Final answer:
Overfishing threatens the fishery ecosystem by causing ecological restructuring, habitat destruction, loss of biodiversity, and negative socio-economic impacts.
Step-by-step explanation:
Husband feels that overfishing threatens the entire fishery ecosystem because it leads to a radical restructuring of the marine ecosystem. Dominant species that are over-harvested become ecologically insignificant, causing a ripple effect that negatively impacts other species in unpredictable ways. Overfishing not only affects biodiversity but also damages the livelihood of local fishing communities, increases cost of living, and has long-lasting effects on aquatic systems as sources of food. Furthermore, fishing gears can cause habitat destruction, particularly in benthic ecosystems. The phenomenon of fishing down the food chain occurs as larger species become scarce, forcing fisheries to target smaller species, which compresses the marine food web and endangers large marine vertebrates.