Ichthyology Exam 2

Fish have what type of circulatory system?

one atrium and one heart ventricle

Teleost Heart

has two chambers- one ventricle and one atrium

both contract

What type of modified circulation do lungfish have

one heart atrium and one ventricle

has a modified swim bladder with its own atrium

Hemoglobin

primary transport of Oxygen in fish blood

What type of fish have no hemoglobin?

environment with high oxygen (extremely cold water)

low metabolic requirements

cardiovascular adaptations

Types of Hemoglobin Characteristics

monomeric

tetrameric

monomeric hemoglobin

single peptide molecule

easier to saturate with oxygen

tetrameric hemoglobin

4 peptide chains

used in fish that have a high metabolic demand

How does Hemoglobin release O2

low pH forces the hemoglobin to open

How do Hb types vary

composition of amino acids and affinity

What do different Hb types allow for

varying levels of O2 absorption

temp response

fish to deal with changing conditions

example: myoglobin

What structures are in charge of getting gases into the swim bladder

rete mirabile and gas gland

what structure is in charge of getting gases out of the swim bladder

ovale

function of rete mirabile

brings Hb with O2 to gas gland

lactic acid secretion

multiplying effect

function of gas gland

pries o2 from Hb

How does pH drop in the gas gland

increase metabolic activity in tissues around mirabile

What is the multiplying effect

a countercurrent exchange that generates a large concentration of gases

allows swim bladder to inflate

Steps of the counter current in Rete Mirabile

capillary fold back on self

1. incoming capillary drop in pH and Hb loses O2 (afferent)

2. outgoing capillary with high partial pressure of dO2 (efferent)

3. O2 diffuses into swim bladder and afferent

afferent

incoming capillary with low pH

efferent

outgoing capillary with high level of O2

Buoyancy strategies

low density compounds (lipids, squalene)

lift generation by swimming (sharks)

reduction of heavy tissues

swim bladders (physostomous, physoclistous)

Phylostomous swim bladder

adjust the volume in swim bladder by gulping or spitting air

pneumatic duct

Physoclistous swim bladder

adjust the volume in swim bladder by using the ovale window for blood-gas exchange

What is carbonic Anhydrase

found in the gas gland to regulate pH

plays crucial role in the swim bladder

Boyles Law

decrease in pressure means higher volume of gas (at constant temp.)

What type of swim bladder do Coelocanths have

oil filled

good for great depths and use little energy

Osmoregulation

the ability for fish to maintain a stable balance between water and solute in their internal body fluids

Euryhaline Osmoregulation

wide range of handling salinity

Stenohaline Osmoregulation

narrow range of handling salinity

Types of Osmoregulation Strategies

isomotic

Isomotic with regulation

Hyperosmotic

Hyposmotic

Isosmotic (osmoconforming) strategy

does not require energy to balance osmosis

(hagfish)

Isosmotic with regulation (elasmobranchs) strategy

requires little energy to balance osmosis

maintain internal salt concentration

retain urea and TMAO

(sharks)

Hyposmotic strategy (marine teleosts)

ionic concentration is 1/3 that of seawater

-fish cells lose water to the ocean

must drink seawater to make up lost H2O

Takes a lot of energy to expel salts (kidneys and Chloride Cells)

Chloride Cells in Marine Teleosts

carrier mechanism allows Cl- and Na+ into chloride cell

builds concentration so Cl- and Na+ can diffuse out of the cell, then out of the fish

Hyperosmotic Strategy (freshwater teleosts)

too much H2O entering cells

-must pump water out

chloride cells work in reverse marine

takes a lot of energy

Chloride Cells in Freshwater Teleosts

takes cl- and Na+ out of H2O

builds concentration so Cl- and Na+ can diffuse out of the cell to be absorbed into the fishes body

What is the purpose of studying fish growth

helps understand the health of the community

growth patterns determine if the fish can reproduce successfully with quality offspring

Factors Affecting Growth

Hormones

Temperature

Water Quality

How does water quality affect growth positively in fish

high dissolved o2

low ammonia levels

salinity in range

(all allow for better growth)

Growth Patterns in Fish

competition

food

photoperiod (seasonal)

Age and maturity

Condition (length v. weight)

Bioenergetic equation

energy ingested= tissue maintaining energy + tissue growth energy + reproduction energy + energy lost

Markers of Periodic Growth

measuring distance from focus to end of scale (total length)

measuring distance between each annual growth ring

Other ways of measuring fish age

Otolith (ear stone)

Rays/spines

vertebrae

What are back calculations

way to calculate the length of a fish at the time of scale formation

Pros and cons of older fish reproducing

pros: more eggs, larger body

cons: higher risk of disease, predation

pros and cons of younger fish reproducing

pros: better chance of passing genes to next generation

cons: fewer eggs, reduced growth, weaker

definition of growth

any positive or negative change in size or body mass

definition of growth energetically

any change in calories stored

Types of fish metamorphosis

complete metamorphosis (eels, lamprey)

asymmetric (flat fish)

smoltification (salmon)

Lamprey Cycle

eggs (nested under rocks in river)

larvae (move to mud backwater)

ammocoete (burrow in mud and filter feed for 7 years)

metamorphosis (gain eyes and disc mouth)

young lamprey (travel to ocean)

adult lamprey (parasitic and feed on host for 2 years to grow)

spawn (adults return to river to spawn and die)

flat Fish Cycle

start off flattened laterally

end flattened dorsal-anally

Smoltification: life cycle of Salmonids

spawn in redd (nest)

eggs

alevins

fry

parr

smolts

adults

(imprint odor allows them to find their place of birth)

Life cycle of Wild Atlantic Salmon (NOT Smoltification)

spawn in redd (nest)

eggs

eyed eggs

alevin

fry

parr

smolt

adult

How is fish growth indeterminate

they never stop growing as long as they have nutrients

pros: larger mouth, more food selection, harder to be killed

Allometric Growth and Age in fish

body mass change (dimension)

cartilage can turn to bone (tissue)

body shape can change (design)

How is fish growth characterized

exponential

tradeoffs to coevolution of reproduction and development?

risk and benefits of continued growth versus reproduction

quantity versus quality of offspring

risk of predation versus finding quality food

Fecundity

the rate of a species reproduction

how does fecundity vary with life history patterns

increased fecundity when increase in body size

early growth and alter reproduction also increases fecundity

how does the size of offspring vary with life history patterns

survival increase with increase of size

fecundity reduces as offspring size increases

Types of mating systems

promiscuous

polygynous

polyandry

monogamy

promiscuous

male and females with multiple partners

polygynous

males with multiple partners

polyandry

females with multiples partners

monogamy

mating for life

Types of reproductive frequency

semelparous

iteroparous

semelparous

single spawn

pros:

metabolically efficient

max fecundity

ideal conditions

overwhelms predators

cons: 

risk of death due to wait

Iteroparous

repeated spawn

pros:

spawn before death

spreads offspring over different seasons

cons:

reduces fecundity

Types of parental care

brood hiding. nest guarding, internal gestation

types of female caregivers

oviparous

ovoviviparous

viviparous

oviparous

egg laying, yolk fed, external development

ovoviviparous

embryo with female, yolk fed, internal development

eggs hatched inside body

viviparous

live birth, yolk supplemented, internal development

external fertilization pros and cons

pros:

less time/energy

increase in potential mates

increase in fecundity

cons:

probability of survival is low

internal fertilization pros and cons

pros:

probability of survival is high

cons:

energy into courtship and preparation

needs altered organs

types of fertilization

internal

external

buccal

types of sex

gonochoristic (single sex fixed at maturity)

hermaphroditic 

simultaneous hermaphrodite

male and female at the same time

sequential hermaphrodite

start life as one sex and change to the other after maturity

protandrous sequential

male to female

protogynous sequential

female to male

types of parthenogenic

gynogenetic

hybridogenetic

gynogenetic

sperm needed for egg but mating does not need fertilization

hybridogenetic

egg development with fertilization from other species males

Secondary sexual characteristics

monomorphic

dimorphic

seasonally dimorphic

polymorphic

monomorphic

can’t tell the difference between male and female

dimorphic

distinguishable difference between male and female

seasonally dimorphic

spawning times cause changes to body and makes males and females distinguishable

reproductive traits of male bony fish

testes, vas deferens, urogenital pore

reproductive traits of female bony fish

ovary, oviduct, urogenital pore

reproductive traits of male cartilaginous fish

testes, leydras gland, seminal vesicle, cloaca, claspers

reproductive traits of female cartilaginous fish

ovary, ostium tubae, oviduct, shell gland, uterus, cloaca

types of spawning behavior

substrate spawners

water column spawners

site preparers

internal fertilization

types of care giving behaviors

non-guarders

guarders

bearers

Process of fish gonadal maturation

1) environmental influences

2) stimulus receptors receive input

3) receptors produce hormones

Endocrine Disrupting Compounds have caused…

vitellogenin:

male fish exposed to EDC stimulates female gonad production

Why are waste-treatment plants still causing vitellogenin in male fish?

focusses only on organic and bacterial removal (not chemical screening)

primary, secondary, tertiary

Mechanoreception

sense responding to movement and stimuli

what does mechanoreception allow for?

hearing, balance, touch/feel, gravity detection