Editor's note: Mark Tupper, an assistant professor at the University of Guam on the island of Guam in the Western Pacific, wrote the following perspective piece in response to the Roberts et al. article in Science. Tupper serves as coordinator of the Marine Protected Areas Research Group at the University of Guam Marine Laboratory.
By Mark Tupper, University of Guam
Many scientists agree that tropical fisheries in developing island nations, such as St. Lucia, stand to gain the most from no-take marine reserves. Many of these island fisheries are seriously overexploited and have little or no management of their reef fish stocks. In such cases, where no-take marine reserves are established they serve as the primary (in some cases sole) controls of catch and effort. It seems obvious that any management regime will produce increased yields over no management at all, and for developing tropical nations with several hundred or more species of reef fish, no-take marine reserves might be much easier to enforce than a complex set of catch limits, size limits, and gear restrictions. However, the St. Lucia example is specific to coral reef fisheries and does not prove the global utility of no-take marine reserves to fisheries.
The Florida Fish & Wildlife Conservation Commission instituted stringent regulations on the recreational fishery for red and black drum and spotted seatrout in the late 1980s. Red drum was declared a protected species in 1985 and black drum was declared a restricted species in 1989. Currently the bag limit for red drum is one fish per person, with a slot limit of 18-27 inches long. The Merritt Island NWR is producing trophy-size fish to a small area around Cape Canaveral, but what effect have the existing regulations had on mean sizes of red and black drum along the entire Florida Atlantic coast?
Data collected by the Marine Recreational Fisheries Statistics Survey show that there was a noticeable increase in the mean length and weight of red drum and black drum in east Florida over the past 20 years. For black drum, the mean weight was less than 1.0 kg for most of the early 1980s but was 2.0 kg in 2000 and again in 2001. Mean weight of red drum also increased from less than 1.0 kg in the early 1980s to a mean of around 2.0 kg through the late 1990s and 2000, reaching a mean of 2.2 kg in 2001. This shows that, whereas an MPA can provide trophy size fish to a limited area outside its boundaries, traditional fisheries management techniques can result in size increases across the entire fishery.
Although the examples discussed by Roberts et al. demonstrate the potential benefits of marine reserves to fisheries, the fact is that the great majority of them have not succeeded in meeting their management objectives, even in tropical coral reef systems. Indeed it is rather surprising that the fairly abysmal performance of MPAs has been the basis for a global movement towards marine reserves for fisheries management. Current estimates place the number of "paper parks" at over 80-90% in some countries, and rich nations have fared no better than poor ones. Rather than charging ahead to create hundreds of new MPAs, it makes sense to determine (1) whether or not a no-take marine reserve is the best management strategy for a particular fishery, and (2) how we can better implement and manage current MPAs so that they reach their stated objectives.
For more information:
Mark H. Tupper, University of Guam Marine Laboratory, UOG Station, Mangilao, Guam 96923, USA. Tel: +1 671 735 2185; E-mail: mtupper [at] guam.uog.edu; Web: www.uog.edu/marinelab/mpa/.