Thursday, December 5, 2013
Skates and rays are really similar and often hard to tell apart. Some rays look like flat sharks and some flat sharks look like rays, so we are going to be general in identifying skates and rays. In general, skates have fins on the tips of their tails.
Only rays can have stingers, and not all of them do. They can have 1 to 3 stingers from 5 to 15 inches long. See the picture below.
I often get asked about Steve Irwin, the famous Crocodile Hunter when we talk about stingrays. Yes, Steve Irwin was killed by a stingray, but his type of accident was very rare. Steve got stabbed in the heart which injected venom right into an important organ. Also, he removed the barb which caused just as much damage going in as it did coming out because of the sharp serrated edge. For more information about Steve Irwin's death check here and here.
Still worried about shark attacks? Check the newest stats here at the Florida site.
Wednesday, December 4, 2013
The fins are harvested for shark fin soup. Shark fin soup is considered a delicacy in some countries and can sell for upwards of a hundred dollars a bowl.
The next thing we talked about was shark attacks. Most shark attacks are actually provoked by humans. Other shark attacks like bump-and-bites and hit-and-runs are the shark investigating a human to see if it is something good to eat. Once the shark tries it, it finds it doesn't like humans, it will swim away. Unfortunately for us humans, we are not so tough and kind of squishy and shark attacks damage us.
Wednesday, November 27, 2013
Monday, November 25, 2013
Not a lot is known about shark reproduction because in many cases it has never been observed. Sharks have internal fertilization and the male shark has two claspers for sperm delivery. These can be seen on male sharks protruding from the pelvic fin.
Shark reproduction is violent with males biting the female. As a result female shark skin is much thicker than the males so that this practice does not ham or kill her. She fights a little to ensure that only strong males with good genes are able to fertilize her eggs.
Some sharks are oviparous and lay eggs (pictured). These egg cases are known as mermaid's purses. You can see the baby shark and its nutrient-rich yolk through the leathery egg case.
Some sharks are viviparous and have live birth a lot like mammals.
And some sharks are ovoviviparous and keep their eggs inside the uterus before releasing them... so its making eggs and then kind of having live birth.
Think you know it all? Try "Romancing the Shark," a quiz from Shark Week.
Follow this link for a cool interactive about how shark jaws stick out when they attack their prey! The interactive is down at the bottom.
If you are doing a final project on a shark... check out this new link! www.shark.ch
Wednesday, November 20, 2013
In the animal kingdom, males are typically brighter and more colorful. The males are trying to prove to the ladies that they have good genes, they are disease free, and they can escape predators.
Larger males can win contests against other males also proving their good genes. Though the males show off, it is the female's choice when she ultimately makes a decision. It is possible for a female to reject all males and choose none.
Differences in size and coloration indicate that there is female choice, the female will choose a male to fertilize her eggs and in most cases, his job is done, and she leaves to finish the baby-forming process. All she wanted was his genes.
When a large group of organisms all spawn at the same time, the organisms rely on luck and statistical chance for genetic variation. Males and females will look similar because there is no choice involved.
When males and females work together and take an equal role in raising young or protecting eggs, the males and females tend to look more similar. They look similar because of their equal roles and because the choice is longer-lasting. She is looking for more than just a pretty face (and pretty faces in the animal world do not indicate good egg care or being able to provide nesting materials, food, etc).
Differences in size between males and females varies widely. There is no set rule for who will be bigger, but there is usually a clear reason as to why one of them is bigger. Males can be bigger because they fight other males, because they have to guard eggs, or other reasons. Females can be bigger because they have to carry and nourish a fetus, carry and develop eggs, protect babies, or other reasons. To know why a male is bigger or a female is bigger the biology and reproductive strategies have to be understood.
Monday, November 18, 2013
1. Shrimp that are farmed in other countries are not as regulated as here in the states, so shrimp farm pollution is not as regulated and it damages coral reefs. Also many mangroves are cleared to build these farms.
2. US boats are required to have turtle excluder devices (TED) on trawl nets so that turtles do not get caught in shrimp nets and drown. Other countries do not regulate this and as a result catch and drown sea turtles.
To make a environmentally responsible seafood choices, choose shrimp that are farmed or caught in the US. For more sustainable seafood choices, check out Seafood Watch.
Friday, November 15, 2013
Netting is the most popular method of commercial fishing because a lot of fish can be caught in short amount of time without a lot of effort.
One the major problems with most commercial fisheries is the amount of bycatch. Bycatch is anything caught in the net that you do not want. This could include edible fish that your company is just not equipped to process.
Most organisms brought up in nets as bycatch do not survive because they are crushed or drowned. Sea turtles and dolphins sometimes get swept into nets and drown because they cannot make it to the surface to breathe.
Most scientists and fisherman agree that the oceans have been and are being overharvested. People may not like regulations, but without regulations, many fish species that we used to commonly consume would be extinct.
There are many ways to harvest fish. If you want more information, check out the links at Monterrey Bay Aquarium's Seafood Watch Organization.
Wednesday, November 13, 2013
Friday, November 8, 2013
Fish reproduce in a variety of ways. Most are broadcast spawners, meaning that when the time is right, the females release their eggs, the males release their sperm. The gamestes meet and mix producing fertilized eggs that develop into meroplankton fish fry and eventually into adult fish. These snapper are spawning and you can tell by the large cloud of gametes in the water.
By producing a lot of eggs, the snapper hope to overwhelm any predators trying to make a meal so that there is no way all the fry are eaten and some will have a chance of surviving.
Some fish do pair bond. In these instances one or both fish will guard the eggs until they hatch into baby mero-plankton, and then once again, the fish fry on their own. There are very very few fish that provide juvenile care.
In seahorses and their relatives, the female transfers the eggs to the male to care for until they hatch. He attaches them to his belly (or into his pouch) and once that set hatches, she gives him another to raise. This allows the seahorses and their relatives to constantly produce offspring. This photo is of a male leafy sea dragon carrying an egg mass (pink).
Wednesday, November 6, 2013
Many fishes are identified by looking at or into the mouth. The number of mouth-types exhibited by different species is nothing short of astonishing. Three lakes in Africa contained about 900 species of cichlids, nearly all differentiated mainly by the way their mouths are shaped. (This number is rapidly dwindling, by the way, as the cichlids in these lakes are driven to extinction). Cichlid mouths are variously adapted to eat other cichlids' eggs, scales pulled from fishes' living bodies, algae from rocks, tiny invertebrates, and many other forms of food. The arrowana of South America has a mouth adapted for spitting water with precision at insects perched on overhead branches. Parrotfish mouths have evolved to look and act like beaks, which they use to grind at coral, making the sand that surrounds coral reefs. Seahorses and pipefish have tubular mouths for sucking in small prey in narrow places like a vacuum cleaner. SOURCE
Fish with forward facing mouths eat what is in front of them - no surprise. Downward mouths eat algae, prey below them like crustaceans and molluscs, or they take in mouth fulls of gravel, eat the particles, and spit the gravel back out. Upward facing mouths indicate the fish eats prey above them - typical of benthic ambush predators. There are also bills and beaks. Bills are long and skinny used for poking in crevices and eating plankton one at a time. Beaks are used for chomping and can be seen on the parrotfish, a fish that chomps on the algae growing on the surface of dead coral. Fish can also have very large mouths common on filter feeders and fish that swallow large prey whole. Fish also have teeth - a surprise to many - and come in many shapes and size.
Body shape also tells you a bit about a fish. Com- pressed fish have flash and look skinny and can only be found in slow moving waters like coral reefs. Fusi-form fish are tapered like footballs and are very streamlined for constant fast swimming. Depressed fish are benthic and squashed looking. Eel shaped fish are poor swimmers and live on the benthos or in cracks and crevices.
Here is a website you can use to identify shapes - realize they are named a bit differently than how I do in class.
Fish tails (caudal fin) indicate how fast and how much a fish swims. For this class, we are focusing on the crescent (not pictured), forked (e), square (d), rounded (b), and funky (c, f, h). As you can see there are more fish tail shapes out there.
Crescent caudal fins indicate a very fast fish that is constantly swimming - not time for resting, it is time to go go go! Forked caudal fins are the second fastest, and very maneuverable. Square fins are for your every day swimming fish - they have ok acceleration ad maneuvering. Round fins and Funky fins are slooooooow swimmers that don't spend a lot of time swimming. They can be quick for very short bursts.
Monday, November 4, 2013
Pictured to the right, you can see five lamprey mouths and one lamprey head with blue eyes and seven gill holes.
Jawless fish include lampreys which are parasites and hagfish which are detritavores. Neither one will ever win a beauty contest.
Thursday, October 24, 2013
We have covered molluscs, crustaceans, and echinoderms in larger units, but there are lots of other invertebrate phyla including three types of worms, sponges, and cnidarians.
There are three types of worms - Flatworms (Platyhelminthes), R0undworms (Nematodes), and Segmented Worms (Annelids).
Flatworms (Platy-hel- minthes) are flat and ribbon like, have bilateral symmetry and include things like tapeworms, planarians, flukes, and brightly colored marine flatworms. Marine flatworms have similar adaptations to nudibranchs (molluscs), but are flat and have no tufts. They are simple animals and are often parasites.
Roundworms (Nematodes) are ubiquitous and found commonly worldwide in every biome... but they are poorly understood because they are very very small. Less than 5cm. They have radial symmetry and often are parasites. Roundworms have scary looking mouths with teeth for attaching - often used in scary movies.
For those of you studying invertebrates, you can use these matching cards to help!
Wednesday, October 23, 2013
Echinoderm means spiny skin. Echinoderms include sea urchins, sea stars, sand dollars, sea cucumbers and some other odd organisms like feather stars and basket stars. All echinoderms have radial symmetry, spiny skin, and an endoskeleton called a test.
Most people are familiar with an orange sea star because on the east coast, that's all we've got. On the west coast and in other places around the world, it is easier to find a variety of sea stars in other colors and with different amounts of legs.
Sea stars have powerful tube feet that use water suction to open molluscs. When they eat molluscs, they actually stick their stomach into the shells of the mollusc, digest it, and then put their stomach.
Feather stars and basket stars both have crazy looking legs that they wave around to filter feed. Sea urchins and sand dollars are both covered with protective spines and eat with a scraping mouth called Aristotle's Lantern.
Sea cucumbers have lost most of their exoskeleton and are a bit squishier than other echinoderms. Sea cucumbers are important detritus eaters on the sea floor. When attacked by predators they will expel their guts as a meal for the predator as they make a get away. Sea cucumbers are able to regenerate these guts over time.
Tuesday, October 22, 2013
- Gulf shrimp are the ones people most people are familiar with because these are the ones we eat!
- Shore shrimp live in sea grasses, are fairly small and clear, and are not commercially harvested because no one would make any money.
- Snapping shrimp (or pistol shrimp) have slightly larger claws and can use them to make sonic waves to stun their prey with sound.
- Mantis shrimp whack their prey with arms that can unfold and strike lightning quick.
- Cleaner shrimp make their living eating parasites off of fish and other sea creatures.
Sunday, October 20, 2013
- Blue Crabs are found in the Chesapeake Bay. They are very agressive, like to pinch, but are good to eat. They have a pointy-ended shell and swim fins. (you can kind of see the swim fins on the last leg of the crabs on the right)
- Spider Crabs have a rounder body shape, often a bumpy shell that will grow algae for camouflage, and longer more spindly legs. Spider Crabs include snow crabs and king crabs like the ones seen on Deadliest Catch. A decorator crab is a kind of spider crab that attaches stuff to its bumpy shell to blend in.
- Fiddler Crab males have one claw that is a lot bigger than the other. This is for impressing the ladies, and used to show dominance over other males.
- Hermit Crabs have a weak exoskeleton and thus protect it with a stolen mollusc shell. They have adapted to this lifestyle and have modified back legs that hook on the inside to hold the shell on and one claw that is slightly larger to use as an operculum.
Friday, October 18, 2013
Monday, October 7, 2013
Cephalopods are characterized by their large well developed eyes, numerous tentacles, a parrot like beak in the center of the tentacles, and well developed chromatophores in their skin that allow them to change color.
We watched numerous videos today to see and understand how and why cephalopods make ink clouds, to see how an octopus can swim with jet propulsion or use its tentacles to crawl around, and we also saw how a octopus can eat a shark!
more information about cephalopods, check out CephBase and the Australian Cephalopod Research page.
Friday, October 4, 2013
Some shells are spiral and have an operculum to act as a door for when they hide inside. The snail lives in the entire shell (all the way up into the top and retreats inside to hide when it feels threatened or exposed. The operculum blocks any would-be attackers and is made of a material similar to fingernails. These types of molluscs include whelks and moon snails.
Other shells are not spiral and the snail has good suction power so that predators have a difficult time pulling the snail off the rocks. These types of molluscs include slipper snails, abalones, and limpets.
Even though they don't have a shell, they do however have some interesting adaptations to keep from getting eaten. Most nudibranch exhibit warning coloration because they are poisonous or have stingers - none that they make - they acquire them from the prey that they eat!
National Geographic did a great article a few years ago full of lovely photos. Both are linked here. Watch the video for a full-range spectrum of photos.
Thursday, October 3, 2013
Today classes got a close up look at the Limax maximus and their slimy mollusc bodies. Thank you Steve for bringing him in! Students looked at the two sets of tentacles (eyespots and sensory tentacles) and the hole the land slug breathes through. Some touched it to see what the slug felt like and quite a few second and third period students let the slug slime all over them. Way to be brave!
Slugs can be considered gross because of the copious amounts of mucus they leave behind. The mucus helps them get a better grip on surfaces and helps prevent dessication, drying out. It can also make the slug more difficult to pick up by predators. More information about slugs can be found here.
Wednesday, October 2, 2013
A mollusc makes a pearl to cover an irritating spot like a piece of sand that gets inside the shell. Pearls can be "glued" to the side of the shell or free to move inside the mollsucs shell. We prefer the "free" kind.
Here is a great short video that explains the process!
Any mollusk that produces a shell can produce a pearl. Nevertheless, naturally occurring pearls are rare, found in perhaps one of every 10,000 animals. The cultured pearl industry, which has flourished since the early 20th century, has developed techniques to greatly improve these odds. Indeed, more pearls are produced now than at any time in human history.( SOURCE This is a good website for lots of information on pearls)
Tuesday, October 1, 2013
- The shells found on the beach are from dead organisms.
- Any mollusc that has a shell, makes it shell.
- Sea shells are made of calcium carbonate.
- Shells are smooth on the inside because slimy molluscs don't want to rub their soft bodies on something rough. If they are smooth on the outside, then the mollusc also wears its body on the outside of its shell.
Today's cool mollusc was the chiton, an odd mollusc that has 8 overlapping plates held together by its soft squishy mantle, and the plates come apart when the animal dies. Chitons are built like armored cars and have great suction to stay on the rocky coast in waves and storms. They spend their days sliming around scraping algae. When pulled off a rock, it can roll into a ball to protect its squishy parts. More info can be found here.
Mussels make byssal threads for attaching (so do ark shells and jingle shells) and scallops have eyespots to see predators. Oysters make cement to stick together and clams have a powerful foot for digging down and hiding.
Tuesday, January 29, 2013
Conservation Report - Can you see me? Is a link to an awesome website with many examples of amazing animal camouflage - some on land and some in the sea. Check it out!
Tuesday, January 22, 2013
Thursday, January 17, 2013
Upwelling is when cold nutrient-rich water comes up to the surface. It is fed by deepwater currents hitting land and rising to the surface. These areas have cold water that is full of nutrients, so there is heaps of plankton, and as a result lots of fish and other marine life.
There are two known upwelling spots in California on either side of Monterrey Bay, shown in blue and purple on the map. There are elephant seal and sea lion rookeries (hang outs) at both of these spots because there is plenty of food for the seals and sea lions and their babies to eat.
Students are working on mapping upwelling and then answering questions about the data gathered from a particular day. If this is not finished in class tomorrow, then it will be homework for the students.
Wednesday, January 16, 2013
Global water movement is important for oxygen and nutrient distribution, but also has major impacts on migration of animals and weather patterns.
Tuesday, January 15, 2013
Today the class was spent working independently on the seafloor features surrounding the United States and reading and answering questions about underwater vehicles. Submarines are larger than submersibles and carry more people and can go longer distances. ROVs and AUVs are robots like remote-controlled cars, but go underwater. ROV's have a tether (cord) connecting them to power and AUVs do not.
Computer Lab Etiquette
You are in the computer lab to do work for this class. If you are not doing work, then we will have problems.
Do not pack up early. Work until the bell or until MsJ says.
SAVE OFTEN. And if you save to a key, also save it to your number. If you lose it, you will have to do it again.
If MsJ asks for your attention, stop what you are doing and listen to what she has to say.
You may watch videos about your organism through reliable websites.
You may listen to music through the computer if you have your own headphones. Rule1 MsJ cannot hear it. You get one warning. Rule2 Turn it on and listen – no million clicks and constant changing. Take both ear phones out when MsJ is talking.