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Arrow squid – stock variability, fishing techniques, trophic linkages - facing the challenges

Project number: 2006-012
Project Status:
Completed
Budget expenditure: $261,120.00
Principal Investigator: Patti Virtue
Organisation: University of Tasmania (UTAS)
Project start/end date: 8 Aug 2006 - 30 Nov 2010
Contact:
FRDC

Need

This project will address key aspects from four highly ranked SSJF research priorities as established by SquidRAG in 2005:

1. Understanding spatial distribution and the effects of environmental variability on squid.
2. Entrapment versus attraction, discovering the biological differences between jig and trawl caught squid.
3. Growth, reproduction, mortality and productivity
4. Squid predator-prey relationships

Research needs for the newly proposed targeted mid-water trawl squid fishery for the GAB will also be addressed.

This project also sits squarely within two strategic goals within the FRDC R&D Program 1 Planned Outcome- Natural Resource Sustainability: (1) “To increase and apply knowledge of the biology of fish and their ecosystems” and (2) “To increase and apply knowledge of interactions between fish and their ecosystems”.

Previous research has established important biological parameters for arrow squid, it has also highlighted large temporal and spatial variability. This variability coupled with the extreme fluctuations in fishery production hinders successful management.

Understanding the role the environment plays in arrow squid population dynamics will help develop models and pinpoint periods when conditions are conducive to squid growth and recruitment.

Understanding whether different techniques (jig vs. trawl) target different components of the population is significant especially for future policies on total allowable effort (TAE).

Understanding squid diet is also important for ecosystem management (ie.; especially for the proposed GAB fishery that will also be harvesting potential prey).

It was recognised at the Canberra meeting that Australia does not have the capacity to undertake broad-scale pre-season recruit net surveys, but using both light trapping of recruits and ecosystem modelling were seen as feasible techniques for understanding recruitment and stock fluctuations.

Both the SquidMAC and the SquidRAG see ongoing research as extremely important for future informed management of the fishery.

Objectives

1. To investigate the influence of environmental and oceanographic variables on arrow squid growth and recruitment
2. To investigate the ecology, population dynamics of squid in the newly proposed mid-water trawl GAB fishery
3. To compare the biological composition of jig and trawl-caught squid
4. To describe the key components, spatial and temporal variability and environmental influences on the diet of arrow squid
5. To assess the use of light traps as samplers of juvenile squid recruitment
6. To develop an ecosystem model based on squid predator-prey relationships for squid stock assessment
7. To provide SquidMac with better information on environmental influences on stock fluctutations to assist in determining trigger points for the fishery
8. VARIATION TO CONTRACTOBJECTIVE 5 "To assess the use of light traps as samplers of juvenile squid recruitment" is still an objective of teh project but has been discontinued beacue this method was considered inappropriate as arrow squid were not attracted by the light traps"
9. VARIATION TO CONTRACTOBJECTIVE 3: "To compare the biological composition of jig and trawl-caught squid"

Final report

ISBN: 978-0-646-55590-4
Author: Patti Virtue
People
PROJECT NUMBER • 2005-307
PROJECT STATUS:
COMPLETED

International symposium on cephalopod lifecycles: biology, management and conservation

The University of Tasmania was invited to host the 7th triennial symposium of the Cephalopod International Advisory Council (CIAC) in February 2006. This is the premier international cephalopod symposium attended by scientists, industry, and managers from around the world. The...
ORGANISATION:
University of Tasmania (UTAS)

Arrow squid in southern Australian waters - supplying management needs through biological investigations

Project number: 1999-112
Project Status:
Completed
Budget expenditure: $177,075.00
Principal Investigator: George Jackson
Organisation: University of Tasmania (UTAS)
Project start/end date: 25 Jul 1999 - 10 Jun 2004
Contact:
FRDC

Need

The recent steps by AFMA to commence discussions on squid management issues and the recent formation of the SquidMAC underpin the increasing importance of squid as a fishery target. Australian fishery managers are in a unique position to obtain basic biological data on arrow squid before they are subject to considerable pressure. In the next several years managers will be faced with developing policy for sustained squid exploitation. However, currently there is scanty biological information with which to base sound scientific management decisions.
There are 3 main needs for the sustained development of the arrow squid fishery:

1) age and population dynamics
Dunning (1988) noted that a more thorough understanding of squid life histories and population dynamics is an essential prerequisite to responsible management of the existing and potential commercial fisheries for ommastrephid squids. There has been no ageing research on Australian arrow squid. We therefore don’t know how old they are, how fast they grow, what their form of growth is and when they hatch. The use of statolith ageing techniques has revolutionised our understanding of squid age, growth, population dynamics. We now know that life spans are measured in days not years (eg. Jackson & Choat 1992, Jackson 1994). Managers therefore face the unique problem of dealing with a completely new population each fishing season. Moreover, squid are known to show extreme plasticity in growth depending on the season of hatching (eg. Jackson et al. 1997).

2) maturity and reproduction
It is currently unclear where, when and how often arrow squid spawn. Furthermore, the effect that reproduction has on body condition or tissue integrity is unknown. Such information is relevant to the timing of fishing effort and condition of squid caught.

3) genetics
An important question is: what is the genetic structure of arrow squid in Australian waters? This is especially relevant now that arrow squid are managed as a Commonwealth fishery. Currently, we do not know if arrow squids form a single population or whether there are discrete stocks within Australian waters, and whether the population is static or migratory. Furthermore, is the arrow squid stock in Australia genetically distinct from arrow squid stock in the northern waters of New Zealand? Although the northern population of arrow squid in New Zealand is the same species found in Australia (Nototodarus gouldi) we have no information on whether there is mixing of the two populations. If the two countries share the same genetic pool than management considerations take on international significance. The genetic structure of squid is further clouded by their high incidence of cryptic speciation.

This project fits squarely within FRDC’s strategic priority of Program 1: Resources Sustainability. This work will therefore provide needed data for priority areas of knowledge of wild fish resources for sustainable management, general biology and genetics and stock definition (FRDC 1996).

References:

Dunning, M.C. (1988). Distribution and comparative life history studies of deepwater squid of the family Ommastrephidae in Australian waters. PhD. Thesis, University of Queensland.

Jackson, G.D. (1994). Application and future potential of statolith increment analysis in squids and sepioids. Can. J. Fish Aquat. Sci, 51: 2612-2625.

Jackson, G.D. & J.H. Choat (1992). Growth in tropical cephalopods, an analysis based on statolith microstructures. Can. J. Fish. Aquat. Sci., 49: 218-228.

Jackson, G.D., J. W. Forsythe, R.F. Hixon & R.T. Hanlon (1997). Age, growth and maturation of Lolliguncula brevis (Cephalopoda: Loliginidae) in the Northwestern Gulf of Mexico with a comparison of length-frequency vs. statolith age analysis. Can. J. Fish. Aquat. Sci., 54: 2907-2919.

Objectives

1. Undertake extensive statolith age studies to determine validated age, growth rates and life spans of arrow squid throughout the fishing region both spatially and temporally
2. Assess rates and timing of maturity, and the effect that the maturation process has on muscle growth and body condition of arrow squid.
3. Identify squid stocks using genetic tools to determine if there is a single or multiple stocks and whether the Australian stock is separated from the New Zealand stock

Final report

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