Ichthyology Lecture Final

Provide examples of how fish ecology involves interactions between species, within populations, and with the environment.

Fish ecology is the study of interactions of fish with each other and their environment. It involves what conditions certain species need to survive, how that species interacts or competes with other species, and the different elements of the environment.

Define and differentiate between habitat, niche, fish population, and fish community.

Habitat is the area in which the species lives in, and is made up of many different elements. Niche is the role that certain fish play in the ecosystem. Fish population is the population of one species of fish in a certain area. Fish community is all of the different species of fish in a certain area.

Explain the difference between a fundamental niche and a realized niche.

A fundamental niche is the potential range a fish would have if there were no limiting factors. Realized niche is the actual range a fish has due to those limiting factors.

Recognize that aquatic ecosystems are categorized by salinity into marine and freshwater systems.

Most water on earth (98%) is salt water and fills in marine life zones such as oceans, estuaries, coral reefs, and coastal wetlands. While the 2% of freshwater is found in freshwater lifezones such as lakes, rivers, wetlands, and streams.

Identify and describe characteristics of marine zones: coastal, open ocean (euphotic, bathyal, abyssal), and ocean bottom.

The coastal zone is the most densely populated area of the marine zones. It holds reefs, estuaries and wetlands.

The open ocean starts where the ocean bottom drops out and the water becomes much deeper. It is split into three zones:

The euphotic zone is the area where light can easily reach allowing for photosynthesis.

The bathyal zone is where light only partially reaches, photosynthesis cannot occur and fish become smaller.

The abyssal zone is where light can no longer reach. The animals may bioluminescence and must face very cold and harsh pressure.

The ocean bottom is home to many bottom dwelling organisms. Most of these organisms are filter feeders or scavengers.

Describe the ecological importance of estuaries and coastal wetlands as highly productive ecosystems.

Estuaries and coastal wetlands are very important as they allow for fresh water to mix with salt water. They are also dense deposits of nutrients, which allow them to be very productive. Unfortunately they also collect any pollutants that flow down stream.

Explain how factors like water depth, temperature, and nutrient availability affect marine biodiversity.

In the Euphotic Zone, the water is warmer, it is brightly light and organisms like phytoplankton live. Larger fish live here, there is also a greater biodiversity and photosynthesis takes place. In the Bathyal Zone there is less biodiversity, with less sunlight, the water becomes colder. There are smaller animals and no photosynthesis producers. In the Abyssal Zone, sunlight does not reach this far, it is cold and dark. The animals that live here have some form of bioluminescence.

Describe lentic (standing water) and lotic (flowing water) freshwater ecosystems and provide examples.

Lentic: Ponds, lakes, wetlands. Standing water that goes through stratification. Fish in these ecosystems are built for maneuverability and buoyancy.
Lotic: Rivers, streams, springs. Fast flowing, fish in these ecosystems have a streamline shape that provides stability in the fast moving water.

Identify physical, chemical, biological, and zoogeographic factors that influence stream fish communities.

Physical: Temperature (many species need specific temperatures to survive), stream order( determines the size and depth of the habitat), gradient (determines the type of substrate; rock vs. sand.) Chemical: dissolved oxygen levels, pH (6.5-8.5 S.U is preferred), hardness/alkalinity, pollution. Biological: Competition for habitat, non-native/invasive introduction, the presence of other native species. Zoogeographic: Habitat diversity and composition.

Explain the role of habitat competition and cover in shaping species interactions.

Habitat competition occurs when multiple species or individuals try to access the same spots for hiding or feeding.

To reduce chances of a negative encounter with other species, fish have evolved to live in different parts of the stream, different diets, and different swimming styles so they do not have to compete as much for the same resources.

Describe how body form and environmental conditions relate to fish habitat preferences.

The body shape of a fish can determine where it thrives. For example fish that live in benthic habitats, catfish, suckers, sculpin, have a flattened body shape and mouths positioned on the bottom of their head; they may also have sensory organs. This is so they can find food in a lowlight habitat. This is opposed to a darter or shiner which has a streamlined and hydrodynamic shape that allows water to pass right over it, as these fish can live in high flow portions of a stream.

Label lake zonation: littoral, limnetic, profundal, and benthic zones.

Littoral (1): The shore and shallows that receives a lot of nutrients from runoff, and a lot of light, therefore there is a lot of plant growth in this zone.
Limnetic (2): This zone is the open water of the pond/lake. And if generally right under the surface. Lots of light still reaches this zone, there is usually a lot of nutrients in this zone depending on the type of lake. It is also usually warmer near the surface.
Profundal (3): This zone is deep and plantless due to the lack of sun light reaching this far under the water.
Benthic (4): The benthic zone is the coldest, darkest and deepest part of the lake. This is where the bottom of the lake is. There are no plants in this zone.

Distinguish between oligotrophic (deep, nutrient-poor) and eutrophic (shallow, nutrient-rich) lakes.

Oligotrophic lakes are nutrient poor so they cannot support large populations of aquatic plants or algae. This leads to less animals being able to live there as well. Fish who appear in oligotrophic lakes are usually large, but with less population.
Eutrophic lakes are nutrient rich, supporting many forms of algae, plants and animals. This also leads to a higher population of fish species, as well as many smaller fish species.

Explain lake stratification and seasonal mixing (turnover) and how it affects habitat structure.

Lake stratification is when a lake separates into different layers of density due to warmer temperatures. Water density depends on temperature.
The first layer, epilimnion, is the warmest and shallowest layer. It contains the most dissolved oxygen than all the other layers. The middle layer is the metalimnion, a transition between the warmest and coolest part of the lake. The deepest part of the lake is the hypolimnion, which is the coldest part of the lake. This level gets the lowest amount of dissolved oxygen.
As summer turns to fall, the warmest layer begins to cool, and sinks down, mixing the layers. Eventually, the entire lake becomes the same temperature, and allows lake turnover to occur.
Turnover is when the water is mixed by wind. This can only happen when the water is all the same temperature and density. Stratification in general causes separate habitats in the lake due to the different temperatures. Turnover breaks part these layers, replenishing dissolved oxygen and redistributing nutrients.

Identify aquatic assessment methods such as fish sampling, macroinvertebrate surveys, and water quality testing.

For fish sampling, we use electroshock or a sein to collect specimens. We can have a better understanding of their health and any threats to them or their habitat by looking and examining them up close.
For macro sampling, usually you use a net to search through leaf litter and other areas macroinvertebrates would be. A net is the most common process for this.
For water quality testing, we use secchi disks, which can tell us the amount of light penetration and algae density. We also use PH meters for alkalinity, acidity.

Describe the function of fish behaviors such as schooling, territory defense, and migration.

Schooling: disrupts predators and makes it harder to focus on an individual fish, helps with foraging and information sharing, reduces drag which allows the group to be more hydrodynamic, and allows coordinated spawning, which means a greater chance of fertilization.
Defense: territorial defense is typically seen as a spawning/nesting behavior, because fish will often aggressively defend their nests and eggs.
Migration: travelling to a new habitat, can be between freshwater and saltwater ecosystems, between freshwater environments, and even within the same body of water (such as along a shoreline or from the depths to the shore).

Understand the structure of aquatic food webs and the roles of fish as primary, secondary, or tertiary consumers.

Food webs are structures made to represent how energy is transferred through an ecosystem. In aquatic environments, algae and phytoplankton serve as the producers, with fish serving as consumers. Primary consumers (fish, zooplankton, crustaceans) eat the algae and phytoplankton. Secondary (and tertiary) consumers eat the primary (and secondary) consumers, fish can fill both of these niches.

Interpret trophic pyramids and identify example species at various trophic levels.

Trophic pyramids are diagrams that show how energy is passed through an ecosystem, and how that energy is lost through transfers. The base is always the primary producers, which have the most energy (phytoplankton as an example). Herbivorous consumers eat the producers (zooplankton). Carnivorous consumers are organisms that eat the herbivorous consumers and any organism on a lower trophic level than themselves (1st level could be crustaceans, 2nd could be fish, 3rd could be squid). Lastly, top carnivores receive the least amount of energy in the pyramid and eat the carnivorous consumers (sharks).

Define Zoogeography

The distribution and range of species as well as habitat needs, watersheds, and ranges. There are 7 regions in the North American Region.

List the main factors that influence fish colonization and fish dispersal

Range, Habitat, Waterfalls, Barriers to colonization, Channelization, Dams, Ag and logging practices, Urban development

Name the North American Fish Provinces and the main characteristics that define each area.

• Mississippi provinces 

  • Richest in species 

  • 30% cyprinidae 

  • Several large river forms 

    • Alligator gar and paddlefish

  • Acted as glacial refuge 

• Atlantic Coast Province 

  • Moderate species richness 

  • Fair number of anadromous species 

    • Atlantic salmon, rainbow smelt

  • Catadromous species 

    • American eel 

• Great Lakes Province 

  • Most extensive freshwater lentic system 

  • Several endemic species 

    • Blue pike 

  • Great diversity of whitefish species 

  • Many invasives 

• Pacific Coast Province 

  • Moderate species richness 

  • Fair number of anadromous species 

    • Including 5 species of salmon 

  • Several endemic large river cyprinids 

    • Bonytail Chub

Understand the effects of glacial history on Ohio’s watersheds and fish distribution, particularly the Pleistocene glaciations.

The pleistocene glaciations left many new large lakes carved out of Ohio. It also rearranged how fish were dispersed across freshwater in Ohio. Ohio waters used to drain out of the Teays river system but now it drains into the Ohio river system and the Lake Erie basin.

Identify major drainages in Ohio:

The two major drainages in Ohio are the Lake Erie and Ohio River watersheds. Lake Erie handles the northern part of Ohio, and eventually drains into the Atlantic ocean. The Ohio River handles the southern part of Ohio and drains into the Gulf of Mexico.

List anthropogenic stressors that affect fish distributions.

Channelization, dams, agricultural development, and urbanization as well as pollution can affect fish distribution. Dams and channelization can prevent many fish species from being able to migrate and have proper territory sizes.

Identify current environmental changes that are shifting fish species ranges and behaviors.

Aquatic ecosystems are very sensitive to changes in the environment, forcing fish species to adapt to increases in pollution, habitat changes (channelization, damming, urban development), runoff, and climate change.

Name examples of the ecological and economic significance of freshwater fish.

About 200 million people rely on freshwater fish for a source of protein; fish are important in nutrient cycling in food web dynamics; are an employment opportunity

Identify the degree of imperilment of freshwater fish compared to other vertebrates worldwide.

They are the most imperiled group of vertebrates. About 25% are threatened due to pollution, dams, and habitat loss

Describe the level of decline in freshwater ecosystems compared to terrestrial or marine ecosystems.

2 to 3 times more losses in freshwater ecosystems than marine or terrestrial. With marine and terrestrial ecosystems being about 35-38% decline, freshwater ecosystems are about a 85% decline between 1970-2020

List the primary causes of fish endangerment:

Pollution, dams, overfishing, invasive species & diseases, and climate change

Explain why freshwater ecosystems are highly vulnerable.

Freshwater habitats host more species per square kilometer than that of land and or oceans despite only covering 0.01% of the Earth’s surface.

List factors that lead to the decline of Atlantic salmon

Climate change affects all stages of the Atlantic Salmon’s life cycle, influencing the development of young salmon, reducing prey availability and allowing invasive species to expand their range. Dams and other barriers block access to spawning and feeding grounds, while pollution and sedimentation from logging and agriculture lead to higher mortality in young salmon.

Name three characteristics leading to endangerment of fish and provide an example of each.

Small, isolated species with low overall population numbers, Miller Lake Lamprey
High levels of endemism, species with specialized or restricted habitat range make up most extinct or endangered species, Snail Darter
Big river fishes that need clean water or large ranges are especially affected by pollution, sedimentation, damming, and water withdrawal, Sturgeon

Define channelization and describe how it affects stream and river functions

Channelization is the process of straightening a natural stream or river to fulfill a variety of purposes. This is done often to fit in with man made boundaries such as roads or property lines, to assist in drainage of the area, to reduce flooding, and to make navigation easier. While these changes may benefit humans, streams are not meant to be straight and doing so reduces habitat quality. Channelization changes the natural depth, gradient, productivity, etc. of streams.

Describe how dam building affects stream and river functions

A dam blocks fish movement for migration, food reproduction. It prevents dispersal of sediments, and water released from cold, lower portions

Describe how introduced, invasive species alter native ecosystems.

Introduced species directly affect through predation on adults, young, and eggs. Indirectly through superior competition, hybridization, or transmission of pathogens. If a species is introduced into an ecosystem not balanced to include it, the species can run rampant or uncontrolled.

Name strategies used in fish conservation

Habitat restoration and protection, pollution control measures, sustainable fisheries management, climate change mitigation strategies, invasive species control, public awareness and education initiatives

Define the following and provide examples of fish from each category.

Endangered: A native species or subspecies threatened with extirpation from the state. The danger may result from one or more causes, such as habitat loss, pollution, predation, interspecific competition, or disease. Example: Spotted Gar

Threatened: A species or subspecies whose survival in Ohio is not in immediate jeopardy, but to which a threat exists. Continued or increased stress will result in it’s becoming endangered. Example: Tippecanoe Darter

Species of Concern: A species or subspecies which might become threatened in Ohio under continued or increased stress. Example: Lake Trout

Extirpated: A species or subspecies that occurred in Ohio at the time of European settlement and that has since disappeared from the state. Example: Alligator Gar

Extinct: a species that existed in Ohio, and has since disappeared from its range. Example: Blue Pike

List the primary causes of fish endangerment in marine ecosystems.

Bycatch and habitat removal, bottom trawls

Summarize two case studies in conservation

Ohio’s Brook Trout- Thought extirpated until 1972, then population discovered in 2 small streams by 1993 only one stream left, other destroyed in building project. Fish captured for breeding and restocking program. Found 16 suitable streams to release trout in based on stream metrics. 1997 fish propagated and stocked. By 2007 annual late summer surveys indicated 10 streams with reproducing populations.
Lake Sturgeon- Unregulated harvest + dam in Lake Erie access to tributary streams for reproduction led to decrease of population. Conservation projects to re-establish the Maumee River as a spawning site for lake sturgeon started in 2018.

Define aquaculture

Rearing aquatic organisms under controlled or semi-controlled conditions.

Provide examples of aquaculture-

Fish Hatcheries, Ponds

Aquaculture is a broad and varied field of study

1. Shellfish grown in submerged Open Ocean Cage Systems

2. There can be modified Ponds implementing green water algal growth

3. Common Commercial Catfish pond like those in the southern US

4. Rearing freshwater prawns

5. Public Aquarium

Identify the main uses of aquaculture-

Food, Fishery management, Research, Conservation, and Aquariums.

Name aquatic organisms raised in aquaculture-

Fin fish, Shellfish, Mollusk, Reptiles and Amphibians.

List challenges that every species presents

Sourcing

1. Sourcing

   1. Where are you going to get your animals/plants?

2. What are the environmental requirements of your species?

   1. Water quality (salt vs. fresh)

   2. Oxygen levels

3. Organisms behavior and interactions

4. Organisms nutrition: commercial diet?

5. Economics, selling the product

Compare extensive (low input) and intensive (high input) management in aquacultural systems

Extensive (lower density) refers to aquaculture with little to no management such as an unmodified pond.

Intensive (higher density) refers to aquaculture with fully controlled variables.

Write the percentage of seafood production that comes from aquaculture.

More than 50% of seafood come through the form of aquaculture

Name examples of the wide range of fields involved in aquaculture.

Economics, Disease study, nutrition study, handling and hauling, research, physiology,

List career opportunities available in aquaculture

hatchery owner, biologist, Aquarium worker, Laboratories,

Describe how stream order affects fish habitat and diversity

Stream Order: The lower the stream order the lower the diversity and water conditions. Low Order- Small, cold, low diversity. Mid- More nutrients, highest diversity. High Order- Wide, slow moving, diversity may decline.

Describe how slope/substrate affects fish habitat and diversity

Slope/Substrate: A high gradient will result in boulders, bedrock and coble substrate. Thus creating small pools, swift currents and high dissolved oxygen. (Sculpin, trout, darters). A low gradient will result in sand, mud, and silt. Thus creating large, deep, quiet pools with low dissolved oxygen. (Catfish, largemouth bass).

Describe how temperature affects fish habitat and diversity

Temperature: Certain species of fish will only live in certain temperatures of water. Largemouth bass and cyprinids like warm water. Trout and sculpin like cold water.