fish swimming
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Swimming and Morphology
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Swimming - modes
Anguilliform - using the body plane through undulations; 1 or morewavelengths per body length (eel, lamprey, burbot)
Subcarangiform - between 1/2 and 1 wavelength per body length (Salmonids).
Carangiform - less than 1/2 wavelength per body length.
Thunniform - low drag, highly fusiform, lunate tail (tunas and sailfishes)
Ostraciform - Sculling motion of the isocercal caudal fin (Boxfish)
Rajiform - Horizontal undulations of large pectoral fins (rays and skates) Labriform - Thrusting of long pectoral fins in an oaring motion (wrasses)
Amiiform - Vertical undulations of the dorsal fin (bowfin, seahorses, and pipefish)
Gymnotiform - Vertical undulations of anal fin (knifefish)
Balistiform - Simultaneous vertical or horizontal undulations of dorsal and anal fins(triggerfish, halibut, and some cichlids)
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Swimming - modes
Functional Morphology Plane Cruisers (Active species, Jobling p 256)
Accelerator(Fast-start performance,Jobling p 262
Maneuverer (Sunfish)
Generalist (Jobling p 263)
Continuum of swimming modesUndulatory to Oscillatory and everything in between
Undulatory is wave motion created in fin or body
Oscillatory is the pivoting of a fin on a stationary base
Functional Morphology
Plane
Cruiser
Accelerator
Maneuverer
Generalist
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Performance Envelope- General
Temperature Tolerance
Acclimation to a giventemperature can
change the temperature
tolerance of a species.
Basically, warm fish can
tolerate higher tempsthan cold fish and cold
fish can tolerate colder
temps than warm fish.
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Species Envelopes-Temperature
Examples oftemperature
preference
envelopes for
several species
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Species Envelopes-Swimming
Oxygen consumption
increases withtemperature increase
Note the change in
standard (basal)
metabolic rate (lower
line) as temperature
increases, and active
metabolic rate (upper
line).
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Poikilothermia
fish are cold-blooded
can raise their body temp through exercise a little, butwarmth soon lost at gills
All organisms warm as they increase respiration
Some fish like the tunas actually can regulate and use
the heat liberated from their exercise to maintain body
temp.
Tunas have vast networks of blood vessels in their muscle
that can be constricted or dilated to increase blood
passage over muscle.
This allows tuna to heat their bodies in cold water or cool
them in warm waters.
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Ecomorphology
Ecomorphology - The study of how abiotic orbiotic factors influence the form orshape of an orga nism.
Any theory of species formation that fails to explain the intimate tie-up that exists between habitat and characters is atthe leastincomplete. Hubbs 1941
Example: Body shape types and swimming
Fusiform: idealized torpedo shape, lowest amountof drag (ex. Trout). Allows fast swimming/tolerance of flowing water.
Dorso-ventrally compressed: flattened on the back and belly (ex.Sturgeon, flounder, rays). Benthic species that lay on the bottomand/or use the current as a hydrofoil
Laterally compressed:flattened on the sides (ex. Centrarchids). Predators that need stability forattacks and maneuverability.
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Ecomorphology- Competing theories
Two competing theories of how ecomorphology works:
Natural selection weeds out unfit individuals and retains the fraction
of the population that best conforms to existing conditions.
OR
Ecological Polymorphism may allow members of a population to
avoid selective pressure by changing their shapes within a
morphologic space to match existing conditions. Plasticity
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Ecomorphology Important to understand what defines the grouping of individuals
1) Species are groups of actual or potential interbreeding natural populations which are reproductively
isolated from other groups (Mayr, 1963)
2) Sub-speciesor races are differentiable from species only in that they can occur with conspecifics yetmaintain their own specific genome and phenotype
3) Strains most likely arose from stocks, but have differentiated enough to display reproducible physiological,
morphological, or performance characteristics that are significantly different from other conspecifics
4) Stocks or sub-populations may arise or be present that partition themselves in response to both abiotic
and biotic factors or are simply isolated from each other
5) Population is defined as a group of organisms occupying a defined area that interbreed regularly and
maintain a randomly variable gene pool
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Ecomorphology: 5 Measurements
Measuring ecomorphometrics? (Chapt 7, 8, & 9 in Cailliet et al.)
Simple distance measurements
Meristic counts
Planar distortion (Truss Analysis)
Fineness Ratio
Performance Testing (relevance of differences measured)
Confounding factors
Sexual Dimorphism (males and females have different forms)
Allometric Growth (ratios and proportions change with size)
Condition (plumpness)
Reproductive changes (salmon, cyprinids; girth)
Natural latitudinal clines (strains - LMB)
Availability of historical collections Fixation and Preservation (shrinkage)
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Ecomorphology: Distance
Distance ratios
eye measurements: may relate to water clarity or mode
of feeding
head measurements: length may relate flow or feeding
fin lengths: related to flow and feeding mode
bone length: related to development period and habitat
mouth length (Gape): related to prey
intestine length: related to diet
brain length: different lobes proportional to their need
for use
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Ecomorphology: Merstics
Meristic Counts
Jordans Rule - latitudinal cline in number of a structure Pleomerism - number of a structure associated with size
Meristic counts can change in two ways
selection for or against a meristic characteristic
embryological development time
rarely - a mutation is incorporated into the population
meristic variation can be cause by:
temperature (vertebrae, fins)
diet (fin rays)
habitat (scale rows, number of scales) stress (all)
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Ecomorphology: Truss
Truss Analysis - a way to detect slight shape distortion in all directions of a 2-
dimensional plane
landmarks are chosen atdiscrete locations.
Points are individually measured or digitized to give Cartesian coordinates. All angles
and distances can be calculated from the Cartesian coordinates.
Data is analyzed using principal components analysis which creates new variables
based on combinations of the raw data to give values that represent dimensions of
shape. Individual length variation is accounted for by shearing first component
Components can be used to determine slight shape distortions between groups not
plainly visible to the naked eye or measurable with simple distances
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Ecomorphology: Fineness
Fineness ratio = L/D where L is standard length and D is greatest
body diameter.
Optimal FR is 4-5, but a range form 3-7 only results in a 10%change in drag.
Fineness Ratio is related to microhabitat and flow (Scarnecchia 88)
In areas where the flows are minimal and pool habitat is available or in
lakes, community-wide fineness ratios are low.
In areas where the flows are high and habitats are channelized,community-wide fineness ratios are high.
Importance: when habitats are modified and made more uniform,
species with certain fineness ratios are selected against. The result
is a decrease in species richness.
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Ecomorphology: Performance
Performance testing - the only way to validate the
significance of morphological differences is to test
performance. Is there and advantage or disadvantage)
associated with a particular form?
Laminar flow tube
Duration (how long they can last at flow X)
Tolerance (flow at which they can no longer maintain their
swimming)
Translocation experiments (plasticity test)
switch the hatching site eggs from two different groups
if parental characteristics are retained, genetic change has
occurred
if characteristics reverse, then habitat is deterministic and
ecomorphological polymorphism is the explanation: plasticity
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Ecomorphology: applications
Management Applications
Measurement of the effect of anthropogenic changes to habitat Differences which may give advantages to one group over another (Dont
stock riverine SMB in a small impoundment with lentic SMB)
Hypolimnetic effluent (COLD) from dams can cause developmental changesthat may be poorly adapted to warm water river reaches
Realization that certain habitat characteristics are a necessity, not just artifactof the environment for species (sturgeon and chubs need flow; sunfish cant
deal with flow very well.
Fields of biology that study ecomorphology Systematics - study of evolutionary & genetic relationships among organisms
Phenitics - The study of phenotype display and differences
Cladistics - study of sequential branching and relationship of similar species
Phylogentics - The study of the evolutionary lineage of an organism
Paleobiology - study fossils and how they fit into the evolutionary landscape
Genetics - The study of the molecular history and evolution of organisms