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Recent policy recommendations have highlighted the nutritional benefits of fisheries that capture small finfish species. Small fish, particularly those that feed in the pelagic zone, tend to be more nutrient dense than larger species, with increased concentrations of calcium, zinc, and omega-3 fatty acids. However, capturing fish below some recommended size limit (i.e., length at first maturity = L mat) in coral reefs is frequently considered to be unsustainable and associated with reduced yields and losses of ecosystem functions. To evaluate the potential effects of fish body size, we analyzed nutrient concentrations of 424 demersal and pelagic finfish species reported from Western Indian Ocean artisanal fisheries. We found that length and food source are associated with only small differences in nutrient density in the artisanal catches of this region (≤7% of a child's daily requirement in most cases). We also analyzed 20 years of catch monitoring data from Kenya, where many of the common species have L mat ∼20–25 cm, to test the potential benefits and tradeoffs of capturing small fishes. Small capture sizes were associated with low yields and sexually immature catches with a mean length of 15 cm resulting in 38% lower catch per unit effort, 37% lower nutrient yield, and a 22% lower maturity index compared to a mean body length of 30 cm. Catches of undersized fish were not associated with substantial increases or decreases in nutrient content relative to human nutritional requirements. Thus, coral reef artisanal fisheries should target moderate to large fishes (>20 cm) to maximize overall yield, nutrient yield, and sustainability. [Display omitted] • On coral reefs, small fishes are not always more nutritious than large ones. • Small capture sizes are not associated with increased nutrient density. • Large capture sizes are associated with increased yields and nutrient production. • Managers should balance quantity, quality, and sustainability of harvest strategies. [ABSTRACT FROM AUTHOR]

Increasing the chances that resource users engage in and comply with management regulations is a continual problem for many conservation initiatives globally. This is particularly common when resource users perceive more personal costs than benefits from specific management actions. Analysis of interviews with managers and fishers from 22 landing sites along the coast of Kenya indicated how key stakeholders perceived the scale of benefits and costs from different management strategies. Potential underlying causes of divergent perceptions towards different management tools were evaluated, including marine protected areas, no-take fisheries closures, gear use, minimum size of fish caught and species restrictions. The analysis identified three distinct opinion groups: (1) a group of nine landing sites that scaled their preference for most management restrictions neutral to low, with exceptions for minimum sizes of captured fish and gear restrictions; (2) a group of eight landing sites that scaled their preference for the above and species restrictions and closed season higher, and were more neutral about closures and marine protected areas; and (3) a group containing four landing sites and the managers’ offices that rated their preference for the above and closed areas and marine protected areas as high. Logistic regression was used to examine whether these groups differed in wealth, education, age, perceptions of disparity in benefits, dependence on fishing and distance to government marine protected areas. The most frequent significant factor was the resource users’ perceived disparity between the benefits of the management to themselves and their communities, with the benefits to the government. Consequently, efforts to reduce this real or perceived disparity are likely to increase adoption and compliance rates. Most widespread positively-viewed restrictions, such as gear use and minimum size of fish, should be promoted at the national level while other restrictions may be more appropriately implemented at the community level. [ABSTRACT FROM PUBLISHER]

Effective management is necessary if small-scale fisheries, such as those found in mixed habitats including seagrass and coral reefs, are to continue providing food for many of the poorest communities of the world. Gear-based management, although under represented and under studied, has the potential to be adaptive, address multiple objectives, and be crafted to the socio-economic setting. Management effectiveness in seagrass and coral reef fisheries has generally been evaluated at the scale of the fish community. However, community level indicators can mask species-specific declines that provide significant portions of the fisheries yields and income. Using a unique dataset, containing ten years of species level length frequency catch data from a multi-gear, multi-species seagrass and coral reef fishery in Kenya, we evaluate species specific fishery statuses, compare gear use to gear regulations and estimate the potential needs for further gear restrictions. Despite the high diversity of the fishery, fifteen species represented over 90% of the catch, and only three species represented 60% of the catch. The three most abundant species in the catch, Lethrinus lentjan (Lacepe`de), Siganus sutor (Valenciennes) and Leptoscarus vaigiensis (Quoy & Gaimard) all showed evidence of growth overfishing. Lethrinus lentjan, with an exploitation rate of 0.82, also shows evidence of recruitment overfishing. Current legal but weakly enforced gear restrictions are capable of protecting a significant portion of the catch up to maturity but optimization of yield will require that the current mesh size be increased from 6.3 to 8.8 and 9.2 cm to increase yields of L. lentjan and S. sutor, respectively. Given the difficulties of enforcing mesh size, we recommend that the economic benefits of these larger mesh sizes be communicated and enforced through co-management. This abstract is also available in Kiswahili (Abstract S1). [ABSTRACT FROM AUTHOR]

We tested the unsustainable fishing hypothesis that species in assemblages of fish differ in relative abundance as a function of their size, growth rates, vagility, trophic level, and diet by comparing species composition in historical bone middens, modern fisheries, and areas closed to fishing. Historical data came from one of the earliest and most enduring Swahili coastal settlements (approximately AD 750-1400). Modern data came from fisheries near the archeological site and intensively harvested fishing grounds in southern Kenya. The areas we sampled that were closed to fishing (closures) were small (<28 km2) and permanent. The midden data indicated changes in the fish assemblage that are consistent with a weak expansion of fishing intensity and the unsustainable fishing hypothesis. Fishes represented in the early midden assemblages from AD 750 to 950 had longer life spans, older age at maturity, and longer generation times than fish assemblages after AD 950, when the abundance of species with longer maximum body lengths increased. Changes in fish life histories during the historical period were, however, one-third smaller than differences between the historical and modern assemblages. Fishes in the modern assemblage had smaller mean body sizes, higher growth and mortality rates, a higher proportion of microinvertivores, omnivores, and herbivores, and higher rates of food consumption, whereas the historical assemblage had a greater proportion of piscivores and macroinvertivores. Differences in fish life histories between modern closures and modern fishing grounds were also small, but the life histories of fishes in modern closures were more similar to those in the midden before AD 950 because they had longer life spans, older age at maturity, and a higher proportion of piscivores and macroinvertivores than the modern fisheries. Modern closures and historical fish assemblages were considerably different, although both contained species with longer life spans. [ABSTRACT FROM AUTHOR]

A challenge for conservation science is predicting the impacts of co-occurring human activities on ecological systems. Multiple anthropogenic and natural stressors impact ecosystems globally and are expected to jeopardize their ecological functions and the success of conservation and management initiatives. The possibility that two or more stressors interact synergistically is of particular concern, but such nonadditive effects remain largely unidentified in nature. A long-term data set of hard coral cover from Kenyan reefs was used to examine the independent and interactive effects of two stressors: fishing and a temperature anomaly in 1998 that caused mass coral bleaching and mortality. While both stressors decreased coral cover, fishing by 51% and bleaching by 74%, they did not interact synergistically. Instead, their combined effect was antagonistic or weakly additive. The observed nonsynergistic response may be caused by the presence of one dominant stressor, bleaching, and cotolerance of coral taxa to both bleaching and fishing stressors. Consequently, coral bleaching has been the dominant driver of coral loss on Kenyan reefs and while marine reserves offer many benefits to reef ecosystems, they may not provide corals with a refuge from climate change. [ABSTRACT FROM AUTHOR]

In early 2002 coral mortality occurred along 600?km of coastline from Tanzania to Kenya.Astreopora, Echinopora, andMontiporaspecies were severely affected, withMontiporabeing nearly eliminated from Kenyan reefs.Acropora,Platygyra,Goniopora, and massivePoriteswere also affected; however,PoritesandGonioporararely died and often recovered, whereas death for most other species occurred within 2?weeks. InEchinoporaandMontipora, a dull ashy tissue color and brittle skeletons characterized the early stages of this event with a mucus layer on the tissue surface in intermediate stages. Mucus and embedded debris then disappeared and surfaces were left covered in a white calcareous dust that sometimes capped a black layer.Astreoporatissues became dull and pale, and seldom produced mucus; eventually the skeleton became bare and white. Either a colorless translucent or brownish thin margin of tissue was visible between living tissue and bare skeleton, depending on species. Scanning electron micrographs of affected corals revealed the presence of fungi. Histology and staining showed that the fungi were mostly in the three genera that died from the syndrome and it may be that fungi invaded and killed corals weakened by another unidentified pathogen. [ABSTRACT FROM AUTHOR]

The adoption of fisheries closures and gear restrictions in the conservation of coral reefs may be limited by poor understanding of the economic profitability of competing economic uses of marine resources. Over the past 12 years, I evaluated the effects of gear regulation and fisheries closures on per person and per area incomes from fishing in coral reefs of Kenya. In two of my study areas, the use of small-meshed beach seines was stopped after 6 years; one of these areas was next to a fishery closure. In my third study area, fishing was unregulated. Fishing yields on per capita daily wet weight basis were 20% higher after seine-net fishing was stopped. The per person daily fishing income adjacent to the closed areas was 14 and 22% higher than the fishing income at areas with only gear restrictions before and after the seine-net restriction, respectively. Incomes differed because larger fish were captured next to the closed area and the price per weight (kilograms) increased as fish size increased and because catches adjacent to the closure contained fish species of higher market value. Per capita incomes were 41 and 135% higher for those who fished in gear-restricted areas and near-closed areas, respectively, compared with those who fished areas with no restrictions. On a per unit area basis (square kilometers), differences in fishing income among the three areas were not large because fishing effort increased as the number of restrictions decreased. Changes in catch were, however, larger and often in the opposite direction expected from changes in effort alone. For example, effort declined 21% but nominal profits per square kilometer (not accounting for inflation) increased 29% near the area with gear restrictions. Gear restrictions also reduced the cost of fishing and increased the proportion of self-employed fishers., (© 2010 Society for Conservation Biology.)