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Thread: Garrick - Recent stock assessment

  1. #1
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    Default Garrick - Recent stock assessment

    How is our garrick/leervis stock doing? Results of a recent stock assessment conducted by ORI.

    By Bruce Mann and Daniel Smith

    The limited distribution range of garrick or leervis (Lichia amia), its popularity as a gamefish to all sectors of the recreational fishery and the degradation of many estuaries which function as important nursery areas for this species, has aroused concern by anglers, fishery managers and scientists about the stock status of this species. Other than a preliminary investigation conducted by ORI in 1992 into the age, growth and stock status of L. amia (van der Elst et al., 1993), surprisingly little research has been undertaken on this important angling species. Considering the value of garrick and the need to provide a scientific basis for its future management, a comprehensive stock assessment was recently undertaken by Daniel Smith, a MSc student from the University of KwaZulu-Natal under the supervision of Bruce Mann and Rudy van der Elst from ORI. The focus of this study was to investigate the age, growth, movement and stock status of garrick in South African waters.

    Some of the key findings of this research project were as follows:

    • Based on ageing of otoliths and analysis of growth rate determined from tag-recapture data, garrick was found to be a relatively fast growing species reaching a maximum age of 10+ years.
    • Based on tag-recapture data, movement behaviour of garrick consists of a resident, estuarine dependent juvenile phase and a highly migratory adult phase with adults migrating to KZN to spawn during the winter months and returning to cooler Cape waters in early summer.
    • Trends in catch rates of garrick were determined from the analysis of data stored on the National Marine Linefish System (NMLS) and the Boat Launch Site Monitoring System databases. This analysis showed a decreasing trend in catch per unit effort (CPUE) of garrick along the KZN coast over time for all sectors of the KZN marine recreational linefishery (i.e. shore fishing, recreational skiboat fishing and spearfishing).
    • Growth parameter estimates and catch data were used in undertaking a per-recruit assessment of the garrick stock in South African waters. The spawner-biomass-per-recruit (SBPR) model indicated that the garrick stock is currently at approximately 14% of its unfished level!

    These results came as a shock to scientists who had previously determined that the garrick stock was in relatively good shape due to is fast growth rate. In terms of the Linefish Management Protocol, this means that the garrick stock has collapsed (i.e. there may now be too few adult fish left to ensure successful spawning and recruitment of juveniles to sustain the population). Appropriate management action is therefore urgently needed to help rebuild the stock. There are a number of management options available which could be used to achieve this. These include one or more of the following: reduce the daily bag limit to one fish/angler/day; increase the minimum size limit to 90 cm TL; introduce a slot size limit with a minimum size of 80 cm TL and a maximum size limit of 100 cm TL; introduce a closed season from 1 October to 30 November; establish estuarine protected areas where juveniles of this species are fully protected.

    The decision, on which of the above management options should be implemented, needs to be taken by the responsible government scientific and management working groups at Marine & Coastal Management (MCM). These decisions should then be passed through a forum fully representative of all user groups such as the South African Marine Linefish Management Association (SAMLMA) to ensure user endorsement before legislation is implemented.
    References cited:
    VAN DER ELST, R.P., GOVENDER, A. and S.A. CHATER 1993 - The biology and status of the garrick (Lichia amia). In Fish, Fishers and Fisheries. Proceedings of the Second South African Marine Linefish Symposium. Beckley, L.E. and van der Elst R.P. (Eds.).

  2. #2
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    Very interesting, thanks for posting. Hmmm, maybe someone should tell the spearos:



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  3. #3

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    It's a frikkin shame to kill a fish like that.

  4. #4
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    Quote Originally Posted by Michael View Post
    It's a frikkin shame to kill a fish like that.
    I agree Michael. Its far better to watch him swim away after a successfull release.
    Disclaimer.... none of my posts are intended to be "expert advice"..just opinions from someone who is willing to help where he can.

  5. #5
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    Quote Originally Posted by Michael View Post
    It's a frikkin shame to kill a fish like that.
    i wholeheartedly agree with this viewpoint. And it's the same when i see people wanting to catch and keep big steenbras (all species) kob and especially those monster marlin.
    at the rate homo sapiens are going to F@ck evrything up in double quick time!

  6. #6
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    I don't think that anyone (on this forum) will agree to killing those big garrick. But I think one needs to look at this thing holistically. I think rock and surf anglers kill much more garrick than spearo's. Especially in KZN.

    Like the artickle suggests, the only way garrick stocks can recover is more catch restictions.

    I would suggest a no-kill period of a few years.

    Worked for stripers in the US.

  7. #7
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    HI Conrad,

    I just cant understand it. When I was in my twenties ( 30 yrs back) we here in the E.C. practised C.A.R. with most species, the leerie was top specie as well. To this day even R &S fishing clubs practice C.A.R. of especially leeries , even with competitions. Fish are measured, tagged and released. Same goes for the ''poenskop'' or black mussel cracker, just to mention another specie. Even our Spero club in those days had restrictions here, parrot fish was also added as a no/no specie to the ones i Have already mentioned.

    Sad stats anyways, just shows us, stricter rules and penalties are really needed.

    DAVE
    Handle every situation like a dog.- If you cant hump it, piss on it and walk away. --JASPER.

  8. #8
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    Quote Originally Posted by poppernel View Post

    To this day even R &S fishing clubs practice C.A.R. of especially leeries , even with competitions. Fish are measured, tagged and released. Same goes for the ''poenskop'' or black mussel cracker, just to mention another specie. Even our Spero club in those days had restrictions here, parrot fish was also added as a no/no specie to the ones i Have already mentioned.

    DAVE
    Hi Dave

    I know many Rock & Surf anglers release their catches. And many spearos go for 'green' species, like yellowtail etc and don't kill garrick, for instance.

    But like firephish's pics shows, not everyone. That's why I posted Bruce Man's article - to hopefully encourage a greater conservation ethic.

  9. #9
    Booger Rose Banned User

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    Conrad, almost all the R&S guys I fish with have always promoted C&R with garrick. It is just a really badly hooked fish that will not be returned.

    I'm with you on the issue that a lot of fish do not get returned, and I've seen a lot of garrick being taken out especially in Natal, but in the Garden route and Eastern Cape, the fish mostly get released again, in my experience. I won't dump this problem on R&S fishing alone, but on individuals withing all areas of fishing that do not practice C&R. As long as it is legal to keep a fish within it's sizelimits etc. you will always get people that keep the fish.

  10. #10
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    i spoke to a chap who spearfishes at breede.he reckons the leeries swim right up against the spear.they arent skittish under water.makes them to easy a target.also sea fisheries must come to the party.our trip to george area,2 weeks ago.the locals there wont think twice bout keeping a bag of juvenile fish.need inspectors 2 get out there and do there job.or even just mantain visible policing.
    stephen is wishing he was fishing location x right now.......



    Stephen Smith

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