Quick questions on Fisheries and marine resource management (QCE Marine Science Unit 4)

Overfishing is harvesting faster than a population can replace itself, so the stock declines. If it continues, the population can collapse and may not recover even when fishing stops, because too few breeding adults remain. Slow-growing, late-maturing species (such as many sharks and the orange roughy fished in southern Australian waters, which lives for over a century) are especially vulnerable because they replace themselves slowly.

Bycatch is the non-target species caught and usually killed alongside the target catch, such as turtles, dugongs, dolphins and juvenile fish caught in trawl nets. Bycatch can drive declines in species that are not even being fished, which is why turtle excluder devices and bycatch reduction devices are required in Queensland prawn trawl fisheries.

Coral trout are roughly twice as abundant and larger inside green zones than in fished zones; larger fish produce far more eggs, and larvae spill over to restock fished areas; whole-ecosystem protection guards habitat and non-target species too.

Zones must be enforced against illegal fishing; they displace effort into open zones, which can be overfished; and they cannot protect reefs from climate change, acidification or runoff, which cross zone boundaries.

Zoning is highly effective for managing fishing pressure and biodiversity, but it must be combined with water-quality and climate action to protect the reef overall. A judgement like this is what "evaluate" requires.