outubro 06, 2011





AQUICULTURA
6 de Outubro de 2011


Folha da mandioca para tilápia
Potencial do uso da parte aérea da mandioca na alimentação de tilápias


Imagem: Divulgação Embrapa
A ração é um dos itens mais representativos para determinação do custo total de produção na piscicultura. Com os sucessivos aumentos dos alimentos convencionais utilizados para a fabricação de ração para peixes, subprodutos e coprodutos da agroindústria podem ser uma alternativa para diminuir o preço deste insumo.

No entanto, para que o alimento alternativo apresente potencial de utilização é necessário que apresente baixo custo, volume de produção, disponibilidade regional, e que não prejudique o desempenho do animal. Nesse último caso é recomendável o amplo conhecimento das características nutricionais, aproveitamento de nutrientes e outros fatores presentes no alimento que possam interferir no desempenho animal.

O Brasil é um grande produtor de mandioca, com o cultivo distribuído de Norte a Sul. Além da característica nutricional, como reconhecida fonte de alimento humano e animal, a mandioca apresenta grande importância econômica e social em muitas regiões. Para alimentação animal, alguns subprodutos do processamento da raiz, tais como raspa, casca, apara, farelo de varredura, além da parte aérea são utilizados principalmente para alimentação de bovinos e caprinos em diversas propriedades rurais. 

Apesar da parte aérea apresentar alto teor protéico, alguns compostos presentes principalmente na folha, desencadeiam a formação de ácido cianídrico que é tóxico ao animal e, portanto, este material deve ser processado de maneira adequada. A secagem é uma forma simples e eficiente de eliminar a toxidez e pode ser facilmente aplicada nas propriedades rurais, tanto diretamente ao sol, quanto à sombra. 

Apesar de existirem algumas recomendações do uso da parte aérea da mandioca para ruminantes, poucas informações com embasamento científico estão disponíveis para peixes. Considerando essas questões, pesquisas foram conduzidas no Laboratório de Piscicultura da Embrapa Agropecuária Oeste (Dourados, MS) com a finalidade de avaliar a secagem da parte aérea da mandioca e identificar o melhor processamento do ponto de vista prático, aliando o melhor aproveitamento do conteúdo nutricional para tilápias. 

Resultados preliminares indicam que a secagem à sombra foi eficiente para reduzir os compostos tóxicos e melhorar o aproveitamento da parte aérea. Além disso, é possível substituir parte do farelo de soja pela parte aérea da mandioca sem interferências no desempenho da tilápia, o que geraria uma redução de custo da ração. 

Contudo, a validação dos resultados a campo, assim como aprimoramentos no processo de obtenção e secagem, ainda são necessários para utilização em escala comercial, no entanto, os resultados experimentais já demonstram o alto potencial de uso da parte aérea da mandioca para alimentação da tilápia e de outras espécies.

Hamilton HisanoZootecnista e pesquisador Embrapa Agropecuária Oeste, Dourados/MS hhisano@cpao.embrapa.br

outubro 01, 2011


Return to frontpage - PRESS TRUST OF INDIA

New technique for easy collection of ‘Karimeen' fish eggs

NEW DELHI, SEPT. 26: The Indian Council of Agricultural Research (ICAR) scientists have developed a unique method for collection of the eggs laid by Pearlspot, also known as the “state fish of Kerala”, which is much more efficient than the earlier method employed.
Pearlspot (Etroplus suratensis) also known as "Karimeen" in Kerala, is an excellent table fish, fetching a good market price up to Rs 350 a kg.
“The fish has very complicated method of breeding and nesting. They bury their eggs in the bottom mud of the ponds, hence, the survival of juveniles is very less, which has been a major concern for fish farmers,” said Mr M. Natrajan, Project in-charge at the Central Institute of Brackishwater Aquaculture (CIBA), Chennai, an institute of the ICAR.
“We can obtain 1,200 juveniles from a pair of parent fishes. However, in traditional techniques, it is hardly 200 juveniles,” added Mr Natrajan.
Pearlspot can be reared in ponds and cages in both freshwater and salt water environments. It is a hardy fish, easy to propagate and culture on a large scale, depending upon the capacity of the entrepreneur and farmer.
Pearlspot can be farmed in homestead ponds in the backyard of houses, enabling poverty alleviation as well as high-value fish production in States such as Kerala.
The Central Institute of Brackishwater Aquaculture (CIBA), Chennai, has developed an innovative technology for easy propagation of the fish by breeding them under controlled conditions.

CAPTIVE BREEDING
At its Muttukadu Field Centre, CIBA has successfully developed a captive broodstock of Pearlspot fish in cages, drawing from a diverse genetic pool (from Pulicat and Muttukadu, in Tamil Nadu, and Kumarakam, in Kerala) to establish a simple and effective facility for consistent egg production by this fish species.
Under the ‘Matsya Keralam' scheme, the State Government is promoting farming of brackishwater fish on a large scale and due to this, the demand for quality Pearlspot fish juveniles has increased.
The CIBA, Chennai, has been approached by the Kerala Government to extend its know-how and expertise with regard to this technology to promote Pearlspot fish production in the State.
Efforts are also being made to promote Pearlspot fish culture in derelict inland saline wetlands of Karnataka.

setembro 22, 2011

É preciso apenas uma fêmea grávida de "guppy" para uma invasão alienígena


How reproductive ecology contributes to 
the spread of a globally invasive fish.
Deacon AE, IW Ramnarine and AE Magurran 

It takes just one pregnant guppy for an alien invasion!
Copyright © Mich De May, Creative Commons


The well-known ability of female guppies (Poecilia reticulata) to store sperm for up to six months and give birth long after being inseminated is responsible for their runaway success as one of the world's worst invasive fish species.

In research published in a recent issue of the online journal PLoS ONE, Amy Deacon, Indar Ramnarine and Anne Magurran document the current global distribution of the guppy, producing the most complete picture of the current distribution of this invasive species to date, and show that it is contributing to the homogenisation of fish communities on a global scale. 
At the same time, they conducted experiments to test the prediction that a single pregnant female guppy is capable of routinely establishing viable populations when introduced to a new habitat.
Despite the small native range of the guppy, the authors found that its introduced range now spans every continent with the exception of Antarctica, as well as numerous oceanic islands. 
Their data show that the worldwide distribution of the guppy is considerably more extensive than previously described in the literature or in any database.
For the second part of their study, the authors carried out an experiment in which 30 plastic mesocosms were established and a single pregnant female wild-caught guppy was added. The experiment was allowed to run for two years, during which the fish were counted, measured and their performance (in activity and evasion) were recorded.
The authors found that the single female guppies were capable of establishing viable populations within the mesocosms during the study period in a large majority of the cases: 91% of mesocosm populations persisted at the end of the first year and 86% at the end of the second.
Furthermore, their studies showed that the behavioural performance of the offspring from such introductions was not impaired. Although inbreeding is very likely to take place as a result of using a single founder individual, the guppies may be employing a number of pre- and post-copulatory strategies to minimise inbreeding, surmise the authors.
The authors conclude, "Our results demonstrate how introductions consisting of a few animals, or even a single individual, can lead to thriving populations of invasive species. A highly specialised reproductive system, coupled with a remarkable adaptability is likely to have led to the phenomenal success of the guppy outside of its native range. These findings reinforce the need for caution when releasing exotic species, and show that seemingly innocuous or beneficial activities such as a child freeing a few pet fish or a concerned householder using guppies to control mosquitoes can result in a thriving population of invasive poeciliids that may then go on to compete with the indigenous freshwater fauna. They also illustrate how many small actions replicated across the globe, in the form of the accidental or deliberate release of a few fish, combined with natural adaptations in these fish for life in ephemeral habitats, can contribute to the reduction of diversity in freshwater fish assemblages worldwide."
Deacon AE, IW Ramnarine and AE Magurran (2011). How reproductive ecology contributes to the spread of a globally invasive fish. PLoS ONE 6, e24416. doi:10.1371/journal.pone.0024416

setembro 09, 2011

Sistema de Transposição de Peixes


Imagem          MEIO AMBIENTE




Época de piracema: Santo Antônio Energia monitora 
migração de peixes do rio Madeira
De: Santo Antônio Energia 
09 de Setembro de 2011

Imagem - Divulgação
Entre agosto e novembro, a equipe do Programa de Conservação da Ictiofauna marcará 4 mil peixes que serão monitorados em um estudo sobre as rotas migratórias no período de reprodução das espécies. O objetivo é verificar se os animais estão utilizando o Sistema de Transposição de Peixes (STP), estrutura construída para ajudá-los a ultrapassar a barragem da Usina na época de piracema.

Equipamentos de telemetria para obtenção e transmissão de dados a longa distância foram instalados em parte dos animais e o monitoramento será feito por antenas instaladas nas margens e em barcos ao longo do rio Madeira. A outra parte dos peixes receberá uma marcação chamada LEA, um tubo com um número que é fixado na barbatana para identificá-lo quando ele for pescado.

setembro 07, 2011

Cuidado Parental!!!! Fantástico momento!!!!

Jawfish Eggs about to Hatch

Photo and caption by Suzan Meldonian
A male Banded Jawfish (Opistognathus macrognathus), incubates it's eggs in it's mouth, assuring survival of at least this stage of their lives. Held in by it's father's teeth at some point the overgrown siblings become cumbersome, yet the devotion of survival mode is so strong that the jawfish will only poof them out for a second or two to quickly catch a morsel of food in the water column, then quickly sucking the eggs back into it's mouth. This process is also called aerating the eggs... so it serves more than one purpose... sort of like rotating the eggs in a hatchery.



agosto 31, 2011

Oportunistas: Ciclídeos seguem raias na busca por alimento

Cichlids follow stingrays to food
Published: Dr Heok Hee Ng 


Copyright © Steven Johnson, Creative Commons

Brazilian scientists have discovered that some cichlids follow potamotrygonid stingrays to opportunistically feed on the invertebrates flushed out by the foraging activity of the rays.

Publishing the results of their study in a recent issue of the Journal Neotropical Ichthyology, Domingos Garrone-Neto and Ivan Sazima record this association while making in situ observations of the fishes at two sites in the upper Paraná river drainage. 

The authors found that the foraging activities of the stingrays Potamotrygon falkneri and P. motoro, attract four cichlid species (Crenicichla britskii, Satanoperca pappaterra, Cichla kelberi, and Geophagus proximus) to follow them. 

The authors describe the association as “…a ray stirring the unconsolidated (loose) substrate to uncover small invertebrates such as insect larvae, crabs, and snails.

Food clouds
This activity stirs the substrate particles and discrete sediment clouds are formed near the foraging ray. These clouds apparently catch the attention of nearby cichlids that approach the ray and feed on small preys and other food types exposed this way.” 

This is yet another case of a nuclear-follower association, which has been reported for a number of South American freshwater fishes.

The nuclear-follower association is an interspecific interaction defined by the presence of a nuclear species that promotes a disturbance during foraging and a follower species that feeds on the items exposed or flushed out by the former.

For more information, see the paper: Garrone-Neto, D and I Sazima (2009) The more stirring the better: cichlid fishes associate with foraging potamotrygonid rays. Neotropical Ichthyology 7, pp. 499–501.

agosto 11, 2011

Fenômeno da Bioluminescência por tornar o Tubarão-Lanterna invisível contra predadores.

Glow-in-the-dark shark can become invisibleAbility to 'disappear' may save it from predators, but researchers find it amazing
By Jennifer Viegas (© 2011 Discovery Channel)

Bioluminescence most likely facilitates the rare splendid 
lantern shark in mating, schooling and other behaviors.
(Jerome Mallefet)
The first detailed study of the rare splendid lantern shark reveals that not only does it glow in the dark, but the light effects create a "cloak of invisibility" that helps shield it from predators.

The study, accepted for publication in the Journal of Experimental Marine Biology and Ecology, is also the first to document the cylindrical-shaped shark's presence in waters around the Okinawa Islands of Japan. Previously, the shark was confirmed to exist only in the East China Sea, off Taiwan, and in the waters around southern Japan.

Its natural light show, produced by light-emitting organs called photophores, serves many functions. The cloak of invisibility is perhaps one of the most beneficial, since it helps to protect the small, shark from upward-looking predators. The lantern shark is a member of the small dogfish sharks.

"The photophores replace the down-welling light from the sun, which is absorbed by the shark's body," lead author Julien Claes explained to Discovery News. "The silhouette of the shark therefore disappears when seen from below."

Claes, a postdoctoral researcher in the Catholic University of Louvain’s Marine Biology Lab, and colleagues Keiichi Sato and Jerome Mallefet collected, and maintained in captivity, three specimens of the splendid lantern shark.

Analysis of the sharks revealed that each had nine distinct luminous zones where light was emitted. Some of these zones, such as one on the belly, contribute to the "cloak of invisibility" effect. Other, even brighter, zones are present on the shark's sexual organs, flanks, tail and pectoral fins. The researchers suspect these are probably used during schooling and sexual communication.

"Sharks use internal fertilization, so the presence of photophores on the sexual organs may facilitate mating," Claes said. "Moreover, it might also be a way for the sharks to signal that they are ready to mate or that they are a better candidate for reproduction in a light-induced sexual selection system."

The scientists believe nerves and hormones primarily control the light, with pigments also moving in cells as part of the process.

The luminescence likely evolved when lantern sharks colonized the deep sea probably during the end of the Cretaceous, 65 to 75 million years ago. The splendid lantern shark to this day lives 656 to 3,281 feet below the water's surface, an area with extremely low light levels.

Claes and his colleagues previously studied another member of this shark family, the velvet belly lantern shark. Both this and the splendid lantern shark share similar luminous zones and other features. It's therefore probable that their ability to glow evolved long before their clades split up at least 31.55 million years ago.

It's even possible that many other prehistoric marine animals could glow in the dark.

"Unfortunately bioluminescence is a soft-tissue phenomenon that leaves no, or extremely few, fossil tracks," Claes said. "It is therefore very difficult to establish if a lot of prehistoric animals were luminous, but it is probably the case at least in the deep sea, since bioluminescence is currently widespread in this environment."

Nicolas Straube, a researcher at the Bavarian State Collection of Zoology, told Discovery News that he "fully agrees" with the new paper's conclusions.

Straube explained that this latest study supports previous theories about lantern shark evolution and luminescence, given both the similarities and differences between the two best-documented species: the velvet belly lantern shark and now the splendid lantern shark.

At least 33 species exist in this diverse shark family, however, so much remains to be discovered about these dwellers of the ocean depths.

agosto 07, 2011

Quais são as técnicas mais adequadas e de baixo custo para engordar peixes em tanques escavados e em tanques circulares?


Tanques para piscicultura
Fabiano Henrique W. Ribas
Barra do Chapéu - SP

O cultivo de peixes para consumo ou para ornamentação (utilizados em aquários, por exemplo) tem se popularizado no Brasil. As boas condições climáticas do país e a grande variedade de espécies nativas contribuem para o desenvolvimento da atividade. Com dedicação e empenho, produtores podem conseguir bons resultados e contar com a criação como fonte de renda principal de sua propriedade. 

Antes de escolher os peixes que mais se adaptem à região de cultivo e dar início ao novo empreendimento, entretanto, é necessário montar uma estrutura apropriada no local. De acordo com o orçamento disponível, pode-se decidir por vários materiais encontrados no mercado e por diferentes sistemas de criação (confira a tabela na página ao lado). 

O tanque de cultivo pode ser apenas escavado na terra ou, após a terraplenagem, ser construído em alvenaria e impermeabilizado com lona, fibra de vidro ou chapa galvanizada. Para o sistema de abastecimento de água, utilize blocos de concreto ou algum tipo de vala, com conexões de tubo de PVC para condução da água até o tanque. A vazão da água pode ser regulada com a instalação de um monge de alvenaria ou um cotovelo articulado, por meio do qual ocorre o escoamento da sujeira acumulada no fundo do tanque. 

De forma geral, é recomendável que os viveiros não sejam muito grandes, para evitar dificuldades no manejo, como nos momentos de alimentação, transferência de peixes e despesca. Uma boa medida recomendada é de 40 por 50 metros, com 1,60 metro de profundidade. O formato retangular é o mais indicado para a criação de várias espécies de peixes, pois facilita a renovação da água. O circular, que exige mais aparatos para a movimentação da água e filtros para a remoção de resíduos, é mais frequentemente usado na criação de trutas, embora também possa ser usado no cultivo de lambari, tilápia e pirarucu, entre outros. 

Piscicultores de algumas localidades do país têm optado por fertilizar a água dos viveiros com resíduos originários da suinocultura, promovendo a proliferação de micro-organismos que servirão de alimento para os peixes. Com produção que chega a 2 mil quilos de pescado por hectare por ano, o sistema é considerado uma opção para baratear os custos.


Muitos criadores brasileiros, no entanto, adotam viveiro com fertilização acrescida de alimentação suplementar. São aproveitadas sobras de hortaliças e/ou fornecidas rações de boa qualidade para a engorda dos peixes. A produção oriunda desses sistemas pode atingir 5 mil quilos por hectare por ano.

Para conseguir uma atividade mais produtiva e com custo baixo, os piscicultores também aproveitam para praticar o policultivo: várias espécies de peixes ocupam o mesmo viveiro, sendo que cada uma aproveita um espaço (mais no fundo, mais junto à superfície, etc.) e um tipo de alimento. Um exemplo de boa convivência é juntar em um único tanque tilápia com variedades de carpa. 

Podem dividir o mesmo ambiente a carpa comum, que, assim como a tilápia, come de tudo (onívora); a carpa capim, que consome plantas (herbívora); a carpa cabeçuda, que se alimenta de minúsculos animais (zooplanctófaga); e a carpa prateada, que gosta de algas (fitoplanctófaga). 

Uma recomendação importante para os iniciantes na criação de peixes é consultar a legislação ambiental. A orientação de um técnico competente pode assegurar o dimensionamento de um projeto econômico e produtivo. Um consultor em piscicultura também tem capacidade para avaliar as condições do local para a atividade, sugerir o melhor sistema a ser adotado, recomendar as espécies para cultivo e sugerir opções para baratear os custos. 

CONSULTOR: Jorge Meneses (consultor na área de piscicultura)
MAIS INFORMAÇÕES: Instituto de Pesca de São Paulo, instituto@pesca.sp.gov.br, www.pesca.sp.gov.br; Centro de Aquicultura de Jaboticabal (Caunesp), http://caunesp.unesp.br

julho 30, 2011

How to breed perfect guppies. (Como reproduzir perfeitos guppies)

Guppy guru Derek Jordan offers advice to experts on how to keep and breed top quality guppies

Copyright © Neil Hepworth
There is a popular belief that Guppies are a hardy fish which can be neglected, yet still flourish, and that they are a fish for the beginner. Now although many fishkeepers started with Guppies, over the years the species has encountered some quite bad press, mainly due to overbreeding and inbreeding issues. 
However, there is absolutely no reason why you cannot have a perfectly healthy tank of these stunningly coloured fish. As Guppies are easy breeders, with a little care you can optimise your chances for a healthy, vibrant stock. 

Getting down to basics
A breeding set-up should be designed for easy maintenance, especially as chances are you'll end up with loads of tanks! I keep my breeding tanks in the bare mode, so no plants or gravel. 
Small tanks will suffice: 25 l./5.5 gal. for a breeding trio and 36-45 l./8-10 gal. tanks for growing on. As a rule of thumb, allow 2.5cm/1" of fish per gallon to allow your fish to achieve their full potential. 
Some enthusiasts opt for higher stocking levels, which is fine if you carry out more frequent water changes. Don't push your luck as you could end up with stunted, poor quality fish.
As for filtration, I opt for air-driven corner filters or sponge filters with plenty of airflow. And I mean plenty, such that the water above the filter looks like it is boiling. 
Such a strong flow serves one purpose; it forces the fish to develop strong muscles, especially in the caudal peduncle. This helps the delta varieties hold their tails in a more natural way and not look like the tail is too heavy, making the fish looks somewhat bent.
Ideal water parameters are pH 7.2 (normal range 6.8-7.8); 8-12 degrees GH (normal range 4-20 degrees GH); and a temperature for fry of 25.5 degrees C/78 degrees F; juveniles (four to eight months) of 24.5 degrees C/76 degrees F, and adults somewhat cooler at 23.5 degrees C/74 degrees F (normal range 10-29 degrees C/50-85 degrees F). 
A Guppy needs 12 hours of lighting each day, best provided using 30-40W fluorescents mounted above your tanks. Don't be misguided into thinking that intensity matters. 
Duration is far more important, and a simple timer will ensure that the lights are turned on and off at the right time.

Care and maintenance
Guppies are omnivores, so offer as wide a range of quality flake food, live and frozen foods as possible. It is also better to feed small amounts every few hours than one gigantic feed. 
Frozen and live food are digested easier than flake food, so can be fed in larger portions. As a guide, if your fish do not eat all the food you put in the tank in two minutes, chances are you're overfeeding them - or they could be ill. 
If you overfeed your Guppies, the excess food passes through the gut without being properly digested and will foul the tank. Try to avoid feeding a diet rich in protein as this can cause constipation, causing a build-up of toxins in the fish's gut. 
Which leads me to the point that fish create waste, and this waste creates both good and bad bacteria. If waste builds up within the tank, eventually the bad bacteria will outnumber the good and the water conditions start to fail. 
Correspondingly, your Guppies' fins and health will deteriorate. Regular water changes are a must. I carry out weekly changes of 25%.

Know your strain
Before you attempt to breed Guppies, you need to understand the characteristics of your chosen strain - each is unique. 
This can be tricky if the person you bought your fish from does not know its genetic make-up. However, all is not lost as close observation and the keeping of breeding logs will reveal much.
The first step is to note all the characteristics of your stock. For instance, does the colour have a uniform look or is it more intense in specific areas? What about fin shapes? Find out what the ideal shape should be. 
Fellow enthusiasts are always a good source of information. Find out if your strain carries the traits you want on the X- or the Y-chromosome. The Internet can be very useful in helping you trace the genetic make-up of your fish.
Obviously if you have a specific goal, eg. solid black fish, this makes it easier to organise your tank space and select the fish you intend to keep out of each litter, ie. as much black in the body, or even a particular dorsal or caudal shape.
Never, ever keep just the one pair of breeders: disease happens, no matter how careful you are, and you do not want to put those years of hard work in jeopardy by losing just two fish. Ideally, aim for two or three trios in separate tanks.

Keep those records

Your breeding log should have the following information:

Identity: Give each breeding pair or trio an identity number, so your first pair is number 1, your second number 2 and so on. This allows you to trace the lineage and any crosses that have been made.
Sex: M or F for male or female.
Colour/strain: eg. half-black red delta or yellow snakeskin.
Generation: Start with P for parentage, followed by F1, F2 etc.
Cross: Are the fish being bred brother to sister (siblings), parents to daughter or son (backcross), or to a genetically related strain (outcross)?
Parents: What was the identity number of the parent fish?
DOB: Date litter was dropped. This is useful to work out the age of fish for breeding and to track their progress for finnage and colour development, which varies according to strain. 
Breeders produced: Did they produce any litters with potential breeders?
Notes: Allow plenty of room for observations about when the fish started to sex out, ratio of males to females, growth rates, etc.
Always mark the tank with the ID number and the date the litter was born. Masking tape is good as you can easily remove this and attach it to the fish's new tank if you move it.

Line breeding
The problem with successive inbreeding is that each generation loses some genetic diversity. Line breeding helps overcome this and keeps a strain true. 
Basically it combines inbreeding with a crossing from a related line every few generations, ensuring healthy Guppies for years.
The most common method is to break your strain into two lines for inbreeding. Then after three generations, cross the lines. A simple illustration of inbreeding is:

Line 1 Line 2
P1 M F P1 M F
F1 M F F1 M F
F2 M F F2 M F

Cross Line 1 F2 female (F) with Line 2 F2 male (M), and Line 2 F2 F with Line 1 F2 M.
Guppies are typically four months old before they can be bred, so to repeat the above for three generations would take about 12 months before your first cross. Also the more lines you run, the more diversified your gene pool will be.

Out-crossing
This refers to the mating of two unrelated Guppies. While inbreeding reduces the variations of your offspring and line breeding helps keep your gene pool intact, out-crossing corrects or adds a gene to your strain. 
For example, you may want to get a bigger dorsal fin, improve the colour or rectify a defect in the caudal fin. Or you may even want to create a totally new strain. 
Having said that, out-crossing is best not attempted by a novice for if you get it wrong, you could lose the strain traits altogether.
With out-crossing, it's critical to ensure strains are compatible - some colour strains mix, others don't. For instance, crossing a variegated snakeskin with a half-black red results in a very mixed-up Guppy. You really need to keep the original strains pure. 
Out-crossing demands plenty of tank space and patience to carry out the required backcrosses to end up with the results you want. You'll need to use established strains whose genetics are stable, meaning that all offspring look identical. 
Finally, try the cross both ways - female to outcross strain and male to outcross strain; you may not know whether the trait you want is X- or Y-chromosome linked.

Backcrossing
This is where you breed, say, the male of a strain that you want to rectify a problem back to one of his daughters from the outcross, or the female of the strain back to her son from the outcross. 
The aim is to restore the strain to its original format, but with the trait fixed. 
You may have to perform this a few times. The way to check is if the sibling-to-sibling mating produces replicas of the parents with the trait fixed.

Who was first?
The Guppy takes its name from Rev. Robert John Lechmere Guppy, a conchologist, geologist and clergyman living in Trinidad. 
Although he is credited with discovering the wild Guppy in 1866, Spaniard De Filippi found the fish in Barbados in 1862 and labelled it Lebistes poeciliodes. 
However, even earlier in 1857 and 1858, amateur German biologist Julius Gollmer found Guppies near Caracas, Venezuela. He sent these fish to the Imperial Prussian Academy of Science, Berlin. 
The ichthyologists were apparently not impressed, gave Gollmer only a small reward and then promptly filed the specimens in its archives. There they remained until 1859, when Wilhelm Karl Hartwig Peters, head of the ichthyology department, wrote a scientific description of them. 
Unfortunately, the jars were not well labelled and he only described the females as belonging to a new species, Poecilia reticulata. Some time after 1866, the males were found and labelled Giradinus guppyi. The females later adopted the name of the male counterpart.
The scientific name has undergone a number of revisions over the past 100 or so years, finally settling on Poecilia reticulata (Rosen and Bailey, 1963). Rosen and Bailey also included Mollies in the genus. 

The pioneer
Great Britain's pioneer in the fancy Guppy world was W. G. Phillips, born in 1883. During the Second World War, he sold his excess Guppies to a shop in London. 
Some months later, he returned to find that a few remained and had bred, with some of the offspring having unusual tail shapes. He took these home and over the next few years, perfected the now familiar Coffer Tail shape.
Phillips created the British Guppy judging standard, from which all subsequent judging standards have been drawn. He also developed and sent overseas the English Leopard Guppy or English Lace Guppy, which may have been the original source of all Snakeskins. 
Phillips won over 500 awards for his Guppies, and his house in Kenton was a shrine to the enthusiast. He was not a secretive man but freely shared his Guppies and ideas, leaving behind a huge legacy today.

Did you know?
The word 'Poecilia' means 'variegated' and 'reticulata' refers to the lacy pattern that is formed by the overlapping scales on the Guppy's body.
The Guppy has been called the Missionary fish as it has converted many to the hobby.
The Coffer Tail Guppy got its name from the fact that it resembles the South Wales miner's shovel.

Published: Derek Jordan

julho 22, 2011

Como reproduzir o Tetra-Neon

How to breed neon tetras

How to breed Neon tetras
Copyright © MP and C Piednoir, Aquapress.com
Breeding expert John Robertson describes how he raised Neons – one of the world’s most popular and recognisable tropical fish.
I had not kept Neon tetras for almost 40 years. They were the first egg layers I ever had in my first 60cm/24” tank — and I had not kept them since.
Yet I have kept Cardinal tetras many times while looking down my nose at Neons. Those Cardinals have much to answer for…
However, I recently found myself with another 24” tank and a dozen Neons. It was filled with rainwater and leaf litter and heavily planted with Java moss and Indian fern. Sitting in the darkest corner of my fish house with a feeble light above, its murk made those Neons look absolutely gorgeous!
The reflective blue-green of that almost luminous stripe set off against red underparts made for a stunning spectacle in the dim light as the little fish danced and darted about. The tank had a DH of less than 1, pH of 5.5 and temperature of 24°C/75°F.
Within a couple of weeks they were spawning every day. I discovered later that Neons can breed from 12 weeks old, which is about the age of most we see for sale. Occasionally a baby would survive and I would spot the tiniest Neon, just beginning to get its colour, peeking out cautiously from the undergrowth.
I decided to try and breed them properly — and my first attempt was the lazy way that always works so well for me with killies and many other species. I just removed the adults and waited!
Sure enough. Within a couple of weeks a handful of baby Neons appeared but, after three attempts, there were never any more. 
Going traditional
Then I tried the traditional method of setting up a bare 30 x 20 x 20cm/12 x 8 x 8” tank with a natural mop of Java moss and fresh rainwater. I darkened the tank, added a well conditioned pair and settled back to observe.
I never saw them spawning and no fry resulted from that first attempt. With later efforts I left the parents together for five to seven days and a few fry were once produced, but they were nothing to write home about. Frustratingly, in the original tank the adults had continued to spawn every day...
I decided to set up a new tank; this time 75cm/30” long, again with rainwater, and with a 2.5cm/1” deep layer of freshly collected oak leaves and one bush of Java moss. I introduced two pairs of adult Neons and watched for about 14 days.
Two things happened. First the water began to go brown and more acidic as the oak leaves softened, and the DH became less than 1, pH less than 5, temperature was 26°C/78°F. The fish took about a week to feel at home in the new tank, but then began to spawn every morning as the room lights were switched on.
The water, tannin stained, became darker and darker and I removed the adults at 14 days and waited. After about a week later I peered into the darkness and spotted a single fry moving hesitantly through the leaf litter. In subsequent days I spotted more and more and I added newly hatched brineshrimp, which they relished.
After about a month I was counting more than 30 fry, and in total this attempt produced about 100 young.
I’m not sure that the pH is critical, but the darkness is. The eggs and fry are susceptible to light, but I believe that the brown water and leaf litter also hid the eggs from the hungry adults which I had fed only sparingly in the breeding tank.
Encouraged by my success I decided to use a similar but larger set-up to try and spawn Congo tetras, but within 24 hours of placing them into the acidic conditions the adults had died.
The Neon tank had acidified over several days and the fish had acclimatised during that period.
However, with the Congos I foolishly let the tank ‘mature’ for a couple of weeks and the fish succumbed when placed into conditions very different to their natural home.
Young Neons colour up at about four weeks and under good conditions are large enough to sell at 12 weeks, but your dealer won’t thank you unless you gradually change the water back to tapwater. I did so over about four weeks and had no ill effects.

Do some babies grow faster? 
One breeding observation still puzzles me. Up to eight weeks after I first spotted fry in the breeding tank, tiny colourless babies still continued to appear. Yet the first baby Neons were already large enough to go back to their parents’ tank and become part of the crowd.
I don’t think it possible that the ‘older’ babies were already breeding as this had been a continuous process, a few tiny babies appearing each day or so. The only reasonable explanations are that some grow much faster than others, or that some eggs experience delayed hatching —  as do many killifish.
The former theory is most likely, as the latter would surely have been noted earlier by better observers.
I’m speculating that in nature some baby Neons stay small and undeveloped, hiding in leaf litter so that if their body of water becomes cut off and evaporates, killing their faster growing siblings, they can survive in tiny amounts of water until the rains come.
I have noticed similar situations with Apistogramma and Ctenopoma, and can’t think of any other explanation.
Published: John Roberston 18 July 2011

julho 20, 2011


Scientific American


Bifocal Fish Sees Differently above and below Water Line
A fish (Anableps anableps) that keeps its eyes half submerged has specially adapted pupils and retinas to see clearly both above and below the water. 
Christopher Intagliata reports
July 20, 2011



Listen to this Podcast: 

http://podcast.sciam.com/daily/sa_d_podcast_110720.mp3


“Hey, four-eyes!” That playground taunt is more accurate when applied to Anableps anableps—a fish related to the guppy. It lives in the brackish waters of mangrove swamps in central and South America, and hunts for food at the water's surface... its bulging eyes submerged halfway. Which poses an evolutionary problem—should those eyes be attuned to the greenish light streaming through the mangroves? Or the yellowish rays drifting up through murky water? Well, these fish eyes see both.
Anableps doesn't actually have four eyes—just the usual two. But each eye has two pupils, one above water, one below. And each pupil sends incoming visual info to a different side of the fish's retina.
Cones in each half of the retina are adapted to produce different light-filtering pigments. So cones hit by underwater rays are primed to sense longer-wavelength yellow light. Cones hit by daylight are sensitive to shorter-wavelength green light. The finding appears in the journal Biology Letters. [Gregory Owens et al., "In the Four-Eyed Fish (Anableps anableps), the Regions of the Retina Exposed to Aquatic and Aerial Light Do Not Express the Same Set of Opsin Genes"]

The entire arrangement makes it easy for this bifocal fish to spot a tasty bug flying above the water, or a bit of algae below. For when it comes to evolution, the ayes have it.