Which phenomenon leads to the phenomena of 'fishing down the food web' in marine ecosystems?

The phenomenon of 'fishing down the food web' in marine ecosystems refers to a pattern where fishers initially target larger, more desirable fish species that occupy higher trophic levels. As these populations become depleted due to extensive fishing practices, fishermen begin to target smaller fish and other organisms at lower trophic levels. This process has significant implications for the structure and function of marine ecosystems, as it can lead to shifts in species composition and the overall health of the ecosystem.

Overfishing is the key driver of this phenomenon because it directly reduces the abundance of top predator fish and larger species in the marine food web. As these species become less available, the fishing industry inevitably turns to smaller fish and invertebrates that were previously less exploited. This shift can disrupt the balance of the ecosystem, leading to decreased biodiversity and altered food web dynamics.

In this context, other options like climate change, pollution, or dredging may affect marine ecosystems and fish populations but are not the primary reason for the fishing down the food web phenomenon. Climate change can alter species distributions and spawning times; pollution can impact fish health and reproductive success; and dredging can disrupt habitats. However, it is the direct impact of overfishing that most clearly drives the sequential targeting of lower