Tag Archives: coral

Top 10 Most Endangered Fish: Number 1

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Bluefin Tuna

Perhaps the most iconic of endangered fish, the bluefin tuna occupies most of the northern Atlantic Ocean. One of the fastest fish in the sea, this species can grow to a length of 10 feet and weigh more than 1,400 pounds. This species’ reputation as a fighter has made it a popular catch among recreational fisherman. And at a going rate of up to $100,000 per fish, it’s highly prized by commercial fisherman as well. Bluefin tuna are heavily overfished, and most experts agree that without prompt intervention, the slow-growing, slow-maturing species will become extinct. International regulation is tricky, however, since the bluefin tuna is known to migrate thousands of miles across the ocean. And so far, efforts to control harvests have largely failed. Chosen by the WWF (formerly known as the World Wildlife Fund) as the sixth most threatened species in the world, sea or land, the bluefin tuna is by all measures critically endangered.

Top 10 Most Endangered Fish: Number 2

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Maltese Ray

Historically, the Maltese ray populated the Mediterranean Sea in the coastal waters of Italy, Algeria, Malta and Tunisia. Today, its range is limited to the heavily-fished Strait of Sicily, a 90-mile-wide channel between Italy and Tunisia. Though little is known about this particular species, it likely displays characteristics similar to other rays: It grows slowly, matures late and produces few offspring. Commercial fishing vessels rarely target the Maltese ray. Rather, it is taken as bycatch in boats harvesting other species. Once they’re caught, these unwanted fish are thrown back into the water, dead or dying. The decreasing population of this species and the slow response by regional governments to save it earned the Maltese ray a critically endangered rating from the IUCN.

Top 10 Most Endangered Fish: Number 3

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Goliath Grouper

All species of grouper are endangered to some extent, but the Goliath Grouper is particularly threatened. Also known as the jewfish, it lives in the subtropical areas of the eastern Pacific (from Baja California to Peru) and the Atlantic (from North Carolina to Brazil). As the name suggests, it’s a very large fish, growing to 7 feet in length in its 40-year life span. Overfishing of the Goliath grouper is a result of two main issues. First, it reproduces for only a short period of time, resulting in relatively few offspring compared to other species. Second, juveniles often become accidental bycatch in other fishing operations. What fish remain are targeted during spawning by hook-and-line fishing boats. Out of concern for the Goliath grouper’s survival, the United States banned harvest of the species, and the IUCN rated them as critically endangered.

Top 10 Most Endangered Fish: Number 4

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European Eel

Found primarily in the North Atlantic and the Baltic and Mediterranean Seas, European eel face a unique set of survival challenges. They have a fascinating development cycle, which begins with their birth out at sea and continues in freshwater streams thousands of miles inland, where they can grow to a length of 4.5. When they reach sexual maturity, at anywhere from 6 to 30 years of age, they return to the sea to spawn. If their route to the sea is blocked, they return to freshwater and can live for 50 years. But if they make it back to salt water and reproduce, they die. Because of this unusual life cycle, any eel that is caught at sea is a juvenile that has not yet had a chance to spawn. This has resulted in catastrophic overfishing of the European eel, and a critically endangered rating from IUCN.

Top 10 Most Endangered Fish: Number 7

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Orange Roughy

Also known as the “slimehead,” the orange roughy has a wide-ranging habitat that includes the coasts of New Zealand, Australia, Namibia and the northeast Atlantic Ocean. Its life expectancy is up to 149 years, and it reaches sexual maturation age between 20 and 32 years, making it the epitome of a species inherently vulnerable to overfishing. The pressure of overfishing is amplified by fishermen’s tendency to trawl for orange roughy when the fish congregate to feed and breed. The resulting catches wipe out generations. Though the IUCN hasn’t reviewed this species to determine if it is endangered, a number of other organizations have recognized the significant decline in its numbers after only 25 years of commercial harvesting.

Bycatch

Bycatch are sea creatures caught unintentionally. This can either be ocean dwellers other than the desired species or juveniles of the desired species.

Top 10 MOst Endangered Fish: Number 8

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Acadian Redfish

This species of North Atlantic fish grows to about 20 inches in length and can live as long as 50 years. Like other overfished species, the Acadian redfish is slow-growing and reaches reproductive age late — at about eight or nine years old. Intensive trawling over the last 10 years has led to the smallest yields since commercial fishing of the species commenced in the 1930s. Worse, the Acadian redfish has been subject to pirate fishing, or fishing done in violation of environmental law. For these reasons, the IUCN lists the species as endangered.

Trawling

Trawling is a fishing technique where a large, deep net is pulled behind a boat. Often this net drags on the ocean floor, stirring up sediment and altering seafloor habitat. The effects of trawling can actually be seen on satellite images taken from space.

Facts about Saylor Eyeballs

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Sailor’s eyeballs are giant single-celled algae found in the Indo-Pacific down to 20 meters depth. They have other common names, such as bubble algae and sea pearl algae.

You will find Saylor Eyeballs everywhere in Indonesia. When you are diving around the Gili Islands, you will find them at Halik Reef, Sunset Reef, Hans Reef and Sharkpoint. You will find them in all diffent sizes.

These algae look rather like huge marbles, reaching up to 5 centimeters in diameter, and grow on coral and rocky reefs, attaching to the substrate by hair-like filaments called rhizoids.

Young plants are translucent with a bluish sheen, while older ones become encrusted, for example by coralline red seaweeds.

Sailor’s eyeballs undergo an interesting process of vegetative or asexual reproduction. Daughter cells grow inside the parent, which dies and breaks down, releasing the new plants

For more information: http://www.oceans5dive.com

Smallest fish in the world

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Scientists have discovered a fish living in forest swamps on the Indonesian island of Sumatra that is only 7.9mm long.

The species of fish belongs to the carp family and is called Paedocypris progenetica . It is the world’s smallest vertebrate or backboned animal.

Living in acid

The tiny, see-through Paedocypris fish have the appearance of larvae and have a reduced head skeleton, which leaves the brain unprotected by bone.

They live in dark tea-coloured waters with an acidity of pH3, which is at least 100 times more acidic than rainwater.

‘This is one of the strangest fish that I’ve seen in my whole career’, said Ralf Britz, zoologist at the Natural History Museum.

‘It’s tiny, it lives in acid and it has these bizarre grasping fins. I hope we’ll have time to find out more about them before their habitat disappears completely.’

Threatened swamps

The swamps were once thought to harbour very few animals, but recent research has revealed that they are highly diverse and home to many species that occur nowhere else.

In 1997 the peat swamps were damaged by large forest fires and they are still threatened by logging, urbanisation and agriculture. Several populations of Paedocypris have already been lost.

Fish discovery

The new fish was discovered by fish experts Maurice Kottelat (from Switzerland) and Tan Heok Hui from the Raffles Museum of Biodiversity Research in Singapore. They were working with their colleagues from Indonesia and with Kai-Erik Witte from the Max Planck Institute in Germany. Ralf Britz, at the Natural History Museum , helped analyse its skeleton and the complex structure of the pelvic fin.

Previous smallest

The previous record for smallest vertebrate was held by an 8mm species of Indo Pacific goby. The UK’s smallest fish is the marine Guillet’s goby, Lebetus guilleti , reaching 24mm in length.

Facts about Cardinalfish

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strong>Cardinalfish (Apogonidae)

Cardinalfish are one of the largest families of Indo Pacific reef fish. An estimated 250 species are currently known, of which 150 species occur on or near reefs in the East Indian region, like the Gili Islands. It is also one of the most dymanic groups for new discoveries. Many new species have been described over the past few years and more can be expected.

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