Marine Biologist for a Day

Monica and I pose for a picture at the end of the day.

My time at the London Aquarium, experiencing the life of a Marine Biologist, was one of the most amazing and wonderful things that I have done in my life. I spent time feeding rays and turtles, dissecting squids, chumming sharks and finding baby rays. It was a fun learning experience, where I got to talk to real people who had taken the same path in life that I want to take myself, and I really got an insight into the different university choices and career paths that would become available to me.

In particular I would like to thank Monica, who guided me through the day, and was kind, helpful and supportive throughout. She taught me a lot about the inhabitants of London Aquarium, diving and careers in Marine Biology, and was a real inspiration for the kind of life I want to lead. If you are reading this Monica, thank you for everything you did that day.

If you are interested in the Marine Biologist for a day course then click here to learn more about it. It was astounding and I recommend it utterly. Places seem readily available, so there’s no better time to get stuck into Marine Biology.

If you want to learn about a Sea Life Centre near you just follow this link. Sea Life run some really amazing aquariums across the globe, and it can be a really magical experience to visit them.

Feeding the Green Turtles

Phoenix, the Green Turtle, moves in to eat some lettuce.

Of all the animals I fed on my Marine Biologist Day at the London Aquarium, the most majestic and magnificent animals of all were the two Green Turtles, Boris and Phoenix. In the large tank of the London Aquarium, you can find sharks, rays and other interesting marine life, but most beautiful of all are these giants of the ocean. Chomping on lettuce, Monica and I fed these behemoths towards the end of the day from the open top of the tank. Green Turtles like Boris and Phoenix become vegetarian as they grow up, and so adult like them are fed lettuce, although they still try to steal food, like squids, from the others animals. In order to remain true to their natural diet, which would consist of seaweeds and kelp, the aquarium makes sure to avoid giving them any kind of meat.

Green Turtles, also known as Chelonia Mydas, are found across the globe, as far north as Britain and south Alaska, and as far down as The Cape of Good Hope. They have particularly large nesting grounds in areas of the Caribbean and Indo-Australia, where they will climb onto land to lay their eggs. Rain Island in the Great Barrier Reef is a huge hotspot for these amazing animals, with many thousands of them dragging themselves up the small strip of land in order to find the best spot to conceal their eggs. Going onto land can be vary dangerous for them, so they will make the journeys from dusk until dawn, to avoid being caught out in the baking sun. Unfortunately as the tide moves out, many turtles cannot make it back to land and are caught left as food for birds and scavengers.Boris takes food from the end of my stick.

Boris and Phoenix surface to take some food I've left in the water.

Adult Green Turtles are about one and a half metres in length and can weigh up to 200kg, although certain exceptional specimens have been up to just under 400kg. Their bodies are a brownish colour, although some individuals have a more mottled pattern. Hatchling start off jet black, with a yellow or white underbelly, and as they grow, begin to develop their unique colour and pattern on the shell, that allows humans to identify individual members of the species. The tails of males are far larger and longer than those of females, which makes it easy to sex the turtles. They are rather unremarkable when compared to their close relatives, with most differences occurring around the mouth and head area, although they are the only turtle that become a herbivore when it matures. Peculiarly, the ‘green’ in the name does not feature visibly on the turtle, instead being attributed to the greenish fat layer beneath the skin. They were named by sailors who hunted and ate them on their long voyages.

The heavy shell of all larger turtles makes for a safe life of eating jellyfish and nibbling on sea kelp, but tiger sharks are still a valid threat to an adult sea turtle. The Tiger Shark has a massively powerful bite, beaten only by the Bull Shark (as well as the Nile and Saltwater Crocodile), and it more than capable or crushing through the shell of a Green Turtle in a couple of bites. As such the adult turtle will turn its body on its side in order to present as larger surface to the shark, which it cannot get its mouth around. Tiger Sharks will often wait for dead turtle bodies to be washed into the ocean of laying season, since they provide easy sources of protein. In this way, turtles are still relatively safe from these sharks, who would rather find an easier target. Juvenile turtles, however, are in much greater danger of being eaten. Eggs are dug up my land mammals as nutritious snacks, birds snatch newly hatched turtles from the sand as they run for the sea, and crabs will easily tear a baby turtle limb from limb. Luckily, with such a large number being born every year, turtles are fairly safe from their natural predator. Unfortunately, turtles are hunted for their flippers to be used as food and ‘traditional medicine’. It is a horrible waste of life, and needs to be stopped if we are to conserve these gentle giants for the future.

I had a brilliant time with Boris and Phoenix, and I must confess that I really love turtles, be they green or loggerhead. Here’s hoping that I have many more opportunities to see them in the future.

Feeding the Cownose Rays

A cownose ray moves forward to take a squid from me.

On my Marine Biologist Day at the London Aquarium, I fed a number of animals, including the school of Cownose Rays living in the large tank at the aquarium. Living in the tank there are a selection of turtles, smaller sharks and guitarfish, as well as these amazing rays. Monica, Pete and I went above the large tank, to where an open top revealed the all of the aquaria below us. Using a long stick, I held out squids for the enthusiastic rays, who surfaced in order to take the food, sometimes squabbling over it. Monica and I made sure that all of the rays got some food, while Pete fed the sharks, and very soon there was no squid left. The turtles in the tank came to eat the squid too, but since they are not meant to eat meat, I had to avoid letting them take away squids.

Cownose Rays, Rhinoptera Bonasus in Latin, are a type of eagle ray, which are the larger open sea rays that live in the more open waters around the world. Whereas some rays stay near the sea bed, eagle rays swim into open waters in order to feed an relax. Cownose Rays travel in groups of nine or ten in the wild, so keeping them in a group in the tank keeps them happy and healthy, as though they were living naturally. The aquarium puts emphasis on making sure the animals do not stray far from their natural roots, so the food that they receive, squids in this case, is similar to the kind of food they would catch in the wild, which includes molluscs such as octopus, oysters and clams. The groups flap their wings in sandy areas to dredge up the seabed and reveal the crustaceans and other prey beneath.Monica and I give one of the smaller rays its lunch.

It was a real pleasure to feed these fun and inquisitive creatures, as they strike truly impressive figures as their shivers (shoals) go gliding through the water. I hope that I have more opportunities like this in the future.

Thornback Ray

A Thornback Ray being kept in the backroom tanks at London Aquarium.

The Thornback Ray is one of the most common rays in the world, encompassing a large area of the world, from Europe to South Africa, where it lives in shallow seas. Many are kept in the ray pools at the London Aquarium, where I spent a day as a Marine Biologist, including the Thornback Ray that I discovered there. You can recognise the Thornback Rays by the spiny ridges that run down their body from the middle of their back to the end of their tail. In terms of colouration, most rays have a number of pale spots on their backs, although the adolescent pictured above in more a matt brown colour. Females often develop spikes on the underside of their body as they grow older, and this is an easy way to sex the ray. Most rays measure at about 3/4 of a metre, although they have been known to reach lengths of just over 1 metre.

The Thornback Ray lives and feeds in the seabed, where it hunts down crustaceans like shrimp and crab, molluscs like sea snails and small fish which hide in the sand, which it grinds up with its plate like teeth. The camouflage on its back means that the ray is almost perfectly disguised from predators when it buries in the sand. Most sea animals have far less developed eyes than humans, and have to rely on other senses to find them. In order to find food themselves, the rays can sense the movement of sea creatures below the sand by the electric signals they produce,  allowing them to catch their prey even though they cannot see the sandy sea floor.

Many of these rays are caught every year by fishing trawlers, and passed off as skate for the fishing market. This repeated overfishing has left them in a near endangered state, so next time you order skate at a fish and chip shop, remember it could be a Thornback Ray instead.

I find rays to be really interesting animals, utterly different from any other creature in the world. I hope to come into contact with other types of ray in the future, perhaps some of the open water rays.

Kenneth or Kinsley

I triumphantly display a captured mermaid's purse.

Of all my experiences at the London Aquarium on my Marine Biologist for a Day trip, the absolute best was when I helped recover and candle mermaid’s purses from the ray pool. Rays and Dogfish keep their young in little cocooned capsule-like eggs that people often call mermaid’s purses, due to their appearance as a little pouch. While not all ray eggs are shaped like this, some being rounder or corkscrew shaped, these are the iconic ray eggs, and they are the type made by the rays at London Aquarium. In the ray pool you can find Undulated and Thornback Rays, who are on a breeding program to help preserve both species, in particular the Undulated Ray. I was sent into the exhibit armed with nothing but a net and my eagle-vision, to spot and recover the eggs. I went around the perimeter, scooping up any within nets reach, and with the help of the public, I managed to spot 18 eggs in total, a tidy sum. The purses further into the middle of the pool, out of net reach, would be collected later that night using a pair of waders to reach in inner pool.I search in vain to locate an egg with a live ray inside.

I brought my hard earned clutch of ray eggs back to the laboratory in London Aquarium, in order to identify and candle the eggs. The eggs of Thornback and Undulated Rays are very similar, both taking the purse like shape, but with the use of a chart, I was able to identify the different eggs. While the undulated eggs had smoother smaller sides with straight points on each corner, the thornbacks had more jagged edges with wavy points on the corners. All but one of the eggs were thornback, a testament to the necessity to help these Undulated Rays breed, before they begin to run thin in the wild. Even then, most ray eggs do not contain live animals, instead merely being empty cases filled with water and yolky sludge. I held the eggs up to a light, which shone through the translucent casing and revealed the contents to me, in a technique called ‘candling’. Nothing. Nothing again. Very little but water in any of the eggs. It is very rare for the aquarium to find live eggs, and I was reassured that this was normal, rather than just exceedingly bad luck. However, as I approached the last few eggs, my luck became fantastic, as I candled an egg to reveal a tiny thornback living inside, only a few weeks into growth. It was the most wonderful feeling I’ve ever had, discovering new life inside the tiny egg, and by the tradition of the aquarium I was allowed to name them. Kenneth if they were a boy, or Kinsley for a girl. They were the first live ray to have been laid for 7 months, and all of the staff were very excited. I was very excited. We took Kenneth/Kinsley and laid them in the egg pool, with the other unhatched mermaid’s purses.I reveal Kenneth or Kinsley for all the world to see.

I cannot truly describe how amazing it felt to find the baby ray in its egg; it was probably the most fantastic and proudest moment of my life so far. The egg will take 9 months to mature and hatch, and I will return again to the aquarium in order to see my baby ray amongst all of the others.

Making Shark Bait

I fill the fish with iodine pills and other tablets.

One of the largest animals kept at the London Aquarium are the two Sand Tiger Sharks, or Grey Nurse Sharks. On my Marine Biologist Day at the aquarium I was asked to help prepare some fishy food for them, since they were feeling poorly that day. In the ocean, the sharks live in saline water that contains a number of essential chemicals that they need to keep their bodies running, in particular iodine. London Aquarium is not on the coast so they can’t bring in water from the sea, like Brighton or Plymouth Aquarium, to use in the tanks. Instead the have to create their own saline solution by salting the tank water themselves. While they are able to keep the water at the correct salt levels, it is difficult and impractical to keep the correct balance of other chemicals, and so these chemicals are added to the food they eat.

If a shark lacks iodine, like a human, they will begin to develop goitres (large inflamed lumps) around their throat and near the base of their fins. This is very dangerous for them, so I had to put together 60 iodine tablets, by pouring the white powder into small transparent casings. While I did this, Monica was cutting slots in the side of the fish we would feed to the sharks, where we would push in the pills. After I had made all 60, I began to stuff an iodine pill and a large pink vitamin pill into each of the smaller fish. The larger fish received 2 iodine and pink tablets.

Sand Tiger Sharks, or Carcharius Taurus, is neither related to the tiger, nurse or sand shark, despite it’s myriad of confusing names, such as Grey Nurse Shark, or Blue-Nurse Sand Tiger. Even it’s scientific name translates to bull shark, which it is also not related to. They are fairly relaxed and gentle sharks, and respond very well to being kept in captivity, which makes them one of the easiest sharks to keep. Many aquariums use them not only because they are so easy to keep, but because they are so fearsome looking, being roughly 2 to 3 metres long with large bodies and sharp heads. The teeth are pointy and lack serration, which most other sharks possess, and they swim with their mouths open, making them seem very scary for visitors to the aquarium. They are seen around most warm waters in the world, at the edges of continents, avoiding the open ocean. The Mediterranean, east coast of America, Australia and most of Africa house them, where they can be found living in sandy shallows, all the way to the edge of the continental shelf.

These sharks are ambush predators in the wild, leaving their shelter at night in order to hunt large fish, rays and even smaller sharks. They have been known to catch fish up to half of their size, which they eat in a few bites. The animals they catch are mainly bottom feeders that live on the sandy sea floor, and they will wait quietly for them to come past. The Sand Tiger Shark has a devious trick in order to remain quiet in the water, in which it rises to the surface and gulps air into its stomach. Like a diver, this air is used to maintain a neutral buoyancy so that they have to move very little in order to swim. This means they can get close to fish while barely making a sound, giving them a big advantage while hunting.

It is good that the Aquarium is keeping these animals, since they are on the endangered protection list, and have one of the slowest reproduction rates of any shark. After Monica and I had finished the fish, Pete, another staff member took them away to be fed to the sharks later.

Feeding the Ray Pool

I feed the juvenile tank in the aquarium ray pool.

On my day as a helper at the London Aquarium, one of the interesting activities I participated in was feeding the ray pools, which are the open pools near the start of the aquarium containing all manner of flatfish, crabs and rays. Taking a delectable tray of calamari, raw fish, freeze dried prawns and other seafood goodies, the staff, Monica (my guide for the day), and I went about the pools making sure all of the animals were fed. Under the direction of the staff I selected the correct creatures and gave them food with the use of a long stick and some well timed throws.

Above I am feeding the juvenile tank, where the adolescent rays are kept after they are old enough to come out of the private tanks in the back of the aquarium. There are a selection of Undulated and Thornback Rays in the ray pools, and we used smaller pieces of fish and squid for these younger ones. In the wild they would act the same way any adult ray did, but for the sake of safety the aquarium places them separate to the larger crabs of the adult pool. The more confident rays came to the surface to receive their food, and would often snatch food away from the shyer animals, meaning I had to make sure those rays got food while the others weren’t looking. It was difficult to time, since they did not always eat the food immediately, but between myself and the staff, every ray got some food.The aquarium staff feed the various denizens of the ray pool.

In the larger ray pool, there were some animals other than rays to feed, such as the aptly named Herbert, who was a Turbot, and a large slow moving Edible Crab. Turbots camouflage is perfect for the sandy sea bed, a mixture of pale yellows and white, only identifiable by the twin eyes poking out from under the sand. Flatfishes eyes start on different sides of their heads when they are born, but as they develop, the eye on the bottom side rise through the head to the other side, since they do not see on the face down side. The crab was slow to move, and I had to dangle the squid and prawns in front of his face before he would try to eat them. Fighting back other hungry rays, I would hold it in front of him, waiting for his soporific claw to close around the food.

It was incredible fun to feed these animals, and I was amazed to be working so closely with such  incredible creatures. I hope to work with animals like this again in the future, and recommend it utterly to all who are considering such opportunities.

Chinese Soft-Shelled Turtle

I feed Rufus the Chinese Softshelled Turtle.

In the back rooms of the London Aquarium, many animals deemed to aggressive to go into the display tanks live in their on private biomes. One such animal is Rufus, the Chinese Soft-Shelled Turtle. As a rule, these strange turtles are angry and short-sighted, which makes them likely candidates for biting the fingers of children who leave them trailing in the open pools around the aquarium, so as you might imagine he is kept safely away. Rufus was donated to the aquarium by a pet owner who no longer had the resources to feed him, or simply got bored of him. While is was better to donate Rufus than to abandon him in a local pond, far too many people donate their pets each year, and this can cause problems for the aquarium, who can only house so many. It’s far better to keep your turtle, or sell them to a local pet shop where they can have a new owner.

The Soft-Shelled Turtle, or Pelodiscus Sinensis, despite its name has a shell no softer than that of any other turtle, instead owing its name to the lack of sharp ridges that cover the shells of most turtles and the flexible edges that their shells have. The centre of the shell (or carapace) is made of bone and as hard as any other species. In general, Chinese Soft-Shelled Turtles are a dark khaki colour across their shell and on their limbs, like Rufus, but some have a more mottled, blotchy colouration. Several darker lines can often be seen around the head area, but they are difficult to spot on Rufus, since he seldom stops moving when people are near. The strange shape of the nostrils, that resemble long tubes, are used as snorkels to breath below the water. They are also useful as they are able to release waste products from that area, which means they don’t lose much water from urinating. This is useful because these turtles live in areas where salt water and freshwater mix, meaning the slightly salty water is often bad to drink.

Chinese Soft-Shelled Turtles eat mainly invertebrates, crustaceans like shrimp and small fish in the wild, which are plentiful in their habitats. However, these turtles are rather opportunistic and have been known to eat plant life, and in captivity, pet food and small vertebrates like mice and young frogs. Be warned though, they don’t make for good ratters. I fed Rufus with a few frozen prawns, which he swam up to the surface to receive. Keeping my fingers out of the way, I waved the food in the water until he smelt it and came to me, and then I released it in front of him so that he could take it away. Unfortunately, Rufus has fairly poor eyesight, and at one point did not see me release the food, where upon it sank to the bottom, with Rufus looking at me angrily and expectantly. He found it eventually, but not after a few malicious looks at my fingers.

In China, people eat soft shelled turtles fairly regularly, even to the point where they are farmed, with many millions being eaten nationally. They are often made into a sort of turtle soup, or stewed with vegetables, and are fairly nutritious. In Japan these turtles are considered a delicacy, and can be eaten in a variety of ways. In the West, they are mainly kept as pets, like Rufus before he came to the aquarium, and you can find them in larger pet shops across the country. Luckily, these turtles are in plentiful supply, and are unlikely to ever be in danger of extinction.

After feeding Rufus his fill of frozen prawns, I waved goodbye to him and went on to feed some of the larger, flatter denizens of the aquarium.

Moon Jelly

Young moon jellyfish at the London Aquarium.

The moon jelly, or Aurelia Aurita, is one of the most widely distributed jellyfish in the world, ranging from equatorial tropics, to more northerly seas around Europe and in the Atlantic. On my ‘Marine Biologist Day’ at the London Aquarium, I saw a tank of young moon jellies being raised until they were ready to go on display in one of the larger Kreisel Tanks. Jellies of the Aurelia genus are very distinctive from other jellyfish, by their large disc shaped bodies, which are roughly 10 – 20 cm in diameter. Unfortunately, it is virtually impossible to identify individual species in the genus without the use of genetic sampling. Like many other species, moon jellies are capable of free swimming, although they often move with the currents which makes them seem as though they are drifting with the current. In reality, most jellyfish swim by undulating their bodies, and one of the only free drifting jellyfish, is not really a jellyfish at all. The Portuguese Man O War is in fact a colony of four separate organisms, working symbiotically as a single siphonophore.

Moon jellies and other jellyfish have no internal systems, such as the nervous, endocrine, respiratory or excretory systems. The transfer of chemicals, oxygen and nutrients throughout the body, as well as the removal of waste products, are dealt with by diffusion, simply allowing the substances to move throughout the thin cell walls of the body, rendering the need for the latter three systems void. Nobody quite understands how the jellyfish is capable of operating without any kind of nervous system, however it is known that jellyfish can detect the direction of current, and respond to it.

Moon jellies normally feed on a diet of plankton, larvae, fish eggs and small molluscs, which they catch with their trailing tentacles and then pull into their stomach. The tentacles contain cnidoblasts, small exploding cells, that deliver the venom to the prey when they burst. Moon jellies are mainly predated by Leatherback Turtles, Sunfish, and various tiny parasites.

I only saw these moon jellies in passing at the London Aquarium, but I find these animals strangely beautiful and alien, and their lack of brain fascinates me. I hope that I will get more chances to interact with Moon Jellyfish in the future.

London Aquarium Non-Display Tanks

A juvenile Thornback Ray in a tank in the London Aquarium tanks.

On my ‘Marine Biologist for a Day’ trip at London Aquarium, one of the first things that the staff showed me were the tanks where all of the animals not on display are kept, including the juveniles, like the Thornback Ray above. Any animal that was not out in the aquarium for the people to see, are kept in smaller tanks around the back of the site. Animals that are stressed, ill, too aggressive or just to young to be with the other animals are brought here until they are ready to be seen.

Every year the aquarium receives dozens of donations of tropical fish and aquatic reptiles, sent in from pet owners who have found they can no longer take care of the animals themselves. Red-Ear Terrapins are one example of animals that the aquarium is offered on a regular basis, and they are now at the stage that they cannot take on any more. This is also where breeding of the animals takes place, with new seahorses and jellyfish being born here, as well as Fire Eels, rays and corals.Some of the corals the aquarium grows for their tanks.

The corals from the aquarium are grown to be used in tank exhibits around the tropical reef sections of the aquarium. Again, most of the coral that the aquarium owns is donated by tank owners who no longer have use for their tanks. There is a common misconception that most of the coral is taken from people trying to smuggle it in and out of the country as ornamental pieces. In fact, there is very little of this occurring, since protection of reefs is so strong that the profit is normally not worth the potential punishment for the smugglers. Some of the corals that are kept in this part of the aquarium are Hammer Coral, which is a hard coral found in Indonesia and Australia, and Mushroom Coral, which originates in the Indian Ocean.Seahorses kept for breeding.Jellyfish kept in the iconic circular tanks.

These jellyfish are called Japanese Sea Nettles, and they are small juveniles kept here until they grow large enough for the exhibit. Jellyfish are always kept in these strange circular tanks, because they require currents to move them around, and in a normal square or oblong tank, the movement of the water will push them into the corners, causing them to get stuck and potentially damaging or killing the jellyfish. Luckily, the jellyfish seem quite beautiful spiralling in their round tanks.

The starfish and crabs that live in the rockpool section are kept on a rotation, since having people touch them can cause them quite a bit of stress. To prevent this from becoming unhealthy, every 2-3 hours the rockpool in changed, moving in new animals through the use of a bucket of cold water. There are about six tanks, meaning a full rotation lasts around 2 days, more than enough time for the starfish to recover. I was allowed to change the animals part way through the day, and had to remove the starfish from the tank by gently stroking their sides, until they let go of the rocks they held on to. Despite harassment from an over animated crab, I changed around the starfish without any trouble.

It was very interesting to see all of the processes that went behind running the aquarium, which I had only every seen from one side of the exhibits. Getting to help was one of the best experiences of my life.