FW 204 - Midterm

biologists toolbox

fish populations, fish habitat, human users

why sample fisheries

monitor health and status of fish, monitor satisfaction of the public, check for unwanted organisms, address management objectives

bad data leads to

bad management

qualitative data

categorical data

ordinal data

qualitative data that can be ranked

nominal data

qualitative data that can be separated into categories

quantitative data

amounts of something

continuous data

quantitative data that is measurements

discrete data

quantitative data that is counts

error check data when

collecting data, making paper data digital, uploading data into a database

accuracy

how close data is to the true value

precision

how much variability is in the data

bias

factors that can affect precision and/or accuracy

basics of sampling design

size of area being sampled, sampling units, location/distribution of sampling units within area, timing of sampling

random sampling

completely random sampling units

stratified random sampling

random sampling units within parameters

systematic sampling

evenly spaced sampling units

for stronger sampling

increase number of samples, repeat the sampling effort, use the same sampling method, use the same people

SAFE

skills, attitudes, facts, equipment

skills

enroll in courses, practice skills with a trainer/observer

attitudes

you are responsible for your own safety and everyone else’s safety

facts

use the information available to you to learn the facts you need to know about safety on your project

equipment

make sure the proper safety and field equipment is available and in good working order

common safety concerns

heat and cold exposure, wildlife, chemicals, weather, equipment failure, people

when wading, be aware of

water depth, clarity, current velocity, substrate

when boating

always wear a PFD

boating safety

wear a PFD, attach kill switch, check drain plug, stop engine when people are in water, have something to bail water, get off water for bad weather, maneuver at low speeds, have a plan for common emergencies

animal safety

fish teeth and spines - safety gloves, biting insects - insect repellent, timing

chemical safety

use common sense, be familiar with hazards, wear PPE

personnel safety

have a good relationship with coworkers

no data is worth jeopardizing

safety

standard length

tip of mouth to end of flesh

fork length

tip of mouth to fork of fin

total length

tip of mouth to tip of fin

measurements are not always consistent for a species

sexual dimorphism, juveniles vs. adults, individual variation

why measure weight and length

look at population size and age structure, develop length vs. weight relationships, calculate relative weight

Wr 90-100

good condition

Wr <90

poor condition

Wr>100

very good condition

quality length

length wanted by anglers

stock length

appropriate length at maturity

the people factor

what do they want, what is it worth, how do they behave

human dimensions study types

creel census, preference study, economic value study, behavioral study

why care about human dimensions

why are resources used a certain way, are public desires being met, how does public behavior affect mortality, how does the public feel about a management strategy

public are the

stakeholders

stakeholder

someone who holds a direct or indirect stake in the management of a fisheries resource

off-site HD data collection

document review + content analysis, group interviews, online/mail survey, diary/fishing log, phone survey

on-site HD data collection

access survey, roving survey, ariel survey, remote sensing

key info for creel census

date/time/location, angler information, angling information, additional items

1 angler-hour

1 hour x 1 angler

lake physical characteristics

dimensions, terrestrial influence, zones, hydrology

lake dimensions

surface area, perimeter, shoreline length, depth, volume

lake terrestrial influences

watershed size and composition, amount/source/duration of inflow, chemical composition of water, nutrient/sediment inflow

lake zones based on

depth, temperature, light penetration

compensation point

where the photosynthesis rate is equal to the respiration rate (P=R); 2x Secchi depth

lake biological sampling

what lives in the lake, how many organisms are present, where do the organisms live, what is the community structure

catch-per-unit-effort (CPUE)

the number of organisms captured (C) with a defined unit of sampling or effort (f); C/f

CPUE units for passive sampling

net-nights, trap-hours

CPUE units for active sampling

fish per anger hour

gear selectivity

bias of a sample attained with a given gear

gear efficiency

amount of effort expended to capture target organisms

passive gear advantages

simple design/construction/use, captures wide range of species in wide range of habitats, deployed with minimal personnel

passive gear disadvantages

selective, hard to define area sampled

passive gears

gill nets, fyke nets, pots/traps, trammel nets, tether bait, angling gears

gill net biases

size, affected by material, fish activity

fyke net biases

targeted species, relative catch rates, size selectivity

active gear advantages

sample a known volume or area over a known amount of time, sampling is mobile in space and time

active gear disadvantages

require more personnel, habitat types can be limiting

trawl biases

size and species, speed of vessel to target species speed, suitable habitats

surrounding/encircling nets advantages

easy to deploy, quick, area sampled is well-defined, fish receive minimal injuries

when angling sampling is optimal

specific targeting, minimize impact, mimic angling pressure

what makes angling a better sampling method

accurate measurement of effort, proficient anglers, standardized tackle

why age fish

get demographic information, better understand growth rates to better understand a fishery

validation of fish aging

multiple readers, quality control against a known age fish

why tag/mark

study growth, movement studies, survival studies, hatchery returns, stock identification, habitat use management evaluations, population estimation

what makes a good tag or mark

long retention time, low cost, ease/speed of application, suitable for multiple fish sizes, fish not affected by the applicaiton

physical water quality

turbidity, temperature

chemical water quality

dissolved oxygen, pH, alkalinity, hardness, pollutants

why care about water quality

aquatic organisms are constantly immersed in water, it directly affects number/diversity/physiology/behavior of aquatic organisms, can be affected by internal and external factors, fish live in the water we drink

water quality regulators

USEPA (national), CDPHE (state), CPW (investigate fish kills, regulation, emergency closures), counties and municipalities

temperature

has biological and physical effects - it affects everything

CTM

critical thermal maxima and minima

ILT

incipient lethal temperatures

physiological effects of water temperature

metabolism, growth, reproduction

behavioral effects of water temperature

thermoregulation/migration

dissolved oxygen

affected by temperature, salinity, altitude

anoxia

no oxygen (0 mg/L)

hypoxia

low oxygen (0-5 mg/L)

normoxia

normal oxygen (5 mg/L)

hyperoxia

supersaturation of oxygen (>saturation)

pH

measure of the strength of an acid or base

low/high pH impairs

gas exchange at gills, internal acid base balance, pollutant toxicity

alkalinity

a measure of a solution’s ability to buffer pH

hardness

amount of dissolved Ca and Mg in the water

conductivity

ability of a solution to conduct electricity

conductivity is affected by

temperature, precipitation, geology, total dissolved solids

turbidity

degree to which light is scattered and absorbed by suspended materials (natural or organic) in the water

effects of turbidity

reduction of sunlight penetration, physical clogging of gill tissues, suspended particles can provide substrate for pathogens, impaired vision

stream physical measurements

watershed characteristics, water chemistry, stream morphology, flow/discharge, channel characteristics, substrate size, cover

watershed

the boundary separating basins