43,264 research outputs found
Age composition, growth, and reproduction of koi carp (Cyprinus carpio L.) in the lower Waikato, New Zealand
No full textA total of 566 koi carp (Cyprinus carpio) from the lower Waikato region were aged from scales and opercular bones, and growth was modelled with the von Bertalanffy growth function. There was no difference in growth rate between male and female carp. Growth of koi carp between zero and 3 years of age was lower than that of common carp in Europe and Australia. However, after 5 years of age the growth of koi carp was higher than that of common carp in Europe, but still below that of carp in Australia. Males rarely lived in excess of 8 years, whereas females lived to 12 years. Mean total fecundity calculated from 44 running-ripe females was 299 000 oocytes (±195 600 SD) (range 29 800–771 000). Relative fecundity ranged from 19 300 to 216 000 oocytes kg–1 total body weight, with a mean of 97 200 (±35 000 SD) oocytes kg–1. Feral koi carp in the Waikato are capable of multiple spawnings within their lifetimes. Within a spawning season, Waikato populations of feral koi carp contained females that spawned once, and females that had the potential to have spawned repeatedly. Female gonadosomatic index (GSI) varied with season and was negatively related to water temperature
Determining and testing the optimal pure-tone frequency for use in acoustic conditioning of free-ranging common carp (Cyprinus carpio)
No full textPure-tone frequencies of 400, 700, and 1000 Hz were tested to determine which achieved the strongest response when used in conditioning experiments on captive common carp (Cyprinus carpio) for the purpose of determining the most effective frequency to use in conditioning experiments on free-ranging common carp. Captive common carp were shown to have the strongest response to the 400 Hz frequency after training that associated sound with food. Response was quantified as moving into a feeding arena when the sound was broadcast, and all frequencies achieved conditioning within five days. Secondly, the attenuation of the three frequencies were compared in a Waikato lake (Lake Kaituna) containing common carp. The ability to maintain signal strength over distance is necessary for frequencies used in the acoustic conditioning of free-ranging common carp due to the potentially large distances involved. Attenuation of the 400 Hz and 700 Hz pure tone frequencies were not significantly different but were both lower than that of the 1000 Hz frequency. The 400 Hz pure tone frequency was used in subsequent experiments on the acoustic conditioning of free-ranging common carp in Lake Kaituna because of superior performance in acoustic conditioning of captive common carp and low attenuation in a natural water body containing free-ranging common carp,. Thirdly, the 400 Hz pure tone was evaluated for its ability to be associated with food by free-ranging common carp. Capture rates at treatment sites where 400 Hz pure tone was broadcast compared to control sites where no sound was broadcast following a five-day training phase and 24 h of no sound or food, were 2.1 times greater during a three-day capture phase. This study demonstrates the trainability of common carp, a trait that can be used to improve control of wild common carp populations
Fumagillin, an efficacious drug against renal sphaerosporosis of the common carp Cyprinus carpio
No full textAt present no reliable and efficacious drugs are available for treating fish diseases caused by myxosporeans. By feeding Fumagillin DCH salt in the diet, the authors achieved very promising results in controlling renal sphaerosporosis, one of the commonest myxosporean parasitoses of common carp Cyprinus carpio. Intraperitoneal injection of Sphaerospora renicola stages developing in the
swimbladder produced sphaerosporosis only in control groups, whereas in fish consuming 0.1 % fumagillin no infection developed. Farm-pond experiments also gave promising results: in fumagillintreated common carp fry a much milder sphaerosporosis developed, both in prevalence and intensity,
than in control fish
An investigation of koi carp (Cyprinus carpio) movement in the Waikato region using laser ablation otolith microchemistry
No full textThe koi carp Cyprinus carpio is an invasive fish that has reached high numbers and biomass in the North Island of New Zealand, particularly in the Waikato region. This species has a variety of negative effects on aquatic ecosystems, increasing turbidity, uprooting aquatic macrophytes, and affecting water column
nutrient levels. Recent research in Australia and New Zealand has shown that adult carp, though largely restricted to small scale movements, are capable of moving long distances. Movement in adult carp may be underestimated by these studies, and comparatively little is known about the movement of smaller carp. This study examined the feasibility of using laser ablation otolith microchemistry to track koi carp movement and identify spawning areas.
Water samples from six locations (Lake Waahi, Lake Whangape, Lake Waikare, the Whangamarino River, and the Waikato River at Aka Aka and Rangiriri) were analysed using inductively coupled plasma mass spectrometry (ICP-MS).
Significant differences between sites were found in the water concentrations of many elements. Koi carp were collected from the above locations, as well as from Opuatia Stream, Pungarehu Stream, the Maramarua River and Lake Hakanoa. The elemental concentrations in the asteriscus otoliths were analysed using laser ablation inductively coupled plasma mass spectrometry (LA‐ICP-MS). Elemental concentrations in the edges and nuclei of adult koi carp and the edges
of young-of-the-year (YOY) koi carp were significantly different between capture sites. No significant differences were found in elemental concentrations between sites in the nuclei of YOY koi carp.
A discriminant function analysis (DFA) was carried out using the otolith edge
elemental signatures of koi carp. The model used Ba, Sr, Mg, Rb and Zn concentrations to differentiate between four capture locations: the Waikato River, Pungarehu Stream, Lake Waahi, and Lake Waikare and Pungarehu Stream. The DFA was able to correctly predict the capture location of 82% of koi carp using their otolith edge elemental signatures.
The classification functions created using koi carp otolith edge signatures were then used as a training set to classify otolith nucleus signatures. The otolith nuclei of 80% of YOY koi carp were classified to their site of capture, suggesting they had not moved between locations. The majority of adult koi carp caught at Lake Waikare, Whangamarino River, Pungarehu Stream and Opuatia Stream had nucleus signatures matching their capture sites, indicating that these fish
originated from their capture location. Koi carp from other sites likely moved there from another location. The majority of adult koi carp (88%) caught at the Waikato River at Rangiriri had otolith nucleus signatures matching Lake Waikare
and Pungarehu Stream. Adult koi carp caught at Lake Waahi and the Waikato River at Aka Aka had otolith signatures corresponding to a range of locations. While some areas (Lake Waikare, Pungarehu Stream) appear to have resident koi
carp populations that likely originated there, others (Lake Waahi, the Waikato River) appear to have koi carp populations of mixed origin. These results indicate that Lake Waikare, Pungarehu Stream and the Whangamarino River may be
important sources of koi carp recruits in the lower Waikato region
Detecting exploitable stages in the life history of koi carp (Cyprinus carpio) in New Zealand
No full textKoi carp are a highly coloured strain of common carp (Cyprinus carpio L.) and are an invasive alien species to New Zealand. The introduction of koi carp to the lower Waikato River during the 1980s has coincided with a dramatic decline in water quality within the regions riverine lakes. Removing koi carp from riverine lakes may improve water quality and preserve native biodiversity. This study used telemetry to examine the movements and seasonal habitat use of adult koi carp to find key locations to efficiently remove koi carp from the lower Waikato River basin.
Common carp are notoriously difficult to monitor in water temperatures above 20˚C using telemetry due to transmitter expulsion. To prepare for telemetry based field experiments, three tank trials were conducted to determine the most appropriate surgical technique for the implantation and retention of telemetry transmitters in koi carp. To reduce transmitter loss, two methods were initially tested in tank trials including two treatment groups and two control groups of ten adult koi carp. In one treatment, radio transmitters were anchored to the pelvic girdle, and in a second treatment, a polymer coating was applied to acoustic transmitters to reduce tissue irritation. After 365 days, expulsion rates for uncoated acoustic transmitters were 60% (n = 6), coated acoustic transmitters 50% (n = 5), unanchored radio transmitters 60% (n = 6) and anchored radio transmitters 90% (n = 9). Bacterial infection of the wound appears to be the primary mechanism for transmitter expulsion.
To reduce the influence of bacterial infection on transmitter expulsion, a slow-release antibiotic was tested to improve transmitter retention. Dummy acoustic transmitters were implanted in two groups of 20 adult koi carp, an untreated control group, and a group treated with a slow-release, single-dose antibiotic. After 176 days, the rejection rate of control fish (40%, n = 8) was twice that of fish treated with a slow-release antibiotic (20%, n = 4). Although we did not find a statistical difference between test groups, this was likely a function of sample size and we view the results as encouraging, justifying further investigation and use of slow-release antibiotics in koi carp.
Koi carp were monitored on the lower Waikato River using both radio and acoustic telemetry for 18 months. Koi carp migrated throughout the basin and frequently used lateral habitat. At least 74% of fish that were monitored for at least 250 days migrated through the waterways between riverine lakes or wetlands and the Waikato River. Waterways connecting riverine lakes and wetlands to the lower Waikato River are ideal locations to intercept migrating koi carp. Fish released at Lake Whangape occupied a total linear range (TLR) of over 120 km in just 218 days, which represents 71% of the potential in river TLR within the lower Waikato River Basin. Adult koi carp were found to be active year-round, but peak movements occurred during spawning season (October) during both years of the study. With a long-term commitment and thoughtful planning, removing a biologically significant proportion of koi carp biomass from the riverine lakes and wetlands of the lower Waikato River is feasible
Comparison of ovarian cycles of Hungarian riverine fish species representing different spawning strategies
No full textInvestigations on the ovarian cycle of fish species that inhabit Hungarian rivers are necessitated by both environmental and economic reasons. The objective of our research was to explore new fundamental knowledge concerning the ovarian cycle of the white bream (Blicca bjoerkna, Linnaeus, 1758), barbel (Barbus barbus, Linnaeus, 1758), orfe (Leuciscus idus, Linnaeus, 1758) and nase (Chondrostoma nasus, Linnaeus, 1758). Histological investigation of ovaries and determination of proportions of oocytes in different stages of development is an appropriate method for the description of spawning characteristics of these species. Our results show that the GSI value for all four investigated species starts to increase at the end of summer and reaches its maximum before spawning. In the barbel and white bream, the presence of oocytes in the stage of cortical alveoli and the heterogeneous size of oocytes in the stage of vitellogenesis in the pre-spawning period indicate that barbel and white bream are multiple spawners. In contrast, in the orfe and nase, the absence of oocytes in the stage of cortical alveoli and the homogeneous size of cells in the stage of vitellogenesis indicate that orfe and nase are single spawners
Pathological and ecological host consequences of infection by an introduced fish parasite
No full textThe infection consequences of the introduced cestode fish parasite Bothriocephalus acheilognathi were studied in a cohort of wild, young-of-the-year common carp Cyprinus carpio that lacked co-evolution with the parasite. Within the cohort, parasite prevalence was 42% and parasite burdens were up to 12% body weight. Pathological changes within the intestinal tract of parasitized carp included distension of the gut wall, epithelial compression and degeneration, pressure necrosis and varied inflammatory changes. These were most pronounced in regions containing the largest proportion of mature proglottids. Although the body lengths of parasitized and non-parasitized fish were not significantly different, parasitized fish were of lower body condition and reduced weight compared to non-parasitized conspecifics. Stable isotope analysis (δ15N and δ13C) revealed trophic impacts associated with infection, particularly for δ15N where values for parasitized fish were significantly reduced as their parasite burden increased. In a controlled aquarium environment where the fish were fed ad libitum on an identical food source, there was no significant difference in values of δ15N and δ13C between parasitized and non-parasitized fish. The growth consequences remained, however, with parasitized fish growing significantly slower than non-parasitized fish, with their feeding rate (items s−1) also significantly lower. Thus, infection by an introduced parasite had multiple pathological, ecological and trophic impacts on a host with no experience of the parasite
Effects of dietary exposure to zearalenone (ZEN) on carp (Cyprinus carpio L.)
No full textThe mycotoxin zearalenone (ZEN) is frequently contaminating animal feedsincluding feed used in aquaculture. In the present study, the effects of dietary exposure toZEN on carp (Cyprinus carpio L.) were investigated. ZEN at three different concentrations(low dose: 332 μg kg−1, medium dose: 621 μg kg−1 and high dose: 797 μg kg−1 final feed,respectively) was administered to juvenile carp for four weeks. Additional groups receivedthe mycotoxin for the same time period but were fed with the uncontaminated diet for twomore weeks to examine the reversibility of the ZEN effects. No effects on growth wereobserved during the feeding trial, but effects on haematological parameters occurred.In addition, an influence on white blood cell counts was noted whereby granulocytes andmonocytes were affected in fish treated with the medium and high dose ZEN diet. In muscle samples, marginal ZEN and α-zearalenol (α-ZEL) concentrations were detected. Furthermore, the genotoxic potential of ZEN was confirmed by analysing formation of micronuclei in erythrocytes. In contrast to previous reports on other fish species, estrogenic effects measured as vitellogenin concentrations in serum samples were not increased by dietary exposure to ZEN. This is probably due to the fact that ZEN is rapidly metabolized in carp
Fish powder as a low-cost component in media for producing bacterial cellulose
No full textSome bacteria can produce extracellular bacterial cellulose (BC). This polysaccharide is chemically identical to cellulose produced by plants but has no associated lignin and hemicelluloses. The unique mechanical properties, chemical stability and purity allow BC to be exploited for a range of biomedical applications. However, medium costs limit commercial BC production. The suitability of using fish powder as a low-cost media component for producing BC by submerged culture of Gluconacetobacter xylinus in shake flasks was investigated. Fish powder was made by drying and grinding Koi carp (Cyprinus carpio), a pest fish in New Zealand waterways. Fermentations were done at 30oC in a growth medium containing 50 g/L glucose, the required minerals, and either 5 g/L yeast extract or 15 g/L fish powder, The BC yield on both yeast extract and fish powder was 0.04 g/g glucose, demonstrating fish powder was a suitable low cost ingredient for supplying nitrogen and amino acids in the media
Using Koi Carp to Produce Fish Silage
No full textThe natural environment of New Zealand is a highly cherished and important factor of the country. Introduced koi carp is considered a pest in New Zealand because it has a deleterious effect on fresh water systems. Hence eradicating the fish is essential. Identifying possible uses for this captured fish will help offset the cost of eradication. The aim of the study was to identify feasible products that could use koi carp as a raw material without the added impediment that a long term stable supply would not exist once fish numbers had been drastically reduced. The applications identified from a literature search could be categorized into three main groups: as food (for example canned carp); processed non-food uses (for example extracting fish collagen); and miscellaneous applications (such as biofertilizer). Silage production is a simple and cost effective method for using whole koi carp. The process involves mixing thawed minced fish with an acid and keeping it at a particular temperature for a short time. The effect of stirring conditions, pH and temperature was determined in the preliminary laboratory trials. A good silage requires a constant pH between 3.5 and 4.0 throughout the process and needed to be kept at 40°C for four days. Throughout the process the mixture needs to be thoroughly mixed. The main trials investigated the effect of different mineral and organic acids (singly and in combination) and the effect of using kiwifruit pulp as a source of proteolytic enzymes. The combination of hydrochloric acid and acetic acid (50:50 v/v) gave the best silage with high soluble solids content. Adding kiwifruit gave higher soluble solids after 36 h but the proteolytic activity then stopped. The process may need daily additions of green kiwifruit pulp to obtain a good silage. It is recommended that further studies on the biochemical changes during the silage process, the effect of other acid combinations in different proportions, the effect of acid strength, and other sources of exogenous proteolytic enzymes be investigated. It is also recommended that the costs of a commercial process be determined
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