Category Archives: Fish


New Population of Mangarahara Cichlid, Ptychochromis insolitus found

Ptychochromis insolitus
The Mangarahara cichlid is known as one of the most endangered cichlids in the world. The Zoological Society of London (ZSL) thought that their two males, together with one fish at the Berlin Zoo might be the last 3  in the world. In a hope to try to save this species they reached out to the public and aquarists around the world to see if anyone had a female Mangarahara cichlid. Continue reading

New Arapaima species -Arapaima leptosoma – Slender Arapaima

arapaima-leptosomaA new species of arapaima, Arapaima leptosoma, has been described by Dr. Donald Stewart of the SUNY College of Environmental Science and Forestry (ESF) at Syracuse University. The new species has been described from specimen that were collected in 2001 near the confluence of the Solimões and Purus rivers in Amazonas State, Brazil. Stewarts discovery brings the total number of Arapaima species up to five . Continue reading

Native American tribes strive to save the lamprey

Lamprey used to be an important source of food for Native American tribes living along the northwestern coast of North America, and the fish was once upon a time harvested in ample amounts from rivers throughout the Columbia Basin, from Oregon to Canada.

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Radioactive strontium-90 found in fish in Vermont, USA

Vermont health officials have found radioactive strontium-90 in a smallmouth bass taken from the Connecticut River.

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Gold Nugget pleco and Mango pleco finally described by science

Two pleco species from the Xingu River drainage that are popular within the aquarium hobby have finally been scientifically described and given scientific names.

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China Releases 1.3 Billion Fish into Yangtze River

Last week, 1.3 billion fish were released into the Yangtze River by the Chinese Ministry of Agriculture (MOA). The release took place in the provinces of Jiangxi, Hubei, Hunan, Anhui and Jiangsu in the middle and lower reaches of the river.

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New species of Brazilian killifish described by science

A new species of killifish native to Brazil has been formally described and given a scientific name. The fish, from now on known as Rivulus albae, belongs to the subgenus Melanorivulus and was found in soft and acidic water in northeastern Brazil.

Rivulus albae

Rivulus albae. Photo By Javier Rabanal

The fish is named after Alba Garcia, the daughter of José Ramón García, one of the authors of the paper in which the species is described.

Appearance

Rivulus albae distinguishes itself from the other members of the subgenus Melanorivulus by having brown oblique bars on the entire flank which on the dorsal portion of the flank often form chevron-like marks with a posterior vertex (vs. chevron-like pattern with vertex pointing anteriorly when present).

Rivulus albae looks quite similar to Rivulus decoratus, but has 6 branchiostegal rays instead of 5, 13 anal fin rays instead of 10 or 11, and 24-26 scales on lateral series instead of 25-28.

Distribution and habitat

All the other recognized species of the subgenus Melanorivulus live in rivers south of the main channel of the Amazon River, but Rivulus albae was collected north of the Amazon River, in the state of Amapá. So far, the species is only known from a handful of localities belonging to Comprido Lake and Tartaruga Grande River.

Rivulus albae was collected in an environment where the savannah meets the forest, close to the banks of large water bodies with clear water at an altitude up to roughly 50 meters above sea level. This fish lives in lakes and lagoons where the underwater vegetation is dense and the water soft and acidic (pH 6.0-6.5).

Authors

  • STEFANO VALDESALICI, ITALYvaldesalici.stefano(at)gmail.com
  • JOSÉ RAMÓN GARCÍA GIL, SPAIN
  • DALTON TAVARES BRESSANE NIELSEN, BRAZIL

The paper was published in Vertebrate Zoology on June 22, 2011.

http://www.vertebrate-zoology.de/vz61-1/06_Vertebrate_Zoology_61-1_Valdesalici.pdf

http://www.vertebrate-zoology.de/

The mystery of bonefish spawning solved

The Bonefish is an extremely popular fishing that lures 1000s of sport fishermen to try their luck each year but until now it has been unknown how this species reproduce. Andy Danylchuk, a researcher working at University of Massachusetts Amherst and his colleagues have been studying bonefish for the last few years using using ultrasonic transmitters to tag and track the fishes movements. The research have been conducted outside Bahamas. The results can now be found in the online version of the journal Marine Biology.

The research show that bonefish gather by the thousands at pre-spawning aggregation sites for a few days each month during the spawning season (October to May). This usually take place during the full and new moon. The fish than migrate together out into deeper water at dusk where they than spawn at depths of more than 1000 ft (300m).

Andy Danylchuk says that “One possible benefit of bonefish migrating to offshore locations to spawn is that it increases the dispersal of their fertilized eggs, especially with the high tides that happen with the new and full moons.”

He also says that this is “This is the first time movement patterns of bonefish to deep water have been formally described,” and that “This new understanding of bonefish movement and spawning aggregations has significant implications for their conservation,”

The researcher have tagged and followed a total of 60 fish over two years.

Aquarium calamity – are you prepared?

Photo Dr P Andreas Svensson

Many pet owners purchase pet insurance for their dogs, cats, horses etcetera but have you ever thought about the insurance needs of your aquarium? While few insurance companies would let you take out a life insurance policy on a guppy or be willing to pay for goldfish surgery, there are other types of insurance that any aquarium owner should consider.

The insurance needs of an aquarium owner can be divided into two categories:
Insurance for the aquarium itself, including equipment and inhabitants
Insurance that covers damages caused by the aquarium, e.g. water damage to the floor and the apartment below you

Your aquariums, their contents, and any damage caused by them may or may not be covered by your homeowner’s or renter’s insurance. You need to check your specific policy to find out more – and don’t forget to read the small print. Many insurance policies have quite a comprehensive exclusion list and it is not unusual for all aquariums, or certain aquariums, to show up on this list. Your insurance company may for instance only be willing to pay for damages caused by an aquarium up to a certain amount of gallons, or only cover aquariums that live up to certain standards. It is also quite common for insurance policies not to cover the inhabitants (livestock) of the aquarium but everything else. Some insurance companies will consider plants and corals inhabitants, while others see them as decor.

If you build your own hobby aquariums this doesn’t necessarily disqualify them from being insured. However, most insurance companies have rules stipulating that only “professional quality” aquariums can be insured. This doesn’t mean that an aquarium has to be built by a professional to insured, only that it has to live up to the same level of quality as a professionally constructed tank. Naturally, this is an area where insurance companies and aquarium owners do not always see eye to eye.

Last but not least, it is common for insurance companies to have a notification limit. If for instance your policy has a $1 500 notification limit, you have to inform the insurance company about any possessions that are worth more than $1 500. If for instance your home is burglarized and you file a claim for a $2 000 necklace that got stolen, the insurance company may refuse to cover the necklace if you failed to notify them about you keeping such a precious piece of jewelery in your home. If you own an aquarium, keep in mind that if you file a claim for the entire aquarium you may hit this $1 500 ceiling even if the tank itself did not cost $1 500 to buy. As any fish owner knows, the dollars can keep piling up quite rapidly. You buy a $500 tank, you add some nice filters and a heater, you get some additional stuff along the way, and soon you’ve reached the notification limit without even realizing it. Take a closer look at your aquarium. Would you file a claim if it was destroyed? If yes, have you notified the insurance company about its value?

Hagfish absorb food directly through its skin

hagfish

Hagfish

Hagfish, an elongated scavenger found on the bottom of the sea, is truly a weird and wonderful creature. A single fossil of hagfish shows that is has undergone little evolutionary change in the last 300 million years, and the hagfish is believed to the be oldest living connection to the first vertebrate. Its the Hagfish, an elongated scavenger found on the bottom of the sea, is truly a weird and wonderful creature. A single fossil of hagfish shows that is has undergone little evolutionary change in the last 300 million years, and the hagfish is believed to the be oldest living connection to the first vertebrate. Its eyespots can detect light but lacks both lens and extrinsic musculature, and is therefore believed to show a significant step in the evolution of more complex eyes. The hagfish is also famous for exuding vast amounts of a gel-like slime when threatened. An adult hagfish can secrete enough slime to turn a 20 litre (5 gallon) bucket of water into slime in a matter of minutes. When captured, e.g. by a human or predatory fish, it will tie itself in an overhand knot which gradually works its way from the head to the tail of the hagfish, scraping off the slime as it goes, thus freeing the hagfish from its captor and from the slime in one swift movement.

Hagfish eat dead and injured sea creatures and will borrow into the body cavity of a dead (or dying!) animal to devour it from within. Once its full, it can go several months without feeding again.

Now, a new study on hagfish caught near Vancouver Island in Canada has unveiled yet another remarkable fact about the hagfish – it seems as though this fish is actually able to eat with its skin and gills, i.e. absorb nutrients through its skin and gills instead of using its mouth.

A research team* headed by Chris Glover of the University of Canterbury in New Zealand and Bamfield Marine Sciences Center took skin and gill tissue from hagfish and tested the tissues’ absorption of two different amino acids.

“We wanted to start with a simple dissolved organic nutrient, and given the fact that the food source is a large decaying pile of protein, an amino acid seemed to be the best place to start,” says Glover.

When a hagfish has managed to burrow its way into a carcass, it will feed surrounded by a high concentration of dissolved nutrients, so being able to absorb food through more than just its mouth could come in handy.

The results of the study carried out by Glover and his colleges indicate that specific molecular mechanisms exist within the hagfish tissues to move the two tested amino acids into the body of the fish. When researchers increased the concentration of amino acids the tissue increased its absorption – but only up to a certain level.

“A quick and simple calculation suggests that the skin in particular may be capable of absorbing nutrients at levels equivalent to that of the digestive tract!”, says Glover.

There are quite a few invertebrates, including many mollusks and worms, that can absorb nutrients through their skin. But up until now, no vertebrates have been known to have this capacity. The hagfish may represent a transition between the feeding habits of aquatic invertebrates like mollusks and the more specialized digestive systems found in vertebrates. While some organisms exchange nutrients with the water around them in order to maintain their body fluid salt concentrations, the hagfish is – according to Glover – likely to transport amino acid molecules through its skin and gills exclusively to feed itself.

The paper “Adaptations to in situ feeding: novel nutrient acquisition pathways in an ancient vertebrate” has been published in the most recent issue of journal Proceedings of the Royal Society B: Biological Sciences.

* Chris N. Glover (http://www.biol.canterbury.ac.nz/people/glover.shtml) School of Biological Sciences, University of Canterbury, Christchurch, New Zealand Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada

Carol Bucking (no bio page available) Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada Department of Zoology, University of British Columbia, British Columbia, Canada

Chris M. Wood (http://www.biology.mcmaster.ca/faculty/wood/wood.htm) Bamfield Marine Sciences Centre, Bamfield, British Columbia, Canada Department of Biology, McMaster University, Ontario, Canada