Monitoring requirements for the management of Spanish mackerel (Scomberomorus commerson) in Queensland

Abstract

Spanish mackerel is an important commercial and recreational species with a total Queensland annual catch of approximately 1100-1500 tonnes. Recent research has divided the fishery into at least 3 stocks; an east coast stock that provides more than 85% of the total Queensland catch as well as stocks in the Torres Strait and the Gulf of Carpentaria. On the Queensland east coast, catches are virtually identical (in terms of total weight) between recreational and commercial sectors with the largest commercial landing coming from the Lucinda area on the north coast, whereas most of the recreational catch is taken from the south.

The current stock assessment for the east-coast Spanish mackerel fishery utilises an age-based population model that requires inputs on commercial and recreational total catches as well as representative catch age structures. These data currently come from a range of sources but rely heavily on the CFISH and RFISH databases as well as fishery dependent length and age data collected from the commercial sector by the Queensland Fisheries Service (QFS) through its Long Term Monitoring Program (LTMP). The LTMP sampling strategy has changed slightly since it began in 1999 but has essentially involved collecting fishery dependent samples of Spanish mackerel lengths and ages from the commercial sector at Lucinda during the spring/summer spawning period. There has also been sampling in the Torres Strait (although this has now ceased) and some preliminary sampling in the Gulf of Carpentaria.