Ricardo S. Santos

Bio: Ricardo S. Santos is an academic researcher from University of the Azores. The author has contributed to research in topics: Seamount & Hydrothermal vent. The author has an hindex of 50, co-authored 250 publications receiving 8086 citations. Previous affiliations of Ricardo S. Santos include International Sleep Products Association & King's College London.

Seamounts: Ecology, Fisheries & Conservation

Abstract: 1 Seamount characteristics Paul Wessel 2 How many seamounts are there and where are they located? Adrian Kitchingman, Sherman Lai, Telmo Morato and Daniel Pauly 3 A history of seamount research Paul E Brewin, Karen I Stocks and Gui Menezes 4 Physical processes and seamount productivity Martin White, Igor Bashmachnikov, Javier Aristegui and Ana Martins 5 Seamount plankton dynamics Amatzia Genin and John F Dower 6 Midwater fish assemblages and seamounts Filipe M Porteiro and Tracey Sutton 7 Seamount benthos Sarah Samadi, Thomas Schlacher and Bertrand Richer de Forges 8 Corals on seamounts Alex D Rogers, A Baco, H Griffiths, T Hart and Jason M Hall-Spencer 9 Seamount fishes: ecology and life histories Telmo Morato and Malcolm R Clark 10 Fish visitors to seamounts Section A: Tunas and billfish at seamounts Kim N Holland and R Dean Grubbs Section B: Aggregations of large pelagic sharks above seamounts Feodor Litvinov 11 Seamounts and cephalopods Malcolm Clarke 12 Air-breathing visitors to seamounts Section A: Marine mammals Kristin Kaschner Section B: Sea turtles Marco A Santos, Alan B Bolten, Helen R Martins, Brian Riewald and Karen A Bjorndal Section C: Importance of seamounts to seabirds David R Thompson 13 Biogeography and biodiversity of seamounts Karen I Stocks and Paul JB Hart 14 Raiding the larder: a quantitative evaluation framework and trophic signature for seamount food webs Tony J Pitcher and Cathy Bulman 15 Modelling seamount ecosystems and their fisheries Beth Fulton, Telmo Morato and Tony J Pitcher 16 Small-scale fishing on seamounts Helder Marques da Silva and Mario Rui Pinho 17 Large-scale distant-water trawl fisheries on seamounts Malcolm R Clark, Vladimir I Vinnichenko, John DM Gordon, Georgy Z Beck-Bulat, Nikolai N Kukharev and Alexander F Kakora 18 Catches from world seamount fisheries Reg Watson, Adrian Kitchingman and William Cheung 19 Impacts of fisheries on seamounts Malcolm R Clark and J Anthony Koslow 20 Management and conservation of seamounts P Keith Probert, Sabine Christiansen, Kristina M Gjerde, Susan Gubbay and Ricardo S Santos 21 The depths of ignorance: an ecosystem evaluation framework for seamount ecology, fisheries and conservation Tony J Pitcher, Telmo Morato, Paul JB Hart, Malcolm R Clark, Nigel Haggan and Ricardo S Santos

CASE STUDIES AND REVIEWS Marine research, resources and conservation in the Azores

Abstract: A history of marine research on the Azores is outlined. Until two decades ago most oceanic and littoral marine studies had been carried out by foreign scientists. Studies by Azorean scientists started to increase in the early 1980s when the University of the Azores was created. 2. Ocean circulation in this part of the Atlantic is described as a background for biogeography and diversity. The picture emerges that Azores is a 'meeting point' for shallow water marine fauna and flora of different origins. 3. The species composition of one of the best studied groups of organisms, the fish, is compared between locations in the northeastern Atlantic. The work on fish is also compared with other well studied groups (algae and hydroids) to highlight the interest of the Azores as a natural biogeographical experiment. 4. Studies of marine resources began less than two decades ago. The development of demersal fisheries is described focusing on the switch from small-scale artisanal fishing to more commercial fisheries. 5. Conservation of species and legislation in force for molluscs, crustaceans, fishes, marine turtles, seabirds and marine mammals are summarized. 6. Protected marine areas already designated are defined, as well as new areas recommended. 7. The paper concludes with a discussion of current threats and future management strategies.

Marine research, resources and conservation in the Azores

Abstract: 1 A history of marine research on the Azores is outlined. Until two decades ago most oceanic and littoral marine studies had been carried out by foreign scientists. Studies by Azorean scientists started to increase in the early 1980s when the University of the Azores was created. 2 Ocean circulation in this part of the Atlantic is described as a background for biogeography and diversity. The picture emerges that Azores is a ‚meeting point’ for shallow water marine fauna and flora of different origins. 3 The species composition of one of the best studied groups of organisms, the fish, is compared between locations in the northeastern Atlantic. The work on fish is also compared with other well studied groups (algae and hydroids) to highlight the interest of the Azores as a natural biogeographical experiment. 4 Studies of marine resources began less than two decades ago. The development of demersal fisheries is described focusing on the switch from small-scale artisanal fishing to more commercial fisheries. 5 Conservation of species and legislation in force for molluscs, crustaceans, fishes, marine turtles, seabirds and marine mammals are summarized. 6 Protected marine areas already designated are defined, as well as new areas recommended. 7 The paper concludes with a discussion of current threats and future management strategies.

A Dark Hole in our Understanding of Marine Ecosystems and their Services: Perspectives from the mesopelagic community.

Abstract: In the face of increasing anthropogenic pressures acting on the Earth system, urgent actions are needed to guarantee efficient resource management and sustainable development for our growing human population. Our oceans - the largest underexplored component of the Earth system - are potentially home for a large number of new resources, which can directly impact upon food security and the wellbeing of humanity. However, the extraction of these resources has repercussions for biodiversity and the oceans ability to sequester green house gases and thereby climate. In the search for “new resources” to unlock the economic potential of the global oceans, recent observations have identified a large unexploited biomass of mesopelagic fish living in the deep ocean. This biomass has recently been estimated to be 10 billion metric tonnes, 10 times larger than previous estimates however the real biomass is still in question. If we are able to exploit this community at sustainable levels without impacting upon biodiversity and compromising the oceans’ ability to sequester carbon, we can produce more food and potentially many new nutraceutical products. However, to meet the needs of present generations without compromising the needs of future generations, we need to guarantee a sustainable exploitation of these resources. To do so requires a holistic assessment of the community and an understanding of the mechanisms controlling this biomass, its role in the preservation of biodiversity and its influence on climate as well as management tools able to weigh the costs and benefits of exploitation of this community.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

Abstract: The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Age and Growth

Abstract: Flatfi shes are very accessible in the wild and hardy in the laboratory, thus many of the early studies of fi sh growth used fl atfi shes, especially plaice (Pleuronectes platessa) in the Atlantic and a number of species in the Pacifi c. As the science of fi sheries developed, so did the need to quantify the population structure and growth characteristics of the different fl atfi sh species. In fact, the importance of ageing fi shes and determining their growth rate was realised early in the last century (Allen 1916). Much of the early information on the aging and growth of fl atfi shes (primarily plaice) is referenced in Wimpenny (1953), Graham (1956) and Beverton & Holt (1957). Prior to the 1950s researchers had gained a fairly good understanding of the methods. A clear pattern of summer and winter growth was recognised in the otoliths, which were fi rst used in the late 1800s. Other bony structures such as opercular bones, the pectoral girdle and the concave faces of the vertebrae exhibited seasonal growth patterns (Cunningham 1905) but these were not as distinctive as those on the otoliths. The observation that a pair of rings may not delimit 1 year’s growth led to early verifi cation studies based on marginal increment analyses. Experimental work on plaice and fl ounder (Platichthys fl esus) showed that the seasonal pattern on both otoliths and scales was primarily driven by seasonal changes in water temperature rather than by variations in food availability. The use of otoliths for age estimation of fl atfi shes was not universal. Species differences slowly became apparent and methodological refi nements followed. Direct measurements of the growth of fl atfi shes were afforded by series of tagging and transplantation experiments, and laboratory or enclosure experiments (Johnstone et al. 1921). In all cases it was apparent that there was considerable variability in individual growth rates and that growth rates varied between areas. The widespread sexual dimorphism in growth with females growing faster and reaching larger sizes than males was also recognised (e.g. Johnstone et al. 1921; Bigelow & Schroeder 1953; Bagenal, 1955). The effects of gear selectivity and ontogenetic behavioural changes of fl atfi shes on the accurate estimation of age structure and growth rates were recognised, especially with the offshore movement of larger juvenile plaice from the nursery grounds and a general offshore movement with size and age. The possibility that fi shing pressure could make major changes to the age structure and growth of commercially exploited fl atfi sh populations was mentioned by Jones (1958), citing the prevalence of Rosa Lee’s phenomenon in plaice.

Mercury as a Global Pollutant: Sources, Pathways, and Effects

Abstract: Mercury (Hg) is a global pollutant that affects human and ecosystem health. We synthesize understanding of sources, atmosphere-land-ocean Hg dynamics and health effects, and consider the implications of Hg-control policies. Primary anthropogenic Hg emissions greatly exceed natural geogenic sources, resulting in increases in Hg reservoirs and subsequent secondary Hg emissions that facilitate its global distribution. The ultimate fate of emitted Hg is primarily recalcitrant soil pools and deep ocean waters and sediments. Transfers of Hg emissions to largely unavailable reservoirs occur over the time scale of centuries, and are primarily mediated through atmospheric exchanges of wet/dry deposition and evasion from vegetation, soil organic matter and ocean surfaces. A key link between inorganic Hg inputs and exposure of humans and wildlife is the net production of methylmercury, which occurs mainly in reducing zones in freshwater, terrestrial, and coastal environments, and the subsurface ocean. Elevated human exposure to methylmercury primarily results from consumption of estuarine and marine fish. Developing fetuses are most at risk from this neurotoxin but health effects of highly exposed populations and wildlife are also a concern. Integration of Hg science with national and international policy efforts is needed to target efforts and evaluate efficacy.

Global conservation outcomes depend on marine protected areas with five key features

Abstract: In line with global targets agreed under the Convention on Biological Diversity, the number of marine protected areas (MPAs) is increasing rapidly, yet socio-economic benefits generated by MPAs remain difficult to predict and under debate1, 2. MPAs often fail to reach their full potential as a consequence of factors such as illegal harvesting, regulations that legally allow detrimental harvesting, or emigration of animals outside boundaries because of continuous habitat or inadequate size of reserve3, 4, 5. Here we show that the conservation benefits of 87 MPAs investigated worldwide increase exponentially with the accumulation of five key features: no take, well enforced, old (>10 years), large (>100 km2), and isolated by deep water or sand. Using effective MPAs with four or five key features as an unfished standard, comparisons of underwater survey data from effective MPAs with predictions based on survey data from fished coasts indicate that total fish biomass has declined about two-thirds from historical baselines as a result of fishing. Effective MPAs also had twice as many large (>250 mm total length) fish species per transect, five times more large fish biomass, and fourteen times more shark biomass than fished areas. Most (59%) of the MPAs studied had only one or two key features and were not ecologically distinguishable from fished sites. Our results show that global conservation targets based on area alone will not optimize protection of marine biodiversity. More emphasis is needed on better MPA design, durable management and compliance to ensure that MPAs achieve their desired conservation value.