Total marine fisheries extractions by country in the Baltic Sea

Total marine fisheries extractions by country in the Baltic Sea: 1950-present, Rossing, Booth and Zeller 229
commercial landings data (Table 1). An optimal source for commercial landings data should have been the
data from the ICES stock assessment working group reports (although only for species with stock
assessments) that are known to attempt adjustment of reported landings data based on additional
information. However, data as presented in these working group reports lack transparency with regards to
country-specific accounting of each catch component (e.g., landings, unallocated, discards, recreational).
This lack of country-specific transparency makes the use of stock assessment report data very difficult
when focusing on country- rather than stock-specific catches.
Unreported landings
Unreported landings are thought to be the
largest component of IUU catches in the Baltic
Sea (Sporrong, 2007), especially if illegal is
defined as pertaining to ‗without permission‘
rather than quota violations. Information on
unreported landings was obtained through
interviews and literature (including grey
literature and media reports). While some
anchor points could be found starting in the late
1980s (Table 2), no information could be found
for the pre-1980 period. Thus, a few assumptions
were made to create anchor points for 1950 and
1980 so that linear interpolations could be done.
In 1950, there were fewer incentives to
underreport landings due to a lack of quota
limitations (Eero et al., 2007), however, there
was also less enforcement for reporting landings
(Anon. pers. comm., Swedish Board of
Fisheries). Therefore, the unreported landings
for all species (except salmon, see below) in 1950
were assumed to be 5% of reported landings,
which is thought to be conservative. To reflect
the introduction of quotas, and the associated
stronger incentives for underreporting, starting
in the 1970s (Søndergaard, 2007), 1980 was used
as a break point. Thus, for 1980, half of the value
for the first post-1980 data anchor point was
applied. This rule was applied to all species,
except salmon (see below), even though not all
have quotas. For species without any
information on unreported landings, an
estimated percentage was derived from anchor
point data for cod in 1987, and herring and sprat
in 1993 (see paragraph ‗other species‘ for
details). Percentage rates were linearly
interpolated between anchor points (Table 2),
and applied to ICES landings statistics +
adjustments to derive a complete time series of
estimated unreported landings.
Cod: Based on information on reported and
unreported landings of cod in the harbor of
Härnösand in 1987 (P.-O. Larsson, pers. comm.,
Table 1. Species specific adjustments to ICES landings
statistics by year.
Common
name
ICES landings
ICES stock
assessment
reports
Swedish
data a
Cod 1950-1964, 1965-1975 -
1976-2007
Herring 1950-1989 1990-2007 -
Salmon 1978 - 1950-1977,
1979-2007
Burbot 1970,
1979-2007
Dab 1950-1975 b ,
1977-2007
Flounder 1950-1969 b ,
1973-1989
Perch 1970,
1974-1975,
1979-2007
Sprat 1950-1955,
1964-1968,
1973-1974,
1978-1986,
1988-1989
- 1950-1969
- 1976
1990-1999 1970-1972
- 1950-1969
1990-2007 1956-1963 c ,
1969-1972 c ,
1975-
1977 c , 1987
Whitefish 1970-1972 d ,
1974-2007 d - 1950-1969
Pike 1970,
1974-1975,
1979-2007
- 1950-1969
Sea trout 1978 - 1950-1977,
1979-2007
Turbot 1950-1961, - 1962-1969
1970-2007
Vendace 1970-1972,
1974-2007
- 1950-1969
a
data from yearbooks of Swedish fisheries statistics 1950-1993,
e.g., Anon. (1952). For 1999 onwards, data are available at
www.fiskeriverket.se. b taxonomic mislabeling between common
dab and European flounder 1956-1959, and 1972. c half of the nonspecies-specific
industrial fishmeal catch for that year was added to
the sprat catch. d European whitefish and ‘whitefish nei’ combined.
Swedish Board of Fisheries, retired), a conservative anchor point for unreported landings was calculated
for 1987 (Table 2) based on the assumption that there were no other unreported landings in Sweden that
year (see next paragraph for details). Anchor points for 1950 and 1980 were derived according to the
assumptions described above. In recent years three different sources (Anon., 2004a; 2007c; 2008b) were
combined to derive an average percentage used as anchor points for 2006 and 2007 (Table 2; see next