Fishy Sauce and a Fishy Date

By Claire Eamer

The Garum Shop in the ancient Roman city of Pompeii was a small business that manufactured and sold a fish sauce called garum that Romans adored. The shop went out of business suddenly and permanently in 79 CE when the nearby volcano, Mount Vesuvius, erupted and buried it, the city, and several other communities under metres of volcanic rock and hot ash.

This is the Triclinium or dining room of a wealthy family
in Pompeii. The diners would have reclined on beds while
eating dishes liberally laced with garum. Claire Eamer photo.

In 1960, archaeologists uncovered the Garum Shop for the first time in 1880 years. Buried with it were six large ceramic containers called dolia and several of the large pottery vessels called amphorae used for everything from wine to -- in this case -- fish processing. The dolia contained the remains of garum in several stages of production, and some of the amphorae contained the well-preserved bones of hundreds of tiny fish.

Fishy flavour

Now, historians have known for centuries that the Romans loved garum and ate it in huge quantities. But they didn't know exactly what it was beyond a liquid made from decomposed, fermented fish, fish blood, fish guts, and other fishy bits. Doesn't sound very appealing, does it? But no one knew how appealing it might be because no one had tasted it in the better part of 2000 years.

A street-food booth in Pompeii. The railings are modern, but the rest of the shop
is just as the owner left it almost 2000 years ago. The counters have large ceramic
containers sunk into them to hold the day's offerings, certainly including garum.
Claire Eamer photo.

And we didn't have a decent recipe. Have you ever tried to recreate your mother's perfect chocolate cake icing or your grandmother's perfect butter tarts? (I have.) Even if you have the original recipe and you know exactly how it should taste, it's not easy. So -- no detailed recipe and no idea of what it should taste like made garum a mystery.

In the last few years, however, archaeological science has reached the point where those garum remains are more than a curiosity. Chemists are analyzing them to determine exactly what went into garum and in what quantities. And archaeozoologists are studying the fish bones to figure out what kind of fish were used.

Fishy calendars

The top is gone from this three-legged table, but the marble lion
feet remain. It was a valued antique. An inscription says it once
belonged to Casca Longus, the first to strike Caesar when he was
murdered in the Roman Senate in 44 BCE. Claire Eamer photo. 

That's where the fishy date comes in. For years, the most widely accepted date for the eruption of Mount Vesuvius was August 24, 79 CE. That was based on a letter written by an eye-witness, Pliny the Younger, whose uncle died in the eruption. But Pliny's letter was written 25 years after the event, and the original disappeared long ago. We only know it from translations and copies, and they don't agree on what the Roman date translates to in modern terms.

Back to the fish. Scientists studying fish bones from the Garum Shop determined that they came from a small Mediterranean fish called the common picarel (Spicara smaris) -- and that all the fish examined were 10 to 13 centimetres long, about a year old, and all female. Fish have growth rings in their bones, much like the growth rings of trees, so the scientists could even tell that they died when the water was warmest -- late summer or early autumn. Then they were thrown whole into amphorae and packed with brine and, probably, herbs. They had been in the amphorae from one to three or four weeks when the heavens rained hot ash and buried them.

The August 24 date for the eruption was already in doubt because of other archaeological evidence, and the fish evidence made it even fishier. Large shoals of female-only picarel come close to the shores of southern Italy in late August and September, so that would push the eruption date to mid-October or later.

Fish-free evidence

Huge millstones still sit in the courtyard
of a Pompeii bakery and flour mill.
Claire Eamer photo

Just a year or so ago, an even more definitive piece of evidence for a later date turned up -- a bit of writing scrawled on a wall in charcoal. It's just a date, probably left by a tradesman working on a house, but the date translates to October 17 in our calendar, almost two months after the workman should have died in the eruption. The latest guess is that Vesuvius blew its top about October 24.

So fish and a long-dead tradesman appear to have corrected a fishy historical date. And while we still don't know exactly what garum tasted like, the chemists are busy fishing (sorry -- couldn't resist) for the recipe.

References:
Carannante A. The last garum of Pompeii: Archaeozoological analyses on fish remains from the "garum shop" and related ecological inferences. Int J Osteoarchaeol. 2019;29:377-386.

Pompeii: Vesuvius eruption may have been later than thought. BBC News, 16 October 2018. Located at https://www.bbc.com/news/world-europe-45874858. 

Nature's Black Boxes

By Claire Eamer

Whenever an airplane crashes, you hear about investigators retrieving the plane's black box. It's a device that records essential information about the plane's operation, and it can help investigators reconstruct what happened to bring the plane down.

Tree rings show a tree's history. Claire Eamer photo

Well, there are black boxes in nature too -- lots of them. And they are important tools for scientists who are trying to figure out how Earth's climate changes and what impact those changes have had on the organisms that live on the planet. They're called climate proxies -- essentially indirect clues that let us deduce what past climates were like.

One of the best known black boxes is tree rings. Each year, a tree puts on a ring of new growth. In a good year, the growth ring will be wider, in a bad year, narrower. The science of studying what tree rings can tell us is called dendrochronology, and it has provided a huge amount of information about both natural and human history.

Trees aren't the only organisms that save information in rings. So do fish -- but their growth rings are in their ears. Tiny, disc-shaped bones in fishes' ears -- called otoliths or ear stones[PDF] -- add a ring of growth for every year of a fish's life. As with tree rings, the otolith rings vary, depending on the conditions the fish encountered that year. Even the chemistry of the annual rings changes, so they can hold information about the water the fish traveled through.

The annuli are visible as ridges on this ram's horns.
Pixabay photo

Mountain sheep have a slightly different kind of black box. The rams' horns grow longer and thicker each year, and the ridges that mark each year's growth are called annuli. Like tree rings and otolith rings, the annuli are larger or smaller depending on the conditions the animal experienced that year. In the Yukon, a long-term study of the horns of thinhorn sheep [PDF] revealed a climate fluctuation that repeats every 10 or 11 years and affects the larger ecosystem in which they live.

The biggest natural black box of all is Earth's ice. The great icefields in places like Greenland and Antarctica have been frozen for hundreds of thousands of years -- or even longer. But that ice didn't arrive all at once. It built up year by year with layers of snow that fell and then were compressed into ice by the layers that followed. Digging straight down into a massive icefield is like digging into the past.

Greenland glaciers like this one contain ice more than 100,000 years old.
Pixabay photo.

And that's what icefield scientists do. They drill into glaciers and icefields and extract long cores of ice. Then they analyze the thin layers, examining the chemistry of the water and bubbles of trapped air, the dust and pollen that settled on the glacier's surface, and anything else that might be frozen in the ice. The oldest ice found so far came from Antarctica and is an amazing 2.7 million years old. Ice cores are among the most powerful climate proxies we have, and much of our knowledge of very ancient climates comes from them.

For more information about dendrochronology, explore the EnvironmentalScience.org website.

For some of the things we can learn from fish otoliths, watch the short video on this page.

For a detailed explanation of ice core science, browse through Ice Core Basics.

And for more on climate proxies, try this NOAA site or this page on Palaeoclimatology.

What Goes Around Comes Around - Undersea Carousel Style!

Photo: http://www.seaglasscarousel.nyc/the-seaglass-story/ 

Post by Helaine Becker


A fantastic new carousel  called Seaglass opened in New York City yesterday. According to Show Canada, the group that fabricated the structure, "visitors find themselves within a musical seashell structure of 30 illuminated fish of different changing sparkling colors and species." 

The fish are up to 4.5 m tall, made of translucent fibreglass "reminiscent of frosted colored pebbles of sea glass." They rise, fall and swirl about in invisible 'currents' much like real fish do in the ocean.  (See a video of the carousel in operation here) It looks totally spectacular, and I can't wait to get to New York so I can ride it myself!

Photo: http://www.seaglasscarousel.nyc/the-seaglass-story/ 

My friend Stephen Sywak was part of the engineering team (McLaren Engineering Group) that helped make the carousel come to life. He has very kindly answered my questions about the engineering challenges involved in making this complicated and gorgeous work of art. This is what he told me, in short:

Can you describe the carousel for me?

It's a multi-axis carousel.  There's a main turntable, but within the main turntable are three smaller turntables.  And on THOSE turntables, there are a number of "fish," like the horses on an old-timey carousel, except for a few things....

Photo: http://www.seaglasscarousel.nyc/the-seaglass-story/ 

* You ride INSIDE the fish, not on top of them

* The post that the fish move up and down on only goes BELOW the fish.  On a carousel horse, it goes THROUGH the horse, from the floor to the canopy.  Structurally, and  from a control point  of view, it's a lot harder to do it THIS way.

* The fish not only move round on the large carousel, but they swing back and forth because of the smaller carousel.  And then they swing back and forth AGAIN, on their own poles.  AND they move up and down on their own poles (There are a few fish on  the MAIN carousel that only move a little or not all; some of these are designed to accommodate wheelchairs.).

So how do you make it all go "swish?" 

The main carousel and the smaller carousels are driven by industrial motors.  The motors run gearboxes, and the gearboxes run "ring bearings" (large, geared bearings--like you would see on a tank turret).  They provide about 20-30 HP for the main carousel, and 8-10 HP each for the small ones.

The fish are mounted to custom hydraulic cylinders.  But we didn't use hydraulics to run them up and down.  The hydraulic cylinders are perfect for guiding and positioning the rods beneath the fish, and holding them stable.  They are designed to handle linear and rotary motion.  Why reinvent, when it's cheaper to buy an existing product?  (That was my idea, by the way!)  Instead, we used two standard electrical motors (and gearboxes) to do the local lifting and the local turning. 

If I recall correctly,  a giant "slip ring" at the center of the table brings in all the power and control signals.  It allows the central turntable to rotate round and round without winding up a bunch of cables.  The inner (smaller) turntables, and the fish themselves, only spin partially around.  We used "Cable Chains" to bring power and signal to them.

We used industrial control systems both for safety, and to allow us to simplify and reduce the number of signals crossing the main, central slip ring.  Basically, it's running on a network, like computers in an office, or a network you might have at home.  But it's got layers of security on it, so that it can't be "hacked."

I never ever considered the possibility that someone would hack a merry-go-round. Go figure. 

***

What were the key challenges in  taking this idea from the drawing board to Battery Park?

One key challenge was was that we had to work very closely with the artists to make sure that we could implement their vision.  There were a few occasions where the "artist" types even took their lead from our designers and engineers! 

On the physical side, there was the fact that the structure on which the Carousel's turntables sit is all below ground. It's about 8-10 feet "tall," but it's all under foot!   

Photo: http://www.seaglasscarousel.nyc/the-seaglass-story/ 

We also had to make sure that all the various motions of the fish (large turntable, small turntable, fish "wag" and fish "heave" up and down) didn't make the riders heave their respective breakfasts and lunches. 

Thanks for that image. What's your next coolio project?

I'm currently working on a test set-up for an actuator (motor, gears, sensors, etc.) that rotates the solar arrays  on geo-synchronous satellites. If it turns out I know what I'm doing, then I hope I get to work on some of the actuator designs for the next Curiosity mission, slated for 2020.   

WOW! From undersea to outer space! An engineer's life is full of thrills! But now the most important question of all: Do you get to ride on the Seaglass Carousel for free?

Unfortunately, no.  But it's only $5!

Ok then. I'll book my ticket to New York and get in line. 

Traditional Fishing Science

By Paula Johanson

Traditional fishing methods are not only the use of a simple hook and line, or tickling fish in a stream. There are surprisingly effective technologies for catching fish, technologies that were used traditionally by First Nations people. Here on the coast of British Columbia in Canada and Washington State in the USA is the area called the Salish Sea, after the Coast Salish-speaking people who have been living here since the end of the last Ice Age. Saltwater fishing techniques were developed to a science by these coastal people.

But the use of Salish reef-nets fell out of practise when these nets were banned by the Canadian government over a hundred years ago. It was only through the efforts of several people living on the Saanich peninsula (in and near the city of Victoria, BC) that the first reef-net in a hundred years has been built and put to use.

Leading their project is Nick Claxton (XEMŦOLTW̱), a member of the Tsawout community and a PhD candidate at the University of Victoria in the Department of Curriculum and Instruction. He worked with a local school and members of the W̱SÁNEĆ nation to build a model of a traditional reef-net. The project was so successful that teachers throughout the school—math teachers, science teachers, socials teachers—began to teach their subjects through the model net.

Then, with the help of relatives from the Lummi Nation just across the border in Washington state, Nick and his associates built a reef-net in the traditional style. They put it to use on August 9, 2014, at a hereditary fishing location off Pender Island, as shown in this video they posted on YouTube.

Their short video will give you a sense of the power of that day and what it means to “carry on our fisheries as formerly,” as agreed to in the Douglas Treaty signed by the Saanich people in 1852.

If you're wondering what's so different about one net compared to another, well, there can be a lot of differences! This isn't a little net held and retrieved by one person. A reef-net is suspended between two open canoes. The upper part of the net is attached to floats, and the lower part is held down by weights.

If the video of this net being used doesn't load on your screen, you can click here to see a six-minute video, showing the project and the reef net being deployed.

Ancient Fish Farming in Hawaii

By Shar Levine

What do science writers do when they go on vacation to the Big Island of Hawaii? If you are Shar Levine and Leslie Johnstone, you look for science at the beach.  At 'Anaeho'omalu Bay, or "A" Bay as the locals call it, the pair spent an afternoon at the anchialine ponds located between the Marriot Hotel and the beach.

Anchialine ponds are only found on two of the Hawaiian islands, Hawaii and Maui. These small inland ponds are found close to the ocean but are not connected to the surface of the sea. Salt water from the ocean seeps through the ground where it is mixed with fresh water flowing from the mountains. The pond is less salty than the ocean, but more salty than fresh water from a stream. The mixture of the two creates a unique "brackish" water for the fish living in the pond.

Anchialine Ponds, with "A" Bay in background

Hiding in the algae and water plants along the sides of the pond you can see shrimp, crabs, mollusks and tiny fish.  Much to the delight of tourists, an eel will sometimes poke its head out from the lava rocks in the waters just below the bridge connecting the pond to the beach. In the deeper section of the pond, large fish including amberjack and barracuda patrol the waters. The salinity of the pond varies with the depth and temperature of the water. Creatures who live in these waters are different from their relatives who live in the ocean and scientists are interested in studying how the fish have adapted to survive in this environment.

Types of fish found at "A" Bay pond

The ancient Hawaiians used these ponds as an early form of fish farming. There was very little work for the people to do. Small fish would enter the pond through a gated channel from the ocean to an outer pond. From there, the fish would thrive on algae and plants growing in the waters. The fish soon became too big to leave the pond through the gate. When the fish were adults,  they could easily be caught in a net and served for dinner.

The ponds form their own ecosystems. Here's how the food chain works:

Over, Under, and On the Arctic Sea Ice

By Claire Eamer

The shrinking sea ice of the Arctic Ocean has been in the news a lot lately, along with photos of polar bears stranded on ice pans or wandering hungrily along bare shores. But what does the disappearing ice affect, apart from polar bears and some shipping companies that see a shorter sea route opening up?

Claire Eamer photo

Arctic sea ice supports a huge and complex ecosystem that ranges from polar bears, birds, and humans down to organisms too small to see without a microscope. Here are a few sites about that world - and a lot of gorgeous photographs!

The Census of Marine Life's Arctic Ocean Diversity website has great information and amazing images. Click on Species to see some of the creatures that make use of the Arctic Ocean and its ice, from top to the ocean bottom.

The US National Earth Science Teachers Association’s page on Arctic Marine Life gives a quick overview of Arctic Ocean biology, from algae to polar bears.

A young Russian scientist and photographer, Alexander Semenov, has been photographing Arctic sea life and sharing his photos with the world. There’s an article about him (with lots of lovely photos) and here's his own website and gallery.

How about the people who live with the ice all their lives? What can they tell us about it? The Inuit of northeastern Canada have been collecting traditional information about sea ice and sharing it at Inuit siku (sea ice) Atlas.

What does it really look like up there, around the Arctic Ocean, both above and below the ice? The photo galleries of Canada’s ArcticNet research program can give you a good idea.

And if you’re a student or a teacher and you want to see the Arctic for yourself, it just might be possible. Check out ArcticNet’s Schools on Board program.

Talking About Salmon Farms

At a potluck dinner this summer, I crowded into a kitchen with several other people. All of us are science fans who volunteer with Straitwatch. We help biologists gather data about how whale-watching affects the local orcas. Over dinner, we chatted about the Cohen Commission that is gathering information on salmon.
Salmon are a big issue here in British Columbia! We Straitwatch volunteers knew that most of what resident killer whales eat is salmon. Humans like these oily fishes, too, locally and around the world. "In the last two decades, global consumption of salmon has risen from 27,000 tons to more than 1 million tons annually," noted McKay Jenkins in his book What’s Gotten Into Us? Staying Healthy In A Toxic World. That's a lot of salmon. And much of the salmon we eat comes from fish farms. "So, what is it about farmed salmon anyway?" one of the volunteers asked. "What's different about it?" He wondered why anyone could complain to the Cohen Commission about fish farms. After all, fish farms supply a lot of food. People need food. If a million tons of wild salmon were harvested every year, there might not be any wild salmon left to spawn in some rivers.
Part of the difference, we explained, is that the farmed salmon doesn't taste the same as wild salmon. Wild fish grow up eating a lot of small sealife, especially tiny invertebrates that look like shrimp. That's why salmon flesh is a pink or red colour. Farmed salmon are fed ground-up fish made into pellets. Without their natural food, the flesh of farmed salmon is more pale and less firm than wild salmon.
The food pellets are very convenient for the fish farmers, but some people worry about what might be in the pellets. Pollution like heavy metals or industrial chemicals can build up in the food chain, affecting both fish and humans. "Farmed salmon turn out to have ‘significantly higher’ levels of flame retardants than wild fish, likely because they are fed ground-up fish that are themselves contaminated," McKay Jenkins observed.
Another difference that we science volunteers noticed here on the Pacific coast is that most of the farmed fish are Atlantic salmon, thousands of miles from the habitat where they evolved. These farmed salmon are raised in large nets, suspended in small ocean bays. The salmon in a farm don't have freedom to move about over a wide area and scatter their wastes. Under the farms, the muck piles up on the sea bottom.
"Salmon farms are dangerous to wild salmon," wrote marine biologist Alexandra
Morton on her website, "because they create a place where viruses, bacteria and parasites breed." Wild salmon migrating past the farms might get sick. The Coastal Alliance for Aquaculture Reform promotes on their website the idea of farming salmon and other fish in closed containers, instead of enclosure nets in narrow sea inlets along the salmon migration routes.
Biologists are taking samples, and bringing their findings to the Cohen Commission. But this Royal commission gets different reports from every expert who testifies! The Norwegian companies building the salmon farms say the germs are no problem. Clam harvesters near salmon farms claim that the clam beds are affected. It won't be easy for the best laws to be written to protect wild salmon as well as support sustainable business development.
At each city the commission visits, the public audiences get to see history being made. And as we science volunteers discussed the same issues, and some of us attended meetings of that commission, we were part of the ongoing public discussion. It's good to know that science isn't only used by specialists in a lab, but by people studying how to work and grow food in the wide world.

Very, Very Fishy

Posted by Vivien Bowers

In late September, I’m off to the salmon spawning creeks along the west coast of Haida Gwaii (Queen Charlotte Islands). For the third year in a row, I get to tag along with a fish biologist who is walking the streams to count the returning fish.

F-words
Fishy. Fecund. Fetid. The first time I walked these salmon spawning creeks I dredged up vocabulary I’d never used before. The moist air stinks of rotting fish, bear musk, bird droppings and compost. Hundreds of eviscerated salmon carcasses (which must also be counted) litter the banks. The bears sometimes just tear out the rich fish brains, leaving the rest to scavengers. Crows peck out the eyes, before the eagles chase them off. I’ve seen seagulls so glutted on fish they can hardly take off.

One little, two little, three little salmon...
I scramble after my biologist friend as he makes his way up the creek, eyes alert to shifting underwater shapes and shadows. He tosses a leaf onto the surface of a deep pool, and fish boil to the surface. In amongst the bigger chum there are fleeting dark silhouettes of coho. He uses his little hand-held clicker to record the count.

The rocks in the creek are slippery and scummy. Some of these watersheds have never been logged and we clamber over an obstacle course of moss-covered giant spruce deadfalls. Wading from one bank to another through tannin-brown water, I feel salmon bumping up against my legs.

Do-si-do with Bear
Bears and salmon go together. A researcher on Haida Gwaii found that a single bear will take about 1600 kilograms of salmon from a creek in one season. It will eat only about one half of what it catches; much of the rest decomposes on the forest floor. That’s how bears transfer massive amounts of nutrients from the ocean to the land. They are handy that way.

I appreciate the bears’ important niche in this ecosystem, but it’s a bit unnerving how many of them we meet. Haida Gwaii bears are particularly big. Last year I was on my own, counting fish in a tributary stream, when I came across a large bear scooping fish out of the water. I stomped on a dead branch, hoping to sound like a REALLY BIG bear and scare him off. Instead, the bear was curious and headed towards my noise. Quickly changing strategies, I stood up with a loud, “Hey bear!” He looked startled and fled. I continued upstream, following the salmon's journey deep into the primeval forest.

Vivien Bowers is the author of Wow Canada!, Crime Scene and other books for children. The cartoon panels are from "Swimming Upstream," an episode of the 'WebVoyagers' comic strip, written by Bowers and illustrated by Mike Cope, that appears in each issue of The Canadian Reader, published by LesPlan Educational Services Ltd. Vivien Bowers lives in Nelson, BC.