Ch.11: The Fishes

Planktivores (sharks)

An organism that feeds on plankton

Oviparous (reproductive strategy)

Animals that produce eggs that hatch externally • the chimaeras and nearly half the sharks and rays are *oviparous* , meaning that they lay eggs (egg laying)

Ovioviviparity (reproductive strategy)

Animals that produce eggs that hatch internally, thus giving live birth (Strategy to protect delicate eggs is to retain the eggs within the female's body for a time)

Vertebrates

Animals with a well-developed backbone (Ex: fish)

rectal gland (Osmoergulation)

A gland in sharks and rays located near the rectum that removes excess salt from the blood (controls salt concentration within the body and releases it into the rectum to be excreted)

Chondrostei

A group mostly cartilaginous-like fishes that exhibit significant ossification; this group includes the sturgeons and birchirs; and, the Neopterygii, which include the gar fish (sturgeons and paddlefishes)

Skates (elasmobranchs)

A group of elasmobranchs that closely resemble, and are related to, the *rays* (flat bodied organism; triangle shaped body; Class Chondrichthyes)

Chimaeras

A group of fishes in the Subclass Holocephalii that split off from the elasmobranchs 400 million yrs ago, but remain similar to them in their having, among other features, a cartilaginous skeleton • their caudal fin is *diphycerl* (meaning it tapers to a point), with the notochord running to the top, but in some species it is more *heterocercal* (meaning that the dorsal love of the caudal fin is larger than the ventral lobe, almost an exacerbated version of that of sharks (these species have plowed, short, and long noses)

year class

A group of fishes or invertebrates that were spawned in the same year (groupings based on year hatched or born and does not change)

Urea (Osmoergulation)

A metabolic waste product from the breakdown of protein • the cartilaginous fishes maintain an internal tissue concentration of solutes that is about the same as seawater, thus reducing the osmotic pressure and the tendency to either lose or gain water across their tissues. This is accomplished by their main ring an elevated concentration of ____ in their blood (waste product formed in the liver, filtered out of the blood by the kidneys, and excreted in urine)

Agnathans

A primitive group that includes the hagfish & lampreys. Also called *jawless fishes*

Myomeres

A segment of body musculature of fishes that corresponds to the vertebrae (Bands of muscle along the sides of fishes used for locomotion)

Post larva

A stage in fish development following absorption of the yolk sac

Neopterygii (Chondrostei)

A subclass of actinopterygian fishes; includes the freshwater gar fishes (Gars, bowfins, teleosts)

gill rakers

Bony protrusion on fish gills that prevent unwanted objects from passing down fish's throat; in some species they are gently enlarged and are used to filter planktonic food particles (Long gill processes that trap plankton while the fish swims with it's mouth open)

fin rays

Bony rod like structures that lend support to fins of the bony fishes (each of the long, slender bony protuberances supporting the fins of most bony fishes)

rays (elasmobranchs)

Cartilaginous fishes in the super order Batoidea that are characterized by their flattened body, greatly expanded, wing-like pectoral fins, and long thin tails (flat bodied organism; diamond shaped body)

Anguilliform

Eel-like • _______ swimming, the entire body moves, producing undulations that form one or more waves along the length of the body and generate forward thrust (shaped like an eel)

Viviparity (ovoviviparity)

Having the characteristic of giving live birth • other species of Chondrichthyes = *ovoviviparity* (as distinguished from live births in mammals, for ex, and even in some fishes, which is known as _____)

jawless fish

Members of the class Agnatha, a primitive group of fishes that lack articulated jaws; includes the *hagfishes & lampreys* (Parasitic fish that have skeletons made of cartilage but lack a proper skull)

Lampreys (jawless fish)

One of 2 groups of extant jawless fishes; the other is the hagfishes • ____, in order Petromyzontiformes, reside in coastal marine waters as well as in some fresh waters, but bc they prefer cool water, they are found in the tropics & subtropics

Hagfish (jawless fish)

One of the agnathans, or jawless fishes, in the order Myxiniformes; they are exclusively marine, lack actual vertebrae in their backbone, and lack paired fins • _____ are scavengers; best known for their tendency to feed on dead or dying fish/ marine mammals, by boring into them or entering through a n orifice and feeding on them from the inside out (marine; tie themselves in knots to escape predator)

Teleostei

The "perfect bone" fishes; the most abundant group of modern bony fishes (The osteichthyan order that contains the cod, tuna, halibut, perch, and other species of bony fishes)

Amphidromous

Refers to a form of fish migration between fresh & salt water at some life cycle stage other than the breeding (fish which move between fresh and salt water unrelated to breeding/spawning)

Catadromous (diadromous)

Refers to fish that lives in freshwater and enters saltwater to breed (Ex: American eel) (Referring to fishes that migrate from fresh water to reproduce in the ocean)

Anadromous (diadromous)

Refers to fish that swim into rivers from the sea to breed (Ex: salmon) (migrating up rivers from the sea to spawn)

yolk-sac larva

Refers to larval fish that has hatched from an egg but which retains a sac with remaining egg yolk

Diphycercal (chimaeras)

Refers to the form of caudal fin where the vertebral column extends all the way to the end of the tail, such as in the coelacanths and chimaeras • chimaeras caudal fin is ________ (meaning it tapers to a point), with the notochord running to the top, but in some species it is more *heterocercal* (meaning that the dorsal love of the caudal fin is larger than the ventral lobe, almost an exacerbated version of that of sharks (A tail that tapers to a point, as in lungfishes, vertebral column extends to tip without upturning)

denticles (cartilagenous fishes)

Scales on cartilaginous fishes; structurally similar to vertebrates teeth (Small, sharp, toothlike structures on the skin of cartilaginous fishes)

chloride cells (Osmoergulation)

Specialized cells in the gills of bony fishes used in osmoregulation by excreting excess salts (Cells in the gills of fishes that are involved in the excretion of excess salts)

lobe-finned fish (bony fishes)

The Sarcopterygii, a clade of bony fishes; characterized by possession of fleshy lobes at the proximal ends of the pelvic and pectoral fins; the tetrapods evolved from this group of fishes • • 2 basic groups of bony fish: the ______ & *ray-finned fishes* (have fleshy fins that are supported by a series of bones; ex. coelacanth and lungfish)

ray-finned fish (bony fish)

The actinopterygians, a subclass, or clade, of bony supporting structures running though their fins; this group includes the majority of modern bony fish • 2 basic groups of bony fish the *lobe-finned fishes* & ______ (have fins supported by bony elements called rays; ex. perch, bass, eels, trout, guppies)

operculum

The bony gill covering in the bony fishes (A protective flap that covers the gills of fishes)

Osmoergulation

The metabolic alteration of internal concentrations of solutes as necessary to maintain a constant internal milieu, different from that of their surroundings (regulation of salt and water in the body)

fecundity (reproductive strategies)

The relative reproductive potential as measured by the numbers of eggs produced per breeding cycle • unlike the bony fishes, the sharks and rays have extremely low *fecundity* —they produce very few young at a time. (fertility; fruitfulness)

lateral line system(elasmobranchs)

• A sensory system of fishes and some amphibians that defects pressure changes from physical disturbances in the water; made up of individual receptors just beneath the skin on the head; often arranged in a line along the sides of animals • that capability is also present in a rudimentary form in the hagfishes/ lampreys in the form of individual *neuromasts* , receptors just beneath the skin that detect minute water motions thru tiny pores (sensitive receptor system that enables fish to detect gentle currents and vibrations in the water)

Heterocercal (chimaeras)

• Refers to the asymmetrical caudal fin of sharks, where the dorsal lobe is larger than the ventral lobe • chimaeras caudal fin is *diphycercal* (meaning it tapers to a point), with the notochord running to the top, but in some species it is more _______ (meaning that the dorsal love of the caudal fin is larger than the ventral lobe, almost an exacerbated version of that of sharks (possessing a tail with the upper lobe larger than the lower and with the vertebral column prolonged into the upper lobe)

Thunniform

• Tuna-like; refers to the general muscular body form • fish like tuna, jacks, pompanos, and mackerel use rapid, powerful, yet almost imperceptible motions of their caudal fins. This swimming mode, _____, is a characteristic of the fastest-swimming fishes (caudal fin provides power)

school

• a *shoal* of fish, almost always the same species, that have a uniform orientation and swimming speed, and which move as one • when under attack these ______s may further contract into *pods* (Aka bait balls)

Elasmobranchs

• a group of cartilaginous fishes that includes sharks, rays, and skates • *lateral line system* —> *neuromasts* • *ampullae of Lorenzini* • *a collective name for the sharks, skates and rays*

semelparity

• a reproductive strategy of some organisms in which all reproductive effort goes into a single breeding episode, reproducing only once in their lifetime, and usually dying soon afterward (Reproduction in which an organism produces all of its offspring in a single event; also known as big-bang reproduction)

pods

• a tightly packed school of fishes, such as a bait ball • when under attack these *schools* may further contract into ______ (Aka bait balls)

shoal

• an aggregation of fishes; distinct from a school of fishes • a _____ is a group of fish. It is made up of a number of fish that have come together or are residing in the same area for social reasons; usually, but not always, they are all of same species (Analogous to a flock of birds.

Shark (elasmobranchs)

• any of numerous elongate mostly marine carnivorous fishes with heterocercal caudal fins and tough skin covered with small toothlike scales • _____ lack fin rays, the firm, rod like support structures in fins that most bony fishes have, but they have well developed pectoral fins and a caudal fin, which not only provide propulsion and maneuvering while swimming, but in pelagic species they also provide lift to the negatively buoyant fish • most _____ are predatory carnivores and sit atop the trophic pyramid; their preferred food is other fishes. But not all ______ are carnivores; some are *planktivores*

Piscivores

• fisheater; many fish are themselves _____ (Eat fish)

Diadromous

• fishes that migrate freely between seawater and freshwater • _____ includes the *anadromous* and *catadromous* fishes (Migrate between fresh and salt water for spawning purposes)

Ampullae of Lorenzini (elasmobranchs)

• network of pores that are sensory organs in the elasmobranchs that detect electric fields (special sensing organs called electroreceptors, forming a network of jelly-filled canals; these organs help sharks sense electric fields in the water)

Neuromasts (lateral line system)

• sensory receptor just beneath the skin in fishes that detects minute water motions thru tiny pores, capable of detecting such disturbances as are created by low-frequency noises and animal movements; usually arranged in the *lateral line system* (a sensory organ of fishes and larval or aquatic amphibians, typically forming part of the lateral line system)

cartilaginous fish

• the class Chondrichthyes; the group of fishes with a cartilaginous skelton • their skeleton is still cartilaginous, like that of more primitive jawless fishes, although it may be heavily calcified in some taxa. Their integument is a tough coating of *denticles* , or placoid scales, oriented backward • member of a group of fishes with flexible skeletons made entirely of cartilage (Ex: *chimaeras, sharks, rays, skates*)

Bony fishes

• the group of fishes with ossified skeletons in the Class Osteicthyes; these are the modern fishes • 2 basic groups of ____: the *lobe-finned fishes* & *ray-finned fishes* (A fish that has a stiff skeleton reinforced by calcium salts)

reproductive strategies

• the particular reproductive biology / behavior of a species, implying an associated survival advantage afforded by such • nearly all fishes reproduce sexually (although there are a handful of reports of parthenogenesis, development of unfertilized eggs) • unlike the bony fishes, the sharks and rays have extremely low *fecundity* —they produce very few young at a time. • the chimaeras and nearly half the sharks and rays are *oviparous* , meaning that they lay eggs • other species of Chondrichthyes = *ovoviviparity* (as distinguished from live births in mammals, for ex, and even in some fishes, which is known as *viviparity* )

recruitment

• the process whereby young fishes have grown sufficiently large as to be susceptible to fishing gear, and are not part of the fishery for that species • _____ is a term that refers to the survivors & is defined by fishery scientists as the # of fish that survive to a particular age, usually 1-3 yrs old, when fish first become large enough that they are available to the fishery

iteroparity

• the reproductive strategy of an organism that reproduces more than once over the course of its lifetime (Reproduction in which adults produce offspring over many years; also known as repeated reproduction)