Estuaries + Quizes FINAL

True estuarine fish

Species that spend their entire life cycle in estuaries.

Dependent marine fish

Marine fish species that require estuaries at some stage of their life cycle.

Nondependent marine fish

Species that do not require estuaries for any part of their life cycle but may still inhabit them.

Euryhaline

Fishes that can tolerate a wide range of salinities.

Ex:

• diadromous fishes (fex: reshwater eels, herrings, shard)

• true estuarial/ estuary resident species (ex: gobies)

• Dependent marine/ estuary dependent species (ex: anchovies, drum)

Stenohaline

Fishes that can tolerate only a narrow range of salt concentrations.

Ex:

• Freshwater ONLY species

  • (ex: poecilids (mosquito fish), chentrarchindae sunfishes, bass), etc)

• nondependant marine species

  • (ex: pinfish, jackes, et.)

Benthic invertebrates

Organisms that live on the bottom of water bodies, playing a crucial role in the estuarine ecosystem.

ex: amphipods

Filtration

A process whereby certain organisms, like clams or oysters, filter out food particles from the water.

Anthropogenic effects

Environmental changes caused by human activity, particularly detrimental impacts on natural ecosystems.

Ecosystem resilience

The ability of an ecosystem to recover from disturbances or resist damage.

Estuary

A transitional environment where freshwater from rivers meets and mixes with saltwater from the ocean.

Euryhaline

Refers to organisms that can tolerate a wide range of salinities.

Stenohaline

Refers to organisms that can tolerate only a narrow range of salt concentrations.

Benthic invertebrates

Organisms that live on the bottom of water bodies, playing a crucial role in the estuarine ecosystem.

• Example: Amphipods

Filtration

A process whereby certain organisms, like clams or oysters, filter out food particles from the water.

Anthropogenic effects

Environmental changes caused by human activity, particularly detrimental impacts on natural ecosystems.

Ecosystem resilience

The ability of an ecosystem to recover from disturbances or resist damage.

Diadromous fish

• Definition: Fish that migrate between freshwater and saltwater during their life cycle.

• Estuary Role: Utilized as migratory corridors or temporary feeding grounds.

• Salinity Tolerance: Euryhaline (can tolerate a wide range of salinities).

• Examples:

  • American Eel (Anguilla rostrata)

  • Various Salmon species (Oncorhynchus spp)

True estuarine fish / Resident estuarine species

• Definition: Species that spend their entire life cycle in estuaries.

• Salinity Tolerance: Demonstrate high tolerance to fluctuating salinity gradients, making them euryhaline.

• Examples:

  • Diamond Killifish (Cyprinodon variegatus)

  • Common Mummichog (Fundulus heteroclitus)

Dependent marine fish / Marine spawners

• Definition: Marine fish species that require estuaries at some stage of their life cycle.

• Estuary Role: Often use estuaries as critical nursery grounds for their juvenile stages.

• Benefits of Estuaries: Provide abundant food resources and protection from predators.

• Salinity Tolerance: Euryhaline (can tolerate a wide range of salinities).

• Examples:

  • Spotted Seatrout (Cynoscion nebulosus)

  • Atlantic Menhaden (Brevoortia tyrannus)

Nondependent marine fish / Marine stragglers

• Definition: Species that do not require estuaries for any part of their life cycle but may still inhabit them.

• Estuary Role: May enter estuaries for foraging or temporary shelter.

• Life Cycle: Can complete their entire life cycle in marine environments.

• Salinity Tolerance: Generally euryhaline, which allows them to venture into estuaries.

• Examples:

  • Bluefish (Pomatomus saltatrix) adults

  • Various species of Black Sea Bass (Centropristis striata)

Freshwater stragglers / Freshwater adventitious

• Definition: Freshwater species that may occasionally enter the upper, lower-salinity reaches of an estuary.

• Estuary Requirement: Do not require estuarine environments for any part of their life cycle.

• Salinity Tolerance: Typically less tolerant of salinity fluctuations than true estuarine species. Generally stenohaline to marine conditions but tolerant of low estuarine salinities.

• Examples:

  • Largemouth Bass (Micropterus salmoides)

  • Bluegill (Lepomis macrochirus)

What does it mean for an organism to be Euryhaline?

• An organism that can tolerate a wide range of salinities (salt concentrations).

• They thrive in environments where salinity often changes, like estuaries.

• Examples:

  • Diadromous fish: American Eel (Anguilla rostrata)

  • True estuarine fish: Diamond Killifish (Cyprinodon variegatus)

  • Dependent marine fish: Spotted Seatrout (Cynoscion nebulosus)

What does it mean for an organism to be Stenohaline?

• An organism that can tolerate only a narrow range of salt concentrations.

• They usually live in environments with stable salinity, such as purely freshwater or purely marine habitats.

• Examples:

  • Most freshwater stragglers (which are generally stenohaline to marine conditions):

  • Largemouth Bass (Micropterus salmoides)

  • Bluegill (Lepomis macrochirus)

Cyprinodontidae (pup fishes)

Can live in diverse environments
- very high salinity and/or temp

Stenohaline marine fish species are more common near crab bank near the north side of charleston harbor estuary

true due to it has higher salinity in that area

Examples of Fishes with spiny rayed dorsal seperated from soft rayed by a broad gap

Mullet (muglidae)

Atherinidae (silversides)

Ictalurids and minnows

stenohaline 

freshwater

can inhabit esturaries but are primarily found in rivers and lakes.

Detritivorus fishes

a type of fish that feed on dead organic matter, known as detritus, such as dead plants, animal carcasses, and other debris

ex: mullets

What is Direct Development in fish?

No larval stage; juvenile develops directly from the egg.

What is Indirect Development in fish?

Includes a distinct larval stage; most fish species follow this pattern.

What is the ecological significance of fish larval stages typically occurring in the planktonic zone?

To reduce predation from benthic predators. Larvae vary widely in size and form, adapted for survival in early life stages.

Describe the Egg stage in fish development.

Divided into early, middle, and late embryonic development.
- Contains yolk which nourishes the embryo.
Fertilization typically external; eggs often pelagic (floating) in many marine species.

What defines the Larva stage in fish development?

Begins at hatching.

Ends at metamorphosis (transition into juvenile).

What are the subdivisions of the larval stage based on notochord development?

- Pre-flexion larva: Straight notochord.
- Flexion larva: Notochord begins dorsal bending.
- Post-flexion larva: Notochord bending complete.

List key developmental traits observed during the larval stage.

- Undergoes fin ray development (not fully formed until end of larval stage).
- Initiation of squamation (scale coverage begins but completes later).
- Loss of larval-specific structures such as finfolds and stalked eyes.
- Early larval stages may not feed; rely on yolk reserves in yolk-sac larvae.

Describe the Juvenile stage in fish development.

Develops after metamorphosis.
- Body shape and pigmentation patterns evolve gradually toward adult form.
- Stronger swimming ability.
- In salmonids, juveniles are termed "fry" and later "smolt" when preparing for ocean migration.

What are Yolk-sac larvae?

Larvae that remain concealed in gravel substrate, absorbing yolk before becoming free-swimming.
- Notably found in salmonids.
- Early larval stages may not feed, relying on yolk reserves.

What is a Transformation larva?

The stage during metamorphosis when larval features are replaced with juvenile/adult features.

Describe the characteristics of eggs and larvae from Pelagic Spawners.

Eggs and larvae develop in open water.
- Eggs have low specific gravity due to oil content, allowing them to stay suspended in plankton.

- Larvae become free-swimming, feed in plankton, and drift until metamorphosis/settlement.

5 ecological classes of estuarine fishes

1. freshwater fish species

   • stenohaline freshwater

2. diadromous (migrating through estuaries)

   • euryhaline
   

3.  True estuarine species (also known as estuary-resident species)

   • entire life cycle in estuary

   • euryhaline
     

4. Dependent marine fish species (meaning

   estuary-dependent marine fish species)

   • at least one stage of life cycle in estuary

   • euryhaline
   

5. Nondependent marine species

   • no part of life cycle needed to be in estuary

   • stenohaline marine

1. freshwater fish species

freshwater fish species

• stenohaline freshwater

• 10-15 ppt. salinity maximum

• ex:

  • Poeciliidae:

    • eastern mosquito fish (Gambusia holbrooki)

  • Ictaluridae: freshwater catfish &bullheads

  • Centrarchidae: Sunfishes & basses

  • Esocide: Pikes & Pickerel

  • Cyprinidae: Carps & Minnoes

2. diadromous (migrating through estuaries)

diadromous (migrating through estuaries)

Fish that migrate between freshwater and saltwater

• euryhaline

  • Anguillidae: Freshwater eels

  • Clupeidae: herrings, shads

  • Aepenseridae: sturgeon

3. true estuarine species (also known as estuary-resident species)

True estuarine species (also known as estuary-resident species)

• entire life cycle in estuary

• euryhaline

• ex:

  • Gobiidae: gobies

  • spotted seatrout

4. Dependent marine fish species

Dependent marine fish species (estuary-dependent marine fish species)

• at least one stage of life cycle in estuary

• euryhaline

• Ex:

  • Engraulidae: anchovies

  • Sciaenidae: drums

  • Serranidae : Sea basses
    

 5. Nondependent marine species

Nondependent marine species

• no part of life cycle needed to be in estuary

• stenohaline marine

• Ex:

  • Sparidae: porgies

    • pinfish

  • Carangidae: jacks

    • horse eye jack

  • Chaetodontidae: butterflyfishes

    • spotfin butterflyfish

Crab bank Vs South Channel

Crab bank = higher salinity

• live bottom: colonial invertebrates, soft corals, sponges, and hydroid colonies all prefer high salinity

South Channel = more freshwater/ mid-salinity

Mid to low estuaries

Often dominated by spiny rayed fishes

Euryhaline

An organism that can tolerate a wide range of salinities (salt concentrations).

• They thrive in environments where salinity often changes, like estuaries.

• Can adapt physiologically to freshwater and marine environments as well as salt concentrations in between

• Examples:

  • Diadromous fish: American Eel (AnguillarostrataAnguillarostrata)

  • True estuarine fish: Diamond Killifish (CyprinodonvariegatusCyprinodonvariegatus)

  • Dependent marine fish: Spotted Seatrout (CynoscionnebulosusCynoscionnebulosus)

Stenohaline

Salt dependent

can only handle a narrow range of salt concentrations.

• They usually live in environments with stable salinity, such as purely freshwater or purely marine habitats.

• Examples:

  • Most freshwater stragglers (which are generally stenohaline to marine conditions):

  • Largemouth Bass (MicropterussalmoidesMicropterussalmoides)

  • Bluegill (LepomismacrochirusLepomismacrochirus)

food web of a typical southeastern estuary

• invertebrate activities give nutrient retention by estuary

• filter-feeding zooplankton fed on by fishes

• fecal matter returned to sediment

  • food for benthic invertebrates like amphipods, copepods, and polychaetes

  • also abundant clams, oysters which filter feed

  • filter-feeding fishes

Anadromous

Fish that migrates from freshwater to saltwater to spawn

Ex: Some species of Clupidae

Leptocephalus Larval stage

Leptocephalus larvae are transparent, ribbon-like, and distinct from typical fish larvae, highlighting an

evolutionary adaptation.

Elopomorpha have a unique larval stage called Leptocephalus larva

• ladyfish (elops)

• Tarpon

• Bonefish

• Eels (order anguilliformes)

The Main function in which hypuals are involved

Locomotion

hypural support caudal fin rays and help with locomotion

Hypurals

Act as a base where the muscles of the caudal peduncle attach, allowing the movements of the tail fin that are necessary for:

• Propulsion through the water (forward movement).

• Steering and control of direction.

• Balance and stability while swimming. 
  

Helps with locomotion

Name a family that is EXCLUSIVELY Freshwater

Leucisidae - carps and minnows

• Exclusively fresh water species

• ex: yellowfin shiner

A kind of fish that lacks jaw teeth

Minnow

Sister group to Actinopterygii

Sarcopterygii (lobed finned fishes)

African Lungfish

has 2 gas bladders

• allows it to breathe air.

The form of the caudal fin in Osteoglossomorphfishes

Homocercal

Specialized morphological feature of Characidae

presence of an adipose fin and the absence of barbels. 

Characidae- tetras/characins

• Characiniformes

•  Characids are related to piranhas

Teleostei

Premaxilla mobile (relative to cranium)

Urostyle and uroneurals present ; Caudal fin homocercal

Sturgeons and paddlefishes similarities

Both in the order Acipenseriformes

Inferior mouths

heterocercal tail

ganoid scales

flattened snout (rostrum) equipped with electroreceptors (ampullae)

Lantern fish

shallow living marine fish

produces own light

Cladogram showing the patters of relationshios amoung 4 basal orders of actinopterygii and DIvision Teleostei

Gadiformes

phycid hakes (often in Gadidae)

Mostly oceanic/marine fishes

Eurohaline

rat body form

Moderatly elongated/slightly globiform

Frogfishes

Order Lophiiformes (Anglerfishes , batfishes, and Frogfishes)

Family Antennariidae

• modified dorsal fin spine (illicium) acting as a “fishing rod” with a bait (esca) at the tip.

• can walk along bottom

• shallow water fish

• Ex: sargassum (Histrio Histrio)

Anglerfishes

Order Lophiiformes

Family Antennariidae (Anglerfishes , batfishes, and Frogfishes)

Ococephalidae

Order Lophiiformes (Anglerfishes , batfishes, and Frogfishes)

batfishes

Australian lungfish are obligate air breathers (true or false)

FALSE
Lungfish can breath air but they do not HAVE to

Poecilids (how they live)

typically live amongst the vegitation and cover along the edges of streams or water bodies

Sturgeons and Lamprey groups similarities

both contain species with anadromous migration

group of fishes that contains species w/ trilobed diphycercal caudal fin

Sarcopterygii (lobe finned fishes)

• contains coelacanths have trilobed diphycercal caudal fin

• Lungfish have diphycercal caudal fin

features of typical soft rays in bony fishes

Segmented and branched

Diphycercal Caudal Fin

Symmetrical internally and externally, vertebral column extends to the tip; seen in lungfishes and coelacanths.

Gnathostomata is characterized by the presence of…..

jaws derived from branchial arches

jaws and paired appendages, including fins in fishes and limbs in tetrapods.

Gnathostomata

jawed vertebrates

includes all living bony fishes:

• both ray-finned and lobe-finned, + tetrapods

• cartilaginous fishes

• and some extinct prehistoric fish (placoderms & acanthodians)

The most phylogenetically basal ("primitive") type of fishes

Myxiniformes (hagfish)

Squalidae

Dogfishes (shark species)

characterized by the lack of an anal fin

Which upper jaw structure in sharks and rays bears teeth

Palatoquadrate

Palatoquadrate

A cartilage structure in elasmobranchs that supports the upper jaw and bears teeth.

Features of a Lamprey

protocercal caudal fin

Notochord Retained throughout life!

Anadromy/anadromous (in some species)

Lampreys and hagfish = chordates

• Jawless fishes = Agnatha

Protocercal caudal fin

Simple, unexpanded, and symmetrical

Vertebral column (notochord) extends to the tip of the tail w/o expanding

provides support without distinct lobes.

Lamprey notochord

• A structural rod made of cartilage or bone

• supports the body

• serves as a primary skeletal element in lampreys.

• Remains throughout life in lampreys

• derived from the mesoderm

which group contains living species in which the intracranial joint is present

Sarcopterygii: Coelacanthiformes (coelacanths)

intracranial joint

• separates jaw into two parts, allowing mouth to open extremely wide for feeding

Coelacanthiformes

Order of lobe-finned fish known for their distinctive intracranial joint and ancient lineage.

Coelacanthiformes characteristics

sacropetergyii (lobe finne)

trilobed (3 lobed) diphycercal caudal fin

intracranial joint (allows mouth to open wider)

Absent choanae (2 internal nostrils/openings at the back of the nasal passage ; connects nasal cavity to nasopharynx)

• only in Coelacanthiformes ; present in Lungfish

fin rays not branched

unconstricted unossified notochord

Actinopterygii

largest class of vertebrates

ray-finned fish characterized by:

• Restricted to segmented rays

• lepidotrichia (segmented bony fin rays), rather than fleshy lobes.

• No internal nostrils (choanae)

• scales ganoid (primitively), cycloid, or ctenoid  (except in soft rayed)

In batoids (rays, skates, and sawfish), the gill opening are located on the _________

ventral surface

_____ is the number of external gill openings (on each side) in chimaeras

1 external gill opening ; the rest are covered by gill cover 

Chimaeras

Ratfishes

Class: Chondrichthyes (cartalagonous fishes)

subclass: Holocephali

Superior mouth

mouth position of surface oriented fishes

Jaw teeth in piscivorous fishes

Villiform Teeth:

Piscivorous Fish

Fish that eat other fish

• carnivorous fish

Have villiform teeth

Villiform Teeth

skinny, sharp, elongated, needle - like teeth found in the mouths of predatory fish (Piscivorous Fish)

The pattern of geographical distribution of living Coelacanthidae (coelacanths)

• in what parts of the world/oceans are living Coelacanthidae found?

Indian Ocean & Indonesia

Guitarfish caudal fin type

Heterocercal tail with unequal lobes

• Vertebral column extends into the upper lobe, making it longer and asymmetrical

Stingray caudal fin type

No Caudal fin

Hagfish caudal fin type

Protocercal caudal fin

• A tail type where the vertebral column extends into the tail, and it lacks lobes.

Coelacanths caudal fin type

3-lobed Diphycercal caudal fin