Ichthyology Lecture exam 1

Diadromous

Diadromous

Fish that migrate between freshwater and saltwater environments for different life stages, such as salmon and eels.

Anadromous

Fish that migrate from saltwater to freshwater to spawn, like salmon.

Catadromous

Fish that migrate from freshwater to saltwater to spawn, like eels.

Peter Artedi

Father of ichthyology

Morphospecies Concept

Distinctive morphological traits define what is a species

Biological Species Concept

Reproductive isolation determines what is a species

Evolutionary Species Concept

Defines a species as a lineage of populations that share a common evolutionary trajectory and fate.

Dichotomous key

A tool used to identify organisms based on a series of choices, leading to a specific classification or identification.

Meristics

any countable structure on a fish (scales, gill rakers, fin rays)

Morphometrics

Any measurable structure (fin length, head length)

Neurocranium

Top half of skull that encloses sensory structures

Branchiocranium

Underside of the skull

Countercurrent flow

A system where two fluids flow in opposite directions, maximizing the exchange of heat or substances between them.

Terminal

mouth opens forward; feed from water column

Superior

mouth opens upward; surface feeders

Sub-terminal

mouth opens downward; benthic feeders

Suctorial

mouth scrapes algae from rocks

Appendicular skeleton

supports the paired pelvic and pectoral fins. Pectoral fin is attached to the skeleton, but not the pelvic fin.

Protocercal

primitive tail, vertebrae extend to tip of tail; lamprey and hagfish

Heterocercal

unequal lobed tail; shark and sturgeon

Hemihomocercal

intermediate tail between heterocercal and homocercal; gar and bowfin

Homocercal

equal lobed tail; most recently evolved bony fish

Leptocercal

most derived tail; modified dorsal and anal fins; lungfish

Gephyrcercal

Most recent tail; ocean sunfish only

Ganoid scales

scales of sturgeon and paddlefish; armored plates

Leptoid scales

type of scales that contains cycloid and ctenoid

Anguilliform

type of swimming of eels

Carangiform

type of swimming that uses more of the tail; salmonids, jacks, tunas; very fast and streamlined

Ostraciiform

Type of swimming where only the tail moves, body stays rigid; boxfish

Tetraodontiform

Type of swimming that oscillate dorsal and anal fins simultaneously; triggers or pufferfish

Rajiform

Type of swimming that undulates down the paired fins; stingrays or skates

Labriform

Type of swimming that rows with the pectoral fins; can use tail for longer distances

Depressiform

flattened body shape (rays)

Filiform

Threadlike body shape (snipe eels)

Anguilliform

Eel shaped body

Globiform

blob-shaped body (frogfish)

Compressiform

laterally compressed body shape (angelfish)

Taeniform

Ribbon shaped body (snakehead)

Sagittiform

Long and thick body shape (barracuda)

sinus venosus, atrium, ventricle, bulbous arteriosus

4 parts of teleost fish heart

Rete mirabile

A network of arteries and veins that allows for countercurrent exchange, aiding in regulating body temperature, oxygen, and gas bladder.

Plasma

part of blood that contains minerals, nutrients, waste products, enzymes, antibodies

Red blood cells

type of blood that uptakes and carries oxygen

White blood cells

type of blood that clots and has immune function

One percent

Water contains about ____ % oxygen by volume. Air has 20%.

Increased surface area of gills

Other than gulping air and increasing their ventilation rate, how can fish get more oxygen in low-oxygen waters?

Obligatory

_____ air breathers have no choice but to gulp air.

Facultative

______ air breathers only gulp air when they have to.

Bohr Effect

Lowering pH lowers the fish’s ability to intake oxygen with hemoglobin in the RBCs.

Root Effect

Lowering pH lowers oxygen intake and overall oxygen carrying capacity.

Low oxygen affinity

High temperatures lead to ___ oxygen affinity.

Metabolic Scope

Difference between maximum metabolic rate and standard metabolic rate

Metabolic rate increases

As temperature increases metabolic rate _____

Higher metabolic rate

Larger fish have a _____ metabolic rate

Higher for small fish

MASS SPECIFIC metabolic rate is ____ for small fish

Central nervous system

contains brain and spinal cord

Peripheral nervous system

relays sensory information and contains Mauthner cells

Mauthner cells

large spinal cord neurons that allow for the rapid C-start motion

Autonomic nervous system

regulates involuntary bodily functions

forebrain, midbrain, hindbrain

3 major parts of brain

Sensory Hair cells

Specialized cells directionally sensitive to water movements; stereocilia bend and trigger kinocilium to fire a neuron; present on semicircular canals, lateral line, otolithic organs

Cristae

sensory hair cells present in the semicircular canals are called:

Neuromasts

sensory hair cells present in the lateral line are called:

Sensory maculae

sensory hair cells present in the otolithic organs are called:

Ampullae

inertia sensing chambers in the semicircular canals; they contain the cristae

Superficial neuromast

type of neuromast that is on the skin; detects small movements

Canal neuromast

type of neuromast that is below scales; detects larger environmental stimuli

Connected to swim bladder

Fish with the best hearing have their inner ears _____ to swim bladder.

Passive

Electroreception that detects electric fields generated by other species or the environment

Active

Uses E-organ to generate electric organ discharges (EOD) to communicate or sense the environment

Ampullary Organs

senses low frequency electric fields; located deep in the skin with conductive gel

Tuberous organs

detects higher frequency electric fields of the fish itself; located in dermis of skin; found mostly in freshwater fish using EODs

Magnetic reception

Used by elasmobranchs and anadromous salmon for navigational information

Rods

part of retina that picks up low light; spaced closely to see fine definition in the dark

Cones

widely spaced for good color vision in the daytime

High ratio

A deep pelagic fish will most likely have a ____ ratio of rods to cones

Ontogenetic shift

changes in photoreceptor composition throughout life; moving from shallow to deep habitat

Choroid gland

behind the retina; acts as a rete mirabile and supplies the eye with nutrients and oxygen

Olfactory epithelium

water goes in and out of the naris and passes over the _____.

Olfactory rosette

Water comes in contact with this smell-sensitive part of the epithelium.

Nociceptors

pain receptors of fish

Endocrine System

Hypothalamus, Posterior pituitary, anterior pituitary, hormone, inter-renal gland

Anterior Pituitary

in contact with posterior pituitary; regulates production of hormones by other tissues

Chromaffin cell

part of inter-renal system; delivers oxygen to body tissues; adrenaline producing fight or flight response

Corticosteroid producing cells

part of inter-renal system; makes cortisol; increases with stress

Endocrine disruptors

Human-released hormones that mess up fish’s reproductive traits and other things

Stenohaline

Can tolerate a small range of salinity concentrations; 95% of teleosts

Euryhaline

Can tolerate a wide range of salinity concentrations; 5% of teleosts

Glomerulus

Part of kidney that filters out salts and other solutes; inside the Bowman’s capsule

Bowman’s capsule

Part of kidney that collects filtrate; holds the glomerulus

Urea

Fish convert ammonia to this less toxic compound for long periods of time out of water

Isoconformer

Type of osmoregulation; Passive transport; same concentrations as seawater expect for Na+ ions; stenohaline

Urea and TMAO

Type of osmoregulation; Passive transport; Stores excess urea and use the rectal gland to change salinity concentrations

Pump ions in

Type of osmoregulation; active transport; freshwater teleosts; internal salt concentration is higher

Pump ions out

Type of osmoregulation; active transport; saltwater teleosts; external salt concentration is higher; uses chloride cells

4 Buoyancy Mechanisms

low density compounds, generate lift from fins and body, reduce muscle and bone, gas bladder

Physostomous

Fish with a swim bladder connected to the esophagus via the pneumatic duct, allowing them to gulp air at the water's surface to regulate buoyancy. Less derived.

Physoclistous

Physoclistous fish have a closed swim bladder that is not connected to the gut, allowing them to regulate their buoyancy by secreting or absorbing gas through the oval.

Circular muscles

Contract to close the oval in physoclists

Longitudinal muscles

contract to open the oval in physoclists