Jorge Santos

• UiT The Arctic University of Norway

Across marine ecosystems, species are redistributing as a response to increased sea temperatures. In the Arctic, rapid warming causes poleward shifts of boreal species. Which species are redistributing and the drivers of their movements can be related to their life history traits. Here, we aimed to characterize and analyze the spatio-temporal chang...

Research on life‐history variations in widely distributed fish species is needed to understand global warming impacts on populations and to improve fisheries management advice. The lane snapper Lutjanus synagris (Linnaeus, 1758) is commercially important to fisheries in the Western Central Atlantic, where spread information on its life‐history trai...

The essential role of coastal fisheries in the Blue Economy is discussed, highlighting the importance of science and technology in their economic and social contexts, as well as that of good governance for their sustainability. The evolution and present situation of global fishery activities are discussed, as well as the effects of fishing on the e...

Value chain analysis can be effectively utilized as an important tool for identifying the required modification for upgrading the fishery industry. This study aims to identify key economic agents, their roles and functions in fisheries value chains, and estimate monetary flows through various marketing channels. The data was collected by using in-d...

The brown mussel Perna perna is the dominant indigenous mussel along the east coast of South Africa, where it is harvested by recreational and subsistence fishers. High fishing pressure near urban areas led to declining abundance and consequently to the closure of some reefs to fishing in 1998. We estimated trends in mussel population dynamics at e...

Estuarine socio-ecological systems (SES) in the Western Indian Ocean (WIO) region face mounting pressures from overexploitation, habitat degradation, impacts of climate change and governance inadequacies. A regional assessment of seasonal-to-decadal change in SES of three estuaries (Bons Sinais in Mozambique, Ruvu in Tanzania and Tana in Kenya) was...

Estuaries provide unique ecosystem goods and services and have been focal points for human settlement andresource use throughout recorded history. In the Western Indian Ocean (WIO) region, the effects of human population growth, rapid economic development and climate change on estuaries threaten their ecological functioning and the sustainability o...

Small-scale fisheries in estuaries of the Western Indian Ocean form a key component of socio-ecological systems (SES) and food security, yet they remain poorly understood. This study describes the estuarine fisheries of the Bons Sinais Estuary in Mozambique based on fisheries and biological data collected by monitors between 2007 and 2016. Multiple...

The conservation status of several pelagic shark species is considered vulnerable with declining populations, yet data on shark fishing mortality remain limited for large ocean regions. Pelagic sharks are increasingly retained by mixed-species fisheries, or are discarded and not reported by selective fisheries for tunas (Thunnus spp.) or swordfish...

The small pelagic fishery has critical importance both in terms of economic and food security concerns for coastal communities around the world. This study aims to investigate the domestic fish value chain along with key economic agents, their roles and functions and to assess the contribution of the value chain to the local food security. In-depth...

The intertidal brown mussel Perna perna is targeted by recreational and subsistence fisheries in KwaZulu-Natal, South Africa. The recreational mussel fishery is monitored by off-site postal, telephone and online questionnaire surveys, assessed in this study. Trends in fisher avidity (proportion of permit holders that went fishing), mean number of o...

Supplementary data for 'Trends in a recreational fishery for mussels in eastern South Africa, based on postal , telephone and online surveys'.

Fishing trials targeting several invasive swimming crab species in their native habitat were undertaken using two types of collapsible pot, one with open-eyed entrances and the other with closed-eyed entrances, to analyse differences in catch retention between them. The open-eyed pot was dome-shaped with two funnel entrances located at opposite end...

The assumption of a proportional relationship between catch-per-unit-effort (CPUE) and the abundance of sharks caught by pelagic longliners is tenuous when based on fisher logbooks that report only retained specimens. Nevertheless, commercial logbooks and landings statistics are often the only data available for stock status assessments. Logbook da...

Unwanted catches are a pervasive problem of world fisheries, representing a wasteful use of marine resources. The 2013 Reform of the EU Common Fisheries Policy has made a legal commitment to end discarding by implementing the Landings Obligation for those species subject to TAC or Minimum Conservation Reference Size. To mitigate the problem, the us...

p>QUESTIONS ASKED What is the real state of fisheries around the world? What experiences have we on the assessment and management of different fish populations? When should we invest, or refrain from investing or intervening, in the fishing industry? </ul

p>QUESTIONS ASKED How does the climate influence a fishery? How to conciliate the interests of predators? How to conciliate the interests of different industries? Corrumane dam ecosystem Mono Corrumane dam ecosystem Multi </p

p>QUESTIONS ASKED How do biologists count organisms in the field? How do they design their sampling? How can one scale or extrapolate observations to other areas? Sampling design scaling Direct counting (general) </p

p>QUESTIONS ASKED How to apply different effort controls in a fishery? What does risk mean in fluctuating fisheries? Do we need information from all fleets involved in a fishery? Shrimp industrial fishery Shrimp multi-fleet fishery </p

p>QUESTIONS ASKED How do discuss and agree on fishery management plans for the future? Can we develop harvest rules in small-scale fisheries, without models? How can we express the probable costs of fishing too much or too little? Forecasts and harves rules - parametric quotas Adaptive harvest rules - non-parametric </p

p>QUESTIONS ASKED What are the bases of the traditional regulations of effort and gear in fisheries? What are the trade-offs between fishing early or late on the reproductive potential of the stocks? How certain is the advice, and what are the risks? Yield pr recruit R-based R-script YR I PR by projection contour F tc R-script YR II by pro...

p>QUESTIONS ASKED How to assess the state of a fishery with a simple series of catch and effort? How is a fishery model different from a trend analysis? Do the assumptions of the model affect the management values of interest? How to word a management advice? Surplus production equilibrium and dynamic models </p

p>QUESTIONS ASKED How to assess the state of a fishery with a minimum of information? Where to obtain national and regional fishery data? How to interpret simple indicators of abundance? Do fisheries have typical cycles that can be recognized? How to compare and adjust the fishing power of different fleets? Trend analysis Standardization o...

p>QUESTIONS ASKED Why rates, and why statistics? How to express such quantities in common speech? How to present much data in a concise and informative way? How to make predictions based on historical trends? Statistics </p

p>QUESTIONS ASKED Am I aware of the basics of scientific writing required to write an informative report? Do I remember the basics of mathematics? How do I use statistics to plan and analyze my field or experimental data? How to lose the fear of using a spreadsheet? How to do basic repetitive calculations? How to present figures and reports i...

p>QUESTIONS ASKED How to describe the life of a cohort? How long to wait until we fish a cohort? The dilemma: catch now or later? How to describe the sexual maturation and the recruitment processes in fish? Pop processes Growth Pop processes Mortality Pop processes Maturation </p

p>This chapter of CONΣERV IT deals with the following questions in aquatic conservation: - Does it matter how fish populations are divided spatially? - How do we deal with different spatial linkages, configurations and populations sizes in fisheries management? - How much biomass or money do we lose by not fishing or by over-fishing small and larg...

p>This chapter of CONΣERV IT deals with the following questions in aquatic conservation: - What do ecologists call diversity? - How can we measure changes in diversity in locally impacted areas? - How can we valuate those changes by simple means? Conservation and valuation of diversity Belize </p

p>This chapter of CONΣERV IT deals with the following questions in aquatic conservation: - What is conservation biology? - Do fish populations get extinct or extirpated? - Is it bad that related populations rescue each other? Extirpation </p

p>This chapter of CONΣERV IT deals with the following questions in aquatic conservation: - How do we express the suitability of habitat for different organisms and communities? - How to make spatial planning of conservation networks that takes into account multiple ecological and social criteria? - How to perform an economic analysis of the non-mo...

p>This introductory chapter of CONΣERV IT deals with the following preparatory skills: - Am I aware of the basics of scientific writing required to write an informative report? - Do I remember the basics of mathematics? - How do I use statistics to plan and analyze my field or experimental data?</p

p> This introductory chapter of CONΣERV IT deals with the following preparatory skills: - How to lose the fear of using a spreadsheet? - How to do basic repetitive calculations? - How to present figures and reports in scientific style? - How to efficiently select and summarize sub-groups of data? Excel basics </p

p>This chapter of CONΣERV IT deals with the following questions in aquatic conservation: - How do escapees from aquaculture affect genetically salmon populations in rivers? - What are the time-scales of change in the gene pool of fish? - Can we eradicate undesirable traits from fish stocks? - Are small populations more or less affected by immigrat...

Central America and the western Caribbean regions form a center of freshwater and marine biodiversity that is increasingly becoming the focus of ecological and evolutionary studies. We conducted an integrated ecological study of Amatique Bay, Guatemala, a major estuary la goon connected to the low-lying Lake Izabal and to the Mesoamerican Reef Syst...

Traceability is a tool used by regulators to manage risk in multiple supply chains, including supply chains of goods derived from genetically modified organisms, human blood, seafood products, toys and hazardous waste. This tool may help support a variety of claims that range from concern for nature to consumer satisfaction and health. This paper e...

The population structure, reproductive biology, age and growth, and diet of shortfin makos caught by pelagic longliners (2005–10) and bather protection nets (1978–2010) in the south-west Indian Ocean were investigated. The mean fork length (FL) of makos measured by observers on longliners targeting tuna, swordfish and sharks was similar, and decrea...

Advection-diffusion models were constructed to simulate migration patterns of juvenile and adult spiny lobsters off southern South Africa. Models based on tag-recapture information collected between 1978 and 2005 (2665 tag recaptures) were used to quantify directional movements and to estimate distances moved along a bathymetric gradient. Sex, leng...

The deep-water trawl fishery along the KwaZulu-Natal coast of South Africa targets several crustacean species, with the knife (or pink) prawn Haliporoides triarthrus contributing most of the catch. Logbook data of fishing effort and catch between 1988 and 2010 were used to assess the distribution and abundance of H. triarthrus on fishing grounds. G...

Abundance trends, population structure, and biology of the langoustine Metanephrops mozambicus (Macpherson, 1990) were investigated, based on commercial logbook information (1988-2010; 49 990 trawls) and biological samples collected off eastern South Africa. A generalized linear model (GLM) framework was used to model variation in catch rates, cara...

The ecology of common snook Centropomus undecimalis in Amatique Bay, a tropical estuary in eastern Guatemala, was investigated and life-history traits were used to conduct a meta-analysis of the species from Florida to Brazil. The reproduction cycle of C. undecimalis in Amatique was strongly related to the precipitation cycle, with a lag of 2 month...

Marine species such as deep-sea geryonid crabs often exhibit high spatio-temporal variability in abundance and size over depth, substratum type and season, therefore data collected from a single gear type may not represent the whole population. Complementary data from trawl (soft substratum) and trap (hard substratum) fisheries were analysed within...

The Sofala Bank (16°–21° S) forms a major discontinuity in the gradients of engraulid distribution along the south-eastern African coast. Although the number of species declines southwards, the density and the catches of species associated with higher turbidity increases within the bank, particularly for Thryssa vitrirostris and a few other Thryssa...

Whole herring, Clupea harengus, were digested and emptied from cod stomachs much more slowly than meals of minced herring, showing that prey integrity is an important factor controlling emptying. Increasing the energy content of the minced herring by addition of fish meal and oil led to a reduction in the percentage of the meal emptied in the 24 h...

Functional relationships were derived in order to describe the effects of fish weight (262–2066 g), temperature (1–14° C), prey size and ration size (0.4–8.4% body weight) on gastric evacuation in cod fed four natural prey types. Interindividual (unexplained) differences among voluntary fed cod were relatively large. Power functions were appropriat...

Particles 2 mm or smaller may be passed relatively easily through the pylorus of the cod, Gadus morhua L., but, under some conditions, 5 mm particles are held in the stomach for prolonged periods. The emptying of indigestible particles appears to be impaired by the consumption of additional meals, and prolonged retention of these particles may occu...

The effects of capture, tagging and release on the growth of male Cape rock lobster Jasus lalandii collected at Olifantsbos (historically a slow-growth site) and Knol (fast-growth site) were studied under controlled conditions in aquaria, cages at sea, and in situ. Growth increments achieved after the first captive moult were related to year and ar...

The present study is the first multidisciplinary study, where it is considered the specificity of the problem of by-catch and discards in the south coast of Portugal. This study not only considers the aspects of identification, quantification and species biology of the by-catch and discards, but also looks at the ecosystem’s dynamic and the possibl...

O principal objectivo do presente estudo foi a análise e avaliação do efeito da arte de pesca do arrasto nas espécies demersais em toda a costa do Algarve, realizada através da quantificação tanto das espécies demersais capturadas com interesse comercial, como das espécies sem valor comercial e, por isso, rejeitadas ao mar. A área estudada neste p...

A preliminary investigation was made of the trophic relationships of three species of cartilaginous fish and 12 species of bony fishes along the upper part of the continental slope off the Algarve. These fish, from the by-catch of crustacean bottom trawlers fishing between 190 and 650 m, were sampled for stomach content analysis. Three major predat...

A steady-state model of food consumption, based upon rates of gastric turnover in Atlantic cod Gadus morhua L., has been developed and the reliability of the consumption model tested by feeding cod according to different feeding regimes using three types of food. At the end of each series, which lasted for at least 23 days, stomach contents of the...

The effects of different combinations of nutritional background, feeding regimes and dietary compositions on growth responses of the Atlantic cod have been examined. Alternating short periods (1–3 weeks) of food deprivation with unlimited provision of food depressed growth below that of controls, but cod that were fed on alternate weeks (1:1) were...

An investigation involving studies of carrying capacity and production potential of wild and released cod, Gadus morhua L., has been undertaken in the Soerfjord-Ullsfjord fjord system, northern Norway. The present paper reports data on the feeding relationships of cod between November 1989 and November 1991. The contents of 1115 cod stomachs have b...

Groups of cod were fed two natural prey types, prawn and herring, and two herring-based wet diets, one with low and the other with high energy density. Cod fed upon whole herring and enriched-herring paste showed the highest growth rates but tended to store increasing amounts of lipid in the liver. Cod fed upon the leanest diet, prawn, showed, howe...

A model that describes single-meal evacuation in Atlantic cod, Gadus morhua L., fed whole natural prey was developed and tested using a large set of data. Evacuation rates and clearance patterns were derived for four important prey. Results of a Monte Carlo error analysis suggested that: (i) the clearance of single meals is a highly temperaturedepe...

A comparison is made of the feeding habits of cod in two fjords in northern Norway, Ullsfjord and Balsfjord. Of the two, Ullsfjord is the warmer and fairly typical of Norwegian coastal waters. Balsfjord is closer to the Barents Sea in its temperature regime and ecosystem. In Balsfjord, the main food of small cod consisted of benthic crustaceans, wh...

In the present work, the feeding habits of four deep-sea shark species (Etmopterus pusillus, E. spinax, Galeus melastomus and Scyliorhinus canicula), taken as bycatch and discarded by commercial trawl fisheries, are studied also as part of some scientific projects that aim to study discards off the south coast of Portugal. Data was collected during...

Gerir pescarias artesanais é tarefa muito complexa em qualquer parte do mundo, e não existem receitas prontas de como o fazer. Os objectivos do presente trabalho são fazer uma ordenação sistemática dos principais conflitos endógenos e exógenos da pesca artesanal, incluindo uma análise do estado das pescarias, da interacção entre frotas, e da relaçã...