Fish females subjected to stress produce highly active offspring but the risk of abnormalities also increases, according to new research carried out by Dr Monica Gagliano, a research fellow with the AIMS@JCU joint venture, and Dr Mark McCormick from the ARC Centre of Excellence for Coral Reef Studies at the James Cook University.

The research focused on the Ambon damsel fish (Chromis amboinensis), a common reef species in the Indo-Pacific, and has deepened our understanding of how stress factors affect not only the adult fish themselves but also their offspring. Being more active than normal affects survival and more active offspring will therefore have important implications for fish populations in a changing environment.

In their laboratory testing, Dr Gagliano and Dr McCormick exposed fertilized Ambon damsel eggs gathered from the wild to various amounts of the stress hormone cortisol. Previous studies have shown that female Ambon damsels release cortisol from their ovaries when subjected to environmental stress. Fish that lived on reefs with few predatory fish around and little competition released less cortisol than those who lived in environments where they had to deal with a lot of competition and predators.

In addition to making the offspring more active, high doses of cortisol also increases the risk of developmental defects.

“If the mother fish is more stressed and she passes on more cortisol, then the offspring will have a faster developmental rhythm and therefore errors will be more likely in their development. One likely result of this is that the offspring are born asymmetrical,” Dr Gagliano said.

“These baby fish can’t make these important hormones until later in life, so their whole initial development is determined by hormones they obtain from their mothers,” Dr McCormick added.

Developmental errors can naturally cause serious problem for fish and lower their chances of survival. In 2008, Dr Gagliano and her colleagues showed that fish born with asymmetrical ear bones have a hard time handling the open ocean stage of their life and that a large percentage of these fishes die before being able to find a reef to settle on. The asymmetry hurts the fish’s hearing ability and makes it difficult for it to pick up reef-related sounds.

In her new research project, Dr Gagliano has been able to show that maternal stress has a large measurable effect on the shape of ear bones. Offspring subjected to a high dose of cortisol are more than twice as likely to have asymmetrical ear bones compared with those that received no dose of cortisol.

You can find more information in the study published in Oecologia.

In a world first, the Australian company Clean Seas Tuna has managed to successfully rear Southern bluefin tuna (Thunnus maccoyii) in captivity. This breakthrough opens up the way for the development of an alternative to wild-caught tuna.

Clean Seas Tuna announced on April 20 that their tuna broodstock had spawned continuously during a 35-day period from March 12 to April 16, and that the company now had succeeded in raising 28-day-old 2.5 cm tuna fingerlings. During the breeding period, over 50 million fertilised eggs and 30 million larvae were produced by the captive held tunas.

“This is equal to Armstrong walking on the moon,” says an elated Hagen Stehr, chairman of Clean Seas Tuna. Clean Seas Tuna now hope to breed tuna in their facilities off Port Lincoln. “The achievements are world firsts and major stepping stones to present the world with a sustainable tuna resource for the future. There are a number of other hurdles to overcome, but Australia can now achieve total sustainability in tuna.“

According to Fisheries Research and Development Corporation executive director Dr Patrick Hone, farm raised tuna can be a solution to the problem of falling world-wide fish stocks and increased seafood consumption.

“Australia uses 450,000 tonnes of fish a year of which 70 per cent is imported,” says Dr Hone. “Our goal is to lift farmed finfish production from about 50,000 tonnes to 100,000 tonnes annually by 2015.”

Large-scale commercial fish farming is however not a completely unproblematic endeavour from an ecological point of view and farmers will be forced to find solutions for sustainable water management, run-off handling, and food procurement if they truly wish to make farmed tuna an environmentally friendly alternative to wild caught fish.  It is however no doubt that it could provide the wild tuna population with a well needed chance to recover.

The tiny whale shark caught off the Philippine coast near San Antonio on March 6 has been confirmed by WWF to be the smallest live whale shark on record ever to be captured and released in the Philippines and arguably also the smallest living whale shark ever to be scientifically recorded.

Picture by WWF PF. Support WWF

The impressive Whale shark, Rhincodon typus, is the largest fish on the planet. The biggest specimen regarded as accurately recorded was caught in Pakistani waters in 1947 and measured 12.65 metres (41.50 ft) in length, with a girth of 7 metres (23.0 ft) and a weight exceeding 21.5 tonnes (47,300 lb).

The small specimen caught near San Antonio was on the other hand no longer than 15 in (38 cm) and may be what biologists call a neonate, i.e. a newborn. This is very interesting, since we still do not know to which part or parts of the world Whale shark females migrate to give birth to their pups. The finding of this tiny pup has caused scientists to speculate that the Philippine waters might be one of the places on the planet where the biggest fish in the world is born.

So, how did this petite Whale shark end up in human hands? On the morning of March 7, word reached Tourism Officer Pedragosa that a whale shark had been caught near San Antonio the day before. Pedragosa immediately sent Butanding Interaction Officer Guadamor to inform the town’s Municipal Agricultural officer Rabulan, and at this point, Aca, WWF’s Project Leader in Donsol, the municipality in which San Antonio is located, also became involved. When a shark is caught, time is of course crucial – examining the animal is important from a scientific point of view, but you don’t want to subject the shark to more stress than necessary. Aca therefore joined the officers of tourism, agriculture, and interaction at the tourism office right away and together they hastily drew up an operational plan and headed for San Antonio. At this stage, Berango, Chief of Police of Pilar, had also been alerted and Ravanilla, Regional Director of Tourism, had informed the resorts closest to the site.

The Chief of Police met up with Aca and the ministers at the seashore, where they found not a gigantic whale but a small stick jammed into the sand with a rope leading away from it into the ocean. As they followed the rope, they saw that it was tied around the tail of the smallest whale shark they had ever encountered before.

Whale Shark – Picture GNU Licensed

The team examined the shark to make sure that it had not been hurt, gave it food, measured it and documented the unique find. Less then three hours after the report first reached the tourism officer, the shark had been safely transferred to a big, water-filled plastic bag and the team was now heading towards deeper water where the shark could be released. Releasing it close to shore was not considered safe enough since the shallows in this area contains a lot of nets.

All this action took place in Sorsogon, a Philippine province famous for hosting the largest known annual congregation of whale sharks in the world. The province has become a popular destination for vacationers interested in snorkelling with sharks and going on shark safaris, and WWF is therefore working with local residents to develop and improve sustainable eco tourism practices along the coast.

A new species of ghost knifefish has been described by ichthyologists James Albert and William Crampton. It has been given the name Compsaraia samueli in honour of Samuel Albert who presented the scientists with the type specimens.

Ghost knifefish (family Apteronotidae) are famous for their body shape and for using a high frequency tone-type electric organ discharge (EOD) to communicate. The native home of these fishes are South and Central America. Within the aquarium hobby, the Black ghost knifefish (Apteronotus albifrons) and Brown ghost knifefish (Apteronotus leptorhynchus) are fairly common.

Samuel’s ghost knifefish lives in the western Amazon of Peru and Brazil and was collected from flooded beaches and deep river channels. It can be distinguished from its close relatives by having a higher number of caudal-fin rays and a less tapering body shape in lateral profile.

Other distinctive features are the relatively short caudal peduncle and the comparatively small body size (as an adult). The mature male sports an extremely slender and elongated snout and engages in sparring with repeated aggressive non-contact postures, usually followed by jaw-locking and biting.

If you wish to learn more about Samuel’s ghost knifefish, see the paper: Albert, JS and WGR Crampton (2009) A new species of electric knifefish, genus Compsaraia (Gymnotiformes: Apteronotidae) from the Amazon River, with extreme sexual dimorphism in snout and jaw length. Systematics and Biodiversity[1] 7, pp. 81–92.

Genus: Compsaraia

New species: Compsaraia samueli

Chinese ichthyologists Yang, Chen and Yang have described three new species of snow trout in a paper[1] published in the journal Zootaxa[2]. All three species have been described from material previously identified as one single species, Schizothorax griseus. True trouts belong to the Salmoninae subfamily in the Salmonidae family, but snow trouts are members of the family Cyprinidae.

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Schizothorax

New species: Schizothorax beipanensis

Schizothorax heterophysallidos

Schizothorax nudiventris

Schizothorax beipanensis

Schizothorax beipanensis is found in southern China where it inhabits the Beipan River drainage, a part of the Pearl River drainage. It has been encountered in both slow-flowing deep pools and fast-flowing rivers with clear water and over a wide range of different bottom substrate, from mud and sand to rocks, boulders and pebbles.

Schizothorax beipanensis differs from its close relatives by having well-developed upper and lower lips (the lower lip is actually tri-lobed), no horny sheath on the lower jaw, and a continuous postlabial groove with a minute median lobe.

Schizothorax heterophysallidos

Just like Schizothorax beipanensis, the snow trout Schizothorax heterophysallidos is found in the Pearl River drainage in southern China, but it lives in the river drainage of Nanpan, not Beipan. Schizothorax heterophysallidos lives in small streams where the bottom consists of sand and pebbles.

The name heterophysallidos is derived from the unusual swim bladder of this fish; physallis is the Greek word for bladder and heteros means different. In addition to the swim bladder (the posterior chamber of the air bladder is three to six times longer than the anterior chamber), Schizothorax heterophysallidos can be recognized on its well-developed and trilobed lower lip, thin upper lip, and blunt snout. It has a continuous postlabial groove with a minute median lobe and the last unbranched dorsal-fin ray has a strong lower part. In mature specimens, the abdomen lacks scales.

Schizothorax nudiventris

Schizothorax nudiventris also lives in southern China, but in the upper parts of the Mekong River drainage. The Mekong basin is one of the richest areas of biodiversity in the world. More than 1200 species of fish have been identified here and the number is believed to increase as the area becomes more thoroughly explored by science.

Schizothorax nudiventris has a well-developed and trilobed lower lip, thin upper lip, blunt snout, and continuous postlabial groove. The body is decorated with irregular black spots on the sides, and the last one-quarter of the last unbranched dorsal-fin ray is soft. In mature specimens, the abdomen has no scales, and it is this feature that has given the fish its name nudiventris. Nudus is the Latin word for naked, while venter means abdomen.

No, this fish is not animated by Pixar – it is a very real fish created by Mother Nature deep down in the ocean. Its name is Macropinna microstoma and it has puzzled ichthyologists since it was first described by Chapman in 1939.

Macropinna microstoma, also known as the Barreleye fish, has a fluid-filled dome on its head through which the lenses of its barrel shaped eyes can be clearly seen. The fish lives at a dept of 600-800 metres where it spends most of its time hanging almost completely still in the water.

Even though the Barreleye was described by science in the late 1930s, the transparent dome is a fairly new discovered since it is normally destroyed when the fish is brought up from the deep. Old drawings of the fish do not show the see-through part of the head and the species was not photographed alive until 2004.

Thanks to new technology, it is now possible for researchers to explore the deep sea much more efficiently than ever before and we are therefore learning more and more about the weird and wonderful creatures that inhabit these baffling parts of the planet. It has long been known that the tubular eyes of the Barreleye are good at collecting light; an adaptation to a life deep down in the ocean where light is scarce. The eyes were however presumed to be fixed and the fish was therefore believed to have a very narrow upwards-facing tunnel-vision. Researchers Bruce Robinson and Kim Reisenbichler from the Monterey Bay Aquarium Research Institute (MBARI) has now changed this notion completely by providing evidence suggesting that this fish can rotate its eyes within the transparent dome in order to see both upwards and straight forward. Robinson and Reisenbichler observed that when suitable prey, e.g. a jellyfish, is spotted, the fish will rotate its eyes to face forward as it turns its body from a horizontal to a vertical position to feed.

Robinson and Reisenbichler were able to get close to five living Barreleyes using Remotely Operated Vehicles (ROVs) at a depth of 600-800 meters off the coast of Central California. In addition to observing and filming the fish in its native habitat, the researchers also captured two specimens and placed them in an aquarium for a few hours in order to study them more closely.

Live specimens of Macropinna microstoma turned out to have beautifully coloured green eyes; probably in order to filter out sunlight from the surface of the ocean since this would make it easier for the fish to spot bioluminescent jellyfish. Robinson also suggests that Macropinna microstoma might be using its supreme eye sight to steal food from siphonophores[1].

If you want to know more about the intriguing Barreleye fish, check out the paper BH Robison and KR Reisenbichler (2008) – Macropinna microstoma and the paradox of its tubular eyes. Copeia[2]. 2008, No. 4, December 18, 2008.

Remember the strange fish discovered by divers off the Indonesian coast in January 2008? This fish has now been scientifically described and given the official name Histiophryne psychedelica. Well, what else would you call a fish that that looks like this and moves like it was permanently and irrevocably under the influence?

Histiophryne psychedelica, also known as the Psychedelic frogfish, was scientifically described by Ted Pietsch[1] and Rachel Arnold[2] of the University of Washington, together with wildlife photographer David Hall[3].

The University of Washington has released videos where you can see the Psychedelic frogfish swim, or rather hop, skip and jump, over a coral reef. http://uwnews.org/article.asp?articleID=47496

Each time the fish strikes the reef, it uses its fins to push off while simultaneously expelling water from tiny gill openings on the sides of the body to aid in propulsion. The fish is well suited for life on the reef and has for instance been blessed with protective thick folds of skin that keeps its gelatinous body out of harms way among the sharp-edged corals. Just as on the other members of the frogfish group, the fins on both sides of the body have evolved into elongated protrusions more similar to legs than fins. Histiophryne psychedelica does however distinguish itself from other frogfish species by having a flat face with eyes facing forward.

Frogfishes are a type of angelfish, but unlike most other anglers Histiophryne psychedelica does not have any lures on its forehead to tempt its prey with. It also seems to keep its vibrant colours in all sorts of environments, unlike most other anglers who prefer to adapt every inch of their body (except for the lures) to the surroundings in order to stay undetected by prey. According to Hall, the psychedelic colouration might be a way for the fish to mimic corals.

When a Psychedelic frogfish is killed and preserved in ethanol, it looses its lively colours and patterns within a few days and takes on a dull white appearance. This made Pietsch curious about two specimens sent to him in 1992 and he decided to take a closer look at them in a microscope. In the newly caught specimen, the distinctive striping of the fish could still be seen through a microscope and this prompted Pietsch to re-examine the two preserved ones in search of patterns. As it turned out, these two fishes had the same characteristic striping as Histiophryne psychedelica – Pietsch had been storing two specimens of the psychedelic fish for 17 years without realizing it.

If you wish to learn more about this mesmerizing fish, check out the paper Theodore W Pietsch, Rachel J. Arnold and David J. Hall. “A Bizarre New Species of Frogfish of the Genus Histiophryne (Lophiiformes: Antennariidae) from Ambon and Bali, Indonesia.” Copeia[4], February 2009. The study was funded by the National Science Foundation.

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Lophiiformes
Family: Antennariidae
Genus: Histiophryne

New species: Histiophryne psychedelica

The catfish L239 has finally been described by science and given a proper name: Baryancistrus beggini. Ichthyologists Lujan, Arce and Armbruster described the species in a paper[1] published in the journal Copeia[2].

Baryancistrus beggini lives in Venezuela and Colombia; in Rio Guaviare and at the confluence of Rio Ventuari and Rio Orinoco. The researchers found the fish in crevices amongst boulders. By analysing stomach contents, they were able to learn that this catfish feeds on periphyton and associated microfauna growing on rocks. (Periphyton is a mixture of algae, heterotrophic microbes, cyanobacteria, and detritus that can be found attached to submerged surfaces, e.g. stones, in most underwater ecosystems.)

In the aquarium trade, L239 is known as Blue panaque or Blue-fin panaque. The name beggini was given by Lujan and his colleagues in honour of Chris Beggin, the owner of an aquarium fish store in Nashville, USA who funded the research. The species has been placed in the genus Baryancistrus, but this might have to be corrected in the future as we learn more about the tribe Ancistrini.

Baryancistrus beggini sports a uniformly dark black to brown base colour with a blue sheen and the abdomen is naked. Along each side of the body you can see a distinctive keel above the pectoral finns; a keel formed by the strongly bent first three to five plates of the midventral series. The body also features two to three symmetrical and ordered predorsal plate rows and the last dorsal-fin ray is connected to the adipose fin.

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Siluriformes
Family: Loricariidae
Subfamily: Hypostominae
Tribe: Ancistrini
Genus: Baryancistrus

New species: Baryancistrus beggini

A new disease has been discovered; a disease that effects both Leafy seadragons (Phycodurus eques) and Weedy seadragons (Phyllopteryx taeniolatus).

The disease, which as now been described by veterinary pathologists, is a type of melanised fungus that causes extensive lesions and necrosis of the gills, kidneys and other areas of the body in seadragons. The disease was discovered in seadragons kept in aquariums.

Experts from the Department of Pathobiology and Veterinary Science at the University of Connecticut has identified the presence of both Exophiala angulospora and an undescribed Exophiala fungus in sick seadragons.

You can find more information in the paper[1] by Nyaoke et al published in the Journal of Veterinary Diagnostic Investigation[2] in January this year.

The Leafy seadragon (Phycodurus eques) and the Weedy seadragon (Phyllopteryx taeniolatus) are both marine fish species belonging to the same family as seahorses and pipefish. The Leafy seadragon is covered in long leaf-like protrusions that serve as camouflage, while the Weedy seadragon is camouflaged by weed-like projections. Both species are native to Australian waters.

The Census of Marine Life[1] has now documented 7,500 species from the Antarctic and 5,500 species from the Arctic. A majority of the species encountered by the census was previously known by science, but at least a few hundred species are believed to be entirely new discoveries. Researchers did for instance encounter an impressive amount of sea spiders species where the adult spider can grow as big as a human hand.

These new findings may force us to change the way we think about the Polar Regions. “The textbooks have said there is less diversity at the poles than the tropics but we found astonishing richness of marine life in the Antarctic and Arctic oceans,” says Dr. Victoria Wadley[2], a researcher from the Australian Antarctic Division who took part in the Antarctic survey. “We are rewriting the textbooks.“

Dr. Gilly Llewellyn[3], who did not take part in the survey but is the leader of the oceans program for the environmental group WWF-Australia, agrees. “We probably know more about deep space than we do about the deep polar oceans in our own backyard. This critical research is helping reveal the amazing biodiversity of the polar regions.”

The survey was carried out by over 500 researchers from 25 different countries as a part of the International Polar Year which ran in 2007-2008. Thanks to newly developed top-notch technology it is now possible to carry out more efficient exploration of these harsh environments than ever before, and the researchers did for instance examine the Arctic basin down to a depth of 3,000 metres where they encountered tiny, shrimp-like crustaceans. The survey also led to the number of known comb jellies (ctenophores) species to double from five to ten.