Perch

We use six decades of catch-at-age data for perch (Perca fluviatilis) and pike (Esox lucius) in Windermere (UK) to estimate age-and sex-specific population sizes, natural mortalities and catchabilities in both species. Population sizes are estimated by fitting age structured population models to the catch-at-age data using standard maximum likelihood methods. We validate our methods using data simulations, and use our estimates of vital rates (natural mortality, recruitment and catahability) to address important aspects of fisheries biology. ...

The construction of the Římov Reservoir on the Malše River in 1978 significantly influenced the fish assemblage within the river, above the reservoir. Fish species that had successfully colonised the reservoir after impoundment expanded to the inflowing river. The changes in the riverine fish assemblage up to the first impassable weir (4 km upstream) reflected the development of the reservoir assemblage after an impoundment boom of pike (<i>Esox lucius</i>), then the perch (<i>Perca fluviatilis</i>) dominated phase and later the final cyprinid-dominated phase. The changes in the fish fauna over the period 1978–2002 were significant (χ<sup>2</sup>, <i>P</i> < 0.001). During the cyprinid-dominated phase, roach (<i>Rutilus rutilus</i>) became the most abundant species both in the reservoir and in the river, outnumbering the pristine river species. We conclude that the cyprinid-dominated assemblage in the reservoir can b...

ABSTRACT Pike-perch (Stizostedion lucioperca (L.)) brood-fish are captured from natural populations just before and during spawning time. One to three spawning pairs are put together with an artificial nest in a net-cage. After spawning the eggs attached to the nest are transported to a hatchery 1 day before hatching begins. The production of newly hatched fry, 30 million in 1994, is used for fingerling production in ponds with natural food. The production of pike-perch fingerlings in Finland increased rapidly in the 1980s and reached 10 million fish in 1994. The fingerlings are stocked into lakes particularly in central Finland, where many lakes lost their native pike-perch populations in the 1960s. In some lakes pike-perch fingerling stockings have been profitable and new populations have been established. Experiments on intensive rearing of newly-hatched pike-perch fry have not been successful. However, one-summer-old pond-reared pike-perch fingerlings are being reared intensively to provide captive brood fish.

Knowledge on the lipid compositions of tropical freshwater aquatic animals is limited despite their importance in the human diet and the health-related benefits of fish lipids. This study examines the lipid content and fatty acid composition from the edible muscle tissue of some common freshwater aquatic animals that inhabit rice fields in Thailand, namely snakehead (Channa striatus), Gunther's walking catfish (Clarias macrocephalus), climbing perch (Anabas testudineus), blackline rasbora (Rasbora borapetensis), swamp barb (Puntius brevis), and freshwater prawn (Macrobrachium nipponense). All specimens were low in muscle fat (≤1.1% of wet weight). There was considerable variation in the fatty acid composition between species. All species were good sources of the essential fatty acids, and particularly of C22:6n-3 (5.2–13.3% total FA) and C20:4n-6 (7.2–14.6% total FA), signifying their high nutritional quality for human nutrition. The findings indicate that strategies for rural d...

The Ponto-Caspian round goby (Neogobius melanostomus, Pallas 1814) most probably was established in the Gulf of Gdańsk, Baltic Sea, in the late 1980’s and has since become one of the dominant species in the region. In this study we assess the role of round gobies as prey for two important fish species in the Gulf of Gdańsk, cod (Gadus morhua) and perch (Perca fluviatilis). We compared their present diet with stomach analyses from the area prior the round goby establishment, as well as with diet analysis from Baltic regions where round gobies are absent. There were large differences in the diet between cods from the Gulf of Gdańsk 2003–2006 compared to cods in earlier studies (1977–1981) from the Southern Baltic Sea. There were also large differences in cod and perch diets from areas with and without round goby. Presently, round goby constitutes the most important prey for medium sized cods in Gulf of Gdańsk, and perch from the same area almost exclusively feed on gobiids. Stomach analysis, trophic level estimates, and stable isotope analyses all indicated that cod and perch in Gulf of Gdańsk after the round goby establishment belonged to a similar trophic level. Beside round goby, no mussel feeding fish contributed much to the diet of cod or at all to the diet of perch. Thus, it is likely that round gobies constitute a new energetic pathway from mussels to top predators. However, due to the short time elapsed after round goby establishment, we can only speculate on the species future impacts on Baltic food webs.

The discovery of isolated dodo bones, Raphus cucullatus (L.) in high perched shelters strongly suggests that the bird's extinction was intimately linked with human predation. The dodo was a lowland bird and could not have had access to high level cliffs. Previously, paleontological remains of the dodo had been collected in the lowlands of Mauritius, which is in agreement with its terrestrial habits. The presence of fugitive slaves and convicts from early 17th century Dutch period may have been responsible for the rapid elimination of the species. This probably represents the first concrete evidence of dodo predation to be associated with direct human activity. Alternatively other dodo bones were found in the lava tunnel system in northeast of the island and are relics due to natural death. The familial status of the raphids is no longer valid in view of recent morphological and molecular phylogenetic analyses, and consequently the genus Raphus is included in the family Columbidae.La découverte d'ossements isolés du dodo Raphus cucullatus (L.) dans des conditions fossilifères autres que celles connues jusqu'à présent indique que l'extinction de l'espèce est fortement liée à la prédation humaine. Le dodo était un oiseau terrestre des terres basses, et ne pouvait avoir accès à des abris sous roche haut perchés dans les falaises du sud de l'île Maurice. La présence d'esclaves fugitifs sur l'île dès le début de la période hollandaise au 17e siècle pourrait avoir une incidence majeure sur la disparition de l'espèce. Cette découverte représente probablement la première évidence matérielle de prédation du dodo par l'homme. Par ailleurs, d'autres ossements du dodo découverts dans les cavernes souterraines dans le nord-est de l'île indiquent une mort naturelle. Du point de vue taxinomique, le statut familial des Raphidés est désormais rendu non valide à la lueur des récentes analyses phylogénétiques tant morphologiques que moléculaires, et en conséquence le genre Raphus est inclus dans les Columbidae.

Jambili Athon is an extraordinary woodcraft of the Karbis, made entirely from Bengwoi ke-er (Wrightia coccinea Sims. (Apocynaceae), whose origin and making of the craft is strictly based on legends. It consists of a central axis and a whorl of four branches, all with beautiful carvings on it and the apices are perched with different species of birds. Jambili Athon is exhibited during socio-religio-cultural festival, Chomkan, during crowning ceremony of social chief, the Lindokpo and also to honour great persons. Jambili Athon has no parallel with any crafts or symbols of other tribes of Northeast India and is claimed as the symbol of pride and cultural identity by Karbis. It covers the philosophy of life & death, social institutions and religious practices of the people. Further, Jambili Athon is often used in logos of many institutions and organizations in Karbi Anglong and also as designs on textiles. A miniature Jambili Athon is usually kept as an artifact in almost every household.

This experiment was conducted to determine the effects of enrichment housing design on performance, selected welfare indicators, chicken meat composition and serum cholesterol concentration of broiler chicken. For this purpose, 480 Ross-308 chicks were assigned to two groups, Control and Test, each with 4 replications. The pens of the Test Group were enriched with perches and sand bedding. At the end of the study, 8 males and 8 females whose live weights were close to the group average from each group were slaughtered. Their blood was collected and serum was separated. For chemical analysis of the chicken meat, whole carcasses of 4 males and 4 females, and half of the breast and left thigh from the remaining 4 males and 4 females were collected. In the carcass group, whole carcass with its bones was minced, whereas in the other groups breast and tight meat were separated from the bones and minced in a meat grinder, homogenized with an electronic mixer, then flash frozen (-40 °C, 8–1...

Production of fish fingers was achieved by using fish species such as sardine (Sardina pilchardus, Walbaum, 1792), whiting (Merlangius merlangus, Linnaeus, 1758) and pike perch (Sander lucioperca, Linnaeus, 1758). Quality changes of battered fish patties during a period of 8 months at −18 °C were investigated. According to the results of microbiological and chemical analysis, fish fingers were found to be within “acceptable limits” during frozen storage for 8 months. However, sensory analysis showed that, at the end of the frozen storage, fish fingers made from sardine could not be consumed because of rancidity.