Overexploitation

The population gains 2,000 individuals per year through reproduction. The population loses 3,500 individuals per year through fishing.

Net change per year $=2000-3500=-1500$ individuals. A negative net change means the population is shrinking each year.

Overexploitation occurs when a species is harvested faster than it can reproduce or recover. Here, the harvest rate (3,500) exceeds the reproduction rate (2,000), so this is overexploitation.

The population will decline because more individuals are being removed each year than are being added through reproduction.

We need to determine the long-term trend of a fish population where reproduction adds 2,000 fish per year and fishing removes 3,500 fish per year.

The option stating the population remains stable is incorrect — stability requires the harvest to equal the reproduction rate. Here $3500\ne 2000$, so stability is impossible.

There is no biological mechanism by which fishing stimulates faster reproduction. This option is biologically unsound.

The option saying decline only occurs 'if fish are caught before they reproduce' adds an unnecessary condition. Since harvesting already exceeds reproduction regardless of timing, the population declines unconditionally.

The correct answer is that the population will decline because the harvest rate exceeds the reproduction rate — this directly matches the definition of overexploitation.

Species are most vulnerable to overexploitation when they have late sexual maturity and low reproductive output. These traits mean populations recover very slowly when individuals are removed.

An animal that matures at age 12 and produces only 2 offspring every 3 years has both late maturity and very low output. Compare this to an animal maturing at age 1 that produces 500 eggs — that population recovers quickly.

The species with late maturity and low reproductive output is by far the most vulnerable. This matches real examples like sharks, elephants, and whales.

The question asks which biological characteristic creates the greatest vulnerability to overexploitation — we need to look for traits that slow population recovery.

A species with early maturity and high reproductive output recovers quickly from population losses — this describes a resilient species, not a vulnerable one.

A wide habitat range reduces vulnerability because individuals can persist in undisturbed areas. This is a protective trait, not a risk factor.

A large natural population provides a buffer against exploitation — more individuals means the population can sustain greater losses before collapsing.

Late sexual maturity (age 12) and very low reproductive output (2 offspring per 3 years) is the correct answer — both traits severely limit how fast a population can recover from harvesting.