Module 2 Exam

Question 1

Commercial Fisheries

Answer 1

union of aquatic organisms and humans for consumptive purposes

treating aquatic organisms as an extractive resource

Extraction and sale of fish for consumptive purposes

Question 2

Are commercial demands the reason aquaculture has been increasing?

Answer 2

Commercial demands may not necessarily be changing, aquaculture has been increasing because of lack of natural fish supply in the oceans and lakes (overfishing)

Question 3

Bottom trawling

Answer 3

very large net dragged across ocean floor by boat

Float line above, chain below (“tickle chain”, encourages things on the bottom to get off of the bottom)

Mesh - smaller fish can sometimes escape; if back end begins to get packed with fish (can drag them for hours), many times small fish can’t even get to the mesh to be able to get out because it is so full of fish

Question 4

Target species of bottom trawling, duration of trawls, and trawl speed

Answer 4

Target species - species on the bottom; pacific cod, rockfish, halibut, shrimp; possibility of getting fish other than target species

Duration of trawls: 3-5 hours, but up to 10-12 hours

Trawl speed - up to 1-7 knots, 4 knots is optimum

Question 5

How do bottom trawlers cause habitat disturbance?

Answer 5

creating a lot of resistance on sea floor, leads to some environmental destruction

Suspension of sediments

Increase in water turbidity = blocks sunlight = reduces photosynthesis

Reduced habitat heterogeneity, less of that means less niches and places for small organisms to live

Resuspension of contaminants (e.g. PCBs)
Impacts on food web

Question 6

Heterogeneity

Answer 6

nooks and crannies in habitat (creates more available niches)

Question 7

Bycatch definition **

Answer 7

part of the capture that is discarded at sea, dead (or injured to an extent that death is result)

Capture = catch + bycatch + released alive

Target (discarded) and non target species

Question 8

Reasons for discarding target species as bycatch **

Answer 8

wrong species, size, sex

fish are damaged

quota is reached

high grading

lack of space, chance of spoiling

Question 9

Longline fishing

Answer 9

long line underwater attached to buoys to keep it close to the surface of the water; main line with smaller lines (snoods) coming off of it with baited hooks to catch fish

Hooks left in water, a lot of occupational hazards

Target species: swordfish, tuna, sablefish, pacific cod

Question 10

Longline bycatch **

Answer 10

Bycatch is mostly pelagic, no crustaceans, must be able to be baited by hooks

Kills many sharks because they have to keep moving to stay alive and will die if stuck on hooks

Question 11

Drift nets

Answer 11

free-floating gill net

25m to 50 km long

Target species: tuna, squid, pelagics

Can become detached and get left in the ocean (“ghost nets”), leads to many fish and other sea life getting entangled and killed

Question 12

Drift net bycatch **

Answer 12

indiscriminate in the way entanglement can happen

Can catch whales, gets caught in the operculum of fish, can catch seabirds

Ghost nets can lead to a lot of lost bycatch

Question 13

Impacts of commercial fishing on fish populations

Answer 13

Reduction in abundance of target and non-target species (overfishing)

Disturbance and loss of essential (critical) habitat (cascading effects on the population and/or individual level)

Impacts on rare or threatened species

Disruption of food web (using up target species, and could be taking up target species’ prey as non-target species, leaving target species less able to feed and reproduce)

Remobilization of contaminants

Fishing induced selection (causing artificial selection by taking larger, more successful, more fecund fish out of the water)

Question 14

Recreational fisheries

Answer 14

where fishing is conducted by individuals for sport or leisure, with the possible secondary objective of catching fish for personal consumption

Compared to commercial, where more often conducted by groups of individuals who capture fish products for sale

Question 15

Freshwater recreational fishing effort represents ______ of the global food fishing relative to all fishing effort

Answer 15

half

Question 16

What is the difference between the location of recreational vs. commercial fishing?

Answer 16

There are many more recreational places to fish - freshwater as well as nearshore regions of oceans including estuaries, reefs, mangroves, and embayments; Often critical habitats of multiple life states (spawning, nursery, migratory) and recreational fishers often target immature individuals

Commercial uses more accessible locations (based on depth and economic profitability) that are often more distant from coastal regions or in larger inland bodies of water (e.g. Great Lakes)

Question 17

Impacts of recreational fisheries

Answer 17

Catch the fish = no longer in the population = impact on the population/ecosystem

Direct harvest - for personal consumption

Discards and bycatch

Abandoned gear (fishing line, hooks, etc)

Accumulation of lead sinkers

Habitat disturbance - anchors, propeller scars, noise

Question 18

Catch-and-release

Answer 18

Voluntary or mandated through regulations

Total bycatch estimates - 28% of total catch

Elements of angling event, can all have a physiological effect on a fish even if the fish lives - capture, handling, release

Question 19

Why is angling duration during catch-and-release important? **

Answer 19

The physical exercise required to fight against being caught leads to an increase in lactic acid, muscle fatigue, increase in blood glucose, disruption of osmotic balance (Na, Cl, K; influences gill/cell functions), and chance of being predated while on the line (depredation)

Question 20

Describe how blood lactate levels change during angling events **

Answer 20

Blood lactate levels increase at the beginning of angling because the fish is fighting back hard against being caught, but then plateaus because there’s only so much that can be maintained in the body before it causes muscle pain and fatigue

Question 21

Capture - external tissue damage

Answer 21

Trauma to eyes, fins, mouth, skin

Feeding impairment, swimming impairment

Infection, compromised immune system

Question 22

Capture - internal tissue damage (gut hooked)

Answer 22

Trauma to esophagus, gills, vital organs (can hook the heart)

Impaired physiology and function

Infection, compromised immune system

Question 23

Barbed hooks (J hooks)

Answer 23

Barbed hooks get caught in the fish’s skin, making it harder for them to escape but also causing more tissue damage

Question 24

Treble hook

Answer 24

more hooks to increase chance of getting a fish

Question 25

Circle hook

Answer 25

made to prevent gut hooking - if fish swallows it, the hook gets pulled out of the guts without getting hooked, and then gets stuck in the corner of the mouth on the way out

Question 26

How can handling cause damage to fish during catch-and-release?

Answer 26

Landing - touching with hand/net, slime removal, scale loss, damage to fish/gills

Hook removal - tissue trauma, especially with barbed hooks

Air exposure - to remove hook, take photo, transfer to live well; gills don’t work outside of water; after physical exertion from catching, being able to get oxygen is even more vital

Question 27

Can lip gripping tools reduce the impacts of handling?

Answer 27

Bonefish held vertically in air, bonefish held horizontally in water, and control - ten bonefish in each group

Examined injury and mortality after 48 hrs

18/20 bonefish handled with boga grip suffered injuries - 100% of those held vertically and 80% of those held horizontally

40% of injuries were severe, likely resulting when bonefish thrashed
(tore through skin, broke jaw on some → bad outcome even if released due to feeding impairment and lack of defense against predators)

Question 28

Impacts of air exposure **

Answer 28

Leads to collapse (no longer supported by water) and adhesion of gill filaments

Compromises respiration

Magnifies physiological disturbance - trying to recover from excessive exercise and now being forced to hold breath (can’t get oxygen in OR CO2 out)

Delays recovery - gill filaments have adhered and take a while to recover and begin working normally

Eventually leads to tissue damage and death

Question 29

Acute impacts of catch-and-release

Answer 29

Slow physiological recovery

Impaired swimming performance - might not be able to swim against current or get away from predators

Altered behavior

Increased susceptibility to predation, especially in marine systems (more predators)

Loss of equilibrium - inability to coordinate movements and remain upright (good indicator of severe stress)

Question 30

Fish without equilibrium were ____ times more likely to suffer predation

Answer 30

six

Question 31

Factors that do NOT influence equilibrium

Answer 31

length of fish, incidence of bleeding, duration of fight

Question 32

Factors that DO influence loss of equilibrium

Answer 32

duration of air exposure (for every minute of air exposure, chance of loss of equilibrium increases by 6 times)

handling time (for every minute of handling, chance of loss of equilibrium increases by 1.2 times)

Question 33

Is mortality/survival alone an appropriate endpoint for assessing the complete effects of catch and release angling?

Answer 33

No, there is a lot of room between a dead fish and one that is a “fit” member of a population, catching also causes:

Physiological disturbances

Energetic consequences

Behavioral alterations

Fitness impairments

Question 34

_____ water temperature causes _____ salmon mortality

Answer 34

higher, higher

Question 35

Fish induced selection

Answer 35

Removal of large individuals from population

Selection favors slower growth rates and smaller body sizes (less susceptible to angling)

Fitness impairment – energy used to recover from angling cannot be spent on growth and reproduction

Individuals contribute less to the population

Question 36

Habitat disturbances

Answer 36

loss or modification of essential habitat for each life stage

Ontogenetic shifts in habitat use

Disturbance or loss of any essential habitat could influence recruitment, growth, reproduction, and survival

Impacts on water quality could also be considered a disturbance of habitat – thermal pollution, nutrient enrichment (eutrophication)

Question 37

What does “ontogenetic shifts in habitat use” mean?

Answer 37

habitat use changes with different life stages

ontogenetic = the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult

Question 38

Water diversion

Answer 38

surface and ground water diverted from its natural course for anthropogenic (human) use

Irrigation of cropland, industrial use (hydro dams), domestic use (wells)

Question 39

Dams and culverts

Answer 39

reduced flow, barrier to movement

Change in thermal regime

Change in sediment flow

Accumulation of contaminants (methylmercury)

Individual, population, and community-level effects

Question 40

Diadromous fishes

Answer 40

migrate between freshwater and seawater environments

usually born in one type, move to another for growth, then move back to original type for spawning

Often very high site fidelity to natal streams/rivers

Question 41

Anadromous fishes

Answer 41

born in freshwater, grow in marine (e.g. Atlantic salmon)

Question 42

Catadromous fishes

Answer 42

born in marine, grow in freshwater (e.g. American eel)

Question 43

What are the potential impacts of dams on populations of anadromous salmon? **

Answer 43

Can’t get out to the ocean to look for food and grow

Not able to return to freshwater to spawn

Question 44

Riparian habitat

Answer 44

ecotone between terrestrial and aquatic ecosystems within a floodplain

Plants are adapted to being inundated with water

Acts as a buffer/filter

Land use practices often put pressure on riparian vegetation

Question 45

Loss of riparian habitat

Answer 45

Disturbances - increase in sediment loads (increased phosphorus, as phosphorus abundant in ground), availability of habitat (less woody debris), nutrient enrichment, change in temperature regime (less shading)

Siltation of critical habitat (nesting grounds), reduced habitat heterogeneity, thermal stress, eutrophication

Question 46

Impacts of forestry practices on riparian habitats

Answer 46

Plants in riparian zones filter out sediments and take up nitrates, so if trees are clear-cut there are more suspended sediments and nitrates

Question 47

How can an increase in nutrient loads following the removal of riparian vegetation influence the life history of fish? **

Answer 47

Larval fish - increase in nutrient load could drive oxygen levels down, larval fish have high oxygen demand, so increased mortality

Juvenile fish - if oxygen is reduced it could impact growth/maturing of the fish, especially if the amount of available food is impacted

Adult fish - if oxygen is reduced it could impact the ability of the fish to reproduce, especially if the amount of available food is impacted

Increase nutrients could have positive effects, such as boosting the food web and increasing growth rates because there is more food available to fish

Question 48

Structural complexity

Answer 48

The three-dimensional (3D) physical structure of an ecosystem, plays a critical role in mediating the dynamics of biological communities

Mosaic of habitat types (ex: coral reef ecosystems)

Food and shelter for inshore species

Biodiversity of the coastal zone

Question 49

What do you think ‘connectivity’ means in the context of habitat use and fish movements? **

Answer 49

Some fish move habitats depending on their life stage because some biomes are better for growth, while others are better for spawning

If a fish has to move between one habitat and another, movement takes energy, which requires food

In a new environment there are also new predators

Question 50

Water pollution

Answer 50

The contamination of water bodies such as streams, lakes, rivers, oceans, wetlands, and groundwater

Naturally occurring or human-generated compounds or conditions that can or will have a negative impact on any aspect of aquatic ecosystems

Direct or indirect impacts (individual fish versus cascading effects through the food web)

Question 51

Point source (PS) pollutants **

Answer 51

Single identifiable localized source of pollution

Factories, sewage

Easy to calculate loading because pollution is coming from an isolated point

Question 52

Non-point source (NPS) pollutants **

Answer 52

From diffuse sources

Runoff, rain, snowmelt

Difficult to calculate loading because anything could be picked up

Question 53

Organic pollutants

Answer 53

Molecule contains carbon

From animals/plants, industry

Natural (methane), synthetic (PVC, plastics)

Question 54

Inorganic pollutants

Answer 54

Mineral origin (e.g. Hg)

Manufacturing, industry, mining

Heavy metals, silt, fertilizer, acids

Question 55

Persistent contaminants **

Answer 55

can be organic or inorganic

Resistant to environmental degradation - can’t be broken down over time (or at least it is very difficult for them to be broken down)

Low water solubility (hydrophobic)

High lipid solubility (lipophilic)

High capacity for long-range transport, potential for considerable impacts on biota

Question 56

Persistent organic pollutants (POPs)

Answer 56

PCBs

Heavy metals (Hg)

Organometallics - methylmercury [CH3Hg]+

Question 57

PFAS

Answer 57

Forever chemicals

per- and polyfluorinated alkyl substances

Question 58

Why is it important that persistent contaminants have low water solubility (hydrophobic) and high lipid solubility (lipophilic)?

Answer 58

Persistent contaminants can stick around for a long time in lipid sources (such as in fish and other organisms because they contain a lot of lipids)

Because they don’t like water, they don’t get flushed out either

Question 59

Bioaccumulation **

Answer 59

rate of accumulation is greater than the rate of loss/breakdown

Lipophilic compounds (organic), chronic effects of toxins

Because it binds to fats, it doesn’t break down easily and therefore sticks in animals for a long time

Increase in concentration within an organism; occurs within a trophic level

Question 60

Biomagnification **

Answer 60

increase in concentration of a persistent contaminant that occurs across trophic levels (up food chain)

Contaminants stick in fats of fish, other animals eat those fish and accumulate a greater amount of contaminant, so when another organism eats that animal it accumulates even more contaminant

Question 61

Mercury

Answer 61

Elemental Hg – naturally occurring but anthropogenic concentrations occur via waste incineration, coal burning, chlorine production, and ore extraction (e.g. gold mining)

Mostly atmospheric – returns to earth in rain or snow

Methylmercury – sulfate-reducing bacteria absorb and convert elemental Hg (inorganic) to this highly toxic, bioavailable form

Bioaccumulates and biomagnifies (lipophilic and hydrophobic)

Question 62

Effects of mercury on fish

Answer 62

Acute exposure - elevated metabolic rates related to damage of gill epithelium (affects oxygen uptake, ion regulation)

Chronic exposure – impaired feeding ability, manifested as reduced foraging efficiency and capture speed

Dietary ingestion – severe liver damage, reduced fecundity, impaired gonadal function, reduced sperm motility, altered sex ratio

Question 63

Effects of mercury up the food chain

Answer 63

Fish as prey for fish-eating birds (loons, eagles) and mammals (otters, mink, pinnipeds), and these animals are impacted through reproductive impairment and even mortality

Human health consequences – severe neurological damage, kidney damage

Cognitive impairment, muscle and joint pain, hair loss, increased coronary heart disease

Question 64

Endocrine disrupting compounds (EDCs) **

Answer 64

Mimic the chemical activity of hormones or stimulate hormone production

Reproductive (estrogens, androgens), thyroid, and corticosteroid hormones

At least 90 chemicals found in food, water, soil, and air are EDCs

Oral contraceptives and diethylstilbestrol (synthetic estrogen), organohalogens (dioxins, PCBs), food antioxidants (BHA), pesticides (DDT, malathion), phthalates (plasticizers, printer ink, adhesives)

Question 65

Function of hormones

Answer 65

A chemical released by one or more cells that affects cells in other parts of the organism

Often transported in blood (endocrine) or duct (exocrine), bind to hormone-specific cell receptors (protein), resulting in activation and cell response

Growth hormones (thyroid-stimulating hormone), hunger hormones (ghrelin), reproductive hormones (testosterone)

Balance of positive and negative feedback cycles -> balance is thrown off by pollution = does wacky things to fish and people

Question 66

Individual-level effects of EDCs **

Answer 66

Reduced rates of sperm and egg production

Reduced gamete quality

Abnormal gonad morphology

Altered reproductive behavior

Altered embryonic development

Reduced reproductive success

Question 67

Population-level effects of EDCs **

Answer 67

Decrease rates of survival, growth, reproductive capacity

Decreased population size

Risk of population extinction

Question 68

Ecosystem-level effects of EDCs **

Answer 68

Disruption of food web

Loss of ecologically and economically important species

Human health concerns

Question 69

Acid deposition

Answer 69

addition of acidic compounds from the atmosphere

Sulfuric (H2SO4), Nitric (HNO3), Nitrous (HNO2)

Industrial operations (factories, power plants, smelters), combustion engines (burning of fossil fuels), wood smoke

Wet deposition (rain, snow, fog), dry deposition (soot, ash)

Remember 1st lecture on water – ideal solvent and easily combines with acids

Leeches compounds out of soils at low pH - Al, Mg (water has limited buffering capacity because of low Ca)

Question 70

Impacts of acid deposition on fish

Answer 70

Mobilization of aluminum (Al) increases as pH decreases

Al increases mucus production, including on gills

Reduced efficiency of oxygen uptake

Interferes with oxygen absorption by hemoglobin

Impaired regulation of ions in blood and tissues

Gill cell necrosis (death)

Reduced survival of eggs and larvae

Question 71

Invasive species

Answer 71

nonnative, nonindigenous, introduced, alien, exotic, transplanted, translocated, feral, biological pollutant

Question 72

Nonindigenous species (NIS)

Answer 72

one that has been moved beyond its natural range or natural zone of potential dispersal

Recognizes natural processes (dispersal, range extensions) as natural events, and focuses on movements that are human-induced and independent of political boundaries

Question 73

Dispersal - indigenous species

Answer 73

Impetus for dispersal:
Response to negative ecological interaction,
normal part of life history

Factors limiting dispersal:
Species mobility, physical barriers, biological barriers, climate (physiology), food (preferred), predators/competitors

Question 74

Dispersal - nonindigenous species

Answer 74

Impetus for dispersal:
Humans!
Food, sport, biological control, unintentional

Factors limiting dispersal:
biological barriers, climate (physiology), food (preferred), predators/competitors (<)
Policy, education, outreach

Question 75

What makes a good nonindigenous species (NIS)? **

Answer 75

High reproductive rate, including high fecundity, short interbreeding period

Short generation time with rapid maturation

High dispersal rate

Broad native range, abundant in native range

Tolerant of a wide range of water quality

Ecological generalist with respect to habitat and tropic requirements

High genetic variability and phenotypic plasticity

Question 76

Mechanisms for successful invasion - replacement

Answer 76

Habitat degradation creates conditions that are no longer favorable for native species, but are acceptable for introduced species

Anthropogenic disturbance (siltation, dredging, climate change)

Natural disturbances (flooding, storms)

Implies that native species are specialists and introduced species are generalists

Does not require interaction between native and introduced species

Question 77

Replacement related to disturbance

Answer 77

Correlation of native and introduced species with land use intensity in southern Appalachian streams

Question 78

Mechanisms for successful invasion - displacement

Answer 78

biotic interactions in the form of predation, competition, or introduced parasites and diseases

Introduced species prey on native species

Competitive exclusion principle (both species vie for the same food, space, reproductive habitat)

Novel parasites & diseases found in introduced species infect native species which have not evolved defenses against them

Question 79

Most successful invasions generally occur as a result of both ____ and _____

Answer 79

replacement and displacement

In some cases, habitat that is successfully invaded typically has been modified by humans leading to decreased habitat diversity and variability

Question 80

Nonindigenous aquatic plants

Answer 80

Dispersal through seeds (propagules), fragments, whole plants

Aquatic macrophytes, wetland vegetation, algae

Biological impacts - shading, sequestration of nutrients, increased decomposition and oxygen depletion

Human impacts - navigation, aesthetics, loss of sport fish, toxic algal blooms

Question 81

Nonindigenous aquatic invertebrates - zebra mussel (Dreissena polymorpha)

Answer 81

Native to the Black, Caspian, and Azov Seas

Filter feeder, pelagic (veliger) larvae

Potential for rapid colonization

Release of larval mussels during the ballast exchange of a single commercial cargo ship traveling from the north shore of the Black Sea to the Great Lakes has been deduced as the likely vector of introduction to North America

Rapid dispersal throughout the Great Lakes and major river systems was due to the passive drifting veliger larvae, and its ability to attach to boats navigating these lakes and rivers

Biofouling capabilities by colonizing water supply pipes of hydroelectric and nuclear power plants, public water supply plants, and industrial facilities

Reduced the biomass of phytoplankton significantly following invasion

Question 82

Nonindigenous fishes - lionfish (Pterois volitans) **

Answer 82

Native to Indo-Pacific

Sit and wait predator, poisonous spines

Popular aquarium species

Lionfish in the Western Atlantic:
Numerous studies now being conducted to determine the impacts of lionfish – the first nonindigenous marine fish to establish the Western North Atlantic and the Caribbean

Question 83

What are the potential impacts of lion fish on coral reef ecosystems?

Answer 83

Negative net recruitment of important native reef fishes

Also prey on juvenile spiny lobster

Ecological, economic, and human health considerations

Question 84

Source of climate change

Answer 84

Rapid increase in the emission of greenhouse gases

Increase in slash and burn land clearing (emissions and loss of carbon sink)

Population growth, industrialization, and ignorance

Question 85

Direct impacts of increasing water temperature on fish (negative) **

Answer 85

Physiological – temperature beyond tolerance limits (critical thermal maximum) can lead to mortality

Increased metabolism and energetic needs

Decrease in growth if prey production is insufficient

Increase in water temperature occurs more rapidly than selective pressures that allow populations to persist

Question 86

Direct impacts of increasing water temperature on fish (positive) **

Answer 86

In some cases survival may increase, especially in temperate regions since constraints of size-dependent overwinter starvation would be relaxed

Also, greater annual growth could occur for coldwater, cool water, and warm water freshwater fishes because an increase in the length of the growing season and the volume of habitat offering preferred temperatures

Collective impacts could result in modified species ranges, both with latitude and with elevation

Question 87

What are effects of climate change beyond warming?

Answer 87

Precipitation regimes will also be altered

Climate change will bring more extreme weather patterns, including droughts, wildfires, heavy rainfall, and storms (e.g hurricanes)

Increased desertification in additions to rapid deforestation = reduction in carbon sinks, increased heat absorption of land, reduction in groundwater and surface water flow

Reduction in global cloud cover - feedback mechanism that accelerates warming because of decreased albedo

Question 88

Impacts of climate change on the water cycle

Answer 88

Non-uniform changes in precipitation, more severe extremes (longer droughts, more intense floods)

Loss of polar ice caps, increase in sea levels, potential reduction in the deep western boundary current in the Atlantic

Question 89

Cascading impacts of climate change

Answer 89

Changes in carbon input and nutrient loading, influencing primary production

Changes in sediment loads and the mobilization of contaminants

Changes in habitat availability; increase in nonindigenous species; changes in movement patterns

Changes in recruitment dynamics of invertebrate, plant, and fish populations

Change in community composition

Question 90

How does ocean acidification affect coral? **

Answer 90

Zooxanthellae – symbiotic algae living in the tissue of corals

Provides the color of corals

Excess production of glucose, glycerol, and alanine for host

Provide the energy for coral to create CaCO3

Zooxanthellae are expelled when the coral is stressed (from acidification or heat stress)

Reduced secretion of CaCO3

Question 91

Decoupling disturbances

Answer 91

decoupling = reducing the amount of resources used to generate economic growth while decreasing environmental deterioration and ecological scarcity

Overharvesting of fish

Coral bleaching related to temperature

Nutrient loading and freshwater input

Loss of herbivores

Increased growth of macroalgae

Question 92

Baselines

Answer 92

an important reference point for measuring the health of ecosystems; provides information against which to evaluate change; it’s how things used to be

Important to keep track of how things have been because baselines are shifting (ex: people visiting degraded coastal environments and calling them beautiful, unaware of how they used to look)