Category Archives: Ichthyology

Overfishing leading to extinction of many shark and ray species

THE EARTH TIMES

Bonn, Germany – Overfishing is leading to the extermination of many species of shark and ray in the world’s oceans, according to a new international study presented Thursday to the UN Biodiversity Conference in Bonn. Released to coincide with International Biodiversity Day, the study of the global status of 21 species of oceanic pelagic sharks and rays reveals that 11 of them are threatened with extinction.

The study, organized by the IUCN international conservation organization, calls on governments to take steps to halt the overfishing of the species. The scientists from around the world found that the sharks and rays, including the Thresher shark, the Silky shark and the Shortfin mako, were facing extinction owing to targeted fishing for fins and meat. Unintentional “bycatch” by other fisheries was also a serious problem. “The traditional view of oceanic sharks and rays as fast and powerful too often leads to a misperception that they are resilient to fishing pressure,” Sonja Fordham, co-author of the paper and member of the IUCN shark group, said. The study noted the increasing demand for the delicacy shark fin soup, which was being driven by growing Asian economies, and the resultant waste when the rest of the shark was simply thrown away. Shark and ray species often take several years to reach sexual maturity, have relatively few young and are thus particularly vulnerable to overfishing. The IUCN called on governments to establish and enforce shark catch limits, halt the practice of removing fins and discarding the rest, cut the bycatch and to invest in further research into populations. The study is published in the latest edition of Aquatic Conservation: Marine and Freshwater Ecosystems.

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Canadian pair pleads guilty to smuggling endangered fish into U.S.

 The Canadian Press

BUFFALO, N.Y. — A pair of Canadian citizens could face up to five years in prison and a $250,000 fine after pleading guilty to charges they tried to smuggle endangered Asian fish into the United States.

Investigators say the couple from Toronto tried to enter the United States last August at the Rainbow Bridge in Buffalo.

They told inspectors they were going shopping and had nothing to declare.

Authorities say border agents found eight Asian arowana fish covered with newspaper in the back of the vehicle.

The fish, also called “Lucky Fish,” are protected under the Endangered Species Act.

Investigators say they bought the fish in Canada and planned to sell them for $2,000 to a person from New York City they planned to meet on the New York State Thruway.

Jian-Cong Huang and Hsaio-Fang Yu, both of Toronto, pleaded guilty Thursday.

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Warning that bluefin tuna ‘face extinction’

EMILY BEAMENT – THE SCOTSMAN

BLUEFIN tuna are being pushed to the brink of extinction in the Mediterranean by far too many fishing vessels pursuing the remaining fish stocks, a report warned yesterday.
A study for conservation charity WWF says there needs to be an urgent reduction of the fleet, which has almost twice the fishing capacity of current quotas set for the increasingly threatened fish.

The yearly catch potential of hi-tech vessels is three and a half times the recommended level, the report says.

According to the conservationists, the “unsustainable” situation is largely the result of massive overfishing of the Mediterranean by what is known as “purse seine” fishing, in which nets are set around the shoal and then closed like a drawstring purse.

This method is fuelled by the increase in tuna farms, which take the catch and fatten the fish in cages for six months.

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Butterfly fish ‘may face extinction’

WILDLIFEEXTRA.COM

Scientists have warned that a beautiful black, white and yellow butterflyfish, much admired by eco-tourists, divers and aquarium keepers alike, may be at risk of extinction.

The case of the Chevroned Butterflyfish is a stark example of how human pressure on the world’s coral reefs is confronting certain species with ‘blind alleys’ from which they may be unable to escape, says Dr Morgan Pratchett of the ARC Centre of Excellence for Coral Reef Studies and James Cook University.

Highly Specialized Feeding Habit
In a study published in the journal Behavioural Ecology and Sociobiology Dr Pratchett and Dr Michael Berumen of Woods Hole Oceanographic Institution (USA) warn that the highly specialized nature of the feeding habits of this particular butterflyfish – the distinctively patterned Chaetodon trifascialis – make it an extinction risk as the world’s coral reefs continue to degrade due to human over-exploitation, pollution and climate change.

‘The irony is that these butterflyfish are widespread around the world, and you’d have thought their chances of survival were pretty good,’ Dr Pratchett said today. But they only eat one sort of coral – Acropora hyacinthus – and when that runs out, the fish just disappear from the reef.’

Rather Starve Than Change Diet
The team found it hard to believe a fish would starve rather than eat a mixed diet, so they tested C. trifascialis in tank trials on a range of different corals. The fish grew well when its favourite coral was available – but when this was removed and other sorts of corals offered, it grew thin, failed to thrive and some died.

‘We call these kinds of fish obligate specialists. It means they have a very strong dietary preference for one sort of food, and when that is no longer available, they go into decline. We still don’t have a satisfactory scientific explanation for this, as it seems like rather a risky tactic in evolutionary terms – but it must confer some advantage provided enough of its preferred food is available,’ Dr Pratchett says.

Bleached coral wih damsel fish. © James Cook University.

Vulnerable Coral
The A. hyacinthus coral, which the butterfly fish feeds on, is itself highly vulnerable – to attacks by plagues of crown-of-thorns starfish (thought to be triggered by humans releasing excess nutrients onto the reef as sediment, fertilizer or sewage), to storms and to the coral bleaching caused by the heating of ocean surface waters to 32 degrees or more, which is thought to be linked to global warming.

‘Although extremely widespread, the Chevroned butterflyfish may be at considerable risk of extinction following ongoing degradation of coral reefs around the world, because the coral itself is exceptionally vulnerable, Dr Pratchett explains.

‘It is estimated that up to 70 per cent of the world’s coral reefs are now badly degraded, which usually involves the loss of this particular coral – and, when it goes, the C. trifascialis also disappear from the reef.

Targeted by Aquarium Collectors
‘To make matters worse, butterfly fishes are one of the main families of coral reef fishes being targeted by aquarium collectors. However, the specialized coral-eaters are clearly not suitable for keeping in aquaria – and often die because they cannot obtain their main food source.’

A previous case in which a coral-dependent fish vanished occurred in the case of Gobiodon a specialized coral-dweller known only from one site, Kimbe Bay in Papua New Guinea, which was thought by scientists to have possibly become extinct after its habitat was destroyed.

Researchers consider that such extinctions are likely to occur as part of the global mass extinction of species now taking place, and that marine ecosystems may be particularly vulnerable in that small changes in habitat or water quality can have a big impact on their species.

Dr Pratchett and Dr Berumen say theirs is one of the few studies so far to consider the evolutionary and ecological basis of dietary versatility, and has implications for the fate of specialised feeders throughout the animal kingdom.

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Oregon’s Coho Return To Endangered Species List

Joseph Friedrichs – New West
Oregon’s coastal coho salmon have once again been placed on the endangered species list, after a recent ruling that found scientific evidence didn’t support delisting the fish.

According to an article in today’s Oregonian, the National Oceanic and Atmospheric Administration Fisheries, a federal agency charged with restoring Northwest salmon, found the fish aren’t as resilient as they believed.

Coho were listed as threatened between 1998 and 2004, then was taken off the list in 2006 when NOAA Fisheries ruled that the coho are “not likely to become endangered” in the foreseeable future, the Oregonian reported.

More than a million coho once filled coastal rivers and streams, but similar to a dozen other spices of salmon in the Pacific Northwest, those numbers have declined dramatically.

As a result of Monday’s announcement, the federal protections could slow logging and other development along coastal rivers and streams where coho spawn.

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Sask. river sturgeon headed for extinction

Hanneke Brooymans – The Star Phoenix

EDMONTON — Canada’s largest freshwater fish could soon find itself on the endangered species list.

And in the North and South Saskatchewan River systems, which span the three Prairie provinces and part of Montana, the population of lake sturgeon — which once shared the planet with dinosaurs — has declined as much as 80 per cent, according to the federal government.

Ottawa is therefore considering using legislation to protect the large, bottom-feeding fish. To that end, it recently ran advertisements, soliciting public reaction to the idea.

But getting the sturgeon on the endangered list could be “very challenging,” said Fred Hnytka, a species-at-risk biologist with the Department of Fisheries and Oceans.

For instance, it could be difficult to restrict how many are caught along some northern rivers, where First Nations people have a cultural attachment to the fish, Hnytka said.

Lake sturgeon are found in waterways from Alberta to Quebec. They can live for decades — some up to 100 years.

In Alberta alone, they once swam at 48 sites in the North Saskatchewan River and 30 in the South Saskatchewan River. They are now found at 16 and 12 sites, respectively.

In August, the Committee on the Status of Endangered Wildlife in Canada recommended listing the sturgeon as endangered, blaming over-fishing and habitat loss from dam construction. Adding to the species’ problems is the late and infrequent spawning of its females.

“The species is just so vulnerable, you need to be extra cautious,” said Joe Nelson, a University of Alberta professor emeritus who wrote Fishes of Alberta. “That’s why I would come down in favour of it being listed.”

Terry Dick, a University of Manitoba zoology professor, said it’s a disgrace the species hasn’t been listed yet.

“It was wiped out in so many areas nearly 100 years ago, and we’re still debating it,” said Dick, who wrote the original proposal to the Committee on the Status of Endangered Wildlife in Canada.

Dick said the government shouldn’t be worried about the challenges of dealing with First Nations, and should seek to involve them directly in the recovery plans.

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One in three fish species threat of extinction

Fish and Fly

A shocking picture of over one in three freshwater fish species struggling for survival has emerged.

In a first ever assessment of European fish research shows how 100 years of industrial development has wreaked havoc on river systems.

The study done by the World Conservation Union (IUCN) and published in the Handbook of European Freshwater Fishes reveals that 200 of the 522 species are threatened with extinction – 12 are already extinct.

William Darwall, from IUCN, said: “Many of these species, not considered as ‘charismatic’ or with any apparent ‘value’ to people, rarely attract the funds needed for their conservation.

“They risk disappearing with only a dedicated few noticing the loss.”

He went on to say that many of the species could be saved just by simple water purification and flood control.

Examples of fish most in danger include the European eel (Anguilla anguilla), Gizani (Ladigesocypis ghigii) and Jarabugo (Anaecypis hispanica).

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