Open Access Repository

Near real-time spatial management based on habitat predictions for a longline bycatch species


Downloads per month over past year

Hobday, AJ and Hartmann, K 2006 , 'Near real-time spatial management based on habitat predictions for a longline bycatch species' , Fisheries Management and Ecology, vol. 13, no. 6 , pp. 365-380 , doi: 10.1111/j.1365-2400.2006.00515.x.

[img] PDF
Hobday_26_Hartm...pdf | Request a copy
Full text restricted
Available under University of Tasmania Standard License.


Southern bluefin tuna (SBT), Thunnus maccoyii (Castelnau), is a quota-managed species that makes
annual winter migrations to the Tasman Sea off south-eastern Australia. During this period it interacts with a
year-round tropical tuna longline fishery (Eastern Tuna and Billfish Fishery, ETBF). ETBF managers seek to
minimise the bycatch of SBT by commercial ETBF longline fishers with limited or no SBT quota through spatial
restrictions. Access to areas where SBT are believed to be present is restricted to fishers holding SBT quota.
A temperature-based SBT habitat model was developed to provide managers with an estimate of tuna distribution
upon which to base their decisions about placement of management boundaries. Adult SBT temperature preferences
were determined using pop-up satellite archival tags. The near real-time predicted location of SBT was
determined by matching temperature preferences to satellite sea surface temperature data and vertical temperature
data from an oceanographic model. Regular reports detailing the location of temperature-based SBT habitat were
produced during the period of the ETBF fishing season when interactions with SBT occur. The SBT habitat model
included: (i) predictions based on the current vertical structure of the ocean; (ii) seasonally adjusted temperature
preference data for the 60 calendar days centred on the prediction date; and (iii) development of a temperaturebased
SBT habitat climatology that allowed visualisation of the expected change in the distribution of the SBT
habitat zones throughout the season. At the conclusion of the fishing season an automated method for placing
management boundaries was compared with the subjective approach used by managers. Applying this automated
procedure to the habitat predictions enabled an investigation of the effects of setting management boundaries
using old data and updating management boundaries infrequently. Direct comparison with the management
boundaries allowed an evaluation of the efficiency and biases produced by this aspect of the fishery management
process. Near real-time fishery management continues to be a realistic prospect that new scientific approaches
using novel tools can support and advance.

Item Type: Article
Authors/Creators:Hobday, AJ and Hartmann, K
Keywords: Eastern Australia, habitat preference, satellite archival tags, southern bluefin tuna, spatial management.
Journal or Publication Title: Fisheries Management and Ecology
ISSN: 0969-997X
DOI / ID Number: 10.1111/j.1365-2400.2006.00515.x
Additional Information:

"The definitive version is available at"

Item Statistics: View statistics for this item

Actions (login required)

Item Control Page Item Control Page