Assessing the feasibility of using 'by-product' data as a pre-recruit index in South Australia's southern calamary (Sepioteuthis australis) fishery
Steer, M.A.; Lloyd, M.T.; Jackson, W.B. (2007). Assessing the feasibility of using 'by-product' data as a pre-recruit index in South Australia's southern calamary (Sepioteuthis australis) fishery. Fish. Res. 88(1-3): 42-50. https://dx.doi.org/10.1016/j.fishres.2007.07.006
In: Fisheries Research. Elsevier: Amsterdam. ISSN 0165-7836; e-ISSN 1872-6763, more
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| Keywords |
Forecasting
Life jackets
Population characteristics > Population structure
Population functions > Recruitment
Cephalopoda [WoRMS]; Sepioteuthis australis Quoy & Gaimard, 1832 [WoRMS]
Marine/Coastal |
| Author keywords |
squid; population structure; life-history; forecast; recruitment |
| Authors | | Top |
- Steer, M.A.
- Lloyd, M.T.
- Jackson, W.B.
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| Abstract |
Trends in spatial and temporal commercial catch, effort and estimates of catch per unit of fishing effort (CPUE) data are currently the only indicators of stock status for the South Australian southern calamary (Sepioteuthis australis) fishery. Time delays associated with collating and analysing these data combined with the squid's sub-annual lifespan means that there is no warning of recruitment failure. Consequently, there is a need for reliable pre-recruit indices that would allow managers to track the status of the fishery and respond quickly to negative indicators in 'real-time'. South Australia is in a unique position as the calamary population is spatially segregated. Juvenile and sub-adults predominantly occur offshore where they are incidentally caught by commercial prawn trawlers operating from December to May, excluding January and February. Spawning adults aggregate inshore where they are targeted by commercial and recreational fishers. A comparison of the size and age structures of the inshore and offshore components confirmed this spatial segregation, revealing that the offshore animals take approximately two months (?55 days) to mature and migrate onto the inshore spawning grounds. A comparison of the mean catch rates of the sub-adults in the offshore prawn fishery with mean CPUE data collected from the inshore commercial fishery, incorporating a 2-month lag, revealed a significant positive relationship. This study suggests that quantifying offshore calamary catch rates, through fishery-independent trawl surveys, provides an encouraging and feasible means of forecasting inshore recruitment into South Australia's calamary fishery. |
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