Practical Flashcards
why are fish important
economic and ecological facots
why sample id
propulation censuses, ecosystems
when moving fish to bucket you need to know how to (2)
CATCH AND MEASURE, ID
2 key approaches to id a fish
meristics and morphometrics
meristics
quantitative features of a fish- number of fins or scales, scales along the lateral line, gill rakers etc
morphometrics
quantitative analysis of form, a concept that is size and shape
KNOW ANATOMY OF FISH
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salmonoids and trout
has adipose fin
silver in overall appearance in ocean phase
single short soft rayed dorsal fin
rockfish
strong spines in first dorsal fin, large scales
spines on head
large mouth
bass like
flatfish
both eyes on one side of head
distinct rayed fins
sharks rays and skates
very rough skin
several gill slits
fins w/o distinct fin rays
tuna and mackerel
series of finlets ahead of tail on bith dorsal and ventral surfaces
body is bullet shaped
billfish
super long and pointy nose
surf perch
compressed laterallt
spiny dorssal fin
siening
big net casting out and reeling in
dipnet
pole with circle net on end
where to measure to
the very end of the tail
pumpkinseed features
orange spots, no lines
bluegill features
stripes blue ish
golden shiner
yellowey uniform color
agnatha
jawless fishes
2 groups of agnatha
lsmprey and hagfosh
chondrichthyes
sharks, rays
osteichthyes
bony fish
characteristics of species
functional morphology, behavior, distribution
fixed fishing gear
lift net
fyke net
hoop net
traps
active fishing gear
dredge
beam trawl
how will mobile pelagic species get caught
trap, mid water trawl, purse siene
how will benthic sedentary fish get caught
bottom trawl
what type of fish is caught in a bottom gillnet
benthic species- specific
what type of fish is caught in a drift net
moving or migrating species
what type of fish is caught in a gilnet
apecific species
what type of fish is caught in a long line
migrating species
what are otoliths used for for humans
migration, aging, elements in environment
what are otoliths used for for fish
orentation
life history of an eel
anadromous
born in salt, live in fresh, spawn in salt in sargasso sea
depends if they are European or north american to where they go to spawn
survey designs
fixed, random, stratified random
fixed survey design
same place, time, individual over time
can be biased if results don’t reflect population
random survey design
equal chance of sampling any unit of the population
this can be very lengthy because you need many many observations over time to have truly unbiased sampling
stratified random sampling
equal chance of sampling any unit within subsets of populations
not biased if equal differences between subsets
if you were to do new england trawl surveys, how would you sample
stratified random sampling that varies by habitat and depth. beam trawl surveys
length, weight, stomach contents, isotope sampling if resources allowed.
if you were to use a purse seine, would you bait it
yes or use a radar to determine where the species is
what do you need to make sure is consistent with a beam trawl
EVERYTHING but specifically doors, net sizing,
why is e-shocking good at knowing which fish are in an area, but not good at knowing the total number of species?
The area of sampling is unknown
it collects diverse species because it’s not biased by size, weight, or preferred habitat necessarily
should you put metal tags in the ocean
no- they will rust
advantage of clipping fins for tagging
small area sampling
no technology
dart tag advantages
number ID to individual
when recaptured then you can see how much it grows, where it went
PIT Tags
EZ pass tag
fish must pass through electrical field to be accounted for
NO battery
so small that they can be injected into most fish
NO SALT WATER!!!!!!!!!!!!!!!!!!!!!!!!!!!
acoustic tag
battery inside
sends off pings that send off specified code for a fish
VERY EXPENSIVE
RFID radiofrequency identification
implanting tag into organism
SURGERY
lots of $
