Total marine fisheries extractions by country in the Baltic Sea

12 Total marine fisheries extractions by country in the Baltic Sea: 1950-present, Rossing, Booth and Zeller
Unreported % = unallocated catches /(total cod landings – Sweden‘s cod landings)
In order to account for historical and political differences, the former
eastern bloc countries (East Germany, Estonia, Latvia, Lithuania,
Poland, and the Russian Federation) were treated separately from
western countries. The western countries, which already had market
economies in 1950, were assumed to have unreported landings
throughout the time period considered here. As there were no reports
documenting unreported landings prior to 1993, we used an
assumption-based approach to derive an anchor point for 1980 and
1950. For 1950, it was conservatively assumed that unreported
landings were 5% of the reported landings, while for 1980,
unreported landings were assumed to have been half the 1993
estimated rate (Table 2). For the former eastern bloc countries, with
state controlled economies in the early years, it was assumed that
there was no incentive to not report all landings because prices for
different species were similar enough to discourage mis-reporting (R.
Oeberst, pers. comm., Johann Heinrich von Thünen-Institut). Thus,
unreported landings by eastern countries were conservatively set to
zero from 1950 to 1990, and then linearly interpolated to 1993, the
first year when estimates of unreported catches were available (Table
2).
Atlantic salmon: Unreported landings of salmon are not presented in
the ICES stock assessment results database; however, some
information on unreported landings of salmon were available from
ICES working group reports (ICES, 2008b). The working group
reports Baltic-wide estimates of the mode, minimum and maximum
of unreported landings for all Baltic countries combined from 1981-
2007. Countries whose reported landings data included recreational
catches (Denmark, Finland, and Sweden; see Table 2.1.2 in ICES,
2008b) had anchor points derived in a slightly different manner than
countries that did not report recreational catches.
Table 2. Default anchor points (%)
used for estimating unreported
landings of eastern cod stocks in the
Baltic Sea based on ICES (2007, Table
2.3.1). Dashes (-) indicate years of
linear interpolation between anchor
points.
Eastern cod
Year Western
countries
Eastern
countries
1950 5.0 a 0.0 b
1951-1979 - 0.0 b
1980 31.1 c 0.0 b
1981-1990 - 0.0 b
1991-1992 - -
1993 62.2 62.2
1994 103.0 103.0
1995 30.0 30.0
1996 10.0 10.0
1997-1999 - -
2000 46.0 46.0
2001 47.6 47.6
2002 46.6 46.6
2003 61.5 61.5
2004 52.9 52.9
2005 46.4 46.4
2006 47.9 47.9
2007 43.2 43.2
a assumption of 5% of reported landings;
b assumption of zero unreported catches;
c assumption of ½ the estimated rate for
1993.
Thus, we used two separate assumption-based approaches to estimate salmon IUU catches:
a) for Denmark, Finland, and Sweden, whose reported landings in Table 2.1.2 in ICES (2008b)
included estimates of recreational catches, we utilized both the mode and the minimum value
of unreported landings from the ICES salmon working group report (Table 2.1.2 in ICES,
2008b) to estimate country specific unreported salmon catches. The mode was used prior to
countries reporting recreational catches, and after countries started to report recreational
catches the minimum was used; and
b) for all other countries, whose reported landings data in Table 2.1.2 in ICES (2008b) did not
include recreational catches, we used the mode value of unreported landings from Table 2.1.2
in ICES (2008b) to estimate country specific unreported catches.
In keeping with the assumption-based approach, the former eastern bloc countries were assumed to report
all landings, and thus, were conservatively assumed to have no unreported landings from 1950-1990
(Table 3). To account for the shift to market economies and the associated underreporting incentives,
linear interpolations were made between 1990 and the first anchor point in 1993 based on the above
described method for estimating unreported landings. Prior to applying this method to the western
countries, a correction was applied to reported landings, as it was assumed that the eastern bloc countries
reported all landings of salmon prior to 1990. For the earlier time periods, assumption-based approaches
were used, but when unreported landings were first documented in ICES working group data, the
estimates of unreported landings between 1950 and 1990 for western countries in each year were
calculated as,
Unreported landings % = mode of unreported catches/[total reported landings – eastern bloc landings]