Chapter 31: Fishes Gopher RockFish eating a small octopus. Photographed at Bluefish Cove, Point Lobos State Reserve, CA Gopher RockFish, Sebastes carnatus.

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

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 Bilateral symmetry; segmented body; three germ layers; well-developed coelom. Notochord (a skeletal rod) present at some stage in life cycle. Single, dorsal, tubular nerve cord; anterior end of cord usually enlarged to form brain. Pharyngeal gill slits present at some stage in life cycle. Postanal tail, usually projecting beyond the anus at some stage but may or may not persist. Segmented muscles in an unsegmented trunk. Ventral heart, with dorsal and ventral blood vessels; closed blood system. Complete digestive system. A cartilaginous or bony endoskeleton present in the majority of members (vertebrates). Human; 5 wks

fishes Subgroups of Chordates:
Subphylum Urochordata - "Tail Cord." There are 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 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) Embryonic notochord Hollow dorsal nerve cord Pharyngeal slits Muscular post-anal tail

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

fishes Charge 1: hagfish are repulsive.
Info from excite.sfu Defending the maligned hagfish 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. Charge 1: hagfish are repulsive. What's more, the hagfish has the remarkable ability to defend itself by emitting an incredible slime when it is touched. The slime comes from glands along the fish's sides, and it comes out almost like runny plastic. Within seconds, a hagfish can produce a gallon of the goop, and slip away from 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 The hagfish may not win any beauty contests, but it does have a kind of elegant simplicity. It does not look like much more than a swimming tube. Its mouth is a fleshy funnel with some horny barbs around it. What really disgusts people is the hagfish's behaviour. It is an ocean vulture, feeding off wounded and dead animals by entering into any available opening and eating from the inside out. You don't want to think about that for too long.

fishes Charge 2: hagfish are primitive. Charge 4: hagfish are useless.
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 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? 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?

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 375F 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 350F 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.

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

Lampreys begin life as burrowing freshwater larva
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 Life Cycle fishes 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 mud-dwelling 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.

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

fishes Class Chondrichthyes: “cartilaginous fishes”
(sharks, rays, skates, chimeras) Key features: cartilaginous skeleton 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 Class Chondrichthyes: sharks mako shark great white shark
bull shark blue shark

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

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

fishes Ventral view

fishes Key features common to all sharks: 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. This shape minimizes drag… (remember, water & air are both fluids!) Why?

fishes Fins 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. Paired pectoral fins lift the shark as it swims. 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)

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

fishes 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. 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

fishes Constant Swimmers
…their constant movement (albeit lazily at times) provide two things: 1. Oxygen 2. Lift The spiracle is a vestigial first gill slit. It appears as an opening behind the eye, as in the spiny dogfish (left). It is absent or reduced in many sharks, especially the fast swimming sharks and is usually larger and present in sedentary or bottom dwelling sharks. In sharks, the spiracle is used to provide oxygenated blood directly to the eye and brain through a separate blood vessel. In rays, 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 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… Also, their gills do not have muscular gill covers capable of rhythmic contraction (hence they cannot ‘bring oxygen-rich water to their gills while still)…and so they must always be on the move…

fishes Razor-sharp teeth
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 Class Osteichthyes: “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)

bony fishes Representative species: largemouth bass External anatomy

bony INTERNAL ANATOMY

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

bony fishes Shapes continued 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.

bony fishes Fins 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 Marbled African Lungfish 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. South American Lungfish

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

bony fishes Types of Scales plate-shaped Rhombic-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

bony fishes Scales continued… 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.

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

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

bony fishes Distinct Lateral line 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. Cuttlefish lateral lines Is this a fish? 

bony fishes Relationship to motion
Two design features distinguish the bony fishes from sharks: 1. Swim bladder 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! 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.

bony fishes Gill ventilation
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.

bony fishes How Fish Breathe
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.

Which direction seems beneficial—and likely? Why?
bony fishes How Fish Breathe Which direction seems beneficial—and likely? Why? 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 place). Which two fluids interact to ensure that fish breathe? Does flow direction matter ?

bony fishes How Fish Breathe
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 butterfly fish
How Fish Breathe When fish are taken out of the water, they suffocate. This is not because they cannot breathe the oxygen available in the air, but because their gill arches collapse and there is not enough surface area for diffusion to take place. There are actually some fish that can survive out of the water, such as the walking catfish (which have modified lamellae allowing them to breathe air). 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. triggerfish

bony fishes Swimming The muscles provide the power for swimming and constitute up to 80% of the fish itself. The muscles are arranged in multiple directions (myomeres) that allow the fish to move in any direction. A sinusoidal wave passes down from the head to the tail. The fins provide a platform to exert the thrust from the muscles onto the water. The density of water makes it very difficult to move in, but fish can move very smoothly and quickly. A swimming fish is relying on its skeleton for framework, its muscles for power, and its fins for thrust and direction. 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 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.

bony fishes Drag When: thrust > drag = swimming!
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! 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.

bony fishes Two types of Swimming
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 Blacksmiths, Chromis punctipinnis Everyone has heard of a school of fish, an aggregation of fish hanging out together; 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? 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.

Advantages (con’t) 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 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 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:

Schooling: Finding Nemo School of Fish

bony fishes Schooling:
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?

fishes Modes of Reproduction Whitetail pup Skate egg vs. oviparous
Hammerhead pulled from dead mother Whitetail pup With their gills exposed to sea water, all marine fishes are faced with the problem of conserving 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: Skate egg Retain the eggs and embryos within the mother's body until they are capable of coping with the marine environment. Enclose the egg in an impervious case filled with isotonic fluid before depositing it in the sea. vs. 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 Modes of reproduction:
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)

fishes + _ Modes of Reproduction angel
In fishes, oviparity is most common: 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. angel + _

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

bony fishes Fancy Guppies Color
Your picture (below, left)shows that your male has a big abdomen area, and his abdomen might deceive you into thinking he's a female. But we know from his gonopodium fin that he is a male. Also, he has very bright colors, and I have never seen a female Guppy with such bright coloration. Good tank mates for Fancy Guppies are Cory Catfish, Small Tetras such as Neon Tetras, White Clouds, Honey Gourami, Glass Fish, Ghost Shrimp, and African 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 well in waters low in dissolved oxygen, that does not mean they require less oxygen than other fish. Bettas have a special respiratory organ that allows them to breath air directly from the surface. In fact they inherently must do so. In experiments where the labyrinth organ was removed, the fish died from suffocation even though the water was saturated with oxygen. For this reason, Bettas must have access to the water surface to breath air directly from the atmosphere.

bony fishes Bettas:growth ©Wayne schmidt
. 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. Seven weeks old: 1.1 inches long. As a reference, the line 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 ©Wayne schmidt Eleven weeks old: 1.9 inches long

bony fishes Common tank fishes neons Dwarf gourami african cichlid
“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 neons closer view of the female Convict carefully watching over her babies on the rock. This picture shows hundreds of eggs that were laid Dwarf gourami african cichlid Convict pair

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

bony fishes Common tank fishes Dwarf Puffers
“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 Dwarf Puffers

bony fishes A strange transformation 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.

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

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

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

bony fishes Impact on man
In the 1860s, sturgeon were looked at as a nuisance to commercial anglers and were deliberately destroyed in large numbers. Then, in the 1870s, people realized that sturgeon were useful for products such as: glue from their skeleton; oil from fat; leather from their tanned skins; roe (eggs) for caviar; and gelatin from their swim bladder, used for liquid clarifyers, jellies and jams. In the 1950s, fish biologists began to study sturgeon populations and spawning sites to help protect and increase their numbers. A large female has been known to yield 100 pounds (45.4 kg) of roe, or eggs, equal to about 8 percent of her body weight. Salted and processed sturgeon roe is used to make caviar that can cost up to U.S. $100 per ounce in the toniest restaurants in New York, London, or Tokyo. Sturgeon roe, weighing 1,122.7 grams, when converted to caviar will be worth roughly $2, at $56.00 an ounce.

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

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

fishes 1. northern anchovy; peacock flounder; white sturgeon; yellow seahorse; Chinese sucker; bobtail snipe eel; secretary blenny; tiger shark; pebbled butterflyfish; 10. blackspotted wrasse; 11. clown triggerfish; 12. swordfish; sockeye salmon; king mackerel; sea lamprey; paddlefish; red-bellied piranha; longnose gar; minnow; 20. catfish; 21. pelican eel; deep sea anglerfish; bicolor parrotfish; green moray Mouth morphology diversity in fish, sharks, and lampreys.

Info & images from liverpoolmuseums.org

shrimpfish stonefish stonefish mackerel leafy sea dragon
The stonefish exactly copies the shape and colour of weed-covered 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 shark shark sea horse Fast cruiser
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). The shark is not the fastest fish in the sea though. The sailfish has been timed at a cool 68 mph (109km/h). Fast cruiser shark shark sea horse

Efficient feeding: best return for E input
Feeding efficiency frogfish 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 barracuda coral butterflyfish

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

fishes the end

fishes

Leopard Sharks Triakis semifasciata
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 sailfish marlin

fishes

Chapter 31: Fishes Gopher RockFish eating a small octopus. Photographed at Bluefish Cove, Point Lobos State Reserve, CA Gopher RockFish, Sebastes carnatus.

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Presentation on theme: "Chapter 31: Fishes Gopher RockFish eating a small octopus. Photographed at Bluefish Cove, Point Lobos State Reserve, CA Gopher RockFish, Sebastes carnatus."— Presentation transcript:

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Chapter 31: Fishes Gopher RockFish eating a small octopus. Photographed at Bluefish Cove, Point Lobos State Reserve, CA Gopher RockFish, Sebastes carnatus.

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Presentation on theme: "Chapter 31: Fishes Gopher RockFish eating a small octopus. Photographed at Bluefish Cove, Point Lobos State Reserve, CA Gopher RockFish, Sebastes carnatus."— Presentation transcript:

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