Commercial and non-commercial use
Reductions in predator populations can have long-term effects on the food chain.
‘uncertain’ or ‘undefined’, including commercially and recreationally important king threadfin, barred javelin, and grey mackerel. The status of other important fishery species, including golden snapper (fingermark), giant queenfish and black jewfish, are not assessed by Fisheries Queensland.42 In a recent ecological risk assessment41, king threadfin are assessed as being at very high risk, and giant queenfish, black jewfish and barred javelin as being at high risk. Reductions in predator populations can have long-term effects57, including direct and indirect effects on the food chain (see Section 3.4.5).58 Changes in predator abundance and behaviour causes changes throughout trophic levels which modify food webs, indirectly acting upon herbivore populations that maintain coral substrates.59 Over half of the weight of the retained commercial catch is comprised of particle feeders (such as prawns and scallops) which fulfil a range of ecosystem roles such as providing prey for other species and assisting with nutrient cycling. Fishing causes lower abundances of some particle feeders, particularly in more heavily trawled areas. The flow-on effect of extraction of particle feeders may include net loss of nutrients from the ecosystem and changes to other ecosystem processes (for example predation through changed feeding opportunities). The amount of effort in the trawl fishery is the main determinant of impacts on particle feeding in the Region. While effort has been relatively low for about the last decade, risks could increase if effort levels rise.53
Predators make up half the retained catch