FishPredation: Difference between revisions
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Size is the most important factor in determining predation rates. For example, there is a decreasing rate of predation with jellyfish as fish larvae size increases. One fish that is commonly found in the Caribbean, the porcupine fish, inflates its body in order to increase its size, therefore decreasing the predators that would be capable of eating it. Predators would have to have a larger jaw in order to eat the porcupine fish. Predation occurs at all sizes of organisms. Microscopic organisms are predators, and so are large whales. The highest rates of predation occur on juvenile fish. This is because predation is most common during life transitions. After fish larvae hatch, the are more susceptible to predators. Fish are also susceptible to predators at another life transition - during mating. <ref name="Hixon">Hixon, Mark A. 1991. Predation as a Process Structuring Coral Reef Communities.Oregon State University Publishing. | Size is the most important factor in determining predation rates. For example, there is a decreasing rate of predation with jellyfish as fish larvae size increases. One fish that is commonly found in the Caribbean, the porcupine fish, inflates its body in order to increase its size, therefore decreasing the predators that would be capable of eating it. Predators would have to have a larger jaw in order to eat the porcupine fish. Predation occurs at all sizes of organisms. Microscopic organisms are predators, and so are large whales. The highest rates of predation occur on juvenile fish. This is because predation is most common during life transitions. After fish larvae hatch, the are more susceptible to predators. Fish are also susceptible to predators at another life transition - during mating. <ref name="Hixon">Hixon, Mark A. 1991. Predation as a Process Structuring Coral Reef Communities.Oregon State University Publishing. | ||
http://hixon.science.oregonstate.edu/files/hixon/publications/026%20-%20Hixon%2091%20Sale%20book.pdf</ref> Most fish are active either during the day or at night, not 24 hours. Their diurnal or nocturnal feeding is normally fixed genetically.<ref name="Houlihan">Houlihan, Dominic. 2001. Food Intake in Fish. Blackwell Science. Pages 189-209.</ref> | http://hixon.science.oregonstate.edu/files/hixon/publications/026%20-%20Hixon%2091%20Sale%20book.pdf</ref> Most fish are active either during the day or at night, not 24 hours. Their diurnal or nocturnal feeding is normally fixed genetically.<ref name="Houlihan">Houlihan, Dominic. 2001. Food Intake in Fish. Blackwell Science. Pages 189-209.</ref> | ||
== Importance of Predation == | == Importance of Predation == |
Revision as of 10:15, 25 February 2015
Fish Predation
Predation Model
- Energy vs. Cost
- Factors Affecting Search:
- For Predator: Hunger
- For Prey: Camouflage
- Factors Affecting Encounter
- For Predator: Swimming speed, water clarity, illumination, schooling, detection mechanisms
- For Prey: Morphology, activity level, pigmentation, distribution
- Factors Affecting Strike:
- For Predator: Alternative prey, location
- For Prey: Body size, sensory ability
- Factors Affecting Capture
- For Predator: Mouth gape, strike speed, handling
- For Prey: Escape capabilities, schooling, shelter seeking behavior [1]
Methods
Prey in an aquatic habitat are harder to capture than those on land due to the difference between the prey and the surrounding medium's density being lower in water; this causes the prey to be pushed away upon approach by a predator. For this reason, fish have developed a variety of methods to become successful predators in water. (need better source)
Suction
When a fish opens its mouth a pressure gradient is created that causes water (and whatever may be in that water) to flow into it. Fish make use of this as a way, called suction feeding, to capture prey. Grouper commonly employ suction feeding as a method of predation.
Ram
Pivot
Protrusion
Filter
Suspension
Lunge
Manipulation
Other Feeding Factors
Size is the most important factor in determining predation rates. For example, there is a decreasing rate of predation with jellyfish as fish larvae size increases. One fish that is commonly found in the Caribbean, the porcupine fish, inflates its body in order to increase its size, therefore decreasing the predators that would be capable of eating it. Predators would have to have a larger jaw in order to eat the porcupine fish. Predation occurs at all sizes of organisms. Microscopic organisms are predators, and so are large whales. The highest rates of predation occur on juvenile fish. This is because predation is most common during life transitions. After fish larvae hatch, the are more susceptible to predators. Fish are also susceptible to predators at another life transition - during mating. [4] Most fish are active either during the day or at night, not 24 hours. Their diurnal or nocturnal feeding is normally fixed genetically.[5]
Importance of Predation
Food Web
Predators help keep the food web in-check. Food webs are divided by trophic levels. Top predators have a “trophic cascade” effect on food webs - having a top-down effect on lower trophic levels. The elimination of predators can cause serious perturbations to an ecosystem. [1]
Important Evolutionary Force
Predation is a strong force of natural selection. The weaker species is eliminated. Fish predation is an important evolutionary force because when certain types of fish are targeted by predators they do not have as great of a survival rate. They are forced to acclimate, and as numbers dwindle and the more advantageous fish win out, and the fish population will evolve over time. [1]
References
- ↑ 1.0 1.1 1.2 1.3 K.M. Bailey, JT. Duffy Anderson. 2001. Fish Predation and Mortality. Encyclopedia of Ocean Sciences (Second Edition). Pages 417-421.
- ↑ A. D. Nunn, L. H. Tewson, and I. G. Cowx. The foraging ecology of larval and juvenile fishes. Hull International Fisheries Institute, Department of Biological Sciences, University of Hull, Hull, HU6 7RX, UK. Published online: 26 October 2011
- ↑ Amsel, Sheri. “Food Webs.” Coral Reef Food Web. Exploring Nature Educational Resource. © 2005 - 2014. April 14, 2014. <http://exploringnature.org/db/detail.php?dbID=2&detID=1221
- ↑ Hixon, Mark A. 1991. Predation as a Process Structuring Coral Reef Communities.Oregon State University Publishing. http://hixon.science.oregonstate.edu/files/hixon/publications/026%20-%20Hixon%2091%20Sale%20book.pdf
- ↑ Houlihan, Dominic. 2001. Food Intake in Fish. Blackwell Science. Pages 189-209.