Total marine fisheries extractions by country in the Baltic Sea

42 Total marine fisheries extractions by country in the Baltic Sea: 1950-present, Rossing, Booth and Zeller
data source additions to officially reported landings data; ii) ‗unreported‘ landings, being landed catches
not reported to authorities (which ICES refers to as ‗unallocated‘); iii) ‗discards‘, being fish caught by
fishing operations but not retained; and iv) ‗recreational‘ catches. Supplementing reported landings with
IUU catches aims to represent the total fisheries catches in Denmark from 1950-2007.
Adjustments to reported landings and estimates of IUU were derived using high-quality, alternate data
sources including ICES stock assessment working group data (ICES, 2009), national datasets, and
interviews with Baltic fisheries officials. For a lack of country-specific data for unreported landings and
discards in the Baltic, we derived an assumed default method using Baltic-wide estimates of unreported
landings and discards from ICES stock assessment working group data. We considered these reported
estimates as proportions of ICES landings statistics, plus adjustments, to derive Baltic-wide rates (%) of
underreporting and discarding which were applied to landings in Denmark. Other assumed default anchor
points were also formed to expand estimates of unreported and discarded catches to time periods when no
data were reported. For years between anchor points, linear interpolations were used to estimate the
various components of IUU. Our catch reconstruction for Denmark was taxon-specific for cod (eastern and
western stocks); herring; sprat; Atlantic salmon; flatfishes, which included common dab, European plaice ,
European flounder, brill and turbot; and a miscellaneous grouping, ‗others‘ comprised of 97 taxa.
Illegal, Unreported and Unregulated (IUU) catches
Four components of IUU were estimated in our catch reconstruction: i) ‗adjustments‘ to reported landings
data; ii) ‗unreported‘ landings; iii) ‗discard‘ catches; and iv) ‗recreational‘ catches. The sum of ICES
landings statistics, adjustments, unreported landings, discards and recreational catches represents the
total reconstructed catch for Denmark from 1950-2007.
Adjustments to reported landings
Adjustments to the ‗officially reported‘ ICES landings statistics for Denmark were based on data and
information originating from ICES stock assessment working group data (ICES, 2007; 2008b). After
comparing these alternate data to ICES landings statistics, adjustments were made for cod (eastern and
western stocks), salmon, and the group flatfishes (Table 3). Sprat and herring did not have any
adjustments incorporated, as ICES stock assessment working group reports (focusing on stock rather than
area of capture), include data representative of an area including the Baltic Sea, the Skagerrak, and the
Kattegat (ICES, 2008a)
Table 3. Years for which adjustments were made to reported landings
data (ICES landings statistics) for Denmark by taxon. Data sources
(ICES, 2007; 2008a).
Common name
Years
Cod (eastern and western stocks) 1965-2007
Atlantic salmon 1980, 1993, 1998-2006
Flatfishes
Brill 1995, 2005
Common dab 2005
European flounder 1968-1970, 1973, 1989, 1992-1994
European plaice 1996, 2005
Turbot 1993
Adjustments to reported landings of
cod were made in all years for the
1965 to 2007 period (Table 3).
Flatfishes and salmon had changes
made in years for which ICES stock
assessment working group data
indicated higher landings than the
ICES landings statistics database
(Table 3). Thus, the ICES landings
statistics plus adjustments form the
best estimate of commercial landings
data to which other IUU components
were applied.
Unreported landings
All rates of unreported landings (%) from 1950-2007, were applied to the sum of ICES landings statistics
(t) plus adjustments (t) to estimate unreported landings (t) in Denmark.
Cod: Estimates of unreported landings from 1950-2007 in Denmark were derived according to a
combination of default, assumption-based methods, ICES stock assessment working group data (Tables