Farm-level returns and costs of yellow catfish (Pelteobagrus fulvidraco) aquaculture in Guangdong and Zhejiang provinces, China

AbstractFreshwater aquaculture in China is expanding and intensifying as this country experiences rapid economic growth, and understanding farm-level profitability is necessary if farmers are to make reasonable decisions about their production plans. We conducted a survey of yellow catfish farmers in 2014 in Guangdong and Zhejiang provinces in order to estimate farm-level profitability of pond aquaculture. We selected representative prefectures from the 2 provinces as study areas and used convenience sampling. Eighty-seven farmers were interviewed between April and May 2014 and the questionnaire collected detailed information on: (1) farmers’ demographics (age, gender, education, training, and experience); (2) production inputs (land, labor, fingerlings, feed, chemicals, machinery, and other miscellaneous costs); and (3) outputs (weight and revenue of harvested fish). Responses of 61 farmers included in the data analysis were post-stratified into 3 categories of farm size (<1.47ha, 1.47–3.67ha, and >3.67ha). We calculated production cost components, returns, and returns-costs ratios by farm size in each province. The overall returns-costs ratio was 1.31 in Guangdong and 1.17 in Zhejiang. Farmers in Guangdong invested more in land and machinery and had higher percentages of labor costs and chemical expenditures, but achieved better returns-costs ratios than farmers in Zhejiang. Higher land rent might be associated with greater yields of yellow catfish in Guangdong, which were almost twice those of Zhejiang

Ensayo de reproducción inducida en Ariopsis Seemanni con gonadotropina coriónica humana y extracto hipofisario de carpa

El bagre marino Ariopsis seemanni hace parte de la tradición alimenticia en pescadores y pobladores de la región pacífica colombiana. Los peces de menor tamaño (5 a 10 cm), tienen un alto comercio como ornamentales a nivel nacional e internacional. La presión pesquera ejercida históricamente de manera indiscriminada sobre la especie establece un escenario de poca viabilidad para su sostenibilidad y la recuperación natural de su población. La información científica obtenida sobre su biología, se constituye en una herramienta base para la creación de estrategias de manejo y alternativas acuícolas en la reproducción de la especie. Esta investigación propuso realizar la descripción macroscópica de madurez sexual, de su fecundidad, índice gonadosomático y factor de condición, en hembras utilizadas en un ensayo de desove inducido con gonadotropina coriónica humana (HCG) y extracto de hipofisis de carpa (EPC). Se utilizaron 24 parejas de peces, con un peso promedio de 263.6±42.2 g y 174.4±30.4 g para hembras y machos, respectivamente. Se utilizaron cuatro tratamientos hormonales: T1: 5 mg EPC/kg; T2: 7 mg EPC/kg; T3: 2000 UI HGC/kg y T4: 1000 UI HGC/kg. En este ensayo, no se obtuvo desove en ninguna de las hembras inducidas con las dosis utilizadas de HCG y EPC. Tampoco se observaron diferencias significativas entre los tratamientos hormonales sobre la cantidad de oocitos en maduración final encontrados en las hembras de cada tratamiento. La fecundidad media fue de 30.07±2.34 oocitos maduros, con tamaño aproximado de 13 a 14 mm de diámetro. Los tratamientos hormonales utilizados lograron inducir maduración final en los oocitos de las hembras de esta especie

Uticaj smeša koncentrata sa različitim učešćem proteina i masti na prirast i konverziju hrane u ishrani mlađi šarana (Cyprinus carpio, L., 1758)

Carp is cultured in all the 3 systems: extensive, semiintensive and intensive. Contrary to extensive rearing where weight gain depends exclusively on natural food, semiintensive and intensive systems are based on partial or complete reliance on added feed. During the rearing season the natural food in fish ponds with the semiintensive system has a prominent seasonality: in the period of natural food depression with optimal temperatures for carp growth (from mid June to the end of August) weight gain is primarily dependent on the quality and quantity of added feed. From an economical, and also an ecological point of view it is important to supply feed that will meet nutritional requirements of fish, and result in low feed conversion coefficient, high growth rate, good health condition, high quality of the final product – fish meat, and as low as possible load of the aquatic environment with organic matter, phosphorus, and nitrogen. Nutritional properties of fish feed are highly dependent on the protein and fat level. It is of utmost importance to stress that the amount of basic components in feed should not be fewer than the requirements of farmed fish, though, particularly from the economic point of view, this amount should’t be too high since the fish will not be able to utilise it. As the main building blocks, proteins are essential for body growth and a number of physiological processes. Their origin and quantity in feed mixtures are of crucial importance for the utilization of feed and growth of cultured fish. Fishmeal is the most desirable component of the feed that provides proteins with good amino acid composition in feed for carnivorous fish species, as well as for omnivorous fish in intensive production. Due to the deficit of this very important nutrient at the world market and their high prices, fishmeal and other feed of animal origin are combined or replaced with alternative sources of plant proteins. There is a constant tendency towards decreasing the share of fishmeal in feed while optimizing the amount of proteins in the meal...Šaran se gaji u sva tri sistema gajenja: ekstenzivni, poluintenzivni i intenzivni. Za razliku od ekstenzivnog gde prirast ribe iskljuĉivo zavisi od prirodne hrane, poluintenzivni i intenzivni sistemi su bazirani na delimiĉnoj ili potpunoj zavisnosti od dodatne hrane. Kako tokom sezone gajenja, prirodna hrana u ribnjacima sa poluintenzivnim sistemom ima veoma izraţen sezonalni karakter, u periodu sa optimalnim temperaturama za rast šarana (od sredine juna pa do kraja avgusta) prirast je u najvećoj meri zavistan od kvaliteta i koliĉine dodatne hrane. Sa ekonomskog, ali i ekološkog aspekta vaţno je obezbediti hranu koja će zadovoljiti nutritivne potrebe riba, rezultirati niskim koeficijentom konverzije, visokim tempom rasta, dobrim zdravstvenim stanjem gajenih riba, visokim kvalitetom finalnog proizvoda, odnosno ribljeg mesa i što manjim opterećenjem vodene sredine organskim materijama, fosforom i azotom. Nutritivna svojstva hrane za ribe u velikoj meri zavise od udela proteina i masti. Veoma je vaţno da osnovnih komponenti u hrani za ribe ne bude manje od potreba gajenih riba, ali i sa ekonomskog aspekta da ih u hrani ne bude više od koliĉine koju ribe mogu iskoristiti. Proteini kao gradivne komponente, su veoma vaţni za izgradnju tela ali i za brojne fiziološke procese u organizmu. Njihovo poreklo, sastav, kao i koliĉina u smešama od presudnog su znaĉaja za iskoristivost hrane i prirast gajenih riba. Najpoţeljnija komponenta, kao nosilac proteina odgovarajućeg aminokiselinskog sastava, za proizvodnju hrane za karnivorne vrste riba, ali i za intenzivno gajenje omnivornih riba je riblje brašno. Zbog deficita ovog veoma vaţnog hraniva na svetskoj pijaci i visoke cene na trţištu, riblje brašno, kao i ostala hraniva animalnog porekla se kombinuju ili pak potiskuju sa alternativnim biljnim izvorima proteina, uz optimizaciju koliĉine u obroku i uz stalnu teţnju da se što veći procenat ribljeg brašna potisne iz hrane. Masti prisutne u hrani doprinose efikasnijem iskorišćavanju proteina iz obroka, zahvaljujući ĉemu se skuplji proteini ĉuvaju od neracioanlnog iskorišćavanja kao dodatni izvor energije. U okviru odreĊenih granica, povećanje nivoa lipida u obroku, dovodi do poboljšanog iskorišćavanja hrane, tako što se lipidi koriste za obezbeĊivanje biološki korisne energije i na taj naĉin se štede proteini..

Effects of mixtures containing different protein and fatlevels on growth and feed conversion ratio of common carp (Cyprinus carpio,L., 1758)

Šaran se gaji u sva tri sistema gajenja: ekstenzivni, poluintenzivni i intenzivni. Za razliku od ekstenzivnog gde prirast ribe iskljuĉivo zavisi od prirodne hrane, poluintenzivni i intenzivni sistemi su bazirani na delimiĉnoj ili potpunoj zavisnosti od dodatne hrane. Kako tokom sezone gajenja, prirodna hrana u ribnjacima sa poluintenzivnim sistemom ima veoma izraţen sezonalni karakter, u periodu sa optimalnim temperaturama za rast šarana (od sredine juna pa do kraja avgusta) prirast je u najvećoj meri zavistan od kvaliteta i koliĉine dodatne hrane. Sa ekonomskog, ali i ekološkog aspekta vaţno je obezbediti hranu koja će zadovoljiti nutritivne potrebe riba, rezultirati niskim koeficijentom konverzije, visokim tempom rasta, dobrim zdravstvenim stanjem gajenih riba, visokim kvalitetom finalnog proizvoda, odnosno ribljeg mesa i što manjim opterećenjem vodene sredine organskim materijama, fosforom i azotom. Nutritivna svojstva hrane za ribe u velikoj meri zavise od udela proteina i masti. Veoma je vaţno da osnovnih komponenti u hrani za ribe ne bude manje od potreba gajenih riba, ali i sa ekonomskog aspekta da ih u hrani ne bude više od koliĉine koju ribe mogu iskoristiti. Proteini kao gradivne komponente, su veoma vaţni za izgradnju tela ali i za brojne fiziološke procese u organizmu. Njihovo poreklo, sastav, kao i koliĉina u smešama od presudnog su znaĉaja za iskoristivost hrane i prirast gajenih riba. Najpoţeljnija komponenta, kao nosilac proteina odgovarajućeg aminokiselinskog sastava, za proizvodnju hrane za karnivorne vrste riba, ali i za intenzivno gajenje omnivornih riba je riblje brašno. Zbog deficita ovog veoma vaţnog hraniva na svetskoj pijaci i visoke cene na trţištu, riblje brašno, kao i ostala hraniva animalnog porekla se kombinuju ili pak potiskuju sa alternativnim biljnim izvorima proteina, uz optimizaciju koliĉine u obroku i uz stalnu teţnju da se što veći procenat ribljeg brašna potisne iz hrane. Masti prisutne u hrani doprinose efikasnijem iskorišćavanju proteina iz obroka, zahvaljujući ĉemu se skuplji proteini ĉuvaju od neracioanlnog iskorišćavanja kao dodatni izvor energije. U okviru odreĊenih granica, povećanje nivoa lipida u obroku, dovodi do poboljšanog iskorišćavanja hrane, tako što se lipidi koriste za obezbeĊivanje biološki korisne energije i na taj naĉin se štede proteini...Carp is cultured in all the 3 systems: extensive, semiintensive and intensive. Contrary to extensive rearing where weight gain depends exclusively on natural food, semiintensive and intensive systems are based on partial or complete reliance on added feed. During the rearing season the natural food in fish ponds with the semiintensive system has a prominent seasonality: in the period of natural food depression with optimal temperatures for carp growth (from mid June to the end of August) weight gain is primarily dependent on the quality and quantity of added feed. From an economical, and also an ecological point of view it is important to supply feed that will meet nutritional requirements of fish, and result in low feed conversion coefficient, high growth rate, good health condition, high quality of the final product – fish meat, and as low as possible load of the aquatic environment with organic matter, phosphorus, and nitrogen. Nutritional properties of fish feed are highly dependent on the protein and fat level. It is of utmost importance to stress that the amount of basic components in feed should not be fewer than the requirements of farmed fish, though, particularly from the economic point of view, this amount should’t be too high since the fish will not be able to utilise it. As the main building blocks, proteins are essential for body growth and a number of physiological processes. Their origin and quantity in feed mixtures are of crucial importance for the utilization of feed and growth of cultured fish. Fishmeal is the most desirable component of the feed that provides proteins with good amino acid composition in feed for carnivorous fish species, as well as for omnivorous fish in intensive production. Due to the deficit of this very important nutrient at the world market and their high prices, fishmeal and other feed of animal origin are combined or replaced with alternative sources of plant proteins. There is a constant tendency towards decreasing the share of fishmeal in feed while optimizing the amount of proteins in the meal..