Domains & Essential Salmon Variables
Every data source in the hub is tagged against two linked vocabularies: the domains a salmon passes through over its life cycle, and the Essential Salmon Variables (ESVs) those sources measure. Each ESV only applies to a specific subset of domains — this page shows both vocabularies and exactly how they connect.
The 8 life-stage domains
Domains represent the stages of a salmon's migratory life cycle, from freshwater rearing out to the ocean and back again to spawn — grouped here into 4 broader environments.
River Rearing
Freshwater
23 ESVs
River Migration Smolt
Freshwater
24 ESVs
Estuary Migration Post-Smolt
Estuary
22 ESVs
Coastal Migration Post-Smolt
Coastal
24 ESVs
Ocean Migration
Shelf Seas Open Ocean
32 ESVs
Coastal Migration Adult
Coastal
20 ESVs
Estuary Migration Adult
Estuary
21 ESVs
River Migration Adult
Freshwater
22 ESVs
What each domain covers
1River Rearing
Juvenile salmon (fry and parr) feeding and growing in fresh water, from emergence until they become smolts, usually after one to four years. Conditions here set smolt size and condition, which carry over into survival at sea.
2River Migration Smolt
Smolts migrating downstream to the head of tide, mostly in spring. A short journey, but delays and predation along the way can reduce how many reach the sea.
3Estuary Migration Post-Smolt
The first days in salt water, as smolts pass through the estuary to the coast. The fish adapt to sea water while exposed to predators, and survival here can vary a great deal from year to year.
4Coastal Migration Post-Smolt
The first weeks and months at sea, along the coast and across the continental shelf on routes particular to each region's stocks, such as the European shelf edge towards the Norwegian Sea. Nearshore waters, within about 50 km of the river mouth, are where coastal aquaculture and predators may matter most.
5Ocean Migration
The open-ocean feeding grounds where salmon from many rivers mix, through one or more winters at sea: chiefly the Norwegian Sea, the Faroes, West Greenland and the Labrador Sea. Growth here shapes when fish mature and return.
6Coastal Migration Adult
Returning adults crossing the shelf seas and following the coast back towards their home river. Coastal net fisheries and bycatch can take fish on this leg.
7Estuary Migration Adult
Adults passing through the estuary, sometimes waiting there for river flows to rise. The last stage of the marine phase before re-entering fresh water.
8River Migration Adult
Adults migrating upstream to their spawning grounds and spawning, along with the kelts that survive afterwards. Skin diseases have been increasingly reported in fish after they enter fresh water.
The 60 Essential Salmon Variables
Every ESV falls into one of three categories, and applies to the domains listed on its card below — a (domain, ESV) pair outside that list isn't applicable, not merely uncovered by data yet.
Physical
(16)Air Temperature
Meteorological temperature records
Alkalinity (freshwater)
Freshwater - alkalinity
Currents (marine subsurface)
Marine - subsurface current speed and direction.
Currents (marine surface)
Marine - surface current speed and direction.
Dissolved Oxygen (freshwater)
Freshwater - dissolved oxygen (DO)
Dissolved Oxygen (marine)
Marine - dissolved oxygen (DO) below the euphotic zone.
Hydrology (freshwater)
Freshwater - hydrological regimes of surface water networks.
Morphology (freshwater)
Freshwater - physical characteristics of surface water networks.
NPS (freshwater)
Freshwater - availability of nitrate (NO3), phosphate (PO4), silicic acid (Si(OH)4), ammonium (NH4), nitrite (NO2)
NPS (marine)
Marine - availability of nitrate (NO3), phosphate (PO4), silicic acid (Si(OH)4), ammonium (NH4), nitrite (NO2)
Salinity (marine subsurface)
Marine - subsurface salinity
Salinity (marine surface)
Marine - surface salinity
Suspended Solids (freshwater)
Freshwater - suspended particles
Water Temperature (freshwater)
Freshwater - water temperature
Water Temperature (marine subsurface)
Marine - subsurface water temperatures.
Water Temperature (marine surface)
Marine - surface water temperatures.
Salmon Trait
(30)Abundance (adult spawning stock)
Freshwater - abundance of the adult spawning stock
Abundance (egg deposition)
Freshwater - abundance of eggs
Abundance (juvenile standing stock)
Freshwater - distribution and abundance of juveniles
Abundance (pfa)
Marine - modelled abundance of salmon cohort on the 1st of January of year 1 marine phase.
Abundance (smolt)
Freshwater - abundance of smolts prior to ocean entry
Age Structure (adult spawning stock)
Freshwater - age composition of the adult spawning stock
Age Structure (juvenile standing stock)
Freshwater - age composition of the juvenile standing stock
Age Structure (pfa)
Marine - age composition of post-smolts on the 1st of January of year 1 marine phase.
Age Structure (smolt)
Freshwater - age composition of smolt population prior to ocean entry
Condition (adult spawning stock)
Freshwater/Marine - indices of physical condition in the adult spawning stock.
Condition (juvenile standing stock)
Freshwater - indices of physical condition in the juvenile standing stock.
Condition (smolt)
Freshwater - indices of physical condition in the smolt population.
Fecundity (adult spawning stock)
Freshwater- the reproductive capacity of females in the adult spawning stock.
Genetic Sampling
Collection and/or analysis of genetic material
Growth Rate From Scales
Freshwater/Marine - back calculated growth rates from scale analysis.
Health State (adult spawning stock)
Freshwater/Marine - indices of health/disease status in the adult spawning stock.
Health State (juvenile standing stock)
Freshwater - indices of health/disease status in the juvenile standing stock.
Health State (smolt)
Freshwater - indices of health/disease status in the smolt population.
Maturation Rate (juvenile standing stock)
Freshwater - Precocious maturation in juvenile standing stock.
Maturation Rate (pfa)
Marine - modelled maturing and non-maturing ratio within cohort on the 1st of January of year 1 marine phase.
Migration Timings (river entry adult)
Freshwater - run timing of adults.
Migration Timings (smolt emigration)
Freshwater - timing of smolt emigration.
Nutritional State (adult spawning stock)
Freshwater/Marine - indices of nutritional state in the adult spawning stock.
Nutritional State (juvenile standing stock)
Freshwater - indices of nutritional state in the juvenile standing stock.
Nutritional State (smolt)
Freshwater - indices of nutritional state in the smolt population.
Sex Ratio (adult spawning stock)
Freshwater - proportions of males and females in the adult spawning stock.
Sex Ratio (pfa)
Marine - modelled proportions of male and females of post-smolts on the 1st of January of year 1 marine phase.
Sex Ratio (smolt)
Freshwater - proportions of males and females in the smolt population.
Sex ratio (juvenile standing stock)
Freshwater - proportions of males and females in the juvenile standing stock.
Tagging, Marking and Tracking
Tagging, marking and/or tracking, including recoveries
Biological
(14)Avian Population Dynamics and Ecology
Abundance, distribution, condition and diet of avian predators of salmon.
Commercial Fishing Bycatch
Occurrence, distribution and/or abundance of salmon caught as bycatch.
Dissolved organic carbon (marine)
Marine - dissolved organic carbon (DOC)
Fish Parasites, Pathogens and Disease
Occurence, distribution, diversity and abundance of salmon parasites, pathogens and diseases.
Fish Population Dynamics and Ecology
Abundance, distribution, condition and diet of fish predators of salmon.
Fish Population Dynamics and Ecology (Prey)
Abundance, distribution, condition and diet of fish species that may be prey for salmon.
Fish Population Dynamics and Ecology (buffer)
Abundance, distribution, condition and diet of fish species that may act as a buffer from predation of salmon
Fish Population Dynamics and Ecology (competitor)
Abundance, distribution, condition and diet of fish species that may compete with salmon for prey.
Ichthyoplankton Indices
Abundance, distribution, condition and diet of fish species larvae that may be prey for salmon (prey or secondary).
Mammal Population Dynamics and Ecology
Abundance, distribution, condition and diet of mammalian predators of salmon.
Phytoplankton Biomass and Diversity (marine)
Marine - phytoplankton biomass and diversity
Prey Indices (freshwater)
Freshwater - invertebrate biomass, distribution, diversity and condition (prey or secondary)
Targetted Harvest Fishery
Occurrence, distribution and/or abundance of salmon caught in targetted fisheries.
Zooplankton Biomass and Diversity (marine)
Marine - zooplankton biomass, diversity and condition (prey or secondary)