Factors for converting the basis of assessment concentrations in biota

The table below gives the typical % dry weight (% dw) and % lipid weight (% lw) for each species and tissue. The values are derived from monitoring data for the years 2001 to 2020 inclusive based on an extration from the ICES data base on 11 January 2022.

species	common name	% lw in muscle	% dw in muscle	% lw in liver	% dw in liver	% lw in soft body	% dw in soft body	% lw in tail muscle	% dw in tail muscle
Clupea harengus	herring	4.6	26.5	4.4	32.0
Gadus morhua	cod	0.3	19.2	43.0	55.0
Lepidorhombus whiffiagonis	megrim	0.3	20.2	24.7	40.2
Limanda limanda	common dab	0.7	20.1	19.6	32.3
Merlangius merlangus	whiting		20.0	36.5	44.5
Merluccius merluccius	hake		20.0	43.7
Molva molva	common ling	0.3	21.1	53.0	64.2
Platichthys flesus	flounder	0.9	21.3	14.9	32.2
Pleuronectes platessa	plaice	0.5	20.0	11.0	27.1
Scomber scombrus	Atlantic mackerel		25.6	7.0	26.6
Zoarces viviparus	eelpout	0.6	18.6	0.6	23.0
Callista chione	smooth clam					0.7	20.0
Cerastoderma edule	common cockle						18.0
Chamelea gallina	striped venus clam					0.7	20.0
Donax trunculus	wedge clam					0.7	20.0
Ensis ensis	sword razor					0.7	20.0
Glycymeris glycymeris	dog cockle					0.7	20.0
Mya arenaria	softshell clam					0.7	15.5
Ruditapes philippinarum	manila clam						16.1
Solen marginatus	grooved razor shell					0.7	20.0
Spisula solida	surf clam					0.7	20.0
Mytilus edulis	blue mussel					1.4	16.4
Mytilus galloprovincialis	Mediteranean mussel					2.0	19.0
Crassostrea gigas	Pacific oyster					1.9	18.0
Ostrea edulis	native oyster					1.7	20.1
Crangon crangon	common shrimp							1.4	27.3
Littorina littorea	common periwinkle						22.3
Nucella lapillus	dog whelk						32.3
Tritia nitida / reticulata	dog whelk (nitida / reticulata)						27.0
Cepphus grylle	black guillemot				32.0
Fulmarus glacialis	northern fulmar				29.4
Globicephala melas	long-finned pilot whale	70.0	29.0		27.6

• The following species (mostly clams) have no dry weight or lipid weight information in the ICES extraction: Callista chione, Chamelea gallina, Donax trunculus, Ensis ensis, Glycymeris glycymeris, Solen marginatus, Spisula solida. The % dry weight and % lipid weight have been set (somewhat arbitrarily) at 20% and 0.7% respectively.
• The % dry weight of bird blood (not tabulated above) has been set at 21%. See Ackerman et al. (2016), Avian mercury exposure and toxicological risk across western North America: a synthesis. Science of the Total Environment 568:749-769.