Ichthyology Exam 3

Define herbivory. How common is it? What are some examples of fish that practice this? What ecosystem has a relatively high proportion of fishes that are herbivores?

Fish that eat photosynthetic material. It is very common and there is a high incidence of it on coral reefs. Some examples of fish that pracitce turf grazing are grass carp, and damselfishes.

Do herbivores require animal food?

Sometimes, small animals associated with plant material provide nutrients and protein along with plants.

Is eating detritus a successful strategy for some fishes? How do they get their protein? Examples of detritivores?

Yes, eating small pieces of dead organic material colonized with decomposers is successful for some fishes. They get their protein by the detritus, which adds 10-20% more protein. Some examples are striped mullet that filters, or tilapia which suction feed.

Name a fish for every type of feeding strategy.

• Herbivorous: Grass carp

• Dentrivorous: Striped mullet

• Benthic: Minnows/darters

• Piscivorous: Bowfin/gar

• Parasitic: Candiru catfish

• Omnivorous: most minnows

• Planktivorous: Basking shark/herring

What are adaptations seen in herbivorous fishes?

• Mastication by pharyngeal teeth

• Many with well-developed stomach

• Symbiotic bacteria that produce cellulase

Why are the African Rift Lake species flocks notable in their feeding strategies? Can you name some out-of-the-ordinary diet preferences of these cichlids?

They are notable for their feeding strategies because they often finely divide food resources, and they have very diverse strategies because of their rapid adaptations. Examples of their diet preferences are fin biters, larval fish eaters, and eye biters.

Give an example for each of the 4 major groups of Teleostei.

• Elopomorpha: tarpons & eels

• Osteoglossomorpha: mooneye, arapaima, butterflyfish

• Otocephala: shad, herrings, minnows

• Euteleostei: trout, bass, flounder

What is a shared-derived characteristic for the Osteoglossomorpha (hint: what does its name mean)? What kinds of fishes are in this group?

These teleosts have a bony tongue (tooth plate on tongue bites against roof of mouth). They are freshwater fish, and examples are mooneyes, arapaimas, and butterflyfish.

Are there any Osteoglossomorph fishes in the United States?

Yes, there is a mooneye species in Georgia, but the rest of the Osteoglossomorpha are found in other parts of the world.

What is remarkable about the mormyrid (elephantfishes/aba) fishes?

They have the largest brain of any fishes which allows them to communicate with each other using electrical signals.

What does the cohort “Otocephala” mean? What kinds of fishes are in this group?

“Ear head fish”. Examples of these fishes are shad, herrings, and minnows.

What fish belongs to the Osteoglossomorpha and will leap out of water for food?

Arowana

What is often considered to be the most important commercial group of fishes? Provide an order of fishes to answer this question.

Order Clupeiformes (shads, herrings, minnows)

What is special about a clupeiform gas bladder related to sound reception?

Their gas bladder has a pair of anterior extensions which enter the skull and connect to the inner ear.

Know that Ostariophysi are the dominant group of freshwater fishes on all continents except Australia and Antarctica. Know the approximate number of species.

The approximate number of Ostariophysi species is 12,000+.

Know shared derived characteristics for the Ostariophysi. Are these good hearing fishes?

• Weberian apparatus that is a don’t connection from the swim ladder to the inner ear (except for Anotophysi - possibly lost connection)

• Alarm substance cells that are located in the dermis and released by injury to the skin

• Pearl organs (tubercles) that males have during breeding season

Where are milkfishes an important food fish?

In SE Asia

Know examples of Cypriniformes, Characiforms, Siluriformes and Gymnotiformes (includes electric eel)

• Cypriniformes: Common carp/ goldfish

• Characiformes: Characins/pacus/piranhas

• Siluriformes: Sea Catfishes/ Gafftopsail catfish

• Gymnotiformes: Electric eel/american knife fish

Be able to discuss the threat of the introduced sharpbelly cypriniform fishes in the U.S. Can you give the common name of at least one of these species?

They are highly invasive and eat eggs of other fish. They can live in extremely versatile habitats and have rapid population growth. A common name example is the grass carp.

What is special about the Robust Redhorse in Georgia?

It is a fish that was lost for over a century and presumed extinct but found again in Georgia. It also is the largest sucker in the south eastern U.S.

Which catfish family has Georgia species that are mouth brooders?

Ariidae (Sea catfishes: gafftopsail catfish & hardhead catfish)

Understand that we have the transition of primitive to advanced teleost characteristics as we work through the Euteleostomorpha. Can you give examples of the 4 subcohorts: Lepidogalaxii, Protoacanthopterygii, Paracanthopterygii, and Acanthopterygii? Which of these have the most species? Bold this term.

• Lepidogalaxii: Salamander fish

• Protoacanthopterygii: Pikes/pickerels/mudminnows

• Paracanthopterygii: Pirate perch/cavefishes

• Acanthopterygii: Mackerels/toadfishes

What is unique about the salamanderfish?

The salamanderfish can bend its head laterally as if it has a neck because of a gap between its anterior vertebrate and its skull. It’s eyes don’t move so it has to use this feature.

What is an anadromous fish? What is an example of an anadromous species?

An anadromous fish spends its early life in freshwater, then migrates to saltwater to live its early life, then goes back to freshwater to spawn and reproduce. An example of a anadromous fish is the Atlantic salmon.