Scientists have been studying four populations in one area of the Atlantic Ocean. In this area, both tuna and dolphins eat squid, and squid eat herring (a type of fish).

The data shows that recently the tuna population increased. How will the increase in the tuna population affect the other populations? Be sure to explain whether the dolphin population, the squid population, and the herring population will change, and why.

the squid population could decrease, because the tuna population is increasing and they would eat more squid, so the dolphin population would also decrease because there would be less squid to eat, and because there are less squid the herring population would increase.

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marianaegarciaperedo marianaegarciaperedo · Answer 2 · 2021-12-07T15:45:57+01:00

In trophic webs, there is an equilibrium between species until a change occurs. The increase in tuna's population causes a decrease in dolphins' and squids' populations, and an increase in herring's one.

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To answer this question, let us first review some theoretical framework.

The trophic web is a relationship process between different organisms, through which occurs transference of energy.

The ones placed at lower levels pass energy to the ones at the higher levels.

Organisms at each level feed on the preceding one and become food for the next one.

The first link corresponds to a producer organism -autotroph-.

The following links are the consumers -heterotrophs-: herbivores and carnivores.

The last links are the decomposers that degrade organic matter from dead organisms.

As it is a web, all organisms are equilibrated until a change occurs.

When the change affects any of the involved links, there can be a cascade effect on the web.

A change in a link population size (increasing or decreasing) will affect the superior links and the immediately anterior link.

Also, when two or more species are competing for the same source of food, a change in any of the population sizes will affect the other ones.

Now, let us analyze the exposed example.

We know that,

tuna and dolphins eat squid,

squid eat herring.

We need to figure out what is the cascade effect caused by the increase in the tuna population.

Tuna and Dolphins

We know that tuna and dolphins compete for food items -squids-.

An increase in the number of tuna individuals means a higher competition pressure for dolphins.

The more tuna there are, the more squids they eat, and the less food available there is for dolphins.

Since there are not enough squids for dolphins, their population decreases in size.

Dolphins are negatively affected by tuna's increase.

**** Tuna population increases ⇒ Dolphins population decreases ****

Tuna and Squids

Tuna applies a significant predation pressure on squids, which are their main source of food.

The more tuna there are, the more squids they eat.

Squids probably can not reach sexual maturity or do not get to successfully reproduce, because they are eaten by tuna.

So squids population is negatively affected by the tuna population increase.

**** Tuna population increases ⇒ Tuna population decreases. ****

Herring and Squids

Since squids feed on herring, any change in squids' population size affects herrings directly.

When the squids' population decreases in size, the herring population increases. More fishes get to survive and successfully reproduce.

The predation pressure of squids on herring decreases.

The herring population is positively affected by the squids' population decrease.

*** Squids population decreases ⇒ Herring population increases. ***

Summing up, the cascade effect is as follows,

Tuna population increases
Dolphin population decreases
Squids population decreases
Herring population increases

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You can learn more about trophic webs at the following link: https://brainly.com/question/516534?referrer=searchResults