Lecture 27 Flashcards
1
Q
Human and fish interactions?
A
- There are more species of fish than all other vertebrates combined (~32,000 known species)
- Fish are harvested from wild stocks as part of global fishing industries or grown under intensive aquaculture conditions
- Most common pet and are widely used for scientific research
- Fish not always given enrichment to express their natural behavioural patterns in captivity
- Fish live in complex environments (social and physical) -> high degree of behavioural plasticity
2
Q
Reviews of fish cognition suggest fish show a rich array of sophisticated behaviours such as…
A
- excellent long-term memories
- develop complex traditions
- show signs of opportunist intelligence
- cooperate with and recognise one another
- capable of tool use
3
Q
‘Wild’ vs ‘Hatchery’ Fish
A
‘wild’
* fish hatched and reared in a natural environment (regardless of parentage)
‘hatchery’
* fish are bred by genetic crosses. Hatched and raised in captivity until juvenile stage then released
- Most hatchery programs are meant to produce fish for harvest
- Increasing number of hatchery programs now have the explicit mission of restoring declining wild populations
4
Q
What is fish stocking?
A
- Fish stocking = management tool that helps manage or change fish populations
- Stocking cannot sustain a fishery above the productive capability of the lake or the species
- Stocking lakes where game fish are capable of reproducing will not result in any improvement to the fishery
- The size of fish stocked in Saskatchewan typically
includes:
* Fry (few days old), Fingerling (8 to 12 cm in length), Catchable (20 to 30 cm in length), Adult (mature fish)
5
Q
wild caught vs aquaculture
A
Wild caught:
* stocks are under pressure
Aquaculture:
* Farming of fish, shellfish, and seaweeds.
* Limited selection/ domestication, captive rearing of wild stocks
* Over 50% of the seafood we eat comes from farms — number continues to increase.
- Types: Fish spp, crustaceans, mollusks
- Intensive: man-made pools, tanks
- Extensive: net cages in open water
6
Q
what are the fish in aquaculture?
A
Mostly Bony fishes-> Osteichthyes
Largest vertebrate class >29,000 species
* Carps, Tilapia
* Catfish
* Sea bass, Sea bream
* Salmonids - Rainbow trout, Atlantic salmon, Arctic char
* Flatfish- newer species, e.g. Turbot
Invertebrates:
* Mussels (mytilus edulis)
* Shrimp, crayfish
* Oysters
* Softshell clams
7
Q
What is fish sensory perception?
A
- To get inside an animal’s head, to try to understand why it does what it does, we must first understand how it views the world around it
- Many fish species occupy an immense array of habitats à it is very difficult to generalise
- The environment in which a fish lives shapes the senses it relies on
- Water differs from air in a wide range of biologically important ways
- Ramifications for understanding the evolution of fish senses, behaviour and cognition
8
Q
What is the fish vison like?
A
- The common goldfish has cones that absorb at 400, 450, 530 and 620 nm (Neumeyer 1982)
- Work in cichlids, guppies and sticklebacks show that ultraviolet (UV) is important for mate choice and species recognition
- Detection of UV can occur in some parts of the life cycle and then be reduced or lost entirely
- Certain spp. of fish use UV as a discrete channel for communication since their predators are unable to see in this part of the spectrum
- Various fish can see polarised light:
(1) increased contrast when foraging on small prey
(2) visual communication
(3) spatial orientation
9
Q
What is chemosensory ability in fish?
A
- Chemosensory ability of most fishes is highly developed
- They use this information for a wide variety of behaviours: feeding, predator recognition, mate choice and navigation
- Sharks sense of smell is ~10,000 times more sensitive than ours
- Because fish are submersed in water -> no restriction on the location of their taste buds
- Variability in location and density of taste buds tells us about their environment and its feeding habits
- Cyprinids have ~300 taste buds per mm2 , and density is associated with the fishes’ feeding habits
- von Frisch (1941) discovered minnows showed an innate fright response when one of their conspecifics was harmed- (‘‘fright stuff’’)
- Now know this substance is held in special skin cells (club cells) in all ostariophysan fishes
- Plays a crucial role in enabling naïve fish to recognise dangerous predators via classical conditioning
- When a conspecific is hurt or killed by a predator, the alarm substance is released into the water resulting in anti-predator responses in the surrounding fish -> Fish can pair the appearance of a predator with an appropriate biological response (e.g. schooling or crypsis)
- One of the greatest examples of animal migrations = return of salmonids to their home streams - spend long time in in ocean and can go back to stream they were born in
10
Q
What is cerebral lateralization in fish?
A
- Fish prefer to use one side of their brain over the other when analysing sources of information
- Pattern of laterality varies between species, between populations of the same species, and between individuals
- Sarasins minnows look at a familiar individuals with their left eye and use their right eye to view unfamiliar individuals
- Right eye is commonly used for looking out for predators or other potentially threatening objects
- Preference for using one eye or the other in social contexts influences the location rainbowfish prefer to adopt within a school
- Those that prefer to use their left eye to view school mates tend to prefer positions on the right side of the school and vice versa
- School would show faster responses to predators and prey on the periphery of the school while also rapidly responding to the behaviour of their school mates -> Shows fish can perform multiple complex tasks simultaneously and provides a non-invasive method to understand which hemisphere fish use when attending to various stimuli.
- Laterality varies with emotive content of stimuli and provides a method of studying emotional responses in fish
11
Q
learning and memory in fish
A
- Associating time of day and location of feeding is known as time-place learning
- Time-place learning has been demonstrated in several fish species
- Typical approach is to feed the fish at one end of an aquarium in the evening and the other end in the morning
- Each day the location of the fish is recorded just prior to feeding
- If the fish show anticipatory behaviour by congregating at the feeding end, then they have learnt the task
- Shown to take 2-4 weeks to learn depending on species
12
Q
Brown et al. (2015) examined the effects of rearing environment on learning using classical or Pavlovian conditioning…. what did they find?
A
- Fish learnt that when a light was turned on food would shortly be delivered down a feeding tube
- Wild rainbowfish showed rapid learning over 7 days (14 trials)
- A captive-reared population was initially slower to learn but they eventually caught up
13
Q
Social learning in fish
A
- Occurs when information passes from one individual to another by observation or interaction
- Lead to a transfer of information through generations (vertical transmission) resulting in cultural traditions
- Hatchery-reared salmon could be taught to recognise novel live prey by pairing them with fish that already recognised the prey
- Naïve observers learn to eat the new food and also learn where to forage for it
- Guppies trained to use routes to locate a foraging patch
14
Q
What is individual and kin recognition like in fish?
A
- Guppies can remember the identities of up to 15 individuals with little difficulty
- In small shoals, familiarity takes ~12 days to develop and may be maintained after 5 weeks of isolation
- When given a choice, fish prefer to shoal with familiar rather than unfamiliar individuals
- Shoals comprised of familiar individuals are better at avoiding predators than groups comprised of strangers
- Social learning is enhanced in groups of familiar fish
- Territorial cichlids show lower levels of aggression towards familiar than unfamiliar neighbours
- Fish may lose preference for familiarity after multiple generations in captivity and could have other consequences on social behaviours
- Fish may also be able to recognise kin using both visual and chemical information
15
Q
What are the 3 social structures in fish and describe them
A
- Solitary
* Territorial fish
* Aggressive defense of feeding area
* Pike (Jack fish) and juvenile salmonids
* Need some refuge, such as weeds or banks - Schools (large, tight groups)
* Deep bodies of water
* Provide refuge to individual fish
* Predator detection
* Synchronization- flooding effect on predator
* Improved foraging - Shoals (small, loose groups)
* Intermediate between solitary and school
* “Aggregation but without synchronization”
