http://people.uncw.edu/pawlikj/2008AquatBotNagle.pdf

The habitat function of mangroves for terrestrial and marine fauna: a review

Mangrove forests are one of the world's most threatened tropical ecosystems with global loss exceeding 35% (ref 1) Juvenile coral reef fish often inhabit mangroves, but the importance of these nurseries to reef fish population dynamics has not been quantified Indeed, mangroves might be expected to have negligible influence on reef fish communities: juvenile fish can inhabit alternative habitats and fish populations may be regulated by other limiting factors such as larval supply or fishing Here we show that mangroves are unexpectedly important, serving as an intermediate nursery habitat that may increase the survivorship of young fish Mangroves in the Caribbean strongly influence the community structure of fish on neighbouring coral reefs In addition, the biomass of several commercially important species is more than doubled when adult habitat is connected to mangroves The largest herbivorous fish in the Atlantic, Scarus guacamaia, has a functional dependency on mangroves and has suffered local extinction after mangrove removal Current rates of mangrove deforestation are likely to have severe deleterious consequences for the ecosystem function, fisheries productivity and resilience of reefs Conservation efforts should protect connected corridors of mangroves, seagrass beds and coral reefs

/pdf/mangroves-enhance-the-biomass-of-coral-reef-fish-communities-4nxzc697m0.pdf

Mangroves enhance the biomass of coral reef fish communities in the Caribbean.

A simple habitat assessment score (HAS) was designed to assess habitat complexity across several different shallow tropical marine habitats including sandy patches, algal beds, seagrass beds and reefs. It measured rugosity, variety of growth forms, height, refuge size categories, percentage live cover and percentage hard substratum. Multiple regression models using HAS variables as predictors accounted for 71 and 22% of the variation in observed species richness and total fish abundance respectively. The two most important predictors of observed species richness were rugosity and variety of growth forms, while height was the most important predictor of total fish abundance. The HAS method worked consistently across a variety of habitat types and the complexity map closely mirrored the map of observed species richness, reflecting the patchy habitat mosaic of shallow tropical marine areas. Stations at the mouth of an enclosed lagoon, however, had a higher number of species than might have been expected judging from the habitat complexity scores. It is possible that this was linked to the preferential settling of pelagic fish larvae in this area as tidal water exchanges between the bay and the reef were funnelled through one small gap. This study highlights the need for fish biodiversity studies to take habitat complexity into account.

The relationship between fish species richness, abundance and habitat complexity in a range of shallow tropical marine habitats

There has been much controversy over the degree to which mangroves and seagrass beds function as nursery habitats for the juveniles of fish species that live on coral reefs as adults In previous studies we have shown that the juveniles of at least 17 Caribbean reef-fish species are highly associated with bays containing mangroves and sea- grass beds as nurseries, and that juveniles of these species are absent in bays lacking such habitats In this study we there- fore hypothesised that on islands lacking these bay nursery habitats, adults of these fish species will be absent or show low densities on the coral reef Densities of the 17 species were compared between the reefs of Caribbean islands with and without mangroves and seagrass beds On reefs of islands lacking these habitats, complete absence or low den- sities were observed for 11 of the 17 species, several of which are of commercial importance to fisheries This finding sug- gests a very important nursery function of such habitats and implies that the densities of several fish species on coral reefs are a function of the presence of nearby bays containing man- groves and seagrass beds as nurseries The results indicate that degradation or loss of these habitats could have signifi- cant impacts on reef-fish stocks in the Caribbean

https://www.int-res.com/articles/meps2002/244/m244p299.pdf

How important are mangroves and seagrass beds for coral-reef fish? The nursery hypothesis tested on an island scale

Coastal marine and estuarine ecosystems are highly productive and serve a nursery function for important fisheries species. They also suffer some of the highest rates of degradation from human impacts of any ecosystems. Identifying and valuing nursery habitats is a critical part of their conservation, but current assessment practices typically take a static approach by considering habitats as individual and homogeneous entities. Here we review current definitions of nursery habitat and propose a novel approach for assigning nursery areas for mobile fauna that incorporates critical ecological habitat linkages. We introduce the term 'seascape nurseries' which conceptualizes a nursery as a spatially-explicit seascape consisting of multiple mosaics of habitat patches that are functionally connected. Hotspots of animal abundances/productivity identify the core area of a habitat mosaic, which is spatially constrained by the home ranges of its occupants. Migration pathways connecting such hotspots at larger spatial and temporal scales, through ontogenetic habitat shifts or inshore–offshore migrations, should be identified and incorporated. The proposed approach provides a realistic step forward in the identification and management of critical coastal areas, especially in situations where large habitat units or entire water bodies cannot be protected as a whole due to socio-economic, practical, or other considerations.

/pdf/the-seascape-nursery-a-novel-spatial-approach-to-identify-45ez6odpn5.pdf

The seascape nursery: a novel spatial approach to identify and manage nurseries for coastal marine fauna

Mangroves and seagrass beds are considered important nursery habitats for coral reef fish species in the Caribbean, but it is not known to what degree the fish depend on these habitats. The fish fauna of 11 different inland bays of the Caribbean island of Curacao were compared; the bays contain 4 different habitat types: seagrass beds in bays containing mangroves, seagrass beds in bays lacking mangroves, mud flats in bays containing mangroves and seagrass beds, and mud flats in bays completely lacking mangroves and seagrass beds. Principal component analysis showed a high similarity of fish fauna among bays belonging to each of the 4 habitat types, despite some dif- ferences in habitat variables and human influence between bays. Juveniles of nursery species—fish species using mangroves and seagrass beds as juvenile nurseries before taking up residence on reefs—showed highest abundance and species richness on the seagrass beds, and on the mud flats near mangroves and seagrass beds, but were almost absent from bays containing only mud flats. The high abundance and species richness on the mud flats near nursery habitats can be explained by fishes migrating from the adjacent mangroves/seagrass beds to the mud flats. Seagrass beds near to mangroves showed a higher richness of nursery species than did seagrass beds alone, suggesting an interaction with the mangroves resulting in an enhancement of species richness. Comparison of fish densities from the 4 different habitat types indicates that for the nursery species the degree of depen- dence on a combination of mangroves and seagrass beds as nurseries for juvenile fish is high for Ocyurus chrysurus and Scarus iserti, the dependence on seagrass beds is high for Haemulon parrai, H. sciurus, Lutjanus apodus, L. griseus, Sparisoma chrysopterum and Sphyraena barracuda, and the dependence on mud flats near mangroves/seagrass beds is high for L. analis. The dependence on mangroves and/or seagrass beds is low for Chaetodon capistratus, Gerres cinereus, H. flavolineatum and L. mahogoni, which can also use alternative nursery habitats.

/pdf/dependence-of-caribbean-reef-fishes-on-mangroves-and-41jubky5lk.pdf

Dependence of Caribbean reef fishes on mangroves and seagrass beds as nursery habitats: a comparison of fish faunas between bays with and without mangroves/seagrass beds

T. Klop

Papers

Dependence of Caribbean reef fishes on mangroves and seagrass beds as nursery habitats: a comparison of fish faunas between bays with and without mangroves/seagrass beds