User:Bcharette17/Planktivore

Factors affecting Planktivory

Habitat characteristics (including light and oxygen availability) and alternative feeding mechanisms that some planktivorous species may possess modulate planktivory

Light penetration into aquatic systems plays a significant role in predator-prey interactions, and has a strong correlation to the ability of visual predators (such as walley, Sander virteus) to consume prey. Plantivore's consumption is magnified in well lit aquatic environments based on their ability to recognize visual cues that help them detect the presence of prey. While predation is not fully inhibited in the absence of light, it is greatly diminished when light penetration falls below measurable levels. However, some planktivores, such as invertebrate planktivores, are still able to recognize and consume prey through tactile detection in low light environments

In addition to light dependency, planktivores are also obligated to the concentration of oxygen at different zones within a stratified system. While many planktivores are able to detect hypoxic conditions and migrate to more suitable conditions, their ability to capture prey can still be affected based on the oxygen saturation of the water. Thus, migration of planktivores away from their native area within an aquatic system can produce adverse effects on their ability to effectively capture prey. This can be attributed to competitive exclusion by other organisms, increased predation of planktivores and plankton, and also migration of plankton to hypoxic areas that serve as refuge based on the inability of planktivores to survive in that hypoxic conditions. This migration of predators out of their native zone due to hypoxic conditions not only increases their vulnerability to higher tier predators, but also to commercial fishing. This migration of plankton to safer conditions ultimately affects planktivores' ability to successfully capture food and survive.

Planktivores can target solely phytoplankton (e.g., Daphnia. spp) or zooplankton (for example, alewife, Alosa pseudoharengus), or switch to omnivory by feeding on both types of plankton, thus feeding at multiple trophic levels [4]. The switch in feeding strategies can benefit both the population of planktivorous fish, as well as that of zooplankton, by acting as a stabilizing effect for the ecosystem [4]. This prevents overexploitation of plankton, and can mediate the dramatic shifts in limit cycles of plankton.

References

Ali, M.A (1959). "The ocular structure, retinonomotor and photo-behavioral responses of juvenile Pacific salmon". Canadian Journal of Zoology. 37 (6): 965–996. doi:10.1139/z59-092.

Pangle, K.L; Peacor, S.D. "Light-dependent predation by the invertebrate planktivore Bythotrephes longimanus". Canadian Journal of Fisheries and Aquatic Sciences. 66 (7): 1748–1757.

Stone, Joshua; Pangle, Kevin; Pothoven, Steven; Vanderploeg, Henry; Brandt, Stephen; Höök, Tomas; Johengen, Thomas; Ludsin, Stuart. "Hypoxia's impact on pelagic fish populations in Lake Erie: a tale of two planktivores". Canadian Journal of Fisheries and Aquatic Sciences. 77 (7): 1131–1148.

Brandt, S.B; Costantini, M; Kolesar, S; Ludsin, S.A; Mason, D.M; Rae, C.M; Zhang, H (2011). "Does hypoxia reduce habitat quality for Lake Erie walleye". Canadian Journal of Fisheries and Aquatic Sciences. 68 (5): 857–879. doi:10.1139/f2011-018

Attayde, J.L; van Nes, E.H; Araujo, A.I.L (2010). "Omnivory by Planktivores Stabilizes Plankton Dynamics, but May Either Promote or Reduce Algal Biomass". Ecosystems. 13: 410–420.