Sharks Exam 4 Flashcards
Where are sharks taste buds?
all over the body
What does the sensory system detect?
Detects prey, tracks it and captures it
Do sharks display sensory switching?
yes, as they get closer they switch senses
This is species dependent.
Where do eddies appear?
the odor near field
Where is the acoustic field?
very close to the prey
they pick up the electric field
How far away can the lateral length detect?
1 to 2 body lengths
What are sharks highly dependent on?
odor
What signals mouth to open?
electro reception
What intensifies the signal?
smell and ions
How sensivity is the nostrils odor detection?
it can detect .1 to .5 second differences in the time odor travels between the nostrils
What happens upon detection of the odor?
It turns toward the first cue/ side odor was detected first
What does turning into the cue do?
Helps maintain contact with the plume
What part does the distance between nostrils play?
It is proposed that the farther apart the nares the better the distinguishability
How many amino acids can a hammerhead detect?
at least 20
How small a concentration can a shark detect?
10 to the minus ten molar-same as bony fish
Are larger rosettes more sensive?
no
What siphons the nare?
water is pushed into the incurrent nostril and out the excurrent nostril grove
Where are the olfactory organs contained?
the olfactory sac
What does the olfactory sac contain?
the olfactory rosette
What does the rosette have?
lamellar array-two rows of lamellae, largest lamellae in the middle and smaller on the outside
What increases the surface area of the rosette?
Each lamellae has folds called secondary lamellae. It is folded like a rose
What is rheotaxis?
large scale/ long distance odor detection
What is odor chemotaxis?
small scale odor detection - detects odor flavored eddies using the lateral line and senses
How do benthopelagic sharks differ from benthic in olfactory?
bp-have more lamellae, larger rosettes and surface area then benthic
DO sharks have an outer ear?
No, only an inner ear
Where is the inner ear?
Inside the cartilage in the endolymph
What are the two parts of the ear?
parssuperior and parsinferior
What is contained in the parssuperior?
it is the upper part of the ear and has three semicircular canals with ampulla at each end.
includes:utriculus/utricle
What is contained in the parsinferior?
Has two parts:sacculus and lagena
What parts has a macula?
utriclulus, saccule and lagena
What is the function of a macula?
area that senses vibrations
What do the macula have that sense vibrations?
thousands of sensory hair cells with a stone on top
What are the stones on top of the sensory hair cells called?
otoconia
What are the utricle, saccule and lagena involved with?
balance and sound reception
Where are the otoconia located?
in cupula-cap
What kinds of stones are there?
Internal - smoke stones - indigneous
external - silica stones - come in through endolymphatic ducts
What does the cupula do?
increase the height of the hair cells
What covers the cristae ampullaris?
sensory hair cells and capula
no otoconia
WHere is the capula located?
on top of the hair cells
Are hair cells oriented in the same direction?
No
Where are the cristae located?
at the inside of the semicircular cannal
What structures do not have otoconia, but have hair cells?
macula neglecta
What does the parssuperior do?
detects exceleration, posture,locomotive stability and visual stability of the eyes
What is involved with hearing?
macula neglecta and macula sacculus
What has stereo cillia and kinocillia?
?
What do each of the sacculus, utriculus and lagena have?
macula-area that senses vibrations
WHat happens when the hair cells bend?
one way causes polarization, the other way depolarizes
What is the parietal fossa?
a cone shaped region on top of the skull
mainly skin tissue with very little cartilage
facilates hearing
has a channel to the macula neglecta
What is part of hearing?
macula neglecta and macula saculla
inner ear is close together
What is the neuromast?
transducer (amplifier)
subdermal canal
runs inside the dermis
has neuromasts inside
What is the lateral line?
a canal nueromast system
What are free neuromasts?
pit organs or superficial nueromasts
little nueromasts on the surface of the shark, skate or ray
Where do they lie in sharks?
in pits with modified scales around them
Wat area has many nueromasts?
cristae
What kind of nerves and what do they do?
pimary afferent nerves
transduce mechanical motion into energy
What does the lateral line detect and how far away?
struggling prey and water direction
1-2 body lengths
Does the canal nueromast system always have pores to the outside?
no, skates and rays have no openings to the outside
Where are free nueromasts located?
face, head and posterior lateral canal
What is inside the canal system?
endolymphs- mechanical receptors of vibrations
Who has the true lateral line system?
sharks, skates, and rays
What frequency do they respond to?
10-200 hz
What is the eye?
conservative
What is the order of tissue layers in the eye?
sclera, argentea, chloroid then retina
What shape is the retina?
generally round
What is the clear layer and where is it in the eye?
cunjuctiva inthe cornea
Were is the aqueous humur and vetrous humos?
aqueous humor is anterior
vitreous humor is posterior
What keeps the eye ridig?
water
what is the iris?
the opening
What is the pupil?
the dark section
How much does the cornea bend the light and how dense is it?
not much
dense as seawater
What is the refractive index of the lense? Why?
very high refractive index because it is spherical
What does the lense do?
beens the light rays and focuses
How does the lense focus?
It is moved back and forth
What can most elsmobranchs do?
restrict the pupil
WHat do some sharks have?
nictitating membrane- 3rd membrane
Carcharhinids-white sharks do not have them
How do sharks protect the eye?
nictitating membrane
roll it back into the condrocranium
What can whale sharks do with their eye?
pull it back into the socket
Do elsmobranchs have rods and cones?
mostly have rods, few cones for receptors
skates only have rods
What are cones used for?
photopic vision-bright conditions
What are rods used for?
scotopic vision-dim light conditions
How is color seen?
with many different pigmented cones
Do sharks see color?
generally no, sharks only have one type of cone
It is believed some may
What is an occlusible tapetum lucidum?
also called occlusible layer
it is a retractable layer that has guanine crystals
What do the guanine crystals allow?
light to be rebounded on the same path to allow them to see better at night
reflective layer that allows higher sensitivity at night
ex. gulper shark
What is a visual streak and areae?
Dense band of receptors
If the streak is on the bottom where does the animal see best?
above
ex. tiger shark
How are visual streaks grouped?
visual streaks correlate to habitat and feeding behavior
Do spots have higher or lower density than streaks?
Higher
What are the biological functions of the electrosensory system?
prey detection
geomagnetic compass sense
predator detection
social behavior and mating
What is the stingray courtship and reproductive behavior?
Females bury in the sand.
Males search, locate, court and mate
How do males detect buried females?
By their electro discharge
males orient based on the electric field produced by the female
Where are sharks taste buds?
All inside the mouth
How do sharks use electromagnetic induced electric field for long distance travel?
As it swims perpendicular to the earths magnetic field it may produce a current
Are sharks passive or active elctrosensory fish?
passive, they do not have organs to create electricity
What do ampullae of lorenzine respond to?
low currents of alternating(ac) and direct (dc) currents.
What are ampullae of lorenzine filled with?
gel
How big are the ampullae of lorenzine?
larger than the lateral line pores
What do alveoli have?
a resting discharge rate
always firing
How far does ampullae of lorenzine work?
10s of cm
max 1/2 meter
How sensitive are the ampullae of lorenzine?
very sensitive, less than 5 nV per cm
What do animals excret that sharks detect?
ions - dc current
muscle contractions - ac current
sharks detect muscle movement by the change in ions
What does the detection cause?
the shark to bite
What is age?
a quantitative description of the LENGTH OF TIME that an organism has lived
What is growth?
is the change in body length between TWO POINTS in time
What is growth rate?
a measure of change in fish size as a FUNCTION OF TIME
What kind of growth do elasmobranch have?
indeterminate growth-increase in life but are asmyttoic
Why is it important to study growth?
fisheries management
conservation
etc
How is age verification completed?
look for growth rings in vertebrae, dorsal spines, nueral arches, caudal thorns
There is an error factor-donot know the rate at which the rings are laid.
What is age determination?
Confirming an age estimate by comparison with other indeterminate methods
What are indeterminate methods?
using rings on spine or vertebrae
How do you prepare a vertebrae?
1-Its frozen or soaked in alcohol
2-centrum exposure(remove tissue)
3-soaked in DI water, bleach or formic acid
4- cut transverse(horizontal) or saggital (vertical)
5-Sometimes stain or x-rays
What is ring/annuli?
narrow translucent band formed in water
What is summer band?
broad opaque bands
What is one year of growth?
1 winter and summer band
normally count rings
What are different age validation methods?
teracycline- animal is captured measured and injected with teracycline then released. Once recaptured vertebrae is removed and cut into thin sections
Carbon dating-bonb carbondating can be completed for animals that were alive during nuclear testing(50-60s) -not precise
What is age validation?
checking accuracy of age by comparing it to determinate methods
WHat is the von Bertalanffy growth equation?
It is utilized for the dtermination of shark growth rate in accordance to length.
Determines age and growth
What is Lt?
length of the fish at time t
What is L-infinity?
asymptotic length (not largest fish caught) (hypothetical length that the shark could grow to)
What is k?
growth coefficient
What is t0?
back calculated x-intercept (no biological value)
uses age at length data-must capture hundreds of sharks and age the vertebrae
plot the data, solving for two things at once(k and L-infinity)
What can use besides length?
weight
What elasmobranch grows faster?
rays
WHat is the range of k?
Sharks-0.1-0.2
Rays and skates 0.2-0.3
What gender grows faster in sand tiger sharks?
Both grow at the same rate
Females are pregnant every other years-reproductive cycle is every 2 years. Two young each litter. Have a resting period between litters.
What is the maturity and max age of rays?
5-6
26
What is the maturity and max age of dogfish?
12-14
13-14
What is the maturity and max age of Carchardon carcharias, white shark?
8-13
35
What is the maturity and max age of Centrophorus squamosus?
45
55-70
What contributes to over fishing?
low k value long time to maturity long gestation period low fecundity long lived
What is unique about the Altantic sharp nose shark?
in the east coast it matures in 2-4 yrs and lives 10
in the gulf it matures in 1.3-1.6 yrs and lives5.5
What is home range?
the area that in animal habitually roams
95% of the area that the animal uses
to determine the animal must be monitored
What is the minimal convex polygon?
it connects the outer dots
but it can over estimate the area
What is another way to estimate area?
Kernal utilization distribtion method
What is the Kernal utilization distribtion method?
a statistical method to determine an animals space utilization
mathematical program
What is a territory?
an area that is actively or overtly(marking) defended
What are different tracking methods?
direct observation catch data acoustic telemetry acoustic monitoring satellite telemetry/archival tags animal-borne video systems
What are the problems with direct observation?
need good water quality
daytime hours
difficult to identify individuals of the study
must identify them by markings
What is catch data?
determines habitat by where the species are being caught
What are the problems with using catch data?
no detailed individual movements
unknown habitat preference
equipment more specific to certain species or sizes
What is an example species of catch data?
juvenile lemon sharks prefer shallow coastal habitats in the bahamas
What are the benifits of dart tags?
inexpensive
easy to use
may be used along with electronic tags
What are the problems to using dart tags?
fall off
low recovery success
large boat time
doesn’t tell you where the animals are between release and capture
What is accoustic telemetry?
It uses ultrasonic waves, pings are picked up by a hydrophone, for a limited amount of time
What are the problems with accoustic telemetry?
only track for a short time
only one individual
there is a human disturbance factor
if you lose the animal thats it
What dives were tracked for the blue shark?
dives to 400m at nights - forging
What did data from a tagged tiger shark reveal?
Have large home ranges and move across open ocean
Where are tags placed?
dorsal
also internally inserted into coelm, skin grows over within 24hrs
How did juvenile bull sharks move?
In the caloosahatchee river, physical factors such as salinity. Use river for osmoregulation and shelter
What is acoustic monitoring/static array?
semi-permanent data logger are placed throughout a specfic area and sharks are recorded as they ping the sensors. effective distance was 250-500m
How is information accessed for acoustic monitoring?
it must be downloaded by a boat or diver
What are the problems acoustic monitoring/static array?
only animals in the area can be monitored
not that accurate
What did data on blacktip sharks in terra ceia bay show?
Prey were located in the south
sharks were located in the north
they think it is used for nursery habitat
How do sharks respond to storm?
sharks generally dont leave nursery areas
13 tagged juveniles fled the bay before the storm
sharks returned 5 to 13 days
thought change in pressure was detected by sharks
What detected the pressure change?
Edolmpatic pores
What is satellite telemetry?
tagged sharks are recorded by satellites
provides information on movement, migration and habitat
How is data collected from satellite telemetry?
data is stored and transmitted via satellite to station
tagged trasnmitted when on the surface for a period of time
if info is stored then it is archival satellite
What is a PSAT
pop off satellite archival tag
it corrodes or comes off after a set period of time and the tag is retrieved.
What information is record on a PSAT?
position, depth, salinity
collect meny variables
wide species possibilities
get more data if the tag is retrieved
What is the problem with a satellite telemtry?
cant use them on small animals
limited species study
accuracy
What did satellite tags in salmon sharks reveal?
sharks move south with the water temperatures
During winter and spring move south into larger habitat
track long term movements
What is the problem with a PSAT?
usually must recapture or obtain tag
expensive
bulky
for large amounts of data tag must be retrieved
What did PSAT information from white sharks reveal?
transoceanic migration from south africa to australia
another study - white sharks move out into the pacific to feed
What did PSAT information from whale sharks reveal?
they aggregate during large plankton blooms from upwelling off of isla holbox
ram filter feeding on the surface, were also seen vertical suction feeding
make deep dives at sunrise and sunset- possible for thermoregulation, parasite removal
What area did the whale shark travel?
some went west into the gulf
some went into the straits of cuba
one went into the atlantic possibly for pupping
What is animal-Borne video systems?
onboard camera(critter cam)
supplies detailed information
see what the animal sees
What are the problems with animal-Borne video systems?
limited tape
recapture to retrieve camera
expensive and technical
must have high water quality, daytime
What did studies in australia reveal about the tiger shark?
prefers shallow water habitats
don’t chase, prefer to stock, use stealth and close approaches
eye concentration of cones and rods is on the ventral side
