The September 2000 issue of MPA News featured an article on the concept of rotating closed areas: that is, alternately closing and re-opening areas to fishing, allowing time for stocks to rebuild after each open season. With managers and researchers around the world beginning to consider the idea, it could represent an emerging trend in fisheries management.

MPA News asked readers to comment on the idea. Below, we’ve printed three of the letters we received. The first is from Graham Edgar, who was quoted in the September article.

Dear MPA News:

I would like to comment further on the benefits of cyclically re-opening MPAs, as discussed in the last issue of MPA news, particularly your suggestion that declaration of MPAs is primarily to protect (1) fisheries or (2) fish. I also feel strongly that MPAs are and should be declared to protect (3) ecosystems/habitat.

It worries me that your discussion of the benefits of cyclically re-opening habitat for trawling has, for example, ignored the substantive impacts of bottom dredging on sediment geochemistry and benthic habitat structure. In most cases, prohibitions on trawling or dredging are for habitat protection rather than fisheries enhancement, as has occurred off southern Tasmania where a large offshore area with numerous seamounts has been closed to bottom trawling. For this particular region, a CSIRO study* found:

(i) seamounts possessed “a diverse fauna characterized by a large proportion of species endemic to local seamounts”

(ii) “all shallow hills were heavily fished”

(iii) “the substrate of all heavily fished seamounts in the area consists predominantly of either bare rock or coral rubble and sand, and this was not seen on any of the (deeper) seamounts that was lightly fished or unfished”

(iv) “trawl operations appear to have significantly impacted the most heavily fished seamounts, where reef aggregate has mostly been removed from the slopes or turned to rubble.”

Re-opening such areas may have limited benefits for fishermen but certainly would be detrimental from a biodiversity perspective.

In the particular case of the New England scallop fishery [as discussed in the September article], re-opening closed areas to scallop fishers seems a good idea for the scallop fishers, but is bad for conservation of biodiversity because of detrimental ecosystem effects, generally bad for other fishing sectors (e.g., groundfishers get no benefit and an indeterminate loss), and possibly bad for the scallop fishers themselves if regional recruitment is related to stock density.

I would also like to clarify a point with respect to the Galapagos marine reserve. I would not like to see any re-opening of areas in the Galapagos that are presently closed to fishing. On the other hand, I think that closing areas currently open to fishing and re-opening them on a cyclical basis is a good idea. From my experience of Galapagos, Tasmania and elsewhere, it is quite clear that closing any area from fishing requires a huge struggle, hence any suggestion that such areas can possibly be reopened will normally prove counterproductive (especially in the usual case where closure was originally intended to be permanent).

Graham Edgar
Head of Marine Research and Conservation
Charles Darwin Research Station

* Koslow, A.J., Gowlett-Holmes, K., 1998; The seamount fauna off southern Tasmania: benthic communities, their conservation and impacts of trawling. Final Report to Environment Australia and the Fisheries Research Development Corporation, CSIRO, Hobart, Australia.

For more information:

Graham Edgar, Charles Darwin Research Station, Puerto Ayora, Santa Cruz, Galapagos, Ecuador. Email:

Dear MPA News:

Having been on the scene for 50+ years, I’ve heard all the various wake-up calls. It’s almost predictable that the trendy stuff rises up and disappears only to be discovered again by the next generation! Maybe they don’t read, or think history is stupid or whatever. For examples:

1) The greenhouse effect was reported first by French mathematician Baron Joseph Fourier in 1827. It was given the label “greenhouse” by the great Swedish scientist Svante Arrhenius in the 1890s; at this same time Jules Verne was writing about sea level rise! I was first alerted to the effect in the 1950s by the reports of the famous oceanographer Roger Revelle.

2) Same thing with rotational fishing (re MPA News: Re-opening closed areas…). Farmers have been doing this since the creation. Re fishing, this was proved conclusively in the early 1940s! When WW II prevented fishing in the North Sea, fish stocks increased exponentially — and there was a short-lived harvest bonanza in 1945-47. So what is this surprising and “astounding success”? Something unexpected?

As T.S. Eliot once said: “We had the experience but missed the meaning.”

John Clark
Adjunct Scientist
Mote Marine Laboratory

For more information:

John Clark, P.O. Box 420-313, Ramrod Key, FL 33042, USA. Tel: +1 305 872 4114; E-mail:

Dear MPA News:

If fishers wish to close currently fished (overfished) areas for a year or more and then re-open them, and then flog them, that is up to them. It may provide some protection for those overfished areas.

Currently closed areas, however, must remain closed to protect biodiversity and the gene pool. If currently closed and protected areas were opened, they would be fished out in a month. The whole idea seems like a push by fisheries managers to open up new and formerly protected ground.

Pat O’Brien
Wildlife Protection Association of Australia, Inc.

For more information:

Pat O’Brien, WPAA Inc., P.O. Box 1334, Yeppoon Q 4703, Australia. Tel: +61 7 4939 7997; E-mail:; Website: