Chapter 31 Fishes Gopher Rock Fish eating a

Chapter 31: Fishes Gopher Rock. Fish eating a small octopus. Photographed at Bluefish Cove, Point Lobos State Reserve, CA Gopher Rock. Fish, Sebastes carnatus “Let the water teem with living creatures…” 1: 28 biology ~ mr. e genesis

fishes toasted. ”

fishes Sometimes the symbol contains the Greek word for fish, "ichthus". What's really cool is that this word forms an acronym for "Jesus Christ, Son of God, Savior" as the following table demonstrates: Greek letter Ι (iota) Χ (chi) Θ (theta) Υ (upsilon) Σ (sigma) greek word Iesous Christos Theos Huios Soter english word Jesus Christ God Son Savior

A somewhat simplified version…

fishes KINGDOM ANIMALIA: Major Characteristics of Phylum Chordata 1. Bilateral symmetry; segmented body; three germ layers; welldeveloped coelom. 2. Notochord (a skeletal rod) present at some stage in life cycle. Notochord 3. Single, dorsal, tubular nerve cord; anterior end of cord usually Single, dorsal, tubular nerve cord enlarged to form brain. 4. Pharyngeal gill slits present at some stage in life cycle. Pharyngeal gill slits Human; 5 wks 5. Postanal tail, usually projecting beyond the anus at some stage but Postanal tail may or may not persist. 6. Segmented muscles in an unsegmented trunk. 7. Ventral heart, with dorsal and ventral blood vessels; closed blood system. 8. Complete digestive system. 9. A cartilaginous or bony endoskeleton present in the majority of members (vertebrates).

fishes Subgroups of Chordates: • Subphylum Urochordata - "Tail Cord. " There approximately 1500 described species of these marine living chordates. They are commonly called tunicates because of the tough, nonliving tunic that surrounds the animal. • The swimming larvae resemble tadpoles and possess all of the four key chordate characteristics. As sessile adults they lose the notochord and the tail, their dorsal hollow nerve cord becomes reduced, but they retain the pharyngeal gill slits. Example: tunicates, sea squirts

fishes • Subphylum Cephalochordata - "Head Cord. " There are only 25 species described in this subphylum of marine lancelets. They are all small, slender, laterally compressed, translucent animals. These simple animals are often used as a textbook example to represent the four key chordate characteristics. • Once considered to be the ancestor of the chordates, they are still believed to more closely resemble the earliest prevertebrates than any other animal known. Examples: Amphioxus (the lancelets) Today, amphioxus may be extremely common in shallow sandy environments: at Discovery Bay, Jamaica, up to five thousand individuals per square meter of sand have been reported. In some parts of the world, amphioxus are eaten by humans or by domestic animals; they are important food items in some parts of Asia, where they are commercially harvested.

fishes • Subphylum Vertebrata - "Backboned. " This is the largest and most diverse subphylum of chordates whose nature is characterized by the basic adaptations of the living endoskeleton, efficient respiration, advanced nervous system, and paired limbs. • This group is divided into those without jaws and those with jawed mouths. This course will take a close look at this subphylum… Examples: lampreys, sharks, fish, frogs, snakes, pigeons, pigs…

fishes KINGDOM ANIMALIA: Phylum Chordata : 4 characteristics Subphylum Urochordata Subphylum Cephalochordata 1. Embryonic notochord 2. Hollow dorsal nerve cord 3. Pharyngeal slits 4. Muscular post-anal tail Subphylum Vertebrata Class Agnatha (hagfishes & lamprey) Class Chondrichthyes (sharks, rays, skates, chimeras) Class Osteichthes (bony fishes like perch, bass, seahorse) Class Actinista (coelacanths) Class Amphibia (frogs, toads, salamanders) Class Reptilia (turtles, tortoises, snakes, lizards, crocidilians) Class Aves (birds) Class Mammalia (mammals)

fishes Key features: Class Agnatha: “without jaws” • notochord persist • jawless vertebrates throughout life • cartilaginous skeleton • lack paired appendages • gills lampreys and hagfishes

Info from excite. sfu Defending the maligned hagfishes The hagfish is one of the most despised creatures in the ocean. Its very name inspires disgust. But does the hagfish deserve its reputation? Maybe it is time to stand up for a fish that can't stand up for itself. Let's look at the charges against the poor hag. C What's more, the hagfish has the harge 1: hagfish are repulsive. remarkable ability to defend itself by The hagfish may emitting an incredible not win any beauty What really disgusts slime when it is contests, but it does people is the hagfish's touched. The slime have a kind of behaviour. It is an ocean comes from glands elegant simplicity. vulture, feeding off along the fish's sides, It does not look like wounded and dead and it comes out almost much more than a animals by entering into like runny plastic. swimming tube. Its any available opening Within seconds, a mouth is a fleshy and eating from the hagfish can produce a funnel with some inside out. You don't gallon of the goop, and horny barbs around want to think about that slip away from it. for too long. predators. If a hagfish seems repulsive, think about what the environment would be without them. They perform an important function by keeping the ocean clean. All of those rotting carcasses would not make the waters very healthy

Charge 2: hagfish are primitive. fishes The hagfish has not changed for millions of years, but that's a virtue. It is so well adapted to its environment that it does not need to "improve. " You might say that it is perfect already. Charge 3: hagfish are stupid. How smart does any fish have to be? Consider this: if you manage to grab onto a hagfish (in spite of all of the slime) and hold on tight, it will tie itself into a knot and tighten the knot until it pulls itself out of your grip. Stupid? Charge 4: hagfish are useless. In fact, hagfish are often used in research. They even have some commercial value. In recent years, tons of the lowly hag have been turned into "eel skin" wallets and belts. Once again, humans have found a way to profit from nature, but whenever we do that, there is a price to pay. What will happen to the marine environment if we remove the "repulsive, primitive, stupid" hagfish?

fishes On the culinary front… …the slime is a sugar and protein solution that coagulates when it's secreted into water, forming a slime that is similar in texture and chemical composition to egg whites. . Hagfish-Slime Cheddar-Gruyere Scones 4 cups all-purpose flour 2 tablespoons baking powder 4 teaspoons sugar 1/2 teaspoon salt 1 cup (two sticks) chilled unsalted butter, cut into 1/2 -inch cubes 2 cups (packed) coarsely grated extra-sharp yellow cheddar cheese (about 9 ounces), or a mix of 6 ounces cheddar and 3 ounces gruyere. 1 -1/2 cups chilled heavy whipping cream 6 tablespoons hagfish slime Preheat oven to 375 F Serve warm or at room temperature. The scones will stand for about 8 hours. Do not refrigerate. If you want to reheat them, warm them in a 350 F oven for about 5 minutes. From a real culinary perspective, I sort of doubt that the pure egg-slime substitution works terribly effectively, since about 1/3 of an egg's mass is the yolk, which contributes texturally since it's both pure fat and it holds air marvelously (it's a born emulsifier). So maybe this would work better with 4 ounces of hagfish slime and two egg yolks. Or you could probably replace the yolks with butter. . . or cook up some hagfish and render the fat, if you want the truly authentic version.

lampreys fishes Mouth (above); two on trout (left)

Lampreys begin life as burrowing freshwater larva. At this stage (not pictured), they are toothless, have rudimentary eyes, and feed on microorganisms. This larval stage can last five to seven years and hence was originally thought to be an independent organism fishes Life Cycle After these five to seven years, they transform into adults in a metamorphosis which is at least as radical as that seen in amphibians, and which involves a radical rearrangement of internal organs, development of eyes and transformation from a muddwelling filter feeder into an efficient swimming predator, which typically moves into the sea to begin a predatory/parasitic life, attaching to a fish by their mouths and feeding on the blood and tissues of the host. In most species this phase lasts about 18 months. Whether lampreys are predators or parasites is a blurred question.

External Anatomy fishes An adult lamprey (below) Opens to blind sacs

fishes Class Chondrichthyes: “cartilaginous fishes” Key features: • cartilaginous skeleton (sharks, rays, skates, chimeras) • notochord replaced by vertebral column • paired appendages • jaws • respiratory gills; NO swim bladders • internal fertilization • acute senses (esp. lateral line system) Dermal denticles from in front of and a bit below the first dorsal fin of a whale shark

fishes great white shark bull shark Class Chondrichthyes: sharks mako shark blue shark

Class Chondrichthyes: Skates & rays Atlantic stingray fishes Ocellated river stingray Blue spotted fantail ray Tampa Bay Ray Southern stingray Manta ray

fishes Q: My Gramma lets me use her computer to learn. Can you help me understand how Rays and Skates are different please? A. Skates and rays are very closely related animals. Both are in the Class Chondrichthyes. These animals are both in the Order Rajiformes, which includes the sharks, skates and rays. All of these animals share several similar anatomical structures: Rays typically have long slender tails that may have a stinger (there are exceptions), whereas skates generally have a broader, well developed tail. Overall, these organisms are remarkably similar, and are only differentiated at the Family level of classification. Rays comprise the Torpedinidae and the Dasyatidae, the skates make up the Family Rajidae. There are differences in the egg cases of these animals, the numbers of embryos present in the egg cases and differences in the developmental process as well. Visually, the animals are hard to distinguish.

External anatomy fishes Representative species: Atlantic Sharpnose Shark Rhizoprionodon terraenovae Heterocercal tail Cloacal vent b/w Lateral view

fishes Ventral view

Key features common to all sharks: fishes Fusiform Shape When engineers came up with the shape of a DC-9 airplane, they were thinking about the fastest way to travel using the least amount of energy. If you compare the DC-9 to a shark, you will see that their shapes are amazingly similar. They both have round bodies tapering off at both ends. This shape allows the plane to glide through the air, and the shark to glide through the water, without using up all their fuel before they get where they want to go. Why? This shape minimizes drag… (remember, water & air are both fluids!)

Fins fishes Sharks, as all fish, use their body and tail in a side to side motion to move through the water. Shark fins are rigid not flexible, and are supported by rods made of cartilage. Sharks have five different kinds of fins. 1. Paired pectoral fins lift the shark as it swims. 2. Paired pelvic fins stabilize the shark. (prevent rolling & provide diving planes) 3. One or two dorsal fins also stabilize the shark. In some species, dorsal fins have spines. 4. Not all sharks have an anal fin, but it provides stability for those that do have one. 5. The caudal or tail fin moves the shark forward. (provides thrust)

“plate-like” Placoid scales fishes Shark skin feels like sandpaper because it has A regular catfish has a very sleek, black skin - no small rough placoid scales, that's why you have (also known as dermal to skin a catfish, not scale it denticles). As a result, it is (that's where the old saying often dried and used as a "more than one way to skin a leather product or cat" comes from, not from killing off the barn cats). sandpaper. Placoid scales consist of a basal bony plate buried within the skin and a raised portion that is exposed. Dermal denticles are homologous in structure spiny dogfish denticles (180 X) to teeth.

Ampullae of Lorenzini The ampullae of Lorenzini are small vesicles and pores that form part of an extensive subcutaneous sensory network system. These are found around the head of the shark and are visible to the naked eye. They appear as dark spots in the photo of a porbeagle shark head (right). The ampullae detect weak magnetic fields/electrical charges produced by other fishes, at least over short ranges. This enables the shark to locate prey that are buried in the sand, or orient to nearby movement. fishes Each ampulla is a bundle of sensory cells that are enervated by several nerve fibers. These fibers are enclosed in a gel-filled tubule which has a direct opening to the surface through a pore. The gel (a glyco-protein based substance) has electrical properties similar to a semiconductor, allowing temperature changes to be translated into electrical information that the shark can use to help detect temperature gradients

Constant Swimmers fishes …their constant movement (albeit lazily at times) provide two things: 1. Oxygen 2. Lift Bony fish have a gas-filled swim bladder which enables them to float in the water, but sharks have no such bladder. Since cartilage is lighter than bone, it helps to keep a shark from just sinking to the bottom of the ocean… The spiracle is a vestigial first gill slit. It appears as an opening behind the eye, Also, their gills do not have as in the spiny dogfish (left). It is absent muscular gill covers capable or reduced in many sharks, especially the fast swimming sharks and is usually of rhythmic contraction (hence larger and present in sedentary or they cannot ‘bring oxygen-rich bottom dwelling sharks. In sharks, the water to their gills while spiracle is used to provide oxygenated blood directly to the eye and brain still)…and so they must through a separate blood vessel. In rays, always be on the move… the spiracle is much larger and more developed and is used to actively pump water over the gills to allow the ray to breathe while buried in the sand

Razor-sharp teeth fishes Shark teeth are not lodged permanently within the jaw, but are attached to a membrane known as a tooth bed. The tooth bed membrane is similar to a conveyor belt, moving the rows of teeth forward as the shark grows, thus always replacing the older teeth in front that have become damaged, fallen out or worn down It is not uncommon for shark teeth to be found lodged in large prey (such as whale carcasses) or loose on the ocean floor. Serrated great white (left); smooth-edged porbeagle (below)

bony fishes AWARD: Most diverse of the vertebrates Class Osteichthyes: “bony fishes” (bony fishes like perch, bass, seahorses) Key features: • bony skeleton & jaws • notochord replaced by vertebral column • paired appendages • swim bladders • respiratory gills • (most) external fertilization • acute senses (esp. lateral line system) line

Representative species: bony fishes External anatomy largemouth bass

bony INTERNAL ANATOMY

bony

Shapes bony fishes Basic shapes flat (horizontally compressed) vertically compressed fusiform (modified) eel-like (serpentine) ribbon Most osteichthyes are which types? round

Shapes continued bony fishes VARIATIONS IN BODY FORM Fish shape has a great bearing on ability to move through the water. • A tuna fish which has a fusiform similar to a torpedo can cruise through the water at very high speeds. • The attenuated shape of the eel allows it to wiggle into small crevices where it hunts prey. • The depressed shape of the angler fish is advantageous for its "sit and wait" strategy of hunting. • The compressed shape found on many reef fishes such as the angel fish gives the fish great agility for movement around the reef and can support sudden bursts of acceleration.

Fins bony fishes paired appendages: pectoral & pelvic fins paired • Three distinct groups: 1. Lobe-finned fishes 2. Fleshy-finned fishes 3. Ray-finned fishes

bony fishes • Three distinct groups: 1. Lobe-finned fishes: have fins and bony rays and lobes of bone-less areas lacking rays. Simple, primitive type of fishes: The coelacanth is a simple bony, lobe-fin fish which was once thought to be extinct, but was found living off the coast of south Africa in 1938. 2. Fleshy-finned fishes: Simple bony fishes represented today by only 3 genera; resemble lobe-fins (have lungs and lobed fins). Although they have gills and lungs, they cannot survive outside of water; can come to the surface and gulp air. Another sp. actually can breathe air for long periods of time; can burrow into mud and form a cocoon to survive the summer in tropical regions. The medial fins are fused to make one large, continuous fin. 3. Ray-finned fishes: Largest group of bony fishes (21, 000 sp. ). Most common and familiar type of bony fish. Fins entirely composed and supported by rays; no lobes present.

bony fishes • Three distinct groups: 1. Lobe-finned fishes 2. Fleshy-finned fishes 3. Ray-finned fishes

bony fishes

bony fishes The CRM "Deep Release" T-shirt (pictured) was a unique concept. The shirts that we sent to the Comoros for the fishermen to wear actually had the Deep Release kit sewn onto the back below the diagram, so that it was available to them while they were fishing. (We discovered that Comoran fishermen love T-shirts. ) When they accidentally caught a coelacanth they could then follow the release procedure diagram on the back of the shirt to set it free. More than 100 of these and 400 of the new more easily produced Type II's have been sent to the Comoros thanks to contributors.

bony fishes

bony fishes Marbled African Lungfish South American Lungfish • Three distinct groups: 1. Lobe-finned fishes 2. Fleshy-finned fishes 3. Ray-finned fishes • While in the water, these fishes excrete their nitrogenous waste as ammonia, just as most ray-finned fishes do. In time of drought, these animals burrow in the mud and switch to produce the less toxic nitrogenous compound urea.

muskellunge bony fishes • Three distinct groups: 1. Lobe-finned fishes 2. Fleshy-finned fishes 3. Ray-finned fishes Reef damsel (left) Tropical tetra

Types of Scales bony fishes plate-shaped Placoid = isolated in sharks Primitive = Ganoid = bone and enamel form a tile mosaic- solid Rhombic-shaped Smooth post. margin Cycloid, ctenoid = reduced: thin, light weight, overlapping Serrated post. margin

Scales continued… bony fishes Why are fish slimy? Fish secrete a type of mucus from their skin. This slime coating is important because it 1. provides protection against parasites and diseases, 2. covers wounds to prevent infection and 3. helps fish move through the water faster (reduces drag) Some species release toxins in their slime which ward off attacking creatures while others use their slime to feed their young.

Distinct Lateral line “What is it? ” “it’s something electrical…” “it helps protect from predators…” fishes

Distinct Lateral line bony fishes Sometimes referred to as the Lateral lines are composed of “sense of distant touch, ” lateral neuromasts (hair cells surrounded HOW DOES IT WORK? lines convert subtle changes in by a protruding jelly-like cupula) water pressure into electrical that usually lie at the bottom of a A swimming fish sets up its own pressure wave in the water that is pulses similar to the way our visible pit or groove. These hair detectable by the lateral line systems of other fish. It also sets up a bow cells — the same sensory cells inner ear responds to sound wave in front of itself, the pressure of which is higher than that of the found in all vertebrate ears — wave flow along its sides. The differences in the two pressures are waves. Running lengthwise convert mechanical energy into registered by its own lateral line system. As the fish approaches an object, down each side of the body and electrical energy when moved. such as a rock or the glass wall of an aquarium, the pressure waves over the head, these pressurearound its body are distorted, and these changes are quickly detected by sensing organs help their the lateral line system, enabling the fish to swerve or to take other owners avoid collisions, collisions “Presumably, auditory and lateral suitable action. participate in schooling line pathways evolved in close behavior, orient to water association since they share many currents, elude predators, and features. ” detect prey.

Distinct Lateral line bony fishes Do we have a sixth sense? Humans have five senses; sight, hearing, feel, taste, and smell. Since mammals don't have a lateral line system, it's very difficult, maybe impossible, to convey just what it must be like to have this added ability. After all, could you really convey what sight is like to someone who has never been able to see? But maybe we can provide an approximation of what the lateral line system is like by trying one particular activity. For this activity, you'll need to blindfold a person and have them move within a room. Make sure there is some open space along one wall and then blindfold a willing subject. The object of this activity will be for the blindfolded person to try and determine when he/she is really close to a wall without touching - they can use other senses other than eyesight. Is this a fish? Cuttlefish lateral lines

Relationship to motion bony fishes Two design features distinguish the bony fishes from sharks: 1. Swim bladder Bony fish have swim bladders to help them maintain buoyancy in the water. The swim bladder is a sac inside the abdomen that contains gas. This sac may be open or closed to the gut. If you have ever caught a fish and wondered why its eyes are bulging out of its head, it is because the air in the swim bladder has expanded and is pushing against the back of the eye. Oxygen is the largest percentage of gas in the bladder; nitrogen and carbon dioxide also fill in passively. 2. Pharyngeal design Muscles cause the fish’s operculae to open & close in concert with their mouth, thereby drawing fresh water in their mouth, over their gills and expelling it back out through their operculae—even when stationary!

Gill ventilation bony fishes How do fish ventilate their gills? Fish must pass new water over their gills continuously to keep a supply of oxygenated water available for diffusion. Fishes use two different methods for keeping a continuous supply of new water available, one is very simple and the other complex. Ram Ventilation: Swim through the water and open your mouth. Very simple, but the fish must swim continuously in order to breathe, not so simple. Opercular pump: an elaborate double pump method in which the fish opens and closes its various seals, covers, and mouth to keep water flowing over its lamellae.

How Fish Breathe bony fishes The water surrounding a fish contains a small percentage of dissolved oxygen. In the surface waters there can be about 5 ml. of oxygen per liter of water. This is much less than the 210 ml. of oxygen per liter of air that we breath, so the fish must use a special system for concentrating the oxygen in the water to meet their physiological needs. The circulation of blood in fish is simple. The heart only has two chambers, in contrast to our heart which has four. This is because the fish heart only pumps blood in one direction. The blood enters the heart through a vein and exits through a vein on its way to the gills. In the gills, the blood picks up oxygen from the surrounding water and leaves the gills in arteries, which go to the body. The oxygen is used in the body and goes back to the heart. A very simple closed-circle circulatory system.

How Fish Breathe bony fishes The gills: the gills are composed of a gill arch (which gives the gill rigid support), gill filaments (always paired), and secondary lamellae, (where gas exchange takes lamellae place). Which direction seems beneficial—and likely? Which two fluids interact to ensure that fish breathe? Does flow direction matter ?

How Fish Breathe bony fishes • The blood flows thorough the gill filaments and secondary lamellae in the opposite direction from the water passing the gills. (countercurrent) This is very important for getting all of the available oxygen out of the water and into the blood. • If the blood flowed concurrently (parallel flow), then the blood would only be able to get half of the available oxygen from the water. The blood and water would reach an equilibrium in oxygen content and diffusion would no longer take place. • By having the blood flow in the opposite direction, the gradient is always such that the water has more available oxygen than the blood, and oxygen diffusion continues to take place after the blood has acquired more than 50% of the water's oxygen content. The countercurrent exchange system gives fish an 80 -90% efficiency in acquiring oxygen.

How Fish Breathe bony fishes • When fish are taken out of the water, they suffocate. This is not because they cannot breathe oxygen available in the air, but because their gill arches collapse and there is not enough surface area for diffusion to take place. There actually some fish that can survive out of the water, such as the walking catfish (which have modified lamellae allowing them to breathe air). triggerfish butterfly fish It is possible for a fish to suffocate in the water. This could happen when the oxygen in the water has been used up by another biotic source such as bacteria decomposing a red tide.

Swimming bony fishes The muscles provide the power for swimming and constitute up to 80% of the fish The density of water makes it very difficult to move in, but fish can move very itself. The muscles are arranged in multiple directions (myomeres) that allow the smoothly and quickly. fish to move in any direction. A sinusoidal wave passes down from the head to A swimming fish is relying on its skeleton for framework, its muscles for the tail. The fins provide a platform to exert the thrust from the muscles onto the power, and its fins for thrust and direction. water. In regards to physics, the skeleton of a fish is radically complex. The skull acts as a fulcrum, the relatively stable part of the fish. The vertebral column acts as levers that operate for the movement of the fish. Diagram of forces when a fish swims. Thrust- force in animal's direction Lift- force opposite in right angles to the thrust Drag- force opposite the direction of movement ** All lift forces cancel out over one complete tail stroke

Drag bony fishes Drag is minimized by the streamlined shape of the fish and a special slime fishes excrete from their skin that minimizes frictional drag and maintains laminar (smooth) flow of water past the fish When: thrust > drag = swimming! When: thrust > drag = swimming Slime is secreted from cells in the very outside layer of the skin. In some cases, the placement of these slime-producing cells determines what species of fish it is. The cells produce what is called a glyco-protein, which is then mixed with the water making the slimy mucus.

Two types of Swimming bony fishes Defined by their method of living, and reflected in their physiology. • Cruisers: These are the fish that swim almost continuously in search for food, such as the tuna. Red Muscle- richly vascularized (blood-carrying capacity), rich in myoglobin (oxygen holder and transferor into the muscles active sites) * able to sustain continuous aerobic movement. • Fast: tend to have rigid bodies with less lateral movement (tail mostly) • Slow: tend to be more flexible with exaggerated lateral motion • Burst Swimmers: These fish usually stay relatively in the same place such as most reef fish.

Schooling: “shoals” School of Blacksmiths in Channel Islands Photographed at Wilson's Rock (Metridium Wall), Channel Islands Everyone has heard of a school of fish, an aggregation of fish hanging out together; Blacksmiths, Chromis punctipinnis but why, they are obviously not learning reading, writing, and arithmetic. Schools of fish may be either polarized (with all the fish facing the same direction) or non polarized (all going every which way) Advantages? 1. Antipredator: by hanging out with other fish, each individual fish may gain an advantage in not being eaten by other fish. A. Confusion effect. A large school of fish may be able to confuse a potential predator into thinking that the school is actually a much larger organism. B. Dilution affect. If a fish hangs out with a lot of other fish and a predator does come around, the predator must usually select one prey item. With so many choices, the chances are that it will not be you. This is known as the 'selfish herd'. C. Predator detection. A bunch of fish has many times the eyes and other senses than a solitary fish; so a school of fish may be better at detecting predators. But a school may also attract predators due to its large size.

Schooling: Advantages (con’t) 2. Spawning Aggregation: Many fish species form schools only when it comes time to mate. They will form a huge school and release their eggs and sperm in mass quantities. Releasing a massive onslaught of fertilized eggs in the water may be advantages over a solitary egg, because a massive onslaught may be enough to overwhelm the egg predators. The predators will eat as many as they can, but some eggs will inevitably survive. 3. Enhanced Foraging: A school of fish may have better abilities to acquire food. With many more eyes to detect food, many more meals may be found; but there would also be many more mouths to feed. By working as a team, the school may be able to take larger food items than any one individual could manage to capture. 4. Migration: The migration abilities of fish in schools may possibly be enhanced due to better navigation, etc. Hydrodynamic efficiency: Due to the complex hydrodynamic properties of water (properties the fish probably discovered only by accident), a fish may gain a swimming advantage by being in a school. The slipstream from the fish ahead of it may make it easier to pass through the water. Good for all the fish except for the ones in front.

Schooling: Finding Nemo School of Fish

Schooling: bony fishes A school of Blue Rockfish congregates around some tattered kelp stipes. Photographed at Pescadero Pinnacles, Carmel, CA, Monterey Bay National Marine Sanctuary. Blue Rockfish, Sebastes mystinus Can you easliy distinguish between leaf & fish?

Modes of Reproduction fishes Hammerhead pulled from dead mother Whitetail pup With their gills exposed to sea water, all marine fishes are faced with the problem of conserving Skate egg body water in a strongly hypertonic environment. Sea water is about 3. 5% salt, over 3 times that of vertebrate blood. The cartilaginous fishes solve the problem by maintaining such a high concentration of urea in their blood (2. 5% — far higher than the 0. 02% of other vertebrates) that it is in osmotic balance with — that is, is isotonic to — sea water. This ability develops late in embryology, so the eggs of these species cannot simply be released in the sea. Two solutions are used: • Retain the eggs • Enclose the egg and embryos in an impervious within the mother's case filled with body until they are vs. isotonic fluid capable of coping before depositing with the marine it in the sea. environment. oviparous ovoviviparous; viviparous Both these solutions require internal fertilization, and, according to the neo-Darwinian phylogenetic tree, the cartilaginous fishes were the first vertebrates to develop this. The pelvic fins of the male are modified for depositing sperm in the reproductive tract of the female.

fishes Dwarf puffer Modes of reproduction: • Ovoparity-- Lay undeveloped eggs, External fertilization (90% of bony fish), Internal fertilization (some sharks and rays) • Ovoviviparity- Internal development- without direct maternal nourishment-Advanced at birth (most sharks and rays)-Larval birth (some scorpeaniforms-rockfish) • Viviparity- Internal development- direct nourishment from mother-Fully advanced at birth (some sharks, surf perches)

Modes of Reproduction fishes In fishes, oviparity is most common: angel 1. the eggs are inexpensive to produce 2. as eggs are in the water, they do not dry out (oxygen, nutrients are not scarce). + 3. The adult can produce many offspring, which they broadcast into the plankton column. 4. When the offspring settle out of the plankton, they may be in totally new environments, allowing for a great area in which the young may survive. This mode also comes with its disadvantages: _ 1. when born, the fish must first go through a vulnerable larval stage for growth before they transform into the adult stage. In this larval stage, they must fend for themselves in obtaining food and avoiding predation. 2. They may not find a suitable environment when they settle out of the plankton column. The survival of individual eggs is very low, so millions of eggs must be produced in order for the parent to successfully produce offspring.

Mangrove Rivulus bony fishes Hippocampus abdominalis Gymnothorax prasinus • The Seahorse belongs to the Syngnathidae family, gymno - bare, naked (Greek) the only group of animals thorax - chest (Greek) where the male becomes prasinos - leek green (Greek) pregnant. When mating, the female Seahorse inserts R. marmoratus is a selfher eggs into the male’s fertilizing hermaphrodite that pouch. The male fertilizes attains a total length of the eggs as they enter his approximately 2 inches (~ 50 pouch and carries them for mm). Hermaphrodites of this species have a prominent caudal up to a month before going ocellus and a whitish border into labour for several along the anal fin. Pure females, hours, giving birth from primary males and secondary anything from 20 to 400 males, have been observed in the laboratory, but only males babies! and hermaphrodites have been observed in natural populations. http: //www. youtube. com/ watch? v=BPlnqck. OPd. Y • Seahorses propel themselves by a dorsal fin on their back, which beats at around 70 times per minute.

Color bony fishes Fancy Guppies Your picture (below, left)shows that your Good tank mates male has a big for Fancy Guppies abdomen area, and his abdomen might are Cory Catfish, deceive you into Small Tetras such thinking he's a female. as Neon Tetras, But we know from his gonopodium fin that he White Clouds, is a male. Also, he has Honey Gourami, very bright colors, and Glass Fish, Ghost I have never seen a Shrimp, and African female Guppy with such bright coloration. Dwarf Frogs. Is it male or female and if it's female does it look like it's carrying fry?

bony fishes bettas Even though Bettas do In experiments well in waters low in where the labyrinth dissolved oxygen, that organ was removed, does not mean they the fish died from require less oxygen than suffocation even other fish. Bettas have a though the water was special respiratory saturated with organ that allows them oxygen. For this to breath air directly reason, Bettas must from the surface. In fact have access to they inherently must do water surface to so. breath air directly from the atmosphere.

. bony fishes Bettas: growth Betta egg: 0. 03 inches in diameter One day old fry: 0. 1 inch long (The tail doesn't show at this scale) One week old: 0. 2 inches long. Two weeks old: 0. 25 inches long. (Starting to show dorsal fins. ) Three weeks old: 0. 34 inches long Four weeks old: 0. 45 inches long on average. Five weeks old: 0. 6 inches long. Size ranges from. 5 to. 75 inches. Six weeks old: 0. 85 inches long. The largest are over an inch. As a reference, the line Seven weeks old: 1. 1 inches long. below is one inch long. Eight weeks old: 1. 3 inches long. ____ Nine weeks old: 1. 55 inches long. Ten weeks old: 1. 7 inches long http: //www. youtube. com/watch? v=r. K 0 m_aw. MOWQ&feature=related Eleven weeks old: 1. 9 inches long ©Wayne schmidt

Common tank fishes bony fishes neons Dwarf gourami Convict pair “P. pulcher is probably the most well established west african cichlid in the international hobby today. I suspect that it is the most available dwarf cichlid of any type. ” Juan Azas closer view of the This picture female Convict shows hundreds carefully watching of eggs that were over her babies laid on the rock. african cichlid

Common tank fishes Plecostimus bony fishes neons Zebra danio Pearl gourami Black molly goby Fantail goldfish

Common tank fishes Dwarf Puffers bony fishes “These tiny guys are SO cute and playful. They're freshwater fish, and do not require a brackish environment. They love live and frozen meaty foods, but reject flake. They are too small for krill, so I stick to brine shrimp, blood worms, baby snails and the like. They are very curious and like to come and see what you're doing when they notice you're in the room. They are VERY responsive to their owners and really wonderful in small tanks. I highly recommend these fish. They're so cute you'll wish you could literally SQUEEZE them!” Contributed by Shawna

A strange transformation bony fishes Larval stage Sexually maturity is reached at age 3. Spawning takes place during the fall and winter while the fish are moving offshore into deeper water or when they reach their winter location. The eggs, which float near the surface, hatch in 3 or 4 days to produce larvae shaped more like conventional fish than flatfish. Water currents carry newly hatched flounder into the estuaries and sounds, where they undergo a transformation in shape and become bottom dwellers.

THE SEXUAL PARASITE fishes Thousands of feet below the Finding a mate in the dark depths of the surface, the waters of the ocean are ocean is a pretty tough job! So what does a male anglerfish do when he finds a cold, still, and dark. Almost no mate? He never lets her go! The male sunlight can penetrate such depths, lives as a parasite on the body of the much larger female, taking his food from her and the water temperature hovers bloodstream. Their bodies fuse together, near freezing. The harsh conditions forming a sort of two body hermaphrodite. Although this arrangement primarily of the abyss houses some of the benefits the male, it also frees both sexes most nightmarish bizarre-looking from constantly seeking out new breeding partners whenever it is time to mate. How creatures on Earth. Here there is a do they find each other in the darkness? need for a light that will help Although at one time it was thought that organisms find their way through each lure was designed only to attract special prey, it now appears that the dark murky waters, this light unique shape also attracts a male of the that is produced from a cool same species who recognizes his future mate by her lure. chemical reaction, unlike sunlight (which is thermal) or electrical light, is known as bioluminescence

Aggressive fish Jack dempsey bony fishes oscar Bass & beam Threespot damsel (salt) firemouth cichlid angels

Some you may have hooked… Bonytongued fish bony fishes Bluegill; “sunny” Common carp Red snapper grouper Spotted tilapia Yellow perch white catfish

bony fishes In the 1860 s, sturgeon were Impact on man looked at as a nuisance to commercial anglers and were A large female has been deliberately destroyed in known to yield 100 pounds large numbers. Then, in the (45. 4 kg) of roe, or eggs, 1870 s, people realized that sturgeon were useful for equal to about 8 percent of products such as: glue from her body weight. Salted and their skeleton; oil from fat; processed sturgeon roe is leather from their tanned used to make caviar that can skins; roe (eggs) for caviar; cost up to U. S. $100 per and gelatin from their swim bladder, used for liquid ounce in the toniest clarifyers, jellies and jams. restaurants in New York, In the 1950 s, fish biologists London, or Tokyo. began to study sturgeon populations and spawning sites to help protect and increase their numbers. Sturgeon roe, weighing 1, 122. 7 grams, when converted to caviar will be worth roughly $2, 245. 00 at $56. 00 an ounce.

bony fishes Do fish have intelligence? Our observations in the lab: • feeder recognition • follow finger • hand feeding • train TA’s

shark • cartilaginous • denticles • swims; oily liver • live birth; eggs bony fishes Skeleton Skin Buoyancy Reproduction eel • bony • slimy skin • swim bladder • Eggs; live birth To Whom is the coelocanth more closely related? Circle the features shared by the coelocanth…

fishes Mouth morphology diversity in fish, sharks, and lampreys. 1. northern anchovy; 2. peacock flounder; 3. white sturgeon; 4. yellow seahorse; 5. Chinese sucker; 6. bobtail snipe eel; 7. secretary blenny; 8. tiger shark; 9. pebbled butterflyfish; 10. blackspotted wrasse; 11. clown triggerfish; 12. swordfish; 13. sockeye salmon; 14. king mackerel; 15. sea lamprey; 16. paddlefish; 17. red-bellied piranha; 18. longnose gar; 19. minnow; 20. catfish; 21. pelican eel; 22. deep sea anglerfish; 23. bicolor parrotfish; 24. green moray

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shrimpfish stonefish The stonefish exactly copies the shape and colour of weedcovered coral. The trouble comes if you stand on him - the poison inside those painful spines can kill a human! Efficient camouflage mackerel leafy sea dragon

monkfish mackerel The shark hunts other fish using its streamlined shape and strong muscles to achieve amazing speeds through the water. If it were slower than the fish it eats (like the mackerel) the shark would go hungry (although it does eat dead animals as well). Fast cruiser The shark is not the fastest fish in the sea though. The sailfish has been timed at a cool 68 mph (109 km/h). shark sea horse

Feeding efficiency frogfish yellow tang A good performance from the frogfish there. Actually, more of a good wait. It simply sits still, waiting until its superb camouflage fools an unsuspecting fish into coming too close. Totally efficient feeding. Efficient feeding: best return for E input coral butterflyfish barracuda

Mouth-brooding cichlid Sea horse What can I do? The European eel is the runaway winner, covering up to 7500 km (4660 miles) on the journey to the Sargasso sea. That long, smooth muscular body helps it cover the miles. European eel salmon

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fishes Leopard Sharks Triakis semifasciata Each summer, hundreds of leopard sharks gather in the waters off La Jolla, California and cruise the shallows. Harmless to humans, these sharks, which reach five feet in length, make a beautiful sight for those lucky enough to swim with them. Quite skittish, they are virtually unapproachable on scuba gear. Fortunately, they prefer the shallows, and are most commonly seen in waters 4 to 5 feet deep, so all that's needed is a mask and snorkel

fishes marlin sailfish

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