Julie P. Hawkins

Extinction risk in the sea

Jean Baptiste de Lamarck and Thomas Huxley, two of the foremost thinkers of the 18th and 19th centuries, believed that humanity could not cause the extinction of marine species. Their opinions reflected a widespread belief that the seas were an inexhaustible source of food and wealth of which people could barely use a fraction. Such views were given weight by the abundant fisheries of the time. Additionally, the incredible fecundity and wide distributions of marine fishes, combined with limited exploitation, provided ample justification for optimism. The ideas of Huxley and Lamarck persist to this day, despite a sea change in the scale and depth of our influence on the oceans. Marine species could be at a far greater risk of extinction than we have assumed.

The role of marine reserves in achieving sustainable fisheries

Many fishery management tools currently in use have conservation value. They are designed to maintain stocks of commercially important species above target levels. However, their limitations are evident from continuing declines in fish stocks throughout the world. We make the case that to reverse fishery declines, safeguard marine life and sustain ecosystem processes, extensive marine reserves that are off limits to fishing must become part of the management strategy. Marine reserves should be incorporated into modern fishery management because they can achieve many things that conventional tools cannot. Only complete and permanent protection from fishing can protect the most sensitive habitats and vulnerable species. Only reserves will allow the development of natural, extended age structures of target species, maintain their genetic variability and prevent deleterious evolutionary change from the effects of fishing. Species with natural age structures will sustain higher rates of reproduction and will be more resilient to environmental variability. Higher stock levels maintained by reserves will provide insurance against management failure, including risk–prone quota setting, provided the broader conservation role of reserves is firmly established and legislatively protected. Fishery management measures outside protected areas are necessary to complement the protection offered by marine reserves, but cannot substitute for it.

Effects of recreational SCUBA diving on fore-reef slope communities of coral reefs

Abstract This study investigated the effects of recreational SCUBA diving on the fore-reef slopes of coral reefs near Sharm-el-Sheikh, a popular resort in Egypt. Benthic communities were compared using randomly placed 1-m2 quadrats at three sites subdivided into heavily and little dived areas. There were significantly more damaged coral colonies, loose fragments of live coral, fragments of coral re-attached to the substratum, partially dead and abraded corals in areas heavily used by divers than in control areas. Damage to corals varied with growth form, branching forms being most vulnerable to breakage. Changes to communities at heavily and little dived sites were studied over 12 months using 3 × 3 m permanent quadrats. No significant increases in damage attributable to diving were detected for the three sites combined. However, when considered individually, the site which had experienced the greatest increase in diving appeared to have accumulated damage (broken coral) whereas the two others did not. For management purposes the results show that some reefs can sustain heavy levels of diving without apparent continued degradation. New dive sites can accumulate damage very rapidly. However, at the levels of diver use encountered during this study this may be more of an aesthetic than a biological problem.

Effects of Recreational Scuba Diving on Coral Reefs: Trampling on Reef-Flat Communities

This study investigated the effects of trampling by scuba divers and snorkellers on reef-flats of coral reefs near Sharm-el-Sheikh, a popular resort in Egypt. There were significantly more damaged coral colonies and loose fragments of live coral in heavily-trampled than in little-trampled areas. Percentage cover of bare rock and rubble was also significantly greater; conversely, numbers of hard coral colonies and total percentage live coral cover were lower. Coral colonies were smaller in trampled compared to control areas, with average height and diameter significantly less in heavily-trampled areas. An area regularly visited by snorkellers exhibited intermediate effects. Coral species composition and the relative abundances of different coral growth forms did not appear to be affected by trampling

Effects of fishing on sex-changing Caribbean parrotfishes

We studied parrotfish (Scaridae) assemblages on coral reefs in relation to fishing pressure around six Caribbean islands. Fishing intensity ranged from virtually none in Bonaire, and increased through Saba, Puerto Rico, St Lucia and Dominica to extremely high levels in Jamaica. In St Lucia we also compared parrotfish assemblages between fishing grounds and fully protected marine reserves, from 1995, 6 months prior to establishment, to 2001. Within each country we performed replicate counts of the number and size of all parrotfish species within, or passing through our counting area. From these data we calculated biomass for seven species. Biomass of the two largest species, Sparisoma viride and Scarus vetula, was greatest in islands with low fishing pressure (P<0.001). By contrast, smaller species constituted an increasing proportion of the total parrotfish assemblage as fishing pressure increased (P<0.001 in all cases). Parrotfish are protogynous hermaphrodites with two distinct colour phases. The initial phase is predominantly female, and the terminal phase exclusive to sexually mature males. The average size of all species except Sc. vetula tended to decrease with increasing fishing pressure. Furthermore, percentages of fish that were terminal phase males showed order of magnitude declines with increasing fishing pressure for Sp. viride and Sc. vetula. Terminal males of these species were absent from counts in Jamaica and virtually absent from Dominica suggesting that persistence of these populations may depend on recruitment from distant sources. Following reserve implementation in St Lucia, all species, except uncommon Sp. chrysopterum, increased in mean biomass (P<0.001 in all cases). In 6 years the total biomass for all species combined increased to become nearly four times as high in reserves and almost twice as high in fishing grounds [P<0.001 (year effect); P<0.001 (protection effect); P<0.001 (year×protection)], and mean size of five species increased significantly in both reserves and fishing grounds.

Sustainability of scuba diving tourism on coral reefs of Saba.

We examine the effects of recreational scuba diving in the Saba Marine Park in the Netherlands Antilles over a nine-year period. Levels of diving have remained low whereas dive fees have provided a major source of income to this park. We studied 5 dive sites where the average number of dives per site per year ranged from 445 to 2,163. At each site we recorded benthic parameters and levels of damage within at least 25 randomly placed quadrats in areas designated to be High use (0–20 m from mooring) or Low use (40–60 m from moorings), at yearly or biennial intervals. Within the same dive site, there was significantly more broken coral and fragments of live coral in High use areas than Low use. However, across sites, damage was not significantly related to diving intensity and nor did it accumulate over time. The Saba Marine Park shows that it is possible to fund protection at sustainable levels of use.

Towards a network of locally managed marine areas (LMMAs) in the Western Indian Ocean.

In the Western Indian Ocean (WIO), local communities are increasingly assuming responsibility for inshore marine resources either on their own or through collaborative management arrangements with governments or non-state actors. In this paper, we trace the evolution and expansion of community management in the WIO and present the first ever inventory and assessment of the region’s locally managed marine areas (LMMAs). We compare the key attributes of these areas to those under government stewardship and assess their relative contributions to progress towards the Convention on Biodiversity (CBD) target of 10% of marine and coastal ecological regions to be effectively conserved by 2020. We also explore the legal frameworks that underpin locally managed marine initiatives in Kenya, Madagascar, Mozambique and Tanzania to assess the potential for future expansion. A principal finding is that whilst LMMAs protect more than 11,000 square kilometres of marine resource in the WIO, they are hampered by underdeveloped local and national legal structures and enforcement mechanisms. In our recommendations to improve local management, we suggest establishing a network of LMMA practitioners in the WIO region to share experiences and best practice.

Conus: First Comprehensive Conservation Red List Assessment of a Marine Gastropod Mollusc Genus

Marine molluscs represent an estimated 23% of all extant marine taxa, but research into their conservation status has so far failed to reflect this importance, with minimal inclusion on the authoritative Red List of the International Union for the Conservation of Nature (IUCN). We assessed the status of all 632 valid species of the tropical marine gastropod mollusc, Conus (cone snails), using Red List standards and procedures to lay the groundwork for future decadal monitoring, one of the first fully comprehensive global assessments of a marine taxon. Three-quarters (75.6%) of species were not currently considered at risk of extinction owing to their wide distribution and perceived abundance. However, 6.5% were considered threatened with extinction with a further 4.1% near threatened. Data deficiency prevented 13.8% of species from being categorised although they also possess characteristics that signal concern. Where hotspots of endemism occur, most notably in the Eastern Atlantic, 42.9% of the 98 species from that biogeographical region were classified as threatened or near threatened with extinction. All 14 species included in the highest categories of Critically Endangered and Endangered are endemic to either Cape Verde or Senegal, with each of the three Critically Endangered species restricted to single islands in Cape Verde. Threats to all these species are driven by habitat loss and anthropogenic disturbance, in particular from urban pollution, tourism and coastal development. Our findings show that levels of extinction risk to which cone snails are exposed are of a similar magnitude to those seen in many fully assessed terrestrial taxa. The widely held view that marine species are less at risk is not upheld.

Sessile and mobile components of a benthic ecosystem display mixed trends within a temperate marine reserve

Despite recent efforts to increase the global coverage of marine protected areas (MPAs), studies investigating the effectiveness of marine protected areas within temperate waters remain scarce. Furthermore, out of the few studies published on MPAs in temperate waters, the majority focus on specific ecological or fishery components rather than investigating the ecosystem as a whole. This study therefore investigated the dynamics of both benthic communities and fish populations within a recently established, fully protected marine reserve in Lamlash Bay, Isle of Arran, United Kingdom, over a four year period. A combination of photo and diver surveys revealed live maerl (Phymatolithon calcareum), macroalgae, sponges, hydroids, feather stars and eyelash worms (Myxicola infundibulum) to be significantly more abundant within the marine reserve than on surrounding fishing grounds. Likewise, the overall composition of epifaunal communities in and outside the reserve was significantly different. Both results are consistent with the hypothesis that protecting areas from fishing can encourage seafloor habitats to recover. In addition, the greater abundance of complex habitats within the reserve appeared to providing nursery habitat for juvenile cod (Gadus morhua) and scallops (Pecten maximus and Aequipecten opercularis). In contrast, there was little difference in the abundance of mobile benthic fauna, such as crabs and starfish, between the reserve and outside. Similarly, the use of baited underwater video cameras revealed no difference in the abundance and size of fish between the reserve and outside. Limited recovery of these ecosystem components may be due to the relatively small size (2.67 km(2)) and young age of the reserve (<5 years), both of which might have limited the extent of any benefits afforded to mobile fauna and fish communities. Overall, this study provides evidence that fully protected marine reserves can encourage seafloor habitats to recover, which in turn, can create a number of benefits that flow back to other species, including those of commercial importance.

Effects of protection and sediment stress on coral reefs in Saint Lucia

The extent to which Marine Protected Areas (MPAs) benefit corals is contentious. On one hand, MPAs could enhance coral growth and survival through increases in herbivory within their borders; on the other, they are unlikely to prevent disturbances, such as terrestrial runoff, that originate outside their boundaries. We examined the effect of spatial protection and terrestrial sediment on the benthic composition of coral reefs in Saint Lucia. In 2011 (10 to 16 years after MPAs were created), we resurveyed 21 reefs that had been surveyed in 2001 and analyzed current benthic assemblages as well as changes in benthic cover over that decade in relation to protection status, terrestrial sediment influence (measured as the proportion of terrigenous material in reef-associated sediment) and depth. The cover of all benthic biotic components has changed significantly over the decade, including a decline in coral and increase in macroalgae. Protection status was not a significant predictor of either current benthic composition or changes in composition, but current cover and change in cover of several components were related to terrigenous content of sediment deposited recently. Sites with a higher proportion of terrigenous sediment had lower current coral cover, higher macroalgal cover and greater coral declines. Our results suggest that terrestrial sediment is an important factor in the recent degradation of coral reefs in Saint Lucia and that the current MPA network should be complemented by measures to reduce runoff from land.