Technical Information Sheet #22

Published 2002

This page contains background and history of the Representative Areas Program.

• View current Zoning information.

Marine Sanctuaries - A Sustainable Future for our Fisheries

Globally, marine sanctuaries have achieved conservation goals and have resulted in social and economic benefits to fisheries. Some of the most convincing success stories are from places where 10–35% of the total fishing grounds have been protected with, in some cases, evidence of yields increasing beyond prior levels in adjacent areas despite a reduction in fishing grounds (Gell and Roberts 2002). Many fishers who once opposed marine sanctuaries are now their avid supporters. Some fishers have described the implementation of marine sanctuaries as ‘short term pain for long term gain’ (Roberts and Hawkins, 2000).

Sustainable fisheries in sustainable ocean ecosystems require changing the extent to which fishing affects exploited species as well as other high-profile species, habitats and ecosystems (Ward and Hegerl 2003).

Potential benefits of marine sanctuaries for fisheries include:

• Protection of important habitat, spawning areas, aggregation sites and nursery grounds
• Increased stock abundance and spawning biomass
• Increased mean age and size
• Improved reproductive potential
• Enhanced settlement and recruitment of juveniles
• Protection of genetic diversity
• Maintenance or enhancement of yields in adjacent fished areas
• Reduced variability and uncertainty in fisheries yields, and
• Increased likelihood of sustainable exploitation

Ecosystem and precautionary approaches, together with the use of the use of no-take reserves, are key elements of the developing new fisheries-management approach.

Improved reproductive potential

Fish mortality is reduced in marine sanctuaries, many individuals live longer and grow larger than in fished areas, producing many more eggs than smaller fish and spawning more frequently (Roberts and Hawkins 2000). Fecundity (egg production) usually increases exponentially with body size for tropical fishes (Russ 2002) so that older, bigger individuals are extremely important to total egg production and population replenishment (Bohnsack 1993). For example:

• one adult 61cm (12.5kg) female red snapper (Lutjanus campechanus) has the same number of eggs (9 300 000) as 212 females of 42cm (Grimes 1987, Plan Development Team 1990);
• a 500g goatfish reproduces 4 to 5 times more often than a goatfish half its size and has 100 times more eggs (Roberts and Hawkins 2000);
• Adams et al. (2000) and Russ (2002) found significantly older and larger females on reefs closed to fishing in the GBRMP, and Mapstone et al. (2003) found that the two main target species of the reef line fishery were more abundant, larger and older in green zones than in adjacent areas and concluded that green zones have the potential to sustain a significant biomass of reproductively mature populations of harvested species despite an active fishery on the GBR.

‘Spillover’ of adults and export of juveniles into fishing grounds

For many species, as the number and size of individual fish within marine sanctuaries increases, their density will reach a point where a proportion of the fish migrate from the sanctuary as ‘spillover’ resulting in maintenance or enhancement of yields in adjacent fished areas.

• Russ and Alcala (1996) found significantly higher densities of target fish immediately adjacent to a Central Philippines sanctuary and local fishers claimed their yields had increased since the establishment of the sanctuary.
• Snapper occurred at higher densities inside a New Zealand reserve than outside, increasing annually over the 3-year survey. Density fluctuated seasonally up to 600%, suggesting that snapper regularly migrate into and out of the reserve (Willis 2000).
• The biomass of six commercially important fish families tripled inside a Caribbean sanctuary in three years and almost doubled in adjacent fished areas. Fishermen claim benefits from the sanctuary (Roberts and Hawkins 2000, Roberts et al.2001).
• In the GBRMP, Graham et al. (2003) found that where there was a high abundance of coral trout in marine sanctuaries and a consequent low abundance of food, some fish are likely to migrate to areas of less trout density where there is less competition and higher prey density (fished zones).
• Under current zoning, about 50% of the GBRMP is open trawling, with each pass of a trawl net removing 5-25% of seabed life, 13 repeated trawls removing 70-90% and up to 20 years required for some communities to recover (Poiner et al.1998). ‘Spillover’ and export of recruits can assist the regeneration of areas now closed to trawling.

Fishers often report their best catches close to marine sanctuaries, a benefit of spillover.

• Within 1 year, fish biomass within a Kenya marine sanctuary was already five times higher than in fished areas surrounding the sanctuary, with catch rates 25% higher near sanctuary boundaries (McClanahan 1994).
• After creation of a New Zealand marine sanctuary, local fishermen reported higher catches outside the sanctuary than before its establishment. High rock lobster catch rates and dramatic increases in lobster density and size have occurred near the sanctuary boundaries (Ballantine 1989, Roberts and Hawkins 2000).
• Within five years, the catch rates adjacent to a marine sanctuary in Egypt increased two-thirds for groupers, emperors and snappers. The marine reserve appears to have played a key role in maintaining fishery sustainability (Galal et al. 2002).

The main benefit of marine sanctuaries to adjacent fisheries lies in the ability of spawning stock in the sanctuaries to export juvenile larval recruits into fished areas.

• Many fish species travel large distances. Adult red emperor spawn on the reef, with juveniles found in deeper waters adjacent to reefs (DPI 2002) and coral trout larvae are able to swim actively in search of a reef on which to settle (Leis and Carson-Ewart 1999).
• James et al. (2003) modelled transport of reef fish larvae among 321 reefs in and around the Cairns Section of the GBRMP over a 20-year period, with most local fish populations shown to be dependent on larvae originating elsewhere - the total proportion of larvae settling on their reef of origin was lower than the total proportion settling elsewhere.

Helping ecosystems recover from disturbances

Impacts and stresses undermine the capacity of ecosystems to cope with major disturbances. Intact, fully functioning ecosystems recover more quickly from catastrophes like cyclones and oil spills than areas subject to other stresses, with ‘spillover’ and larval export from sanctuaries contributing to recovery of adjacent areas (Roberts and Hawkins 2000).

Insurance against fishery management failure

In recent years, overexploitation and collapse of many fisheries, reduced fishery yields, and associated biodiversity losses and environmental damage have alerted fisheries managers world-wide to weaknesses in conventional fisheries management approaches (Ward et al.2000, BRS 2001). Fisheries management using quotas, seasonal closures, size and bag limits, etc. relies on highly uncertain data and has failed to sustain fisheries and maintain biodiversity (Mangel 2000, Bohnsack 1993). For many fish stocks in the GBRMP, stock sizes are unknown (BRS 2001) and the status of most stocks is uncertain. During the last decade many fisheries globally have been overfished and/or collapsed leading to high unemployment and economic problems for fishers.

FAO (2000) estimated that about 73% of world fisheries are over-exploited, fully exploited or depleted. Management failure has occurred world-wide despite, in many cases, high levels of knowledge and management resources and effort. Uncertainties in conventional fisheries management and political influence have been blamed for the current status of many of the world’s fisheries. Of the fisheries resources on which the 67 most important fisheries in Australia are based, 11 are fully exploited, 35 are of uncertain status (no available estimates), 10 are not classified, and none are underfished (BRS 2001).

In 1992, the collapse of the Newfoundland cod fishery provided a sobering example of how conventional fisheries management can fail. This fishery was perceived to be one of the best-studied and well-managed fisheries in the world, but its collapse forced the closure of the fishery, with over 40,000 jobs lost. Stocks have not yet recovered (O’Malley et al. 2000). In 1990, the International Council for the Exploration of the Sea (ICES) advised fisheries ministers responsible for the North Sea to reduce the quota of 3 target species by 30%. In 1991, after much political negotiation, the ministers approved only an 8% cut in quota for cod and haddock. This process was repeated each year. By 2002, the stock size was half that of 1991 and ICES recommended that all fishing for cod in the North Sea should be banned.

It has been argued that uncertainty regarding the effects of marine sanctuaries is too great. However, conventional fisheries management often is based on even greater uncertainty. Russ (2002) argues that benefits of marine sanctuaries outweigh uncertainties because:

• Conventional fisheries management (effort/catch controls) alone generally has failed to control fishing effort and has often failed to prevent recruitment overfishing.
• Techniques such as effort/catch controls often are difficult to administer.
• Marine sanctuaries simplify management of multi-species fisheries, providing a refuge for species with life histories that make them more susceptible to intense, relatively non-selective fishing.
• Marine sanctuaries should be viewed for what they are – a healthy dose of the precautionary principle. They are sanctuaries for target fish stocks and are not advocated as the only, or even the optimum, method of fisheries management, but simply provide an insurance policy against possible future fisheries management failure and overfishing

Reduced variability and uncertainty in fisheries yields / increased fishery sustainability

‘Marine sanctuaries offer us a chance to have our fish and eat them too!’ (Russ 2002). Sanctuaries provide a precautionary management strategy to reduce variability associated with the interaction between fishing and environmental dynamics (Murray et al. 1999, Ward et al.2000). Spawning stocks protected by marine sanctuaries will produce more recruits, recruitment will be more predictable and the fishery will be less likely to experience high annual variations in catch, making it is easier for fishers to predict future income (Sladek Nowlis and Roberts 1999).

Halpern (2002) found that establishment of marine sanctuaries appears to result in significant increases in average levels of fish density, biomass, and diversity within 1 to 3 years, persisting over time, with slow-growing, late-maturing species likely to respond more slowly to protection than short-lived, fast-growing species.

Recreational fishing benefits

Marine sanctuaries can benefit both recreational and commercial fisheries.

• The International Game Fishing Association (IGFA) records world record catches according to strict criteria. A clear pattern emerged in Florida, around the Merritt Island sanctuary, where the numbers of fish caught has increased gradually (this did not happen at other places along the coast). Since 1985, all new Florida records for black drum and most records of red drum have been for fish caught adjacent to the sanctuary (Roberts et al.2001).
• In the Palm Island and the Whitsunday Island Groups, Williamson (1999) and Graham et al. (2003) found significantly larger and 3-4 times higher density of coral trout in the green zones than in adjacent fishing zones mostly fished by recreational fishers. Graham et al. (2003) found that the density of prey for coral trout in the fished zone was twice that of the green zone.

REFERENCES:

Adams, S, Mapstone, B D, Russ, G R and Davies, C R 2000. Geographic variation in the sex ratio, sex specific size, and age structure of Plectropomus leopardus (Serranidae) between reefs open and closed to fishing on the Great Barrier Reef. Can. J. Fish. Aquat. Sci. Vol. 57: 1448-1458.

Ballantine, W J 1989. Marine Reserves: Lessons from New Zealand. Progress in Underwater Science, Vol. 13: 1-14

Bohnsack, J A 1993. Marine Reserves. They Enhance Fisheries, Reduce Conflicts, and Protect Resources. Oceanus, Fall 1993: 63- 71.

BRS 2001. Fishery Status Report 2000-2001. O’Brien (ed.). Bureau of Rural Sciences. Department of Agriculture, Fisheries and Forestry, Australia.

DPI 2002. Queensland fisheries resources: Current condition and recent trends 1988-2000. Williams, LE. (ed.) Queensland Department of Primary Industries & Fisheries, Information Series QI02012.

FAO 2000. The state of world fisheries and aquaculture 2000. Food and Agriculture Organisation of United Nations.

Galal, N, Ormond, R F G and Hassan, O 2002. Effect of a network of no-take reserves in increasing catch per unit effort and stocks of exploited reef fish at Nabq, South Sinai, Egypt. Marine and Freshwater Research 53: 199-205.

Gell, F R and Roberts, C M 2002. The Fishery Effects of Marine Reserves and Fishery Closures. WWF-US, 1250 24th Street, NW, Washington, DC 20037, USA.

Graham, N A J, Evans, R D and Russ, G R 2003. The effects of marine reserve protection on the trophic relationships of reef fishes on the Great Barrier Reef. Environmental Conservation. In press

Grimes, D B 1987. Reproductive biology of the Lutjanidae: A review. In Tropical Snappers and Groupers: Biology and Fisheries Management. Polovina JJ and Ralston S (editors). 1987. Westview Press, Boulder. Pp 239-294.

Halpern, B S 2003. The impact of marine reserves. Ecological Applications 13(1): 117-137.

Halpern, B 2002. The impact of marine reserves: do reserves work and does reserve size matter? Ecological Applications. In press.

ICES 2002. International Council for the Exploration of the Sea, homepage WWW user survey (19/02/ 2003) http://www.ices.dk/aboutus/pressrelease/codstatement.asp

James, M K, Armsworth, P R, Mason, L B and Bode, L 2003. The structure of reef fish metapopulations: modelling larval dispersal and retention patterns (submitted).

Leis, J M and Carson-Ewart, B M 1999. In situ swimming and settlement

behaviour of larvae of an Indo-Pacific coral-reef fish, the coral trout Plectropomus leopardus (Pisces: Serranidae) Marine Biology. Vol. 134: 51-64.

McClanahan, T R 1994. Kenyan coral reef lagoon fish. Effects of fishing, substrate complexity, and sea urchins. Coral Reefs Vol 13: 231-241.

Mangel, M 2000. Trade-offs between fish habitat and fishing mortality and the role of reserves. Bulletin of Marine Science. Vol. 66:663-674.

Mapstone, B D, Davies, C R, Little, L R, Punt, A E, Smith, A D M, Pantus, F, Lou, D C,Williams, A J, Jones, A, Russ G R and MacDonald, A D 2003. The Effects of Line Fishing on the Great Barrier Reef and Evaluations of Alternative Potential Management Strategies, CRC Reef Research Centre, Townsville.

Murray, S N, Ambrose, R F, Bohnsack, J A, Botsford, L W, Carr, M H, Davis, G E, Dayton, P K, Gotshall, D, Gunderson, D R, Hixon, M A, Lubchenco, J, Mangel, M, MacCall, A, McArdle, D A, Ogden, J C, Roughgarden, J, Starr, R M, Tegner, M J and Yoklavich M M 1999. No-take reserve networks: sustaining fishery populations and marine ecosystems. Fisheries 24:11-25.

O’Malley, M, Wood, O and Foulkes, A 2000. “Newfoundland fishery’s up, but the cod ain’t coming back.” CBC News online. WWW user survey (Feb. 27 2003) http://cbc.ca/news/indepth/background/cod_fishing.html

Plan Development Team 1990. The Potential of Marine Fishery Reserves for Reef Fish Management in the U.S. Southern Atlantic. NOAA Technical Memorandum, NMFS-SEFC-261. U.S. Department of Commerce.

Roberts, C M and Hawkins, J P 2000. Fully protected marine reserves: a guide. WWF Endangered Seas Campaign, 1250 24^th Street, NW, Washington, DC 20037, USA and Environment Department, University of York, YO10 5DD, UK.

Roberts, C M, Bohnsack, J A, Gell, F, Hawkins, J P and Goodridge, R 2001. Effects of Marine Reserves on Adjacent Fisheries. Science. Vol 294: 1920-1923.

Russ, G R 2002. Yet Another Review of Marine Reserves as Fishery Management Tools. Coral Reef Fishes, 2^nd edition. Elsevier Science. Pp 421-443.

Russ, G R and Alcala, A C 1996. Do marine reserves export adult fish biomass? Evidence from Apo Island, central Philippines. Marine Ecology Progress Series. Vol 132: 1-9.

Sladek Nowlis, J and Roberts, C M 1999. Fisheries benefits and optimal design of marine reserves. Fishery Bulletin. Vol.97:604-616.

Ward, T and Hegerl, E 2003. Marine Protected Areas in Ecosystem-based Management of Fisheries - A Report for Environment Australia. Draft for Review March 2003.

Ward, T J, Heinemann, D and Evans, N 2001. The role of marine reserves as fisheries management tools – a review of concepts, evidence and international experience. Bureau of Rural Sciences, Canberra.

Williamson, D 1999. An assessment of the effectiveness of management zoning in protecting reef fish stocks of the Palm Islands and the Whitsunday Islands, Central Section, Great Barrier Reef. MSc Qualifying Small Thesis, Dept of Marine Biology and Aquaculture, James Cook University of North Queensland, Unpublished.

Willis, T J 2000. ‘Te Whanganui a Hei Marine Reserve fish monitoring program: II. Changes in snapper and blue cod density.’ Report to the Department of Conservation. Investigation NRO 02/04,Leigh Marine Laboratory. University of Auckland, http://www2.auckland.ac.nz/leigh