Sunfish Media Release and rebuttal.

[Lucky_Phill]

Representing the interests of Recreational Fishing
Queensland Recreational Fishers Challenge Scientists' Statements

Members of the peak body representing recreational fishing in Queensland, Sunfish Queensland, are concerned about recent statements and publications from scientists employed by the ARC Centre of Excellence for Coral Reef Studies, headquartered at James Cook University in Townsville.

Two examples are given.

A media release in February this year by the Centre "urged the Australian Federal Government to create the World’s largest no-take marine reserve in the Coral Sea." Such an action would prevent recreational fishing over an extremely large area off the Queensland coastline, and has no scientific justification. View the whole statement on: http://www.coralcoe.org.au/news_stories/coralsea2.html

More recently scientists at the Centre published a strongly worded paper claiming that marine park green zones can make a significant contribution to the replenishment of fish populations in fished areas. See the Centre's media release on: http://www.coralcoe.org.au/news_stor...erveswork.html

An appraisal of this paper by the Sunfish Scientific Officer, Dr. Barry Pollock has questioned the scientific basis for such a claim. The Executive Officer of Sunfish Qld, Judy Lynne has expressed disappointment that scientists at the Coral Reef Studies Centre would use their status to unreasonably support and promote marine park conservation zones at the expense of recreational fishing.

Mrs. Lynne said that Sunfish supports management measures that ensure the sustainability of fish stocks and protect the essential environment, but Sunfish opposes the introduction of unjustified zones which stop recreational fishing.

Science should be independent and not used to make statements that support any particular “Government” or “interest group” position she said. These concerns by Sunfish have been referred back to the Coral Reef Studies Centre, and provided to relevant Government agencies and other stakeholders.

20 July, 2012

Contact Details – Mrs. Judy Lynne Executive Officer Sunfish, telephone 07 38824518 Dr. Barry Pollock Scientific Officer Sunfish email: br_pollock@yahoo.com.au
PO BOX 3013 Warner QLD 4500 Phone (07) 3882 4518
www.sunfishqld.com.au ABN 26 590 693 754
Fishing for the Future
MEDIA RELEASE


Rebuttal to science:-

Does the movement of larval fish from a reserve constitute a fisheries benefit?



Prof. Colin Buxton, Director Fisheries, Aquaculture and Coasts, IMAS University of Tasmania
Assoc. Prof. Caleb Gardner, Program Leader Fisheries, IMAS University of Tasmania
Prof. Bob Kearney, Emeritus Professor University of Canberra


Comment published online by Current Biology on Thursday 21 June 2012.
http://www.cell.com/current-biology/...395-8#Comments


This study claims to provide compelling evidence that no-take reserve networks can make a significant contribution to the replenishment of populations on both reserve and fished reefs at a scale that benefits local fishing stakeholders. We contend that this paper makes several simple and fundamental mistakes, one of which is the basis of much misinterpretation of the benefits of MPAs.


This is that the authors fail to account for the impact of catch and effort displaced from the park to fished areas – that is, they don’t attempt to consider the overall effect, and hence possible benefit of the park.


The interpretation that MPA networks can provide a significant source of recruitment to populations and that this constitutes a benefit to adjacent fisheries is an unsubstantiated conclusion for several reasons:

1. It is expected that egg, and subsequent juvenile production of some species will increase in MPAs when fishing stops, because numbers and size of individuals of some species increase. However, increased numbers and size of fish inside the park comes at the expense of a decrease in fished areas that now experience greater fishing mortality due to catch displaced by the parks (unless catch outside the park is decreased by a separate management action). Harrison’s results suggest that more larvae originate from inside the park than would be predicted by the 28% spatial coverage alone. However this would be expected given the shift in fishing mortality between areas and doesn’t imply any overall improvement. To claim a benefit from the parks it is critical to understand the net effect of the parks on fish density and reproductive output in fished and unfished areas combined. In this case there was no before and after sampling so the effect of the park on total production is unknown.
2. 
   
3. It may well be that the areas that are now closed to fishing have always produced more larvae in the areas that were sampled. That is, source sink dynamics operate in marine systems and were ignored by Harrison. Again, the absence of before and after sampling makes it impossible to examine this possibility.
4. Only two species were sampled and both of these were top predators. It could be expected that the numbers of adults and subsequent larval production of species that are preyed upon by the two species that were studied would decline in areas where predators were more abundant. Assertions of net benefit should accommodate such possibilities and their impacts.
5. Increased larval contribution to an area can only constitute a fishery benefit if there had been insufficient larvae in the area prior to the increase. No evidence has been given of a recruitment limitation on either of the two species studied; nor would one be expected if the density in the fished area is actually at the reported approx. 50% level of that in the unfished area. Stock-recruitment relationships do not usually become limiting until population levels fall well below the 50% reported in this study.
6. Even if the productivity of the selected species in the fished area did increase as a result of the declaration of the reserve, this would only constitute a net benefit to the fishery if the increase in total catch of all species combined exceeded any loss in catch that resulted from closing 28% of the region to all fishing for all species.
7. Even if a net benefit did result from closing the area to all fishing this may well not represent the most efficient means of achieving that benefit; management targeted at individuals species or selected components (gear types?) of the fishery may well provide greater net benefit.

The results of the Harrison et al. (2012) paper in reality do little more than provide some quantification of three fairly well understood processes:

1. Eggs and larvae of many marine fish drift away from spawning areas.
2. Biomass of some species of fish inside a reserve increases because they’re not killed by fishing, and as a result they may produce more larvae. These larvae, because of random movement, are likely to form a greater proportion on the reef adjacent to the reserve.
3. Density of individuals of some species outside the park is reduced by fishing so that larval production of these species may be reduced relative to the unfished state.

None of these observations are novel and collectively they do not imply a net benefit to fisheries.


Ref: Harrison, H.B., Williamson, D.H., Evans, R.D, et al. (2012). Larval Export from Marine Reserves and the Recruitment Benefit for Fish and Fisheries. Current Biology 22, 1023–1028.






LP

[Moonlighter]

I also read the paper that has been criticized above, and wondered how they could be sure, even with genetic coding, that larvae flund outside originated from fish inside the protection zones. I posed that question to a learned marine biologist friend who also shared the same concerns.

I think this is a fairly lightweight study that leaves a fair bit to be explained both in terms of the methodology they used and its veracity, and the points raised by Profs Buxton and Kearney above.

I met and had some dealings with Colin Buxton when he made a important contribution to the MBAA's work on the Moreton Bay zoning. He is an incredibly knowledgeable fellow.

He saw first hand the entrenched, ideological, almost religous position taken by the Govts EPA scientists and their colleagues in the green lobby, and was shocked. He confront them on numerous points, none of which they had anything like credible responses to.

Thanks for posting, Phill.

Grant

[Feral]

James Cook has quite the reputation for "Loony left" academics, there is a woman professor up there whom makes Germain Greer look sane.

Unfortunately there is a very valid reason these looney left scientists congregate in govt and academia, thats because they cant get a job in the real world.