L21 - Bony Fish Flashcards
How many extant species of fish are their?
35,400
What are the two class of the superclass Agnatha?
Cephalaspidomorphi & Myxini
What is the order of the class Cephalaspidomorphi?
Petromyzontiformes: lampreys (48 extant spp)
What is the order of the class Myxini?
Myxiniformes: hagfish (88 extant spp)
What are the two sub-class of the class Chondrichthyes?
Elasmobranchii & Holocephali
What is the sub-class Elasmobranchii?
Sharks, skates, rays (1,279 extant spp)
What is the sub-class Holocephali?
Chimaeras (55 extant spp)
What are the class of the superclass Osteichthyes?
Sarcopterygii & Actinopterygii
What is the class Sarcopterygii?
Lobe-finned fish (8 extant spp)
What are the subclass of the class Sarcopterygii?
Actinistia: coelacanths (2 spp)
Dipnomorpha: lungfish (6 spp)
What is the class Actinopterygii?
Ray-finned fish (33,969 extant spp)
What is the subclass of the class actinopterygii?
Chondrostei: sturgeons, paddlefish (52 extant spp)
What are the infraclass of the subclass Chondrostei?
Holostei: bowfins, gars (8 spp), Teleostei: Teleosts; 96% of all living fish
How many orders and families in the superclass Osteichthyes?
> 50 orders, >500 families.
How do most teleosts feed?
Most teleosts suction feed.
Buoyancy in Osteichthyes?
Neutral buoyancy, much lower cost of transport, new niches
What is specific gravity?
Specific gravity is the ratio of the density of a substance to the density of distilled water. Unit = g ml-1. Freshwater 1.00, seawater 1.026, fish muscle 1.050, cartilage 1.100, bone 2.000, average lipid 0.900, air (at 20 degC) 0.001204.
What are the advantages of using gas as a buoyancy aid?
Gas is >800-times less dense than lipid; much less is required for neutral buoyancy. Without buoyancy: 7% denser than freshwater, 5% denser than seawater. Only requires 5-7% increase in volume. Quantity of gas can be adjusted quickly so able to compensate for short-term changes.
What are physostomatous fish?
Pneumatic duct between swimbladder and gut open throughout life (lower teleosts, e.g. clupeids, anguilla).
What are physoclistous fish?
Pneumatic duct closes early in development (higher teleosts)
What opens up a multitude of life styles?
Short deep body best for manoeuvrability, but produces high drag when swimming
What is the ideal shape for continuous swimming?
Fusiform (spindle shaped). E.g. scombrids (mackerels, tunas, etc)
What increases linearly with depth?
Pressure (atm)
What are particularly affected by pressure?
Gases
How does the swim bladder change on descent?
It compresses, fish becomes negatively buoyant. To maintain neutral buoyancy: more gas into gas-bladder.
How does the swim bladder change on ascent?
It expands, fish becomes positively buoyant. To maintain neutral buoyancy: expel gas from gas-bladder.
What are the adaptations for buoyancy in deep-sea fish?
Quanity and speed of gas secretion into swim bladder depends on the size of capillary bed, so many deep sea fish have multiple gas glands. Deep water fish tend to have larger oval per volume of swim bladder. Lightly ossified skeleton, few if any scales, reduced musculature (important if weak bones), loss of swimbladder entirely.
How does tissue change after being pulled up?
Extreme tissue damage from being pulled up.
How do teleosts reproduce?
Most are broadcast spawners, unique to aquatic animals, high fecundity of small eggs - gametes released into water column for external fertilisation without mate selection. Attrition: far more zygotes produced than will ever reach maturity - mortality rates of over 99.99%
What are the vast majority of fish?
All elasmobranchs are predatory except for 13 species of filter feeders. Large, terminal mouths with well developed biting or grasping teeth.
What are grazers and browsers?
Many with specialised morphologies and therefore narrow diets width (e.g. butterfly fish); others may be more generalist. Grazers may be herbivorous (cichlids, blennies damselfish) but true herbivory is quite rare in fish. Some grazers may be carnivorous, e.g. some catfish and cichlids browse on scales and mucous of other fish. Some grazers are omnivorous, e.g. parrotfish browse coral, seagrass, algae.
What are strainers/filter feeders?
Often large, toothless mouths, long gill rakers, food selection by particle size.
What are bottom feeders?
Mostly bottom feeding fish sucking food/detritus into mouth and ejecting non-digestible items. Grey mullets scrape mud in estuaries. Sturgeons hoover river/sea bed.
What is an example of symbioses?
Cleaner fish remove dead and damaged tissue/scales and parasites. Often have characteristic colouration and set up cleaner stations where fish in search of cleaning will adopt stereotypical poses to ilicit cleaning. Some species are obligate cleaners. Many other species show facultative cleaning behaviour as juveniles (butterfly fish, angelfish).
What are the clupeiformes?
5 of the top 14 fished species/genera in 2020 (including 4 in the top 10 and the number one spot: Engraulis ringens). 15% of all fish biomass, 10072000 tonnes.
What are the Scombridae?
4 of the top 14 fished species/genera in 2020 (including the number three spot, Katsuwonus pelamis). 10% of all fish biomass, 6805000 tonnes
What are the Gadiformes?
3 of the top 14 fished species/genera in 2016 (including the number two spot: Gadus chalcogrammus). 9% of all fish biomass, 6109000 tonnes.
What are the four different types of fisheries?
Capture fisheries - Marine or inland waters
Aquaculture - marine or inland waters
What are the Cyprinidae?
9 of the top 15 inland aquacultured species/groups in 2020 were cyprinids, (including the number one and two spots). 28 726 500 tonnes, representing 58% of all finfish aqua culture in 2020 (by biomass).
