Young herring, lots of them, video


This video is about many young Atlantic herring, swimming in Grevelingen lake in the Netherlands on 23 January 2015.

Diver Peter van Rodijnen made the video. Before seeing the herring, Peter and his two companions had seen a male common dragonet, and a Galathea strigosa squat lobster.

Rare fish in London, new research


This video says about itself:

Sparling (or smelt) spawning run in the River Cree in 2010, this is the last population of Osmerus eperlanus known on the West coast of Scotland. This footage was taken as part of a larger project working on rare fish in the River Cree.

From Wildlife Extra:

Breeding ground sought of small Thames fish that smells of cucumber

There is a call-out to Londoners for volunteers to help scientists find out more about a rare species of British fish, the smelt (Osmersus eperlanus), which curiously smells like cucumbers. It is found in the Thames in central London.

The project by scientists from the Zoological Society of London (ZSL), funded by a grant of £97,800 from the Heritage Lottery Fund, will launch in March, with the aim of discovering where this silver-coloured fish breeds in the river.

Smelt are an important fish species; not only as a potential food source for other animals but because their presence indicates good health in an estuary.

In the Thames there is a small but significant breeding population, one of the few remaining in the country.

Joe Pecorelli, manager of the London’s Rivers project at ZSL, says: “The Thames is London’s greatest wilderness, yet still there are many things we don’t know about life in the river.

“The fact that the smelt, a nationally rare fish, returned to the Thames 20 years ago after more than a hundred years’ absence is a good sign.

“However, to ensure long-term survival of this species, we need to know where their key breeding grounds are in order to protect them.

“This project will be one of the most ambitious studies of the Thames yet and will see scientists and volunteers surveying the river from Chiswick to Greenwich.”

Pollution and habitat destruction caused the once-common smelt to disappear from South East estuaries during the early 1800s.

Improvements to water quality in the latter half of the 1900s led to a gradual return of the fish to a number of rivers in England, including the Thames.

Today, the smelt is still considered significantly threatened and continues to be relatively rare.

In addition to providing scientists with important information about the smelt, it is hoped this project will help more Londoners understand the rich ecology and history of their river and experience London’s aquatic wildlife first-hand.

To take part in the project (training is provided) or for more information, contact marineandfreshwater@zsl.org or visit www.zsl.org/smelt.

Rare megamouth shark beaches in the Philippines


This video is called Alien Sharks: The Megamouth.

By Cheryl Eddy, 29 January 2015:

Incredibly Rare And Mysterious Deep-Sea Megamouth Shark Washes Ashore

There have been fewer than 100 confirmed sightings of the megamouth shark, an elusive deep-sea species that uses its huge maw to trap tiny bits of plankton and krill. So when a 15-foot specimen washed ashore in the Philippines this week, scientists were more than overjoyed.

Pro-shark pioneer diver Lotte Hass dies


This video is called Lotte Hass snorkeling, vintage film.

From Wildlife Extra:

Lotte Hass, one of the world’s first female divers, has died

The Hans Hass Institute in Germany recently announced the death of Lotte Hass, one of the world’s first female scuba divers.

She passed away at the age of 86 on Wednesday, 14th January 2015 after a happy and multi-faceted life.

The first woman to dive with autonomous diving equipment, Lotte Hass entered a formerly male dominated field in 1949 and opened up a whole new world for women.

Against strong opposition she first starred as underwater photo model before moving behind the camera to become an underwater photographer.

Spectacular scenes that showed her diving with sharks certainly contributed to the success of her husband Hans Hass’ films in the 1950s, and a greater understanding of sharks with the public.

The importance of her extraordinary lifetime achievements were highlighted by the 2011 screen adaption of her autobiography A Girl on the Ocean Floor.

The Institute has asked those who want to acknowledge the accomplishments of Lotte Hass as a diving pioneer to support SHARKPROJECT, an organisation that is dedicated to preventing the destruction of the oceans and the extinction of sharks.

Fish under Antarctic ice discovery


This video is called Antarctic Fish.

From Smart News blog in the USA today:

Fish Live Under Antarctica’s Ice Shelf, Where It Seems They Shouldn’t Survive

Biologists expected the seafloor under a glacier to be nearly barren, until life swam into view

By Marissa Fessenden

SMITHSONIAN.COM

This month, a National Science Foundation-funded expedition began drilling through the Whillans Ice Stream, a glacier that flows from the West Antarctic Ice Shelf to the Ross Ice Shelf. The team wanted to see how the ice was faring and responding to climate change, so they drilled to the glacier’s grounding zone — where it leaves bedrock and meets the sea.

At that zone, the sea bottom looks bare and “rocky, like a lunar surface,” glacial geologist Ross Powell told Douglas Fox for Scientific American. They sent a little underwater vehicle called Deep-SCINI down the borehole to investigate. Its cameras would capture images of the rocks and sediment down on the sea floor. The researchers took sediment cores and seawater samples, which betrayed only the presence of a few microbes — no sign of crustaceans or other life normally found at the bottom of the sea.

This wasn’t a surprise: Under 2,428 feet of ice and 528 miles from the edge of the ice shelf, the site is far from any hint of sunlight, the energy source that typically powers marine food webs. So the next thing they found was shocking.

The ROV had paused while technicians adjusted some controls (it was the bot’s maiden voyage) when they saw something through the down-looking camera. Fox writes:

A graceful, undulating shadow glided across its view, tapered front to back like an exclamation point—the shadow cast by a bulb-eyed fish. Then people saw the creature casting that shadow: bluish-brownish-pinkish, as long as a butter knife, its internal organs showing through its translucent body.

It was a fish. About 20 to 30 fish visited the ROV that day, perhaps attracted to light. And that wasn’t all. Two other kinds of fish, shrimp-like crustaceans and few other invertebrates were also spotted.

“I’ve worked in this area for my whole career,” Ross says. “You get the picture of these areas having very little food, being desolate, not supporting much life.”

The food web down there is still unknown. “Food is in short supply and any energy gained is hard-won,” says Brent Christner, a microbiologist from Louisiana State University. “This is a tough place to live.” Without sunlight, the scant microbes there might be relying on chemical energy — minerals delivered by the moving ice above, currents traveling long distances or seeping up from sediments. “The lack of mud dwellers might indicate that animals living this far under the ice shelf must be mobile enough to follow intermittent food sources from place to place,” writes Fox.

Answering where food comes from is just the beginning of a long list of questions for this chilly, dark underwater community. But for now, the discovery proves yet again that life can eek out in the most remote, unexpected places.

Biology of the megamouth shark


This video is about megamouth sharks.

By Kazuhiro Nakaya in Japan:

Biology of the Megamouth Shark, Megachasma pelagios (Lamniformes: Megachasmidae)

Graduate School of Fisheries Sciences, Hokkaido University 3-1-1, Minato-cho, Hakodate, Hokkaido 041-8611, Japan

Abstract

All records to date (end of June, 2008) of the megamouth shark, Megachasma pelagios were analyzed and the biology of the megamouth shark was inferred from them. The megamouth shark is a wide-ranging species, distributed from the tropical to temperate seas, with the most numerous occurrences in the western North Pacific Ocean. Young individuals tend to be distributed in warmer waters, while mature individuals broaden their habitat to higher latitudes. Males become mature at about 4 m in total length and females at about 5 m. The megamouth shark may copulate all year round, giving birth to young
in warmer waters, and may be spatially segregated by sex.

The discovery of the megamouth shark was one of the ichthyological highlights of the last century.

The first specimen of the megamouth shark was accidentally collected in Hawaii in 1976, and the species was eventually named Megachasma pelagios by Taylor, Compagno and Struhsaker (1983). The second specimen was captured in 1984 in California, U.S.A., eight years after the capture of the first Hawaiian specimen (Lavenberg and Seigel, 1985). The third specimen was found stranded in 1988 off western Australia in the Indian Ocean (Berra and Hutchins, 1990). Then, the fourth and fifth specimens were reported from Japan in 1989 (Nakaya, 1989; Miya et al., 1992). The sixth specimen was captured and released in California with a sonic transmitter (Lavenberg, 1991), and its horizontal and vertical movements were recorded for a few days (Nelson et al., 1997). These specimens were all giant males of about five meters in total length, except for the fifth one of unknown sex, and finally the first female megamouth was caught in Japan in 1994 (Takada et al., 1997).

At present, the worldwide total of megamouth shark captured, found stranded or sighted is forty specimens. Some of the specimens were studied for their morphology and phylogenetic relationships, but most of them were discarded, consumed or not studied. Among the few studies available, Nelson et al. (1997) reported part of their way of life, showing that the megamouth shark makes clear daily vertical movements within depths shallower than 200 meters. However, most of the biology of the megamouth shark still remains to be disclosed.

The purposes of the present study are to synthesize the scattered information of the 40 specimens recorded as of June, 2008, to study the morphological and biological evidence of each specimen, to analyze their capture data, and to discuss the biology of the megamouth shark.