The Davis Strait - DCE - Nationalt Center for Miljø og Energi

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Right before the females extrude the eggs the male attaches a spermatophore
to the female. On extrusion of the eggs the females carry them on their legs
for approximately 6-9 months.
Distribution: The northern shrimp is an expansive species (Bergstrom 2000)
with a circumpolar occurrence. In West Greenland shrimps are distributed
along the entire coastline at depths ranging from 9- 1,450 m, but are most
common at 100-600 m in depth. However the striped pink shrimp is more
abundant in shallow and costal water (Simpson et al. 1970). In recent years
the extension area for northern shrimp has moved northwards (Ziemer et al.
2010) and the main biomass is now concentrated north of 67°N.
Movements: The shrimps are highly mobile both horizontally and vertically
and have a diurnal migration where they forage at the bottom during daytime
and in the pelagic foodweb at night (Horsted & Smidth 1956).
Breeding distribution: The shrimps migrate horizontally into the inshore shallow
areas in order to spawn (Hjort & Ruud 1938, Horsted & Smidth 1956,
Haynes & Wigley 1969, Bergstrom 1991) and the northern shrimp spawns in
Greenland waters during April (Horsted 1978).
Population size: The northern shrimp stock is assessed as a single population.
The total biomass of northern shrimp in West Greenland has increased since
the early 1990s, reaching its highest level in 2005 and decreasing since. However,
total biomass in 2010 appears to be above the level where it can produce
its maximum sustainable yield and is above the average for the entire
time series (Hammeken & Kingsley 2010). Since 2007 the stock has declined
in the assessment area as the population of northern shrimp has contracted
northwards (Ziemer et al. 2010). The recruitment of northern shrimp has
been low since 2006, but the reason for this is uncertain (Ziemer et al. 2010).
Pedersen & Storm (2002) and Koeller (2009) suggest that the recruitment of
shrimps is dependent on food availability.
Buch et al. (2003) has shown a tight relationship between the occurrence of cod
and the disappearance of shrimps. Nevertheless in recent years the estimated
biomass of cod has been very low and there must therefore be other explanations
for the decline in biomass. It would be reasonable to look into the matchmismatch
theory for shrimp egg hatching and the peak of phytoplankton
bloom in order to investigate possible correlations (Wieland & Hovgaard
2009).
Sensitivity and impacts of oil spill: Boertmann et al. (2009) assumed that fish
and shrimp larvae are more sensitive to oil than adults, but consequences for
survival, the impacts of annual recruitment strength and subsequent population
size are unknown. The shrimp larvae have a pelagic phase and the resources
will be especially sensitive to oil spill in that season.
Knowledge gaps: Early life history of shrimp, including larval drift between
offshore and inshore sites and along the west coast, nursery grounds as well
as settling and occurrence of benthic stages is unknown or poorly understood
in the assessment area. Furthermore, there is a need to understand
whether or not there is a link between shrimp recruitment and climate
changes due to a mismatch in the timing of shrimp larval hatching and the
peak of the phytoplankton bloom in West Greenland. The underlying mechanisms
for the dispersal of the northern shrimp stock, moving south (around