Camallanus cotti Fujita, 1927 (Nematoda, Camallanoidea) in ornamental aquarium fishes: pathology and morphology

The pathology induced by the nematode Camallanus cotti in the aquarium fishes Beta splendens (beta fish) and Poecilia reticulata (guppy) consisted of gross and microscopic lesions, the former characterized by abdominal swelling with reddish parasites protruding from the anus in both fish hosts and the latter, similar in the beta fishes and guppies, by hemorrhage, congestion, edema, a few glandular elements, and extensive erosion areas in the rectum mucosa, with a marked thickening of the wall and absence of inflammatory infiltrate. Lesions were associated with the presence of several worms attached to the wall or free in the rectal lumen. This is the second reference of the parasite in Brazil and the first report of pathological findings related to this nematode species that is also briefly redescribed and illustrated for the first time on the basis of Brazilian samples.     

Introduction history of non-native freshwater fish in Okinawa-jima Island: ornamental aquarium fish pose the greatest risk for future invasions

We examined the introduction history of non-native freshwater fish in Okinawa-jima Island, Japan, to identify the pathway posing the greater risk for future invasions and to measure the strength of ornamental fish introductions as a vector of new invasions using all available records of freshwater fish introductions to date. At least 45 non-native freshwater fish have been introduced to Okinawa-jima Island. Of those, 22 species have successfully established in natural waters and, consequently, non-native fish species represent 76 % of the total freshwater fish fauna. The most important pathway was via the dumping of unwanted ornamental aquarium fish, which accounted for 71 % of the total introductions. The introduction of ornamental fish has occurred extensively in recent decades, and all fish introduced since the 1980s have been ornamental aquarium fish. The overall rate of establishment success was estimated at 51 %, although this is undoubtedly an overestimate because of unreported failed introductions. Establishment rates varied between stocked fish (100 %) and dumped ornamental fish (39 %), which may reflect the low propagule pressure of ornamental fish. From the observed trends in freshwater fish introductions, the dumping of ornamental fish into natural waters is expected to continue if no action is taken to reduce this most important pathway. We recommend regulations against the release of unwanted pet fish into natural waters, better programs for returning unwanted pet fish to stores or local zoos, educational programs for aquarists and retailers, and regulations against selling and trading ornamental fish that are judged to pose a high risk of causing economic or ecological harm.     

Revealing the appetite of the marine aquarium fish trade: the volume and biodiversity of fish imported into the United States

The aquarium trade and other wildlife consumers are at a crossroads forced by threats from global climate change and other anthropogenic stressors that have weakened coastal ecosystems. While the wildlife trade may put additional stress on coral reefs, it brings income into impoverished parts of the world and may stimulate interest in marine conservation. To better understand the influence of the trade, we must first be able to quantify coral reef fauna moving through it. Herein, we discuss the lack of a data system for monitoring the wildlife aquarium trade and analyze problems that arise when trying to monitor the trade using a system not specifically designed for this purpose. To do this, we examined an entire year of import records of marine tropical fish entering the United States in detail, and discuss the relationship between trade volume, biodiversity and introduction of non-native marine fishes. Our analyses showed that biodiversity levels are higher than previous estimates. Additionally, more than half of government importation forms have numerical or other reporting discrepancies resulting in the overestimation of trade volumes by 27%. While some commonly imported species have been introduced into the coastal waters of the USA (as expected), we also found that some uncommon species in the trade have also been introduced. This is the first study of aquarium trade imports to compare commercial invoices to government forms and provides a means to, routinely and in real time, examine the biodiversity of the trade in coral reef wildlife species.     

Cytotaxonomic characteristics of the genus Glyptotendipes Kieffer (Chironomidae, Diptera) from fish and retention ponds (Silesia, southern Poland)

The cytotaxonomic characteristics of species of the genus Glyptotendipes (Chironomidae): G. glaucus Meigen, G. paripes Edwards, and G. barbipes (Staeger) are described. The studied material was collected from a fish pond at Go?ysz and a sewage retention pond at Chybie in Silesia. All the studied species have the chromosome set 2n = 8, but with many specific structural and functional changes. The cytogenetic data of G. glaucus showed that the studied specimens of this species have been produced by the introgressive hybridization of two sibling species: G. glaucus x G. pallens, and subsequent crossing-over in the hybrid chromosome CD. Owing to this process, the band pattern of chromosome arm D coincided with those of G. pallens. New aberrations (homo- and heterozygous deletions in arm G as well as heterozygous inversions in chromosome arm B) were detected in G. glaucus. Specific band sequences were discovered in chromosomes of G. paripes. The band patterns established in chromosomes AB and G of this species were identical with those of Siberian populations. The banding patterns of the polytene chromosomes of G. barbipes do not differ from the standard. However, high frequency of pericentric inversion of chromosome AB was established. Many new puffs were found in the polytene chromosomes of all the studied species. Their nucleolar organizer was very sensitive to environmental changes. In G. glaucus it appeared in three different states: very active, slightly active, and heterozygous state. The organic pollution existing in the sewage retention pond may contribute to possible mutations and chromosomal damage in Glypotendipes species. Structural and functional rearrangements of the polytene chromosomes of these species mobilized their genomes and provide for survival under polluted conditions.     

Emergence of the damselfly Pyrrhosoma nymphula (Sulzer) (Zygoptera: Coenagrionidae) from two adjacent ponds in northern England

Emergence of the damselfly Pyrrhosoma nymphula was followed closely at two similar and adjacent ponds in northern England. Males emerged earlier than females at both ponds (significantly so at one). The sex ratio was significantly male biased at both ponds. Size of emerging adults declined through the emergence period at both ponds. Adults emerging from one pond did so significantly earlier and were significantly larger than those from the other pond. The density of larvae was approximately twice as high in the pond from which larvae emerged early; this pond was also slightly deeper and usually achieved higher maximum daily water temperatures. These findings are discussed in the light of the conventional view of seasonal regulation in a spring-emerging damselfly.     

An experiment on the culture of Tilapia esculenta (Graham) and Tilapia zillii (Gervais) (Cichlidae) in fish ponds

Segregated populations of Tilapia zillii and Tilapia esculenta were kept in artificial ponds. Supplementary food was given and phytoplankton was encouraged by the addition of superphosphate and ammonium sulphate fertilisers. The fry were cropped regularly in an attempt to control population size. A control population of T. zillii was also established in which none of these procedures were carried out.
The growth of T. esculenta was found to be dependent upon the phytoplankton density of the pond whilst T. zillii successfully utilized the supplementary food and grew well. The T. esculenta population also produced more fry than the T. zillii population. The comparative advantages of planktrvorous/brooders and herbivorous/guarders in fish culture are considered.
Despite the fecundity of the species used a population of known composition was maintained by manual cropping of the fry.
The addition of ammonium sulphate to the ponds caused blooms of phytoplankton which in turn had effects upon the base reserves and pH of the water, and probably caused some reduction of oxygen concentration beneath surface scums. This last point is used to explain the changes in phosphate and calcium content of the water also observed.
The low oxygen concentration frequently noted in the mornings probably affected the feeding behaviour of the fishes, and was low enough to have affected metabolism directly.     

A new psittaciform bird from the London Clay (Lower Eocene) of England

A new psittaciform bird from the Lower Eocene (Ypresian) London Clay of England is described. This taxon, Pulchrapollia gracilis gen. et sp. nov., is assigned to the order Psittaciformes (parrots) on the basis of several distinctive structures of the tarsometatarsus, namely the trochlea for metatarsal III (trochlea metatarsi III) bearing a tubercle on its lateral side and the trochlea for metatarsal IV (trochlea metatarsi IV) completely retroverted (fully zygodactyl foot). Comparisons with other fossil and Recent taxa further support this conclusion. Cladistic analysis shows that Pulchrapollia is the sister-taxon of the single extant family within Psittaciformes, the Psittacidae. Palaeopsittacus georgei, a taxon previously described from the London Clay, is most likely based on some unassociated material and is regarded here as incertae sedis.     

Bottlenecks and multiple introductions: population genetics of the vector of avian malaria in Hawaii

Avian malaria has had a profound impact on the demographics and behaviour of Hawaiian forest birds since its vector, Culex quinquefasciatus the southern house mosquito, was first introduced to Hawaii around 1830. In order to understand the dynamics of the disease in Hawaii and gain insights into the evolution of vector-mediated parasite-host interactions in general we studied the population genetics of Cx. quinquefasciatus in the Hawaiian Islands. We used both microsatellite and mitochondrial loci. Not surprisingly we found that mosquitoes in Midway, a small island in the Western group, are quite distinct from the populations in the main Hawaiian Islands. However, we also found that in general mosquito populations are relatively isolated even among the main islands, in particular between Hawaii (the Big Island) and the remaining Hawaiian Islands. We found evidence of bottlenecks among populations within the Big Island and an excess of alleles in Maui, the site of the original introduction. The mitochondrial diversity was typically low but higher than expected. The current distribution of mitochondrial haplotypes combined with the microsatellite information lead us to conclude that there have been several introductions and to speculate on some processes that may be responsible for the current population genetics of vectors of avian malaria in Hawaii.     

The seasonal periodicity of emergence of insects from two ponds in Hertfordshire,England, with special reference to the chironomidae (Diptera: Nematocera)

The onset, duration and periodicity of emergence of insect species, principally chironomids, caught in floating emergence-traps from two ponds in southern England, are given and compared with emergence data from other sites.     

Turbidity generation and biological impacts of an exotic fish Carassius auratus, introduced into shallow seasonally anoxic ponds

Over the last decade, goldfish Carassius auratus L., have been introduced into lakes and ponds in the Montreal region. Controlled experiments compared the impact of goldfish in both mud-and gravel-bottomed outdoor pools, with either caged or non-caged vegetation. High levels of turbidity were generated by foraging goldfish in mud pools (P<0.01). All non-caged submersed plants ( Potamogeton ) showed extensive grazing damage and all of the unprotected submersed and emergent forms were uprooted. Data from Stoneycroft pond where a feral goldfish population reached 15–17 000 individuals ha^-1, confirmed the experimental findings showing goldfish to be benthic herbivores, causing a visible increase in turbidity and decrease in aquatic vegetation. Gut analysis revealed goldfish to have little diet overlap with native amphibians. High turbidity should reduce the success of predators feeding on goldfish, and may decrease the foraging success of other competitors. The sporadic distribution of goldfish in Canada may be linked to site characteristics, specifically the susceptibility of the area to turbidity generation.     

Maturity and gonad changes of Oreochromis (Nyasalapia) karongae raised in fish ponds in Malawi

The reproductive biology of pond-raised Oreochromis (Nyasalapia) karongae was investigated. Gonad histology and gonadosomatic indices (GSIs) indicated a potential for multiple spawning in a season. Several peaks of oocyte-size distribution and several maturation stages occurred in the same gonad. GSIs of 2.5% and 1.4% were recorded in female and male fish, respectively. Three stages of oocyte maturation (primary growth, formation of yolk vesicles, vitellogenesis) and three stages of sperm development (spermatogonia, spermatid, spermatozoa) were observed. With the exception of the final maturation stage, all development phases seemed to proceed satisfactorily. The final stage of maturation was attained at oocyte size of 2.70 ± 0.54 mm and was selectively impaired in some female fish by a lack of deposition of vitellogenin. This abnormal condition led to atrophic oocytes lacking yolk granules and vesicles. Sexual maturation was attained at a relatively large size of 16.0 cm (114 g) compared with other tilapia of the mossambicoid group (i.e. Oreochromis mossambicus and Oreochromis shiranus ). A combination of gravimetric and histological techniques was successful in charting gonad changes and calibrating external against internal gonad features.     

Origins and introductions of the Caribbean frog, Eleutherodactylus johnstonei (Leptodactylidae): management and conservation concerns

Johnstone's Whistling Frog, Eleutherodactylus johnstonei, is a highly successful colonizer that has become widely distributed throughout the Caribbean region. It has been introduced both purposefully and unintentionally by humans, and it continues to expand its range locally and regionally. Its current distribution and recent expansion do not support the hypothesis that E. johnstonei is expanding into new habitats exclusively by outcompeting native species. Instead, its range expansion progresses mainly parallel to human expansion (habitat disturbance through land development) and extreme climatic events (habitat disturbance through hurricanes and volcanism). Once a habitat has been disturbed and E. johnstonei has arrived, any previously existing endemic Eleutherodactylus species tend not to be found again at their previous ranges or population densities. The most probable explanation for this is that the broader physiological tolerance of the ecological generalist E. johnstonei allows it to become permanently established in a disturbed biota, whereas ecologically specialized endemics are prevented from recolonizing such habitats. Invasion of E. johnstonei can result in a parapatric distribution with endemics (e.g. E. euphronides, E. shrevei) or in sympatry (e.g. E. martinicensis), and habitats include areas with widely divergent climatic conditions (e.g. xeric: Anguilla, Barbuda; mesic: Grenada, St Vincent). Management for this species includes prevention of further or repeat introductions, close monitoring of ranges, and preservation of native habitats to ensure survival of local endemics.     

Wild caught ornamental fish: a perspective from the UK ornamental aquatic industry on the sustainability of aquatic organisms and livelihoods

The ornamental aquatic industry involves the global commercial trade of live aquatic organisms such as fish, invertebrates and plants. It comprises a range of businesses including collectors, breeders, exporters, importers and retailers. Together, these form a supply chain through which aquatic organisms pass from their point of origin to the end point e.g., domestic aquaria and ponds. On a worldwide basis, the legal and legitimate ornamental aquatic trade is subject to regulation and monitoring throughout the majority of its supply chain. Approximately 90% of ornamental freshwater fish species traded are captive-bred, but, due to their complex breeding cycles, 90–95% of ornamental marine fish species are wild-caught. The ornamental aquatic industry and consumers therefore have a responsibility to ensure that wild-caught species are sourced sustainably, legally and to good welfare standards. Such good practice should be considered a necessity for the longevity, not only of the ornamental aquatic industry, but of the livelihoods which depend on it and the future of ecosystems dependent on such communities.     

Enzymatic Pathways for the Consumption of Carbonyl Sulphide (COS) by Higher Plants*

Carbonyl sulphide (COS) is an important trace gas of the atmosphere. Considerable uncertainties remain concerning the global sinks of COS. Vegetation is believed to be an unqualified sink in the global cycle of COS. We investigated whether there is an enzymological background for the consumption of COS by higher plants in analogy to CO₂. Photometric measurements demonstrated that all enzymes involved in C0₂ assimilation by higher plants can also metabolise COS. The key enzyme for COS metabolism in higher plants is carbonic anhydrase, an enzyme which probably directly splits COS into C0₂ and H₂S. Such a pathway would explain the observed deposition of COS to vegetation.     

Colonization of a newly constructed urban wetland by mosquitoes in England: implications for nuisance and vector species

Urban wetlands are being created in the UK as part of sustainable urban drainage strategies, to create wetland habitats lost during development, to provide a habitat for protected species, and to increase the public's access to ‘blue‐space’ for the improvement of health and well‐being. Sewage treatment reedbeds are also being incorporated into newly constructed wetlands to offer an alternative approach to dealing with sewage. This field study aims to provide the first UK evidence of how such newly constructed aquatic habitats are colonized by mosquitoes. A number of new aquatic habitats were surveyed for immature mosquitoes every fortnight over the first two years following wetland construction. The majority of mosquitoes collected were Culex sp. and were significantly associated with the sewage treatment reedbed system, particularly following storm events and sewage inflow. Other more natural aquatic habitats that were subject to cycles of drying and re‐wetting contributed the majority of the remaining mosquitoes colonizing. Colonization of permanent habitats was slow, particularly where fluctuations in water levels inhibited emergent vegetation growth. It is recommended that during the planning process for newly constructed wetlands consideration is given on a case‐by‐case basis to the impact of mosquitoes, either as a cause of nuisance or as potential vectors. Although ornithophagic Culex dominated in this wetland, their potential role as enzootic West Nile virus vectors should not be overlooked.     

Spawning of the Australian freshwater fish Murray cod, Maccullochella peeli (Mitchell), in earthen ponds

Murray cod, Maccullochella peeli , spawned naturally in earthen ponds in four consecutive breeding seasons. Spawning was induced by a rise in water temperature up to or above 20°C during spring, however, an associated rise in water level was not required. Response to the temperature rise was more rapid later in the season and increasing daylength may have also been involved. Eggs were deposited on firm substrates at depths between 0·5 and 2·3 m, and hollow pipes, logs or similar structures were not necessary to provide suitable sites for egg deposition. At two spawning sites, mud had been removed from the pond banks by the broodfish and the eggs attached to the exposed clay. At one spawning site, a male cod was observed protecting the eggs during incubation.
It is suggested that high survival of cod larvae will only occur when a significant rise in water level coincides with the breeding season and as a consequence the control of water levels for irrigation and flood mitigation purposes during spring and summer has affected Murray cod to a greater extent than golden perch, Macauaria ambigua , which spawns only after a substantial rise in water level, when conditions are more favourable for larval survival.