| Abstract: |
The project STELLA (Gillnet-Solution-Approaches) aimed at finding finding
solutions for the mitigation of unwanted by-catches of sea birds and marine
mammals, and thus reconcile nature conservation interests and the interests of
coastal fisheries in the Baltic Sea. The project was carried out by the Thünen
Institute of Baltic Sea Fisheries (OF) from November 2016 to January 2020,
funded by the Federal Ministry for the Environment, Nature Conservation and
Nuclear Safety in cooperation with the Federal Agency for Nature Conservation.
From February to July 2020, pending work was continued with funds of the
Thünen Institute. The objectives of the project were executed in five work
packages (WP): WP1 aimed to improve data collection from the gillnet fishery;
WP 2 focused on technical modifications of gillnets to reduce unwanted
bycatches; WP3 addressed improvements to two alternatives to the gillnet, the
fish trap and the pontoon trap; the social-science WP4 dealt with the fishing
practice in relation to the avoidance of undesirable by-catches. Finally, WP5
synthesised the results of WPs 1 to 4 and derived recommendations to policy
makers. WP1 analyzed the structure of the German small-scale gillnet fleet in
the Baltic Sea and was able to identify eight distinct groups, similar in
terms of activity and fishing pattern, that were stable over time. The
identification of these fishing groups is essential in order to find tailored
solutions, because there can be no uniform approach to the transformation of
the gillnet fleet given its heterogeneity. In addition, means of data
collection have been improved in this WP. In particular, reliable,
high-resolution effort data that have not yet been reliably available from
this fishing segment can now be collected on vessels of all sizes using the
smartphone application “Mofi” (“mobile fisheries log”) developed in the
project. A test lasting several months in the commercial fishery was
successful. The "Mofi-App" is continuously developed further to allow for e.g.
the photographic documentation of unwanted bycatch or gear damage caused by
grey seals in the area, aiming at making its use more attractive for fishers.
After a thorough review of the state of knowledge at the beginning of the
project, WP2 focused on improving the acoustic "visibility" of gillnets. In
order to prevent harbor porpoises from entangling and drowning in gill nets,
acrylic beads were identified as the smallest possible neutrally buoyant
bodies, which appear like much larger objects for the acoustically-oriented
harbor porpoise due to a resonance frequency. These beads, which were glued
into the meshes of the gill nets, could make the net acoustically perceivable
(“visible”) for porpoises. In order to test the effectiveness of this net
modification, the “beads net” was tested in a commercial fishery which is
known for elevated bycatch rates of porpoises (gillnet fishery for turbot in
the Black Sea). The experiments showed evidence of a reduction in by-catches,
but statistically significant evidence is still pending due to the overall low
by-catch rates during the experiment. WP3, the second technical WP, advanced
fish traps and a pontoon trap as an alternative to gill nets. Fish traps and
pontoon traps are known to reduce the bycatch of seabirds and marine mammals
considerably, but so far have a lower catchability for the target species;
they are also more complex to handle than gill nets and are therefore rarely
used in German Baltic Sea fisheries. It has been possible to increase the
catchability of the fish traps and to adapt the pontoon trap to the special
conditions in the German Baltic fisheries (e.g. use in exposed shallow-water
areas, adaptation to the target-species spectrum). The increase in the number
of grey seals in German Baltic waters and the increasing catch losses and
damage to gill nets caused by this species will make the use of alternative
fishing gear - such as fish traps - necessary in the near future. This could
protect both the fishermen's catch from damage by the seals and the grey seals
from drowning in the fishing gear. WP4 took the approach of using social
science to develop adapted bycatch management. Research on fisheries
management has called for years for consideration of people in the development
of management tools, since successful management is based on behavioral
responses of fishermen to imposed measures. Three types of fishermen and two
different attitudes toward bycatch were categorised within the German Baltic
small-scale gillnet fishery. An expert workshop identified potential
management approaches that could avoid bycatch. Summary 5 These results were
analysed in light of the types of fishers and their attitudes toward bycatch,
and conclusions were drawn about which types of fishers could be targeted best
with which management tools to promote their compliance. At the same time,
changing fisher's attitudes toward bycatch events to understand the
significance for a sustainable fishing was identified as one of the key
actions. To date, a discourse has prevailed among fishers that describes
seabird bycatch largely as a part of daily routine. Significant progress in
transforming fisheries to reduce environmental impacts requires a change in
discourse, fostered, for example, through co-management processes. In a number
of important areas of work, STELLA was able to lay the foundation for the
mitigation of by-catches of seabirds and marine mammals by gillnet fishing in
the western Baltic Sea. Most of the work will be continued seamlessly,
including in the context of follow-up projects, so that it could be
implemented in fisheries in the foreseeable future. Gaps in knowledge exist
mainly in aspects that are necessary to avoid seabird by-catches. These could
not be addressed within STELLA, mainly because basic knowledge on sea bird
behaviour is lacking. Such insights are a prerequisite for a systematic
development of technical bycatch mitigation. The project results demonstrate
that effort data can be recorded area-wide and in high resolution even on
smallest fishing vessels, simple and cost-efficient using the smarthphone
application “Mofi” developed within the Stella project. We therefore recommend
to implement the required incentives or regulations to ensure a rapid start of
such a data collection. With some time lag, needed for an unaltered
determination of initial effort, by-catch data for endangered, threatened and
protected (ETP) species should be systematically recorded and verified with
the help of electronic monitoring systems. For their rapid uptake in the
fishery, incentives should be created that can be specific to the needs of the
identified fishing groups; quota additions and excemptions from closed areas
appear to be a stronger incentive than monetary aids. For the individual
identified fishing groups, tailor-made solutions should be developed, which on
the one hand can ensure economically viable German inshore fisheries, and on
the other hand reduce their environmental impact. This requires the timely
development of an overall strategy. If available, technical solutions for
fishing gear that are already in use can probably be introduced relatively
quickly and with little conflict because they require little change in
fisher’s behaviour. Depending on the solution, a mandatory introduction (like
in case of the “beads net”) or a voluntary introduction with incentives (in
case of alternative fishing techniques) should be provided. If technical
solutions are (presently) not available, legal actions for the mitigation are
required. Social-science aspects should be included from the very beginning
when designing and implementing measures to reduce the environmental impact of
fishing; and full involvement of all actors should be ensured for each measure
(comanagement). The creation of incentives carefully tailored to the specific
target groups identified in this project is necessary because of the great
heterogeneity of German gillnet fleet. This will help to convey that the
measures are also in the interest of the fishery. |