Planktivore
[15] As an important source of revenue for humans through tourism and commercial uses in fisheries, many conservation efforts are going on globally to protect these diverse animals known as planktivores.
[22][19] Due to their environmental requirements for light and nutrients, phytoplankton are most commonly found near continental margins, the equator, high-latitudes, and nutrient-rich areas.
[25] Zooplankton are, in turn, common prey items for planktivores; they respond to environmental change very rapidly due to their relatively short life spans, and so scientists can track their dynamics to understand what might be occurring in the larger marine food web and environment.
[16][34] Planktivorous seabirds can be indicators of ecosystem status because their dynamics often reflect processes affecting many trophic levels, like the consequences of climate change.
[17][36] Blue whales were recently found to consume a vast amount more plankton than was previously understood, representing an important element of the ocean biogeochemical cycle.
[7] Obligate planktivores have fewer options for prey choices; they are typically restricted to marine pelagic ecosystems that have a dominant plankton presence, such as highly productive upwelling regions.
[37] Some species actively hunt plankton: in certain habitats such as the deep open ocean, as mentioned above, the planktivorous basking shark (Cetorhinus maximus) track the movements of their prey closely up and down the water column.
[11] The megamouth shark (Megachasma pelagios), another planktivorous species, adopts a similar feeding strategy that mirrors the movement in the water column of their planktonic prey.
[41] Similar to active hunting, some zooplankton, like copepods, are ambush hunters meaning they wait in the water column for prey to come within range and then rapidly attack and consume.
Lau et al.[44] discovered that warming conditions and inorganic nutrient depletion in lakes as a result of climate change decreased the nutritional value of plankton communities.
[3] Scientists also recently discovered the fossilized remains of another ancient organism, which they named the "false megamouth" (Pseudomegachasma) shark, and which was likely a filter-feeding planktivore during the Cretaceous period.
Planktivorous pink salmon are common in the Arctic and the Bering Strait and have been suggested to exert significant control on structuring the phytoplankton and zooplankton dynamics in the subarctic North Pacific.
[36] Little auks are the most common Arctic planktivore species; as they reproduce on land, their planktivory creates an important link between marine and terrestrial nutrient reserves.
[47] This link is formed as little auks consume plankton with marine-derived nutrients at sea, then deposit nutrient-rich waste products on land during their reproductive process.
In contrast to deeper and colder natural lakes, reservoirs are warmer, shallower, heavily modified human made systems with different ecosystem dynamics.
For example, competitive superiority of large zooplankton over smaller species in lake systems leads to large-body dominance in the absence of planktivorous fish as a result of increased food availability and grazing efficiency.
For example, planktivorous minnows in Lake Gatun experienced a rapid population decline after the introduction of peacock bass (Cichla ocellaris).
[4][56] One notable example of trophic control is how planktivores have the ability to impact the species distribution of larval crabs in estuaries and coastal waters.
[58] The physical transport of nutrients and plankton can greatly affect the community composition and food web structure within oceanic ecosystems.
In nearshore regions, planktivores and piscivores have been shown to be highly sensitive to changes in ocean currents while zooplankton populations are unable to tainted levels of predation pressure.
[61] The increasing concentration of some toxins through trophic levels presented here is called bioaccumulation, and this can lead to a range of impacts from non-lethal changes in behavior to major die-offs of large marine animals.
[65] Krill are another example of a planktivore that may exhibit high levels of domoic acid in their system; these large plankton are then consumed by humpback and blue whales.
The Arctic has been hit hard with shorter winters and hotter summers creating less permafrost and rapidly melting ice caps causing lower salinity levels.
Plankton was replaced by solitary Cylindrotheca closterium or Pseudo-nitzschia spp., a common HAB causing phytoplankton, under higher temperature and lower salinity in combination.
According to the Oscillating Control Hypothesis, early ice retreat caused by a warming climate creates a later bloom of copepods and aphids (a plankton species).
This ice melt creates changes in freshwater input and ocean stratification, consequently affecting nutrient delivery to primary producers.
There has been a large shift from piscivorous seabirds such as pacific loons and black-legged kittiwakes to planktivores sea birds such as ancient auklets and short-tailed shearwaters.
Similar to corals, planktivorous reef fish are directly affected by these changing systems and these negative effects then disrupt food webs through the oceans.
In 2021, the take home total profits, before bonuses, actually going into fishermen's pockets, from the Alaskan salmon, cod, flounder, and groundfish fishing season came to $248 million.
In 2017 Alaska pollock was the United States' largest commercial fishery by volume with 3.4 billion pounds being caught and coming in at total value of $413 million.
