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1.
Abstract. The vulnerability of common carp to angling was studied in a drainable pond of 0–4 ha, stocked near the carrying capacity (700 kg/ha) with known numbers of individually marked carp. The numbers of carp hooked and landed ('caught') by each angler were registered during a period of one month. Landed carp were checked for marks. All carp were returned to the pond. The catch results were analysed with use of a simulation model of a pond fishery. The observed catch and recapture frequencies were compared with the expected values. It was shown that the vulnerability of carp to hooking decreased after one experience with a fish hook. Differences in decreased vulnerability to hooking were found within the carp population. This resulted in unequal recapture sequences for the various groups in the population. Analysis of the growth of carp and the capture data indicated that under the experimental conditions of high stocking density, carp that were more vulnerable to angling showed better growth than carp that avoided the hook after a hook experience. The experiments showed that the decreased vulnerability to the fish hook disappeared when the population was not angled for about one year. The carp acquired the hook avoidance behaviour again after one experience with a hook.  相似文献   

2.
Abstract  Because of low fishing mortality that results from catch-and-release angling for carp, Cyprinius carpio L, it is counterintuitive that voluntary catch-and-release (vC&R) of this species induces conflicts within the angling community. Originally motivated by animal welfare concerns, vC&R is today probably as or more strongly criticised within the angling community itself than it is intersectorally. This study reviews the institutional treatment of C&R in Germany and explores within a sociological conflict model the conflicting views surrounding vC&R, specifically in specialised carp angling. It is argued that the intrasectoral (i.e. among angler groups) conflicts around vC&R fishing may divide the recreational angling community, which in turn may weaken the coherence of the entire angling sector. Restricting the opportunity to practice vC&R also can have important social and biological implications, which suggest a rethinking on the current treatment of vC&R recreational angling in Germany.  相似文献   

3.
A human dimensions investigation into tourist anglers in a coastal recreational fishing hotspot in northern Australia is presented. Tourist anglers target one species, javelin grunter, Pomadasys kaakan (Cuvier), raising concerns about the sustainability of the fishery. Data from a survey of 427 tourist angling parties that fished in the coastal water off Karumba (Queensland) were analysed. Exploratory factor analysis was performed on angler target species and motivation for fishing to establish a typology of fishing intentions, with fishing for food found to be the principal factor. Anglers with high fishing for food factor scores were more consumptive, lower spending (per day) and more averse to any potential measures that might reduce legal possession (creel) limits or impose a cost of fishing. It was concluded that a combination of tourism and fisheries management interventions is required to safeguard Karumba's iconic javelin grunter fishery into the future. Diversification of tourist activity options can reduce the tourism industry's current reliance on high‐consumptive tourist anglers and increase the destination's appeal to non‐fishing tourists and low‐consumptive anglers. Modification of angler behaviour can be achieved through reduced possession limits for javelin grunter and possibly other target species, improved monitoring and law enforcement efforts, and targeted education and information.  相似文献   

4.
Diel rhythmicity of grazing, swimming, resting and social interactions of rohu (Labeo rohita) (weight 66.5–68.3 g) and common carp (Cyprinus carpio) (79.9–82.0 g) were observed in 1 m2 simulated ponds using video images. Fish behaviour was monitored during a full 24‐h period, starting at 08:00 hours with a 15‐min recording, which was repeated every 3 h. Rohu spent more time grazing during the day than at night. Grazing activity peaked at the beginning and at the end of the day. Grazing and resting of rohu were negatively correlated. Common carp grazed day and night, showing no distinct grazing peak. Considering the grazing time of rohu and common carp, a feeding schedule with two feeding times at 07:30 and 16:30 hours might be appropriate for better food intake and conversion in rohu–common carp polyculture system.  相似文献   

5.
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6.
Angling catch records are frequently used to reveal fish population developments. It is therefore important to understand the determinants of angling catches. This study focused on angler‐related, biotic and abiotic factors influencing catchability of Eurasian perch, Perca fluviatilis L. A multi‐lake (21 lakes) study based on angling diaries collected in Mecklenburg‐Vorpommern, Germany (2006/2007), found that angler‐related factors such as fishing experience, species preference and bait/lure type had a large impact on perch catch rates. Additionally, environmental conditions (nutritional status and water transparency) affected either the size or the number of perch caught by anglers. Catch rates varied seasonally, which was confirmed by an experimental fishery on a gravel pit (2008). This portion of the study showed that altered food availabilities in the course of the year caused food limitation in perch, which in turn facilitated high catch rates and female‐biased exploitation in autumn. It is concluded that both angler‐related and abiotic factors interact affecting perch catch rates and size of perch captured in recreational angling.  相似文献   

7.
Common carp Cyprinus carpio occurs in several non‐native areas worldwide, where it is generally regarded as either naturalised or invasive. Anatolia (Turkey) represents a unique region for evaluating common carp growth, due both to its location at the southernmost range of expansion of the species' wild form and to most of its water bodies having been stocked with domesticated strains. Based on a review of length‐at‐age data for common carp stocks from 45 water bodies sampled between 1953 and 2007, regional patterns in growth across climates, water body types, scalation variants and sexes, along with altitudinal gradients in growth performance and mortality, were investigated. Growth rates were lower in cold and arid relative to temperate climates, and also under hot or dry summers; this was true also of the mirror relative to the scale variant, males to females, but not of water body types (i.e., man‐made reservoirs, natural lakes, water courses). Growth performance and mortality decreased with increasing altitude and decreasing temperature, likely due to optimisation of resource allocation between growth and reproduction. Growth rate of common carp from Anatolia was consistently lower compared to its native (Eurasian) and, especially, invasive (North American) counterparts, which reflected an opportunistic life‐history strategy. Lower growth rates in Anatolia were ascribed to lower resilience of the widespread mirror variant together with limited habitat for spawning in man‐made reservoirs. Better knowledge of common carp growth in Anatolia will improve stock management and conservation efforts. Further studies will help clarify the mechanisms responsible for evolutionary genotype–phenotype inter‐relationships.  相似文献   

8.
Abstract Predation is an important force structuring aquatic communities, but predator–prey interactions are complex and regulated by multiple factors. Invasive fishes may interact with native fishes to alter predator–prey preferences and community dynamics. For example, common carp, Cyprinus carpio L., is an invasive species that can become abundant and negatively affect aquatic ecosystems. Juvenile common carp are occasionally found in predator diets, but predator preferences for common carp compared with alternative prey remains unknown. Prey selection and feeding behaviour of five piscivores (flathead catfish, Pylodictis olivaris (Rafinesque); largemouth bass, Micropterus salmoides (Lacepède); smallmouth bass, M. dolomieu Lacepède; walleye, Sander vitreus (Mitchill); and northern pike, Esox lucius L.) foraging on juvenile common carp and two alternative prey (fathead minnow, Pimephales promelas Rafinesque, and yellow perch, Perca flavescens Mitchill) at variable densities and habitats were evaluated. Common carp and fathead minnow were generally selected for or neutrally selected across predator species, habitat types and prey assemblages. By contrast, yellow perch was generally selected against. Common carp were easily captured but difficult to manipulate and ingest compared with other prey. These results reveal that common carp are vulnerable to a variety of predators, suggesting control of this detrimental invader may be possible through biomanipulation.  相似文献   

9.
To predict recreational‐fishing impacts on freshwater fish species, it is important to understand the interplay between fish populations, anglers and management actions. We use an integrated bioeconomic model to study the importance of fish life‐history type (LHT) for determining (i) vulnerability to over‐exploitation by diverse angler types (generic, consumptive and trophy anglers), who respond dynamically to fishing‐quality changes; (ii) regulations [i.e., minimum‐size limits (MSLs) and licence densities] that maximize the social welfare of angler populations; and (iii) biological and social conditions resulting under such socially optimal regulations. We examine five prototypical freshwater species: European perch (Perca fluviatilis), brown trout (Salmo trutta), pikeperch (Sander lucioperca), pike (Esox lucius) and bull trout (Salvelinus confluentus). We find that LHT is important for determining the vulnerability of fish populations to overfishing, with pike, pikeperch, and bull trout being more vulnerable than perch and brown trout. Angler type influences the magnitude of fishing impacts, because of differences in fishing practices and angler‐type‐specific effects of LHT on angling effort. Our results indicate that angler types are systematically attracted to particular LHTs. Socially optimal minimum‐size limits generally increase with LHT vulnerability, whereas optimal licence densities are similar across LHTs. Yet, both regulations vary among angler types. Despite this variation, we find that biological sustainability occurs under socially optimal regulations, with one exception. Our results highlight the importance of jointly considering fish diversity, angler diversity and regulations when predicting sustainable management strategies for recreational fisheries. Failure to do so could result in socially suboptimal management and/or fishery collapse.  相似文献   

10.
Abstract  This study evaluated how different angling practices affect the short-term post-release behaviour of nest-guarding male black bass, Micropterus spp. Male largemouth bass, M. salmoides (Lacepède), and smallmouth bass, M. dolomieu (Lacepède), were angled from their nests and subjected to treatments designed to simulate a variety of common angling practices associated with catch-and-release angling, including fishing tournaments. In addition, some nests had broods reduced (removal of the majority of the eggs or fry from the nest) during the angling treatments to simulate predation of offspring during the angling event. Fish subjected to procedures simulating fishing tournaments (including a 1-h livewell confinement and release 100 m from the nest) exhibited significantly longer rest periods prior to returning to their nest than did other treatment groups. This rest period was longer for largemouth bass than smallmouth bass. Brood removal and air exposure increased abandonment rates compared with controls. These results show that sublethal stressors inherent in some angling practices (such as air exposure and livewell confinement) may delay the return of male black bass to their nest. In the presence of nest predators, the delay in return time could result in increased nest abandonment.  相似文献   

11.
Six male carp, caught in the water system surrounding the Anna Paulowna (AP) Polder in The Netherlands, were characterized using allozyme and microsatellite markers. At the sMDH‐A1,2* loci an allele was found, which has previously only been found in wild River Rhine and wild Vietnamese common carp. Microsatellite allele frequencies showed that these AP carp were significantly different from a group of carp originating from several different domesticated strains. Based on both allozyme and microsatellite data, the AP carp probably originated from a wild or feral self‐sustaining population.  相似文献   

12.
It is well known that fish can learn to avoid angling gear after experiencing a catch‐and‐release event, that is, after a private hooking experience. However, the possible importance of social information cues and their influence on an individual's vulnerability to angling remains largely unexplored, that is, social experience of a conspecific capture. The effects of private and social experience of hooking on the stress response of fish and subsequent catch rates were examined. Hatchery‐reared rainbow trout, Oncorhynchus mykiss (Walbaum), were implanted with heart rate loggers and experimentally subjected to private or social experience of hooking. Private and social experience of angling induced an increased heart rate in fish compared with naïve control fish. While private experience of hooking explained most of the reduced vulnerability to capture, no clear evidence was found that social experience of hooking affected angling vulnerability in fish that had never been hooked before. While both private and social experiences of angling constitute significant physiological stressors for rainbow trout, only the private experience reduces an individual's vulnerability to angling and in turn affecting population‐level catchability.  相似文献   

13.
J Wang  & D Xia 《Aquaculture Research》2002,33(12):942-947
One Tilapia hybridization, Oreochromis aureus, (Steindachner) ♂ × Oreochromis niloticus, (Linnaeus) ♀, and two common carp, Cyprinus carpio, (Linnaeus) ♂, hybridizations, Russian mirror carp ♂ × Xingguo red carp ♀, and German mirror carp ♂ × Xingguo red carp ♀ were used to study the feasibility of predicting heterosis using genetic distance from DNA fingerprinting. The results indicated that highly polymorphic DNA fingerprints could be obtained with human minisatellite 33.6 as a probe on the studied varieties. The within‐population similarity indices of O. aureus, O. niloticus, Russian mirror carp, German mirror carp and Xingguo red carp were 0.785, 0.577, 0.432, 0.348 and 0.339 respectively. The similarity indices between F1 and their parents of three hybridization combinations were not significantly different (P > 0.05). There were larger genetic distances between two hybridization combinations, O. aureus♂ × O. niloticus♀ and Russian mirror carp ♂ × Xingguo red carp ♀, which showed heterosis in production and were extensively used in Chinese aquaculture. The genetic distance between O. aureus♂ and O. niloticus♀ was 0.338, and that between Russian mirror carp and Xingguo red carp was 0.344. However, the genetic distance between German mirror carp and Xingguo red carp was 0.129; this corresponded with the fact that their F1 generation did not show heterosis in the Chinese fish hybridization experiment. The study suggested that genetic distance could be used to predict fish heterosis.  相似文献   

14.
1. An extensive questionnaire (181 questions) was devised to examine the relationships and attitudes of angling clubs to their local environment and conservation organizations. Questions related to the fishery itself and the economics of the club were also asked. The questionnaire was sent to 59 coarse‐angling clubs that fished shallow Sites of Special Scientific Interest (SSSIs) in England. SSSIs are statutorily designated sites of the highest conservation value in Britain. Thirty‐one valid questionnaires were returned. 2. The average cost of leasing a water body was £645 ha?1 year?1 (1997 prices) and an adult angler paid, on average, £67 year?1 to fish at a club. The overall profit made by an angling club in an SSSI was, on average, £1760 year?1. Most clubs were not run on a profit basis. Compensatory cash payments were unlikely to influence attitudes to restrictions on stocking. 3. Angling clubs generally had a positive attitude to nature conservation and its enhancement. In 83% of cases, where stocking restrictions had been introduced by English Nature (the statutory nature conservation organization in England) the club involved agreed with the decision. Only 10% of respondents thought that a close season was detrimental to fishing. Aesthetic qualities and tranquillity were considered very important for a fishery to be successful and these were seen to be consistent with nature conservation values. 4. There were areas of concern. Common carp was the fish most likely to be stocked, largely because of financial benefits. Nonetheless, a trend towards carp stocking may have reached a peak. Management culling of fish such as pike took place at 42% of sites and some clubs believed that stronger ties with environmental groups should not be pursued. It may be some time before certain aspects of fishery management, suggested by English Nature as best conservation practice, are accepted by all angling clubs in SSSIs, but attitudes were found to be more positive than often assumed. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

15.
To assess strain related differences in growth performance and growth patterns under the same culture environment, four strains of common carp, two each of the scale carp, Cyprinus carpio var. communis (Chinese big-belly carp and long bodied carp) and mirror carp, C. carpio var. specularis (scattered carp and linear carp) were communally stocked in three fertilized earthen ponds of 0.14 ha each at 5,000 fish ha?1 in the ratio of 1:1:1:1 during an 11-month (February to December) culture cycle. Chinese big-belly carp grew larger than other groups, among which there were no significant differences. Scale carp strains performed relatively better than mirror carp at higher temperatures and then essentially stopped growing as temperatures declined into winter. The strains of mirror carp, on the other hand continued growing well later into the cold season.  相似文献   

16.
The objective of this study was to determine the differences in disease resistance against artificial infection with Aeromonas hydrophila between genetically different common carp families. Four strains differing in their origin and breeding history were selected from the live gene bank of common carp maintained at the Research Institute for Fisheries, Aquaculture and Irrigation (HAKI, Szarvas, Hungary) to establish families with wide genetic background: Szarvas 15 (15), an inbred mirror line; Tata (T) scaly noble carp; Duna (D), a Hungarian wild carp and Amur (A), an East Asian wild carp. A diallele mating structure was used to allow the assessment of genetic variation within and between the tested 96 families for a variety of traits. The existing technologies of fertilization and incubation of carp eggs, as well as larval and fingerling rearing had been modified because of the large number of baseline populations. Two challenge trials of the 96 families of carp with Aeromonas hydrophila were done. The 10 most resistant and 10 most susceptible families to A. hydrophila were identified from these two challenges. The crosses that produced the most resistant families were mainly those having parents from Tata and Szarvas 15 domesticated strains, while the most susceptible families were from the wild strains Duna and Amur.  相似文献   

17.
Processes influencing fish recruitment are often highly complex and inherently difficult to understand. Invasive species may complicate recruitment through habitat and food web modifications resulting in competitive bottlenecks. Common carp Cyprinus carpio have been distributed worldwide, and their introductions have resulted in destructive effects on aquatic ecosystems and food web dynamics. Common carp are highly fecund, and high densities of age‐0 carp may occur in some years that may reduce invertebrate prey resources and adversely affect native age‐0 fishes. We used enclosures and field observations to examine potential effects of age‐0 common carp on growth and survival of age‐0 yellow perch Perca flavescens and bluegill Lepomis macrochirus. Yellow perch and bluegill were stocked into enclosures with and without common carp (31 fish/m3) using a substitution experimental design, and fish growth and survival and invertebrate prey resources were assessed. Common carp reduced growth of yellow perch but not bluegill and did not affect survival of either species in mesocosms. Next, we used patterns of common carp, bluegill, and yellow perch abundance and total length across 38 lake‐years to evaluate potential interspecific interactions in natural systems. Age‐0 common carp abundance was not negatively related to size or abundance of bluegill or yellow perch. However, adult common carp and age‐0 yellow perch abundance were inversely related, suggesting a potential competitive bottleneck. Thus, age‐0 common carp may suppress growth of yellow perch when prey is limited, but adult common carp may have larger effects than early life stages on native juvenile fishes.  相似文献   

18.
China and Hungary are major providers of the common carp (Cyprinus carpio L.) in East Asia and Europe respectively. However, the genetic variation and relationship of this species in the two countries have been poorly understood. In this study, mitochondrial COII‐tRNALys and D‐loop sequences were analysed to investigate the genetic structure and relationships of the representative wild and domesticated common carps distributed in China and Hungary. The results indicated that the genetic diversities of the Chinese common carps are higher than those of Hungarian common carps, and the diversities of the wild common carps are higher than those of domesticated common carps in both the countries. Analysis of molecular variance and pairwise FST demonstrated a significant genetic divergence between the Chinese and the Hungarian common carps, and between the wild and the domesticated common carps. Bayesian phylogenetic analysis and statistical parsimony network showed an obvious genetic differentiation between the Chinese and the Hungarian common carps, between the wild and the domesticated common carps. However, a few specimens and haplotypes from the Chinese wild common carps appeared in the Hungarian common carps, demonstrating that there was no absolutely isolated and possible genetic linker between the Chinese and the Hungarian common carps.  相似文献   

19.
A polyculture experiment with the large carp rohu, Labeo rohita (Hamilton), catla, Catla catla (Hamilton) and either mrigal, Cirrhinus mrigala (Hamilton) or common carp, Cyprinus carpio (L.) (as cash crop fish), and the small indigenous fish punti, Puntius sophore (Hamilton) (as food for the small‐scale farmer family) was carried out at the Field Laboratory of the Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh. The main objective was to compare polycultures of large carp in which the bottom feeder is either the native mrigal or the exotic common carp. Secondary objectives were to assess the effects of adding the small indigenous species punti to polycultures of large carp, and to compare the effects of mrigal and common carp on punti production and reproduction. It was found that (i) common carp damaged embankments, had no effect on catla, improved rohu performance by 50% and total fish production by 20%; (ii) punti addition did not affect rohu, catla and total yield, improved mrigal performance by 50%, and decreased common carp performance by 20%; and (iii) punti was not affected either by common carp or by mrigal. However, its performance was not satisfactory, probably owing to frequent netting, which might have hindered growth and breeding. In spite of the embankment damage caused by common carp, this bottom feeder seems to be more promising than mrigal, because it leads to higher fish production. The addition of punti to the large carp polyculture is a viable proposition, as it does not reduce cash crop production, and might be a good food source for a small‐scale farmer's family.  相似文献   

20.
Abstract  Recaptures of adult, hatchery-reared, brown trout, Salmo trutta L., and fishing time from anglers were used to evaluate the benefits of stocking programmes with repeated releases of adult brown trout. The recapture rate varied between 17% and 29%. The time between stocking and capture (referred to as residence time) varied between 1 and 160 days (median 3–49 days). Between 67% and 84% of trout caught in the river were recently released fish. Fishing effort increased after stocking, thereby increasing the impact of angling on wild stocks. Stocking with adult brown trout decreases the impact of angling on wild trout only if the time spent fishing by all anglers is kept stable. Furthermore, because of the short residence time of stocked trout, long-term impacts through competition for space and food, or genetic impact through introgression, are limited.  相似文献   

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