Tag Archives: Fish


New tetra described from Xingu River

A new species of Jupiaba tetra has been described by Brazilian ichtyologists Birindelli, JLO, AM Zanata, LM Sousa and AL Netto-Ferreira.

The fish has been given the name Juipaba kurua, a name derived from the type locality; the Curuá River which is part of the Xingu River drainage. The river name Curuá comes from the tupo language kurua.

Researchers analysed the gut content of these fishes to find out more about their habits and the results indicate that Juipaba kurua is an omnivore clearwater species that feeds along the entire length of the water column.

The faint dark Juipaba kurua is differs from its close relatives by sporting an elongate humeral blotch, a distinct dark spot on the caudal peduncle, and a pattern of dark spots on most of the scales on the sides of the body. The fish has teeth cusps of similar size and the lower jaw teeth gradually decrease in size posteriorly. The number of branched anal-fin rays varies from 21 to 24.

The description of Juipaba kurua was published in the latest issue of the journal Neotropical Ichthyology.

Birindelli, JLO, AM Zanata, LM Sousa and AL Netto-Ferreira (2009) New species of Jupiaba Zanata (Characiformes: Characidae) from Serra do Cachimbo, with comments on the endemism of upper rio Curuá, rio Xingu basin, Brazil. Neotropical Ichthyology 7, pp. 11–18.

Dogfish explosion causes problem for U.S. fishermen

Commercial, recreational and party/charter boat fishermen from Maine to North Carolina have all rallied together to deal with an out-of-balance population of predatory spiny dogfish sharks that threatens the recovery of New England groundfish and several others fish stocks living along the U.S. East Coast.

The newly formed Fishermen Organized for Rational Dogfish Management (FORDM) has requested the assistance of Dr. Jane Lubchenco, newly appointed National Oceanic and Atmospheric Administration head, in dealing with the predator.

spiny dogfish
Spiny dogfish

The disproportionate abundance of dogfish is not a new problem; as early as 1992 Dr. Steven Murawski, now chief scientist of the National Marine Fisheries Service’s, wrote “Given the current high abundance of skates and dogfish, it may not be possible to increase gadoid (cod and haddock) and flounder abundance without ‘extracting’ some of the current standing stock.”

That was over 15 years ago and the situation has not improved. On the contrary, the amount of dogfish now exceeds that of skates, and dogfish comprises over half of all fish taken in the annual trawl surveys carried out by the Northeast Fisheries Science Center.

The spiny dogfish can exceed 150 cm in length and preys on virtually all species of fish smaller than itself. Dogfishes can also create a problem for other species by competing with them for prey fish.

This remarkable abundance of dogfish is most likely the result of countless years of ever increasing over-fishing. Spiny dogfish is not an appreciated food fish and the depletion of other species seems to have favoured it greatly in these waters.

Fishing fleets from the European Union hampers cod recovery in the Grand Banks near Canada

According to WWF Canada, excessive bycatch* of cod is undermining the cod moratorium imposed in 1994. On the southern Grand Banks near Canada, cod bycatch is now at least 70 percent higher than target levels and this is hampering the recovery of one the world’s best known fisheries.

WWF Canada also states that ships from the European Union are responsible for the largest proportion of the overrun bycatch.

cod

In 2003, bycatch amounts were estimated to be over 80 per cent of the remaining cod stock which caused WWF to push for a 2008 cod recovery strategy that included setting a bycatch reduction target of 40 per cent for the southern Grand Banks at the September 2007 annual meeting of the Northwest Atlantic Fisheries Organization (NAFO).

The 40 percent target level was based on estimations of how much the cod population could endure and still have at least some chance of recovery. 40 percent is equivalent of 420 tonnes of cod, but unofficial fishing statistics for the year 2008 show that almost twice as much, 713 tonnes, was caught as bycatch last year. Of these 713 tonnes, ships from the European Union member states accounted for 444 tonnes.

It should be noted that these figures does not account for misreported bycatch and illegal fishing.

WWF Canada is now urging NAFO to adopt an effective recovery plan for southern Grand Banks cod; one hat will include immediate bycatch reduction targets as well as long-term recovery goals. Gear-based solutions need to be combined with protection of spawning and nursery areas for the plan to be effective and the arrangements must naturally be backed by efficient monitoring and enforcement to have any effect. Such a recovery plan would be consistent with the Ecosystem management approach adopted in the newly revised NAFO Convention.

Cod and other fish stocks can never recover as long as NAFO refuses to see the urgency of the bycatch problem and acknowledge that voluntary measures are not working,” says Dr. Robert Rangeley, Vice President Atlantic, WWF-Canada. If NAFO’s Scientific Council starts working on solutions at their June meeting then it will be the responsibility of the Fisheries Commission, in September, to impose strict management measures that will give cod recovery a chance.”

* Bycatch is here defined as unused and unmanaged catch. You can find more information about bycatch in “Defining and Estimating Global Marine Fisheries Bycatch”; a paper co-authored by WWF for the journal Marine Policy. According to this paper, the global bycatch now constitutes over 40 percent of the global reported catch.

New genus created in danioninae revision

A study of the molecular phylogenetic interrelationships of south Asian cyprinid genera Danio, Devario and Microrasbora has resulted in a reclassification of the group and the creation of a new genus: Microdevario.

The study, which has been published in a recent issue of the journal Zoologica Scripta, was carried out by Fang Fang and his colleges at the Swedish Museum of Natural History.

The researchers examined the molecular phylogeny of the Danioninae using fragments of the mitochondrial cytochrome b and nuclear rhodopsin genes from 68 species, including 43 danioinine species.

The analysis revealed the species Microrasbora rubescens and the genera Chela, Laubuca, Devario, and Inlecypris to form a natural group, the Devario clade, with the species Microrasbora gatesi, Microrasbora kubotai and Microrasbora nana being in sister group position to the rest.

zebrafish
Zebrafish

These findings, in combination with subsequent analysis of morphological characters, have made the authors propose four taxonomic changes:

· The species Inlecypris auropurpurea is reassigned as Devario auropurpureus.

· Microrasbora gatesi, Microrasbora kubotai and Microrasbora nana are reassigned to a new genus named Microdevario. Fish of this genus are distinguished from other danioinines by a combination of skull and jaw characters.

· Reassignment of the species Celestichthys margaritatus to the genus Danio in previous studies is confirmed.

· The membership of Chela is restricted to Chela cachius. All other species previously placed in this genus are reassigned to the genus Laubuca, except Chela maassi, which is in the genus Malayochela.

For more information about the study and the suggested taxonomic changes, see the paper Fang, F, M Norén, TY Liao, M Källersjö and SO Kullander (2009) Molecular phylogenetic interrelationships of the south Asian cyprinid genera Danio, Devario and Microrasbora (Teleostei, Cyprinidae, Danioninae). Zoologica Scripta 38, pp. 237–256.

Rare Megamouth shark found in pot with milk, malunggay leaves and chilli

The elusive Megamouth shark (Megachasma pelagios) is such an uncommon sight that only 42 confirmed reports of this fish exists since the species was first scientifically described in 1976.

The most recent report, the 42nd one, comes from a group of Philippine fishermen from the city of Donsol who accidently caught a four-metre long specimen while trawling for mackerel.

Mega mouth
Mega mouth shark exhibited at the Aburatsubo Marine

Worldwide Fund for Nature project manager Elson Aca examined the fish and identified it as a megamouth shark. The shark weighed an estimated 500 kg and was captured at a depth of 200 metres off the eastern coast of Burias Isle. This wasn’t the shark’s first encounter with fishing gear; it had scars on its face from gill nets.

Soon after being landed at Barangay Dancalan in Donsol, the shark died. Aca entreated the fishermen not to butcher the shark, but the fishermen had a more traditional than scientific approach to caught fish and promptly cooked it with coconut milk, malunggay leaves and chilli to make a Philipine dish known as kinunot.

According to Aca, the the Donsol-Masbate region deserve more attention from conversationalists.

The presence of two of the world’s three filter feeding sharks warrants special attention for the Donsol-Masbate region”, Aca said. “Whale and megamouth sharks, manta rays, dolphins and other charismatic giants indicate that the region’s ecosystem is still relatively healthy. By protecting megafauna, we help maintain the dynamic balance of our seas, and ensure the entire ecosystem’s resilience and natural productivity.”

One eel, One rectum, One wonderful story!

According to the journal Surgery, a 50 cm (20 in) eel was removed from a man’s rectum at the Kwong Wah Hospital in Kowloon, Hong Kong.

The 50-year old man was admitted to the Accident and Emergency Department complaining about abdominal pain.

Euripean eel
European Eel – Picture by Ron Offermans; GNU

Doctors diagnosed him with peritonitis, inflammation of the peritoneum*, and did an x-ray to find out the underlying cause. Interestingly enough, what they saw on the x-ray was an eel stuck inside the man’s rectum.

The eel was still alive and biting the patient’s splenic flexure, which is a sharp bend located between the transverse and the descending colon. Doctors also found a 3 cm perforation over the anterior wall of the rectum.

“On further questioning,” says the paper, “the patient admitted an eel was inserted into the rectum in an attempt to relieve constipation. This may be related to a bizarre healthcare belief, inadvertent sexual behaviour, or criminal assault. However, the true reason may never be known.”

The patient was released from hospital a week later. We have been unable to find any information about what happened to the eel.

* The peritoneum is a serous membrane that forms the lining of the abdominal cavity or the coelom.

Cigarette filters dangerous for fish

Filtered cigarette butts should have new requirements for disposal, says Public Health Professor Tom Novotny after a San Diego State University (SDSU) study revealed filter-tipped cigarette butts to be toxic to marine and fresh-water fish.

According to Novotny and other members of the Cigarette Butt Advisory Group, used cigarette filters ought to be classified as hazardous waste since toxins present in them harm wildlife.

cigarette but kills fish

It is toxic at rather low concentrations,” Novotny explains. “Even one butt in a liter of water can kill the fish in a period of 96 hours.”

Novotny says one way of reducing the amount of cigarette filters in our environment is stronger enforcement of anti-litter laws and non-smoking areas. Fines, waste fees or special taxes are other options, if the money is used to pay for cigarette butt recycling. A third alternative is to force manufacturers to pick up the bill for clean-up costs incurred by their products.

A thrown away cigarette butt is a combination of the original plastic filter and the compounds caught by the filter while the cigarette was being smoked. The plastic makes the filter non-biodegradable and the trapped compounds are toxic until they eventually biodegrades into the environment.

According to Novotny, cigarette butts are the number one littered substance in the world and have been the number one single item picked up on beach cleanup days in San Diego for several years.

When they unconsciously throw their butts onto the ground, it’s not just litter, it’s a toxic hazardous waste product,” Novotny says. “And that’s what we’re trying to say. So that may be regulated at the local or state level. And we hope people will be more conscious about what they do with these cigarette butts.”

The study was carried out by SDSU Public Health Professor Rick Gersberg.

Picture by: Chris Sanderson, in Peterborough, Ontario, Canada.

Increasing numbers of juvenile whale sharks arrive to Ningaloo Marine Park

According to a new report from Ningaloo Reef, the number of whale sharks in its waters is on the increase. The study, published in the journal Endangered Species Research (ESR), was made possible thanks to ECOCEAN – a new type of online photo-identification technology.

The system works by encouraging members of the public to send in their photos of whale shark, photos which are then stored in the in a database. Once they are in the data base, scientist can identify each whale shark using the pattern-recognition software.

Baby whale shark

Baby whale shark in the Phillipines.
Picture by WWF PF. Support WWF

The new technology in combination with the aid of citizens makes it easier for scientists to learn more about the migratory habits of the whale shark, the world’s larger fish. Prior to the 1980’s there were no more than 350 confirmed sightings of whale shark around the globe.

Since the project first began in 1993, over 500 new individual whale sharks have been discovered at Ningaloo Reef.

Why are more and more juveniles arriving on the reef? It’s unclear, but it’s positive news,” says Jason Holmberg, lead author of the study.

Brad Norman, founder of the ECOCEAN whale shark project and Murdoch University, says the research shows that whale sharks can increase where they are well-protected.

We have also demonstrated the power of citizen-science, that ordinary people around the world can make a real contribution to serious research and conservation,” he says. “Thanks to increasing levels of data collection, we’re finally able to estimate how many whale sharks appear annually, how long they typically remain at Ningaloo Marine Park (NMP), their patterns of arrival and departure and shifts in their population structure.”

In some countries whale sharks are still harvested commercially, while others have shifted over to whale safaris which can generate a substantial income through ecotourism. The researchers from Curtin University have shown that whale shark ecotourism can be advantageous for local communities around whale shark ‘hotspots’ such as the Ningaloo Reef.

Our results indicate that without whale sharks at Ningaloo Marine Park (NMP) up to $4.6 million* would be lost from the local economy,” says Norman.

The success of the online collaboration between scientist and citizens has prompted researchers to issue a worldwide call to vacationers and divers to join in a global effort to monitor and protect the whale shark. You can find more information at www.whaleshark.org.

* 4.6 million AUD equals roughly 3.4 million USD

Mexico requests Emergency Rule to Protect Sea Turtles

After a request from the Mexico Fishery Management Council, NOAA’s* Fisheries Service announced an emergency rule to protect the threatened sea turtles living in the Gulf of Mexico.

The emergency rule, which was announced on April 30, will take effect on May 18. From May 18 and onwards, the commercial reef fish longline fleet active in these waters will only be allowed to fish seaward of a line approximating the 50-fathom contour in the Gulf of Mexico. (Current regulations allow the fleet to fish as close as the 20-fathoms line.)

loggerhead turtle

The emergency rule will also outlaw all reef fish longline fishing east of 85 degrees 30 minutes west longitude in the Gulf of Mexico after the quotas for deep water grouper and tilefish are reached.

The Mexico Fishery Management Council requested the emergency rule after a NOAA observer study documented how the reef fish longline fleet was incidentally catching and killing a substantial amount of loggerhead sea turtles, a species listed as “threatened” under the Endangered Species Act.

The emergency rule will be in effect for 180 days, but can be extended for up to an additional 186 days if necessary. The new rule will primarily affect those who fish for shallow-water grouper species, such as the popular food fish red grouper, since this type of fishing typically takes place in shallow waters within the 50-fathom contour off the west Florida shelf. Fishermen and groupers are however not the only ones occupying this area – it is also a very important feeding ground for sea turtles and therefore the place where most of the incidental sea turtle by-catches take place.

We are working closely with the council and constituents to find more permanent solutions to protect sea turtles affected by this fishing gear,” said Roy Crabtree, NOAA’s Fisheries Service southeast regional administrator. “I hope we can identify options that not only provide sea turtles the protection they need, but minimize the economic affects to the fishing industry.”

The Gulf of Mexico Fishery Management Council is also considering actions to address the problem on a long-term basis.

The emergency rule is implemented in accordance with both the Endangered Species Act and the Magnuson-Stevens Act. The Magnuson-Stevens Act requires that conservation and management measures minimize bycatch of non-target species and minimize mortality when bycatch cannot be avoided.

* National Oceanic and Atmospheric Administration (NOAA)

Squeaker catfish evolved from single ancestor

The members of the genus Synodontis, commonly known as the squeaker catfishes of Lake Tanganyika, evolved from a single common ancestor according to a paper* published in a recent issue of the Journal of Evolutionary Biology.

synodontis catfish
synodontis catfish

Researchers Day, Bills and Friel** analysed 1697 base-pair sequences consisting of nuclear (ribosomal protein-codin gene S7), mitochondrial (cytochrome b) and transfer RNA gene fragments in 65 samples (representing about 40 species) of squeaker catfishes to study the evolutionary relationships of the group.

Through their research, the authors were able to track down a single origin for the Lake Tanganyika species flock. The members of the genus Synodontis all evolved within the last 5.5 million years which makes them a comparatively new addition to this Great Rift Valley Lake which is believed to be at least 9 million, perhaps even 12 million, years old.

Day, Bills and Friel also recovered a monophyletic group of southern African riverine species which seems to have diversified very rapidly (during the last 890,000 years). This group was believed to have been formed due to adaptive radiation within Lake Makgadikgadi; a lake which is now extinct.

* Day, JJ, R Bills & JP Friel (2009) Lacustrine radiations in African Synodontis catfish. Journal of Evolutionary Biology 22, pp. 805–817.

**Julia Day, Roger Bills and John Friel