Sarpa salpa, a fish species capable of causing long-lasting hallucinatory experiences in humans, has been caught far north of its normal range. Normally found in the warm waters of the Mediterranean and off the African west coast, Sarpa salpa is an unusual guest in northern Europe. Only three previous recordings exist from British waters, with the third being from 1983 when a single specimen was caught off the Channel Islands.

The most recent specimen of this mind altering Sparidae was caught six miles south of Polperro, Cornwall, by fisherman Andy Giles. When Giles found the strange looking creature entangled in his net he brought it back to shore to have it identified.

Picture by by Sam and Ian

“We were trawling for lemon sole but hauled up the net at the end of the day and almost immediately saw this striped fish”, Giles said. “I had never seen one before so brought it back for experts to have a look at it. But now I realise what it was – and the crazy effects it can have – perhaps I should have taken it into town to sell to some clubbers.”

Instead of selling it to clubbers, Giles could also have brought it home to the dinner table – without much risk of having any mind altering experiences. Within its native range, Sarpa salpa, commonly known as Salema porgy, is a popular food fish and suffering from hallucinations after ordering a plate of Salema in a Mediterranean restaurant is very rare.

According to marine experts, Sarpa salpa has to feed on a certain types of plankton in order to become hallucinogen. In 2006, two men were hospitalized in southern France after eating Sarpa salpa who evidently had feasted on vast amounts of psychedelic plankton before being caught.

“Plankton has very minute amounts of poison and fish that eat a great deal of it can develop this poisoning”, says Oliver Crimmen, fish curator at the Natural History Museum. Sarpa salpa are a popular fish to eat in the Mediterranean and I think the 2006 incident was a rare event.”

So, why can urge a Sarpa salpa to leave the pleasant waters of Africa and head for chilly Britain? According to James Wright, senior biologist at the National Marine Aquarium in Plymouth, the fish may simply have tagged along when some other species decided to head north, but it may also be possible that the species is on the rise in northern Europe.

“These are a fairly common fish off Tenerife, Malta and Cyprus but it is very rare to get them this far north. It could be a single fish that was shoaling with a different species, says Wright. But it could be that there are more of them in our waters.”

Scientists are unaware of the state of nearly two-thirds of Europe’s fish stocks and do not have enough information to assess the exact scale of the crisis the European fishing industry is facing, says the European Commission.

This is naturally alarming, since the commission last month admitted that nothing short of a completely new fisheries management system based on scientific evidence could stop the downward spiral of years of dangerously depleted fish stocks and get the struggling European fishing industry back on its feet.

Europe

The European Commission is now proposing smaller annual EU fish catch quotas and have given governments and industry representatives until the end of July to submit their views.

“The contribution of EU fisheries to the European economy and food supply is far smaller today than it was in the past. Even more worryingly, the status of some 59 per cent of stocks is unknown to scientists, largely due to inaccurate catch reporting,” the European Commission says in an official statement.

The policy has not been reformed since 2002 and the European Commission admits there has been “slow progress” in stock recovery, since quotas consistently have been set at unsustainably high levels.

Genetic pattern analysis strongly suggests that California and British Columbia urchins are not connected via larval dispersal and comprise two distinct populations. Sea urchins have one of the longest larval periods of any known marine invertebrate and it has therefore been tempting to assume that ocean currents must be mixing urchin larvae all over the place, making it difficult for any distinct populations to form. But research results from the University of California now indicate that these two Pacific populations are two clearly separated ones.

Sea urchins –  Picture from the Red Sea

Together with former* graduate student Celeste Benham, marine biology professor Ron Burton of the University of California at San Diego have analyzed 500 adult sea urchins from Californian waters across five microsatellite markers and then compared the genetic patterns to an existing, similar database of 1,400 urchins from British Columbia. The Californian specimens were collected off the coast of San Diego, Los Angeles and Mendocino counties.

The genetic signatures found by Burton and Benham strongly suggest that the southern and northern populations are not connected via larval dispersal.

“From my evolutionary perspective, our results are important because they imply that, even on long time scales, there is no mixing, Burton explains. This means there is at least the potential for populations to adapt to different ocean conditions and gradually diverge. This is the first step in the two populations potentially becoming different species.”

This is the first time scientists have detected any population structure in the species. Similar studies carried out in the past have used fewer genetic markers and found no population genetics structure in the species despite having tested many different patches across its range.

“The take-home message of this study is that if you use more markers and newer techniques you will find some population differentiation that before nobody found,” says Burton.

* Benham is now a research assistant at the marine mammal laboratory at Hubbs-SeaWorld Research Institute in San Diego.

The Turkish government has set their own very high catch limit for endangered Mediterranean bluefin tuna without showing any regard for internationally agreed quotas and the survival of this already severally overfished species. By telling the Turkish fishermen to conduct this type of overfishing, the Turkish government is effectively killing the future of this important domestic industry.

Turkey currently operates the largest Mediterranean fleet fishing for bluefin tuna, a commercially important species that – if properly managed – could continue to create jobs and support fishermen in the region for years and years to come. Mediterranean societies have a long tradition of fishing and eating bluefin tuna and this species was for instance an appreciated food fish in ancient Rome. Today, rampant overfishing is threatening to make the Mediterranean bluefin tuna a thing of the past.

Management of bluefin tuna is entrusted to the International Commission for the Conservation of Atlantic Tunas (ICCAT), an intergovernmental organisation. Last year, the Turkish government objected to the Bluefin tuna quota that was agreed upon at the ICCAT meeting in November and is now ignoring it completely.

The agreed tuna quota is accompanied by a minimum legal landing size set at 30 kg to make it possible for the fish to go through at least one reproductive cycle before it is removed from the sea, but this important limit is being widely neglected as well. Catches below the 30 kg mark have recently been reported by both Turkish and Italian media.

To make things even worse, Mediterranean fishermen are also involved in substantial illegal catching and selling of Mediterranean bluefin tuna. This year’s tuna fishing season has just begun and Turkish fishermen have already got caught red-handed while landing over five tonnes of juvenile bluefin tuna in Karaburun.

According to scientific estimations, Mediterranean blue fin tuna fishing must be kept at 15,000 tonnes a year and the spawning grounds must be protected during May and June if this species shall have any chance of avoiding extinction in the Mediterranean. This contrasts sharply against the actual hauls of 61,100 tonnes in 2007, a number which is over four times the recommended level and twice the internationally agreed quota. The crucial spawning grounds are also being ravished by industrial fishing fleets.

By blatantly ignoring international quota limits, the Turkish government is in fact threatening not only the tuna but also the future livelihood of numerous Mediterranean fishermen, including the Turkish ones.

A strange algae plume has turned the normally crystal clear Caribbean Sea around the Virgin Islands green down to a depth of roughly 80 feet (25 metres) and sharply decreased visibility in these popular dive waters. How and if the plume will have any long-term effect on the region’s marine life remains unknown.

Tyler Smith, assistant professor at the Center for Marine and Environmental Studies at the University of the Virgin Islands, said that when he went diving Tuesday the visibility inside the plume was no more than 10 feet (3 metres). Below 80 feet, the water was just as clear as normally.

The reason behind the extraordinary plume can be found in South America, in the Orinoco River which flows through Venezuela before reaching the Atlantic Ocean. When the Orinoco outflow is larger than normal, the vast amounts of nutrient-rich freshwater from Venezuela cause a major algae bloom in the nearby ocean. Mixed fresh- and saltwater is lighter than seawater and will therefore rise to the top of the water column.

“It’s very stable, so it just sits there,” Smith explains.

Carried by currents, the algae plume has now spread from the South American east-coast to the Caribbean Sea and can currently be seen not only off the British and U.S. Virgin Islands but in Puerto Rican waters as well. The first patch was noticed by Smith and his colleagues in the waters off St. Croix on April 9.

When the amount of photosynthesising alga increases in a region, it attracts all sorts of organisms that feed on algae and make it possible for these populations to boom as well. The algae plume around the Virgin Islands supports an entire food chain of marine life, including plankton, jellyfish, crustaceans and fish. It is not dangerous to swim or scuba dive in, but some people might dislike the high density of jellyfish.

“This is an event that occurs every year, but we haven’t seen it come this far north,” says Trika Gerard, marine ecologist with the U.S. National Oceanic and Atmospheric Administration (NOAA). In a stroke of good luck, a NOAA research vessel was scheduled to research reef fish in these waters from April 7 to April 20 – right at the peak of the unexpected plume.

To find out more about how the plume effects marine life, the Caribbean Fisheries Management Council is urging anyone who goes out fishing in the green plume to report their location, target species and success rate of each trip. According to local fishermen the fishing is always awfully bad when the water is green, but this has not been scientifically researched yet and all data is of interest.

You can reach the Caribbean Fisheries Management Council by calling (787) 766-5927. Their website is http://www.caribbeanfmc.com.

Alabama fishermen and scuba divers will receive a welcome present from the state of Alabama in a few years: the coordinates to a series of man-made coral reefs teaming with fish and other reef creatures.

In order to promote coral growth, the state has placed 100 federally funded concrete pyramids at depths ranging from 150 to 250 feet (45 to 75 metres). Each pyramid is 9 feet (3 metres) tall and weighs about 7,500 lbs (3,400 kg).

The pyramids have now been resting off the coast of Alabama for three years and will continue to be studied by scientists and regulators for a few years more before their exact location is made public.

In order to find out differences when it comes to fish-attracting power, some pyramids have been placed alone while others stand in groups of up to six pyramids. Some reefs have also been fitted with so called FADs – Fish Attracting Devices. These FADs are essentially chains rising up from the reef to buoys suspended underwater. Scientists hope to determine if the use of FADs has any effect on the number of snapper and grouper; both highly priced food fishes that are becoming increasingly rare along the Atlantic coast of the Americas.

Early settlers and late followers

Some species of fish arrived to check out the pyramids in no time, such as grunt and spadefish. Other species, like sculpins and blennies, didn’t like the habitat until corals and barnacles began to spread over the concrete.

“The red snapper and the red porgies are the two initial species that you see,” says Bob Shipp, head of marine sciences at the University of South Alabama. After that, you see vermilion snapper and triggerfish as the next order of abundance. Groupers are the last fish to set in.”

Both the University of South Alabama and the Alabama state Marine Resources division are using tiny unmanned submarines fitted with underwater video cameras to keep an eye on the reefs and their videos show dense congregations of spadefish, porgies, snapper, soap fish, queen angelfish and grouper.

“My gut feeling is that fish populations on the reefs are a reflection of relative local abundance in the adjacent habitat,” says Shipp. “Red snapper and red porgy are the most abundant fish in that depth. They forage away from their home reefs and find new areas. That’s why they are first and the most abundant.”

What if anyone finds out?

So, how can you keep one hundred 7,500 pound concrete structures a secret for years and years in the extremely busy Mexican Gulf? Shipp says he believes at least one of the reefs has been discovered, since they got only a few fish when they sampled that reef using rod and reel. Compared to other nearby pyramid reefs, that yield was miniscule which may indicate that fishermen are on to the secret. As Shipp and his crew approached the reef, a commercial fishing boat could be seen motoring away from the spot.

“The ‘underwater turbulence’ the jellies create is being debated as a major player in ocean energy budgets,” says marine scientist John Dabiri of the California Institute of Technology.

Jellyfish are often seen to be aimless aquatic drifters, propelled by nothing but haphazard currents and waves, but the truth is that these gooey creatures continuously contract and relax their bells to move in desired directions.

The jellyfish Mastigias papua carries algae-like zooxanthellae within its tissues from which it derives energy and since the zooxanthellae depend on photosynthesis, the jellyfish has to stay in sunny locations. Research carried out in the so called Jellyfish Lake, located in the island nation of Palau 550 miles east of the Philippines, shows that this jellyfish doesn’t rely on currents to bring it to sunny spots – it willingly budges through the lake as the sun moves across the sky.

In Jellyfish Lake, enormous congregations of Mastigias papua can be found in the western half of the lake each morning, eagerly awaiting dawn. As the sun rises in the east, all jellyfish turn towards it and starts swimming towards east. The smarmy creatures will swim for several hours until they draw near the eastern end of the lake. They will however never reach the eastern shore, since the shadows cast by trees growing along the shoreline cause them to stop swimming. They shun the shadows and will therefore come to a halt in the now sundrenched eastern part of the lake. As the solar cycle reverses later in the afternoon, millions of jellyfish will leave the eastern part of the lake and commence their journey back to the western shore.

Together with his research partner, marine scientists Michael Dawson of the University of California at Merced, John Dabiri have investigated how this daily migration of millions of jellyfish affects the ecosystem of the lake.

What the jellies are doing, says Dabiri, is “biomixing”. As they swim, their body motion efficiently churns the waters and nutrients of the lake.

Dabiri and Dawson are exploring whether biomixing could be responsible for an important part of how ocean, sea and lake waters form so called eddies. Eddies are circular currents responsible for bringing nitrogen, carbon and other elements from one part of a water body to another. The two researchers have already shown how Jellyfish like Mastigias papua and the moon jelly Aurelia aurita use body motion to generate water flow that transports small copepods within jellyfish feeding range; now they want to see if jellyfish movements make any impact on a larger scale.

“Biomixing may be a form of ‘ecosystem engineering’ by jellyfish, and a major contributor to carbon sequestration, especially in semi-enclosed coastal waters,” says Dawson.

The Spanish police have seized 11 tonnes of shark fins in destined to be shipped to Hong Kong.

According to a statement from the police, the shark fins did not appear to come from a protected species but were found in a warehouse that lacked authorization to export shark fins.

The confiscation took place in Huelva in south-western Spain, to where the fins had been transported from a port in Galicia in the north-western part of the country.

The shark fins have an estimated value of 136,800 Euros (186,335 USD). European Union countries are the main exporters of shark fins to China.

In many markets, shark meat does not yield a high price and fishermen therefore normally remove the fin from caught sharks and let the shark back to the sea. Without its fin the shark can no longer swim and will sink to the bottom where it either dies from suffocation (sharks need to swim to breathe) or gets eaten alive by other aquatic animals.

In parts of Asia, shark fins are used in folk remedies and to make traditional shark fin soup. As the standard of living rises in China, more and more people can afford to purchase shark fins and one pound of dried shark fin can now retail for over 300 USD.

An expansion of vertical seagrass occurring some 25 million years ago was probably what prompted seahorses to evolve from horizontal swimmers to upright creatures. If you live in vertical seagrass, an upright position is ideal since it allows you to stay hidden among the vertical blades.

This new idea is put forward in a report by Professor Beheregaray* and Dr Teske** published in the journal Biology Letters on May 6.

Sea horse picture from our Seahorse section.

Only two known fossils of seahorse have been found and this scarcity of fossil records has made it difficult for scientists to determine when seahorses evolved to swim upright. The older of the two fossils is “just” 13 million years old and no links between the two fossils and horizontally-swimming fish has been found.

“When you look back in time, you don’t see intermediate seahorse-like fish,” Beheregaray explains. There are however fish alive today that look like horizontally-swimming seahorses and Beheregaray and Teske have therefore studied them in hope of finding clues as to when seahorses made the transition from horizontal to vertical swimming.

By comparing DNA from seahorses with DNA from other species of the same family, Beheregaray and Teske were able to determine who the closest living relative to seahorses was.

“The pygmy pipehorses are by far the most seahorse-like fish on earth, says Beheregaray. “They do look like the seahorses, but they swim horizontally“.

When you have two closely related species, you can use molecular dating techniques to calculate when the two species diverged from each other. Beheregaray and Teske used a molecular dating technique that relies on the accumulation of differences in the DNA between the two species, and then used the two existing fossils to calibrate the rate of evolution of DNA in their molecular clock. By doing so, the two researchers could conclude that the last common ancestor of seahorses and pygmy pipehorses lived around 25 to 28 million years ago. At this point, something must have happened that led to the formation of two distinct species, and Beheregaray and Teske believe that this “thing” was the expansion of seagrass in the habitat where seahorses first evolved.

The time in history when seahorses arose, the Oligocene epoch, coincided with the formation of vast areas of shallow water in Austalasia. These shallow waters became overgrown with seagrass and turned into the perfect habitat for upright swimming seahorses that could remain hidden from predators among the vertical blades. The pygmy pipehorse on the other hand lived in large algae on reefs and had no use for an upright position, hence it continued to swim horizontally just like their common ancestor.

“The two groups split in a period when there were conditions favouring that split,” says Beheregaray. “It’s like us. We started walking upright when we moved to the savannahs. On the other hand, the seahorses invaded the new vast areas of seagrass.”

* Associate Professor Luciano Beheregaray of Flinders University

http://www.flinders.edu.au

** Dr Peter Teske of Macquarie University

http://www.macquarie.edu.au

Basking sharks have surprised researchers by leaving the cold waters of the north Atlantic during fall and head down to Bahamas and the Caribbean.

“While commonly sighted in surface waters during summer and autumn months, the disappearance of basking sharks during winter has been a great source of debate ever since an article in 1954 suggested that they hibernate on the ocean floor during this time,” said Gregory Skomal of Massachusetts Marine Fisheries. “Some 50 years later, we have helped to solve the mystery while completely re-defining the known distribution of this species.”

Basking Shark

Basking sharks are notoriously difficult to study for several reasons. They feed exclusively on plankton which means you can’t catch them using traditional rod-and-reel methods and they disappear down to deep waters for extended periods of time. During the part of the year when they do stay close to the surface, they are only found in cool waters teaming with plankton where the underwater visibility is close to zilch.

This situation has led to a lot of speculation about their life style and where they actually spend the winters. Despite being the second largest fish in the world, the basking shark is remarkably elusive and mysterious.

What finally solved the puzzle was the aid of new satellite-based tagging technology and a novel geolocation system which made it possible to track the basking whales as they commenced their annual migration. Data sent out from the tags unveiled that basking sharks migrates to warm tropical waters in fall. Their migrations have been able to go undetected until know since the sharks travel at depths of 200 to 1,000 meters and sometimes remain at those depths for weeks or even months at a time.

Skomal said he and his fellow researchers were absolutely surprised when they first received a signal from the tagged sharks coming from the tropical waters of the western Atlantic, since virtually everyone assumed basking sharks to be cool-water dwellers found in temperate regions only.

This new breakthrough show just how little we still know about even the largest marine animals inhabiting the world’s oceans. The basking shark can reach a length of 10 metres and weigh up to seven metric tons, yet it has managed to spend every summer in the Caribbean without anyone noticing it.

You can find more information in the report published on May 7 in Current Biology.