the 11th segment (the first one bearing uncini with the main fang in an alternated direction) indicate that the uncini appear at the dorsal extremity of the torus and then move toward the medio-ventral axis as they increase in size. The uncini are shed when they reach the ventral extremity of the torus. These changes may result in taxonomic confusions unless the complete sequence of development is known.  相似文献   

4.

Background

Ciguatera is a type of fish poisoning that occurs throughout the tropics, particularly in vulnerable island communities such as the developing Pacific Island Countries and Territories (PICTs). After consuming ciguatoxin-contaminated fish, people report a range of acute neurologic, gastrointestinal, and cardiac symptoms, with some experiencing chronic neurologic symptoms lasting weeks to months. Unfortunately, the true extent of illness and its impact on human communities and ecosystem health are still poorly understood.

Methods

A questionnaire was emailed to the Health and Fisheries Authorities of the PICTs to quantify the extent of ciguatera. The data were analyzed using t-test, incidence rate ratios, ranked correlation, and regression analysis.

Results

There were 39,677 reported cases from 17 PICTs, with a mean annual incidence of 194 cases per 100,000 people across the region from 1998–2008 compared to the reported annual incidence of 104/100,000 from 1973–1983. There has been a 60% increase in the annual incidence of ciguatera between the two time periods based on PICTs that reported for both time periods. Taking into account under-reporting, in the last 35 years an estimated 500,000 Pacific islanders might have suffered from ciguatera.

Conclusions

This level of incidence exceeds prior ciguatera estimates locally and globally, and raises the status of ciguatera to an acute and chronic illness with major public health significance. To address this significant public health problem, which is expected to increase in parallel with environmental change, well-funded multidisciplinary research teams are needed to translate research advances into practical management solutions.  相似文献   

5.
This paper reports the relationship among pico-, nano- and microplanktoniccommunities observed in two different shallow marine hydrothermalenvironments. Seawater samples from five stations in the coastalarea of the ‘Porto di Levante’ (Vulcano Island)and from three stations off the Island of Panarea (Eolian Islands,Italy) were collected in May and July of 1989, respectively.Microbiological investigations were carried out in order todetermine the density of: (i) the total picoplankton (both autotrophicand heterotrophic): (ii) the total picophytoplankton (autofluorescentpicoplanktonic cells); (iii) the larger phytoplankton (>2µm): (iv) the ‘metabolically active’ cellsof total picoplankton and cyanobacteria; (v) the heterotrophicaerobic bacteria. The peak values of picoplankton and picophytoplanktoncomponents, with an order of magnitude of 109 and 107 cells11, respectively, were registered in the wannest water samples(30–75°C) collected from the Vulcano area. At Panarea.eukaryotic picophytoplankton and ‘metabolically active’coccoid cyanobacteria showed an opposite trend. A possible competitionbetween the two groups is to be considered. Cyanobacteria, diatomsand the genus Licmophora. in particular, were prevalent in thewarmest hydrothermal vents of Vulcano. Nano- and microphytoplanktoniccommunities in the offshore waters of the Island of Panareashowed more variability than in Vulcano. Moreover, in the Panareawaters the prevalence of phytoflagellates above the thermoclinewas observed, whereas diatoms were predominant below this layer.  相似文献   

6.
The authors' names were presented incorrectly making it appearthat there were three authors. The two authors' names are M.LucilaC.Acosta Pomar and Giovanni GiuffrÈ  相似文献   

7.
Eleven Diplectanidae (Monogenea) gill parasites from various Sparidae and Serranidae of the Kerkennah Islands are noted. Three new species: Lamellodiscus hilii, L. bidens, L. impervius, parasites of Puntazzo puntazzo (Sparidae) are described.  相似文献   

8.
2012年11月—2013年9月对浙江沿海七星列岛省级海洋特别保护区的鸟类资源进行了调查,共记录到鸟类42种,隶属于6目17科28属,其中留鸟8种,占19.05%,夏候鸟10种,占23.81%,冬候鸟21种,占50.00%,旅鸟3种,占7.14%;从区系特征上看东洋种和古北种混杂分布,以东洋种为主;国家Ⅱ级重点保护动物3种,浙江省重点保护动物5种;列入濒危野生动植物种国际贸易公约附录Ⅰ1种和附录Ⅱ2种;列入《中国物种红色名录》濒危种类1种,易危种类1种,近危种类2种;中日候鸟保护协定种类21种,中澳候鸟保护协定种类6种。七星列岛地处太平洋西海岸,是迁飞候鸟的中间停歇站,具有非常重要的保护价值。  相似文献   

9.
Out of 29 species of fish from the Kerkennah Islands examined, 30 species of parasitic copepoda were collected which belong to seven families and nine different genera. Among them three new species have been found and ten were reported for the first time in Tunisia.  相似文献   

10.
Larval development from the early stages to metamorphosis ofthe Pleuronectiform Citharus linguatula is described and illustratedfor the first time; until now only its eggs and newly hatchedlarvae were known. The specimens used in this study were collectedon plankton samples taken from the Catalan continental shelf(western Mediterranean) on two surveys made in September andOctober 1983. The descnption of larval development includesmorphological and morphometnc characters and pigmentation. Relationshipsbetween various parts of the body and standard length duringdevelopment are also considered. Information of their seasonaland spatial distribution along the studied area is provided.  相似文献   

11.
Long-eared bats of the genus Plecotus are widespread and common over most of the western Palaearctic. Based on recent molecular evidence, they proved to represent a complex of several cryptic species, with three new species being described from Europe in 2002. Evolutionary relationships among the different lineages are still fragmentary because of the limited geographic coverage of previous studies. Here we analyze Plecotus mitochondrial DNA sequences from the entire Mediterranean region and Atlantic Islands. Phylogenetic reconstructions group these western Palaearctic Plecotus into two major clades which split at least 5 Myr ago and that are each subdivided into further subgroups. An 'auritus group' includes the traditional P. auritus species and its sister taxon P. macrobullaris (=P. alpinus) plus related specimens from the Middle East. P. auritus and P. macrobullaris have broadly overlapping distributions in Europe, although the latter is apparently more restricted to mountain ranges. The other major clade, the 'austriacus group,' includes the European species P. austriacus and at least two other related taxa from North Africa (including P. teneriffae from the Canary Islands), the Balkans and Anatolia (P. kolombatovici). The sister species of this 'austriacus group' is P. balensis, an Ethiopian endemic. Phylogenetic reconstructions further suggest that P. austriacus reached Madeira during its relatively recent westward expansion through Europe, while the Canary Islands were colonized by a North African ancestor. Although colonization of the two groups of Atlantic Islands by Plecotus bats followed very distinct routes, neither involved lineages from the 'auritus group.' Furthermore, the Strait of Gibraltar perfectly segregates the distinct lineages, which confirms its key role as a geographic barrier. This study also stresses the biogeographical importance of the Mediterranean region, and particularly of North Africa, in understanding the evolution of the western Palaearctic biotas.  相似文献   

12.
The different components of the benthic community of a sandy microtidal beach (Arenzano) in Liguria (NW Mediterranean) were investigated during late spring (May) 2002 and 2003. Sampling was carried out in two transects, chosen in order to represent the characteristics of the entire beach and their eventual spatial variations. Each transect included two stations: one placed in the swash zone (SW) and one in the surf zone (SF). Although no significant differences were found in the sediment texture over the 2 years (t-tests p > 0.1 for all the granulometric fractions), notwithstanding an increase in the mean grain size (from 0.8 to 1.1 mm) between the sampling periods, 2002 was characterised by a higher quantity of organic matter (on average 14.4 vs. 3.6 gC m−2 for the sum of proteins, carbohydrates and lipids) and higher bacterial biomass (on average 1.9 vs. 0.9 gC m−2). The metazoan assemblages (meiofauna and macrofauna) were also richer (density = 2.9 × 105 vs. 1.0 × 105 ind. m−2, biomass = 0.09 vs. 0.03 gC m−2 for meiofauna; density = 1988 vs. 739 ind. m−2, biomass = 0.14 vs. 0.03 gC m−2 for macrofauna) in 2002. A significant quantitative reduction (t-test for proteins, carbohydrates and lipids, at least p = 0.004) in the food supply in 2003 affected the abundance of the metazoans, as confirmed by a multivariate analysis that clearly differentiated the 2 years, and seemed to inhibit their relationships within the benthic food web. The bacterial biomass was always dominant, even under the least favourable trophic conditions, due to the ability of bacteria to adapt to a very harsh environment. Our results suggest that the food supply played an important role in the benthic community structures of the beach during late spring, bacteria being the key organisms within the benthic system. The communities seemed to be bottom-up controlled, while predation seemed to be irrelevant.  相似文献   

13.
14.
Abstract

Encysted larval horsehair worms (Phylum Nematomorpha) were recovered from the tissues of upland bullies (Gobiomorphus breviceps) and a galaxiid (Galaxias vulgaris) from the Seaward River, Canterbury. The cysts were mostly in the alimentary submucosa. A few occurred in the liver. An adult digenean fluke (Coitocaecum sp.), parasitic within the gut of a bully, also contained nematomorph larvae in its tissues. It is suggested that the fish became infected by eating nematomorph larvae or egg strings.  相似文献   

15.
Generalized linear models were used to test the effect of fish, using ponds with and without fish and habitat features as covariates, on richness and abundance of amphibian species. Five fish species and six amphibian species were recorded in 60 permanent ponds located in central Italy. The choice of covariates (macrophyte cover and pond surface area) was made after studying the correlations. The richness of amphibian species was not significantly affected by fish presence or macrophyte cover, in line with previous studies, since almost all the fish species were non-predatory. However, abundance of urodeles (newts) was negatively affected by fish and positively affected by macrophyte cover. Although fish may strongly influence the abundance and composition of amphibian communities, the results indicate that the cover of aquatic macrophytes may increase the available habitat for amphibians and therefore their abundance. Anuran species preferred ponds where fish were present, since both groups preferred larger ponds. Concordance between fish and amphibian species composition was not found by the Mantel and Partial Mantel tests. This indicates that the fish assemblages do not predict which amphibian species occur in the pond.  相似文献   

16.
An episode of parasitic enteritis causing trickling mortalities at an exhibition aquarium reproducing Mediterranean ecosystems was found to be caused by the myxozoan parasite Myxidium leei Diamant, Lom & Dykova 1994. The myxozoan was recorded in 25 different fish species belonging to 16 Genera, 10 Families and 4 Orders. It was mainly detected in the intestine of affected fish, and was responsible for severe chronic enteritis. The parasite was probably introduced into the facilities with infected wild fish, and transmitted directly from fish to fish by cohabitation, transfer of infected material and necrophagia. Fish belonging to the Families Labridae and Blenniidae appeared as most susceptible, and the incidence of infections in members of the Sparidae was low. This study significantly widens the host spectrum for this virulent parasite and now includes many ubiquitous coastal Mediterranean species. Wild fish may have a significant role in the transmission of myxidiosis of cultured sparid fish.  相似文献   

17.
Based on seven larvae from northern Australia, development ofCentrogenys vaigiensis—a species of uncertain phylogenetic affinities—is described for the first time. Identification was established from meristic and osteological characters. Development is characterized by few morphological specializations and is apparently completed at a small size (ca 5 mm standard length). Larvae are deep-bodied and compressed, with very limited head spination (small spines on preopercle, subopercle, opercle and supracleithrum). Fin development takes place at about the time of notochord flexion, and is complete at about 4.3 mm, with the exception of anal spine three, which does not fully transform from a soft ray until after settlement. Fin spines are short, smooth and weak. Larvae are apparently limited to near-shore, shallow marine waters, and based on the size of what are apparently settlement-stage larvae, the pelagic period may be short.  相似文献   

18.
Microphytoplankton and zooplankton composition and distributionin the vicinity of the Prince Edward Islands and at the Sub-antarcticFront (SAF) were investigated in late austral summer (April/May)1996. Samples were collected for analysis of chlorophyll a concentration(Chi a), microphytoplankton and zooplankton abundance. Generally,the highest Chl a concentrations (up to 2.0 µg l–1)and zooplankton densities (up to 192 ind. m–3) were recordedat stations within the inter-island area while the lowest values(<0.4 µg l–1) were observed at stations upstreamof the islands. High Chl a and zooplankton biomass values werealso associated with the SAF. Microphytoplankton were dominatedby chain-forming species of the genera Chaetoceros (mainly C.neglectus),Fragilariopsis spp. and the large diatom Dactyliosolen antarcticus.The zooplankton assemblages were always dominated by mesozooplanktonwhich at times contributed up to 98% of total zooplankton abundanceand up to 95% of total biomass. Among mesozooplankton, copepods,mainly Clausocalanus brevipes and Metridia lucens numericallydominated. Among the macrozooplankton euphausiids, mainly Euphausiavallentini, E.longirostis and Stylocheiron maximum, and chaetognaths(Sagitta gazellae) accounted for the bulk of abundance and biomass.Cluster and ordination analysis did not identify any distinctbiogeographic regions among either the microphytoplankton orzooplankton.  相似文献   

19.
Mesopelagic fish assemblages were investigated in the Polar Frontal Zone off the Kerguelen Islands during summer 1995, in parallel with a king penguin tracking study. During the day, the upper offshore water layers (0–200 m) have low potential prey diversity and abundance with only three fish species: a lanternfish, Krefftichthys anderssoni, a member of the Muraenolepididae, Muraenolepis marmoratus, and the early stages of the nototheniid, Lepidonotothen squamifrons. The mesopelagic fish community, including the typical myctophids, first appears in the deeper layer (300 m). At night, the surface layer (50 m) is invaded by the mesopelagic Myctophidae Electrona antarctica, Gymnoscopelus braueri, G. piabilis, G. fraseri, G. nicholsi, Protomyctophum bolini and P. tenisoni. Deeper (>100 m), a cline of species assemblages from the coast to offshore is observed. Accepted: 4 August 1999  相似文献   

20.
Labropoulou  M.  Papaconstantinou  C. 《Hydrobiologia》2000,440(1-3):281-296
The spatial structure and seasonal changes of the demersal fish assemblages on the continental shelf (100–200 m) and upper slope (200–500 m) in the North Aegean Sea (Northern Aegean and Thracian Seas, northeastern Mediterranean, Greece) were analysed. Seasonal experimental trawl surveys, carried out from summer 1990 to autumn 1993, provided a total of 151 demersal fish species. Analysis of 259 bottom trawls showed the existence of four groups associated with the continental shelf and the upper slope; each group was dominated by a small number of species. The bathymetric distribution of the species, established using measures of the centre of gravity and habitat width, revealed that most of the species had a wide distributional range within the study area, although a few were restricted to the greatest depths. Density, biomass, species richness and diversity decreased significantly with depth, and were also indicative of distinctive characteristics between these fish assemblages. Mean fish weight exhibited two different trends: a bigger-deeper phenomenon at the continental shelf and a smaller-deeper phenomenon at the upper slope. The variability in assemblage structure was determined mainly by depth and, to a lesser extent, by season and geographical location. For some species, results suggest a pattern of gradual species replacement along the depth gradient coupled with ontogenetic habitat shifts.  相似文献   

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