Marine Pollution Bulletin xxx (xxxx) xxx–xxx

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Marine Pollution Bulletinjournal homepage: www.elsevier.com/locate/marpolbul

Early steps for successful management in small-scale ﬁsheries: An analysis ofﬁshers', managers' and scientists' opinions preceding implementation
Sieglind Wallner-Hahna,⁎, Maricela de la Torre-Castrob,caDepartment of Ecology, Environment and Plant Sciences, Stockholm University, 106 91, Sweden
Department of Physical Geography, Stockholm University, 106 91, SwedencStockholm Resilience Centre, Stockholm University, 106 91, Swedenb

A R T I C L E I N F O

A B S T R A C T

Keywords:
Heterogeneity
Small-scale ﬁsheries
Co-management
Environmental governance
Seagrass meadowsSocial-ecological
Seascape
Gear restrictions

This study analyzes ﬁshers', managers' and scientists' opinions on management measures to facilitate the initiation of management processes towards more sustainable small-scale seagrass ﬁsheries in Zanzibar, Tanzania.
The results show that most ﬁshers and managers agreed on the need to include seagrasses speciﬁcally in future
management. There was further agreement on dragnets being the most destructive gears, and the use of dragnets
being a major threat to local seagrass ecosystems. Gear restrictions excluding illegal dragnets were the favoredmanagement measure among ﬁshers. Diﬀerences between ﬁshers and managers were found concerning seaweedfarming, eutrophication and erosion being potential threats to seagrass meadows. A majority of the interviewed
ﬁshers were willing to participate in monitoring and controls, and most ﬁshers thought that they themselves andtheir communities would beneﬁt the most from establishing seagrass management. Co-managed gear restrictions
and the inclusion of diﬀerent key actos in the management process including enforcement are promising starting
points for management implementation.

1. Introduction
To maintain, or ideally to improve people's livelihoods by sustainably managing the resources they depend on, is one of today's biggest
challenges. The degradation of marine resources due to intense ﬁshingpressure and the use of non-sustainable gears is a global concern(Jackson et al., 2001; Myers and Worm, 2003; Berkes et al., 2006).
However, in ﬁsheries management, the positive outcomes managers
strive for when designing protected or restricted areas are often notreached after implementation (McClanahan, 1999; Pitcher and Lam,
2010). It has been highlighted that participation of ﬁshers in planning,decision-making and governance is crucial for the success of management schemes which restrict access to ﬁshing grounds (Jentoft andMcCay, 1995; Jentoft et al., 1998; Berkes, 2009; Jentoft et al., 2012).
Further, perceptions and common values and goals among stakeholders
and resource users have been pointed out to be of highest importancefor sustainable management (McClanahan et al., 2005b; Gelcich et al.,2006; Gelcich et al., 2007). The chances of management to be successful
increase when ﬁshers and managers share preferences for certain
management measures and cooperate on their implementation (Jentoft
et al., 1998; Defeo and Castilla, 2005), and shared attitudes can improve compliance and reduce the costs of enforcement (McClanahan⁎

et al., 2004). These attitudes, perceptions and actions which ﬁshers andmanagers share or which deviate from each other, are in turn based onvalues, images and principles which shape their worldviews (Songet al., 2013). The more diverse the stakeholders' and managers' images
are, the more complex to govern are the ﬁsheries (Jentoft et al., 2012).
In many cases, the images and perceptions of resource users may deviate substantially from those of managers, which can lead to misunderstandings, confrontations and even challenge the overall governability of a ﬁshery system (Jentoft and Chuenpagdee, 2009; Songet al., 2013). Attitudes to management can also diﬀer between andwithin groups of ﬁshers, for example with varying management experiences (Gelcich et al., 2005) or between diﬀerent gear users (Blythet al., 2002; de la Torre-Castro and Lindström, 2010). In such situations,
it is valuable to explore the priorities of the diﬀerent stakeholder
groups, which can build respect and trust and can help to identify areasof agreement (Hicks et al., 2013). Therefore, the assessment and comparison of perceptions and opinions is a constructive ﬁrst step towards
communicating, rationalizing and bringing them into convergence for
implementation (McClanahan et al., 2005b; McClanahan et al., 2009;
Jentoft et al., 2012).
Most studies on attitudes and perceptions of resource users are conducted after new rules or restrictions already have been implemented.

Corresponding author at: Finnbergsvägen 2, 13131 Nacka, Sweden.
E-mail address: sieglind.wallner-hahn@su.se (S. Wallner-Hahn).

http://dx.doi.org/10.1016/j.marpolbul.2017.07.058
Received 31 March 2017; Received in revised form 23 July 2017; Accepted 24 July 20170025-326X/ © 2017 Published by Elsevier Ltd.

Please cite this article as: Wallner-Hahn, S., Marine Pollution Bulletin (2017), http://dx.doi.org/10.1016/j.marpolbul.2017.07.058

Marine Pollution Bulletin xxx (xxxx) xxx–xxx

S. Wallner-Hahn, M. de la Torre-Castroﬁsheries resources (DoFD, 2010). Many ﬁshers are marginalized and live
close to the extreme poverty line of US$ 1.25 per day (de la Torre-Castro
et al., 2014). Local ﬁnﬁsh-ﬁsheries employ roughly 34,000 people, themajority of which are men, are predominantly low-tech and generate low
income (Jiddawi and Khatib, 2007; DoFD, 2010; Frocklin et al., 2013).
Due to the dominance of low-technology gear and non-motorized ﬁshingvessels, most ﬁshers operate in shallow inshore waters at patchy andfringing coral reefs and seagrass beds, resulting in a heavy ﬁshing pressure on these ecosystems (de la Torre-Castro et al., 2014). Typical ﬁshingvessels used are dugout canoes, outrigger canoes or wooden boats withsails but also engine-driven wooden boats or ﬁberglass boats are used tosome extent (Jiddawi and Khatib, 2007). A high variety of ﬁsh species istargeted and ﬁshing gears used are mainly of traditional character (including ‘madema’ basket traps, smaller nets and handlines), but also
more modern gears are used (like larger gillnets, beach seines or spear
guns (DoFD, 2010). The ﬁsh catches are used for own consumption as
well as sold to local markets and ﬁsh traders, restaurants or hotels(Thyresson et al., 2013). Fisheries related activities like processing andtrading employs another 2900 people (Lange and Jiddawi, 2009),
whereof many women (Frocklin et al., 2013).
In many areas of Zanzibar's coast, local ﬁshing communities used
traditional systems for self-regulation to avoid overexploitation(Jiddawi, 1998). Due to population growth, migration, few employment opportunities, growing tourism and the open access ﬁsheries
character however, the demand for marine resources is growing andsigns of overexploitation of near-shore ecosystems have been reported(Tobisson et al., 1998; Jiddawi and Öhman, 2002). The use of destructive gears like dragnets and nets with small mesh-sizes (whichdragnets often are) endangers, among other factors, a sustainable provision of marine resources due to their damaging eﬀect on habitats likeseagrasses and corals or catches of undersized ﬁsh (McClanahan andMangi, 2001; Jiddawi and Öhman, 2002; Mangi and Roberts, 2006).
The ﬁshing communities in Zanzibar are heterogeneous e.g. in terms ofused ﬁshing gears or attitudes and opinions concerning the government(Lindström, 2012). As managing small-scale ﬁsheries is a complex endeavor (Jentoft and Chuenpagdee, 2009), shortcomings in local ﬁsheries management have also been described for Zanzibar (de la TorreCastro, 2012a; Lindström, 2012). These are for example illustrated in
the use of illegal gears or conﬂicts over gears and ﬁshing grounds incertain areas (de la Torre-Castro and Lindström, 2010). De la TorreCastro (2012b) describes that the “dominating focus on conservation,
the lack of a holistic approach and failure to consider resource users
seriously” have led to unsuccessful management, and that current
management plans often miss the context of poverty and resource dependency. Promising approaches for the management of such smallscale ﬁsheries have been suggested to be the seascape approach incombination with co-management and ecosystem stewardship, and afocus on resource users as central actors (Chapin et al., 2010).
In Zanzibar's National Integrated Coastal Management (ICM)
Strategies, an emphasis is put on community involvement in ﬁsheries
management (ICM, 2003). For the time being however, the communities' participation is mainly regulated in top-down fashion(Lindström, 2012) rather than through self-organization and –mobilization which has been emphasized as an essential starting point forsuccessful ﬁsheries co-management (Chuenpagdee and Jentoft, 2007).
However, de la Torre-Castro and Lindström (2010) describe cases ofself-organization, but on the purpose of defending ﬁshing gears, ﬁshinggrounds and ﬁshing rights in times of conﬂict rather than to act forenvironmental conservation. Beach recorders, called “Bwana Dikos” inlocal Swahili, are monitoring agents and build, together with village
ﬁshery committees, the links to higher levels of organization like thegovernment and its' ministries and agencies or to international organizations (de la Torre-Castro, 2006; Lindström, 2012). These local
committees representing local people on village level have howeverbeen described as to be to a substantial part creations of the government and international organizations (Lindström, 2012), and it can be

However, studies of ﬁshers' and managers' opinions preceding management implementation can be a valuable ﬁrst step, as they might help todecide how to proceed and may be decisive for the outcome of the
management process (Chuenpagdee and Jentoft, 2007).
Seagrasses fulﬁll a key role in the marine environment (e.g. Shortand Green, 2003) and the global importance of seagrass-associatedsmall-scale ﬁsheries as social-ecological systems has recently beenhighlighted (Cullen-Unsworth et al., 2014). This study was conductedin Zanzibar, Tanzania, where seagrass-associated ﬁsheries play an explicitly important role for the livelihoods of local communities(Gullström et al., 2002; de la Torre-Castro and Rönnbäck, 2004;
Nordlund et al., 2010). For certain ﬁshing communities in Zanzibar,
seagrasses have even been shown to serve as the most frequently visited
ﬁshing grounds (de la Torre-Castro and Rönnbäck, 2004; de la TorreCastro et al., 2014). Despite their importance for local livelihoods,
seagrass ecosystems receive only little attention in research, management and policy compared to other marine habitats (Duarte et al.,2008). Recent studies emphasize the need for an inclusion of all key
ecosystems in coastal management and explicitly seagrasses and theirsocial dimensions (Unsworth and Cullen, 2010; de la Torre-Castro et al.,2014). In Zanzibar, current management eﬀorts of marine resources
appear to focus on the protection of corals for tourism beneﬁts rather
than ﬁsh provision services (de la Torre-Castro, 2012b), and there are to
the authors' knowledge currently no national laws, rules, regulations or
management plans focusing on or including seagrasses speciﬁcally.
The background of Zanzibar's small-scale ﬁsheries is, among otherfactors, shaped by weak resource user participation in management,
low compliance, negative experiences from past management eﬀorts,lack of seagrass-speciﬁc incentives and newly planned eﬀorts on monitoring and enforcement. We consider the need for improved management in the area, and act on the assumption that management is more
likely to be successful if resource users support it. Consequently, themain objective of this study is to assess agreements as well as diﬀerences in ﬁshers' and managers' attitudes and opinions towards management of seagrass-associated small-scale ﬁsheries a priori rather thanafter management implementation. We identify areas of congruence
and/or disparity between ﬁshers' and managers' views, which cancontribute as a basis for communication among stakeholder groups,
which in turn enables the process of reaching equitable solutions for
future seagrass management. The four speciﬁc aims were to assess andcompare the ﬁshers' and managers' opinions concerning i) the importance, current state and eventual need for management of local
seagrass ecosystems, ii) the present threats to seagrasses and measures
to lessen them, iii) the readiness of ﬁshers to adopt diﬀerent management measures and iv) the ﬁshers' willingness to participate in monitoring as well as the perceived distribution of beneﬁts of seagrassmanagement. The results of this study contribute insights for a valuable
step towards the co-management of seagrass ﬁsheries in Zanzibar,
where ﬁshers are not only at the receivers' end, but are active players in
the implementation and preceding steps (Chuenpagdee and Jentoft,2007).
2. Methods
2.1. Study site description
The data was collected in Unguja Island in the Zanzibar Archipelago,
situated ca. 50 km outside of Tanzania (hereafter referred to as‘Zanzibar’). Typical for Zanzibar's coastlines are shallow lagoons withcoral reefs, seagrass beds and in certain areas mangrove forests. As incoastal East Africa in general, small-scale ﬁsheries are of highest importance as a source of food and income for Zanzibar's population(Jiddawi and Öhman, 2002; DoFD, 2010; de la Torre-Castro, 2012a;
Thyresson et al., 2013). In Tanzania including Zanzibar, 95% of all
marine catches originate from small-scale ﬁsheries (Jiddawi and Öhman,2002), and a big part of Zanzibar's population is directly dependent on
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Mangi, 2001; McClanahan and Mangi, 2004), the six management
measures suggested in this interview guideline were: no take zones,
temporary closures, gear restrictions (meaning the exclusion of dragnets), mesh size restrictions (meaning the exclusions of nets with ameshsize smaller than the legal size of 1.5 in. (RGZ (Revolutionary
Government of Zanzibar), 1993), minimum ﬁsh size restrictions, andeducation e.g. on the socio-economic as well as ecological eﬀects ofdiﬀerent ﬁshing gears. The ﬁshers were given color illustrations of thediﬀerent seagrass threats, ﬁshing gears and management measures tofacilitate understanding of these more complex questions. All interviews with ﬁshers took place at ﬁshery landing sites or at public
meeting points in the villages and were conducted in Swahili withtranslation services of local interpreters. Answers were noted in theinterview guidelines, and later coded for data analysis.
Further, all available managers and scientists were interviewed:
eight managers from the Department of Fisheries Development andMarine Resources (Ministry of Fisheries and Livestock Development)
and one manager from the department of Environment; ﬁve scientists
with expertise concerning marine habitats, seagrass and/or ﬁsheries
from the Institute of Marine Science (University of Dar es Salaam). An
initial inspection of the data showed general similarities in the answersof scientists and managers. Due to this similarity as well as the low
numbers of respondents in the managers and scientists groups, these
two groups were pooled into one manager/scientist group for data
analysis. The interview guidelines covered the same questions concerning seagrass state- and importance as well as seagrass threats and –management. Additionally, questions concerning compliance, monitoring and gear exchange were included.
Fig. 1. Zanzibar (Unguja Island) and the study sites.

2.3. Data analysis

questioned to which degree they are able to independently defend thecommunities' interests and/or serve as extensions of the law (de la
Torre-Castro, 2006).

To analyze the data quantitatively, the answers were transcribedfrom the interview guidelines and coded into answer groups. The
Fisher's exact test was used to test for statistical diﬀerences between
groups of respondents: a) between manages/scientists and trap- anddragnet ﬁshers; b) between managers/scientists and all ﬁshers; and c)
between trap- and dragnet ﬁshers. The statistical analyses were performed using Stata version 13, considering p-values of < 0.05 as statistically signiﬁcant. A compilation of the results of all statistical tests
can be found in Appendix A. The qualitative data derived from theinterviews was pooled in diﬀerent answer groups, compiled after topic
and summarized as percentages of respondents.

2.2. Interviews
The data collection was conducted between November–December
2013, and was based on a triangulation of methods to collect bothquantitative and qualitative data. The methods comprised interviews
with individuals representing three groups: ﬁshers, managers and scientists. Further, ﬁshery-related activities at landing sites and ﬁshmarkets were observed. A total of 108 ﬁshers were interviewed at sevendiﬀerent landing sites/villages in Zanizbar (Fig. 1): Mkokotoni(n = 17), Kivunge (n = 16), Fukuchani (n = 14), Kendwa (n = 15),
Unguja Ukuu (n = 29), Uzi Ngamb'wa (n = 3) and Marumbi (n = 14).
With the help of local monitoring agents (beach recorders, “Bwana
Dikos”) ﬁshers were informed about the purpose of the study, and thosewilling to participate were interviewed after giving oral consent. Semistructured interview guidelines (Kvale and Brinkmann, 1997;
Denscombe, 1998) were used, comprising information on demography,
ﬁshing practices, income, livelihood preferences, seagrass state and-importance, seagrass threats and -management suggestions, and information concerning ﬁshery legislation, monitoring and compliance.
Questions included in the questionnaire were both of open character(e.g. concerning the ﬁshers' own suggestions of seagrass threats and-management) as well as more speciﬁed (e.g. concerning the ﬁshers'
attitudes on given seagrass threats or management measures). Based onliterature from the area, the suggested threats to seagrasses included in
the questionnaire were: dragnet ﬁshing, eutrophication, pollution,
erosion/sand mining, turbidity, seaweed farming, sea urchin overgrazing and trampling (Gullström et al., 2002; Jiddawi and Öhman,
2002; Eklöf et al., 2006b; Nordlund et al., 2010; Nordlund et al., 2014).
Based on literature concerning gear management in Kenya, whereclosed areas, restrictions on gears and ﬁsh size regulations were described as among the most suitable for management (McClanahan and

3. Results & discussion
3.1. General ﬁshing information
The interviewed ﬁnﬁsh ﬁshers were all men, since few women are
involved in the harvesting activity (Frocklin et al., 2014). Their age
ranged from 18 and 80 years, with a median of 61.5 years. Fishingexperience varied from 0.5 to 69 years, with a median of 30.25. All
respondents mentioned ﬁshing to be their main occupation, but many
had other occupations besides ﬁshing, including farming and carpentry.
The main ﬁshing gears used were basket traps (56%; n = 108), dragnets (40%), gill nets (17%), ringnets (5%) and spearguns (2%) (multiple
mentions were allowed as some ﬁshers used diﬀerent main gears depending on season). Eighty-ﬁve percent of the ﬁshers mentioned togenerally ﬁsh on seagrasses, and as many on corals. Fourty-six percent
mentioned corals as their mostly used substrate to ﬁsh on, followed by
35% mentioning seagrasses.
3.2. Seagrass importance, current state and protection suggestions
All ﬁshers (n = 108) and managers/scientists (n = 14) mentioned
seagrasses to be important. This is concordant with earlier social-ecological studies from Zanzibar, which highlight the contributions of3

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Fig. 2. Reasons for seagrass decrease suggested by managers/scientists (n = 8) and ﬁshers (n = 63). In percent ofrespondents earlier mentioning a seagrass decrease.

managers/scientists group: to stop dragnet ﬁshing, education andmarine protected areas. This is interesting as it shows a consensus ofﬁshers and managers/scientists on a reduction of dragnets to be one thebest approaches for seagrass protection. A quite large proportion of thedragnet ﬁshers (26%, n = 35) thought that it was impossible to protect
seagrasses, which could imply that they perceive dragnets as a problem
for seagrasses, but don't see a way to protect them as they are dragnet
users themselves.
Reasons given for an increase in seagrasses were a perceived decrease in dragnet ﬁshing (mentioned by 44% of the ﬁshers earlier
mentioning a seagrass increase; n = 16) and seasonal changes (6%),
while 31% did not know what the reason could be.

seagrass ecosystems to local livelihoods (de la Torre-Castro and
Rönnbäck, 2004; Nordlund et al., 2010). On the subsequent question
why seagrasses where important, 44% (n = 108; multiple answers allowed) of all ﬁshers mentioned that they were important as a general
habitat for ﬁsh (often referring to seagrasses as “houses of the ﬁsh”),
34% that they were important as breeding grounds, 28% that they were
important as foraging grounds, while 2% mentioned their function for
erosion control.
A majority of ﬁshers' and managers/scientists' perceptions accordedwith each other concerning a decrease of seagrasses (57% of the managers/scientists, n = 14; and 56% of the ﬁshers, n = 108). Twenty-one
percent of the managers/scientists and 27% of the ﬁshers thought there
was no change, while 14% of the ﬁshers opposed to none of the managers/scientists thought they were increasing. Dragnet use was the mostfrequently given reason of both ﬁshers and managers for the perceived
seagrass decline (Fig. 2). A few ﬁshers, but no managers/scientists,
mentioned sea urchin overgrazing, climate change or strong wind- andwave action as well as ﬁshing activities and erosion as reasons for aseagrass decrease. This shows a high level of awareness and local
knowledge among these few respondents as all these factors have been
described as seagrass threats in the area (Alcoverro and Mariani, 2002;
Gullström et al., 2002; Wallner-Hahn et al., 2015). The second mostfrequently given answer by managers/scientists (25%), but only by 3%of the ﬁshers, was intertidal activities in general which includes e.g.
seaweed farming or gleaning. This diﬀerence could be explained byeither a lower awareness concerning the impacts of human activities in
the intertidal, or a reluctance to point out intertidal activities as destructive due to kinship and loyalty towards family and friends (de la
Torre-Castro and Lindström, 2010), as seaweed farming or gleaning arecommon activities in Zanzibar, especially among women (Nordlund
et al., 2010; Frocklin et al., 2014). Seaweed farming has however beenshown to negatively inﬂuence seagrass abundance (Eklöf et al., 2005)
and ﬁsh biodiversity within the farms (Eklöf et al., 2006a). There ishowever no scientiﬁc data on the spatial distribution of seagrasses andits' eventual changes in the study sites which the respondents' perceptions could be related to.
In terms of how to respond to the changes in the seagrass ecosystem,
95% of the ﬁshers and 100% of the managers felt that there was a needto protect seagrasses on Zanzibar. The mangers/scientists' and ﬁshers'suggestions for seagrass protection are shown in Fig. 3. The dominatingsuggestion for seagrass protection from all ﬁshers (40%, n = 100;dragnet ﬁshers: 43%, n = 35 and trap ﬁshers: 43%, n = 60) was to stop
dragnet ﬁshing. This was also one of the three top answers from the

3.3. Seagrass threats and management
All seagrass threats mentioned in the interview guideline wereconﬁrmed by the respondents (Fig. 4A), with ﬁshing gear leading for all
respondent groups, followed by turbidity and eutrophication. No major
deviations could be seen between the respondents groups, only slightly
higher numbers of managers mentioning eutrophication, seaweedfarming and erosion compared to trap- and dragnet ﬁshers, whichmight be explained by their higher level of education, as these threats
might not be directly obvious, and kinship might play a role for theanswers on seaweed farming (as mentioned earlier). The by far mostfrequently given most serious threat (65% of all ﬁshers, n = 106) which
the three respondent groups agreed on was ﬁshing gear again, althoughwith a slightly lower percentage of dragnet ﬁshers compared to managers/scientists and trap ﬁshers (Fig. 4B), which might indicate ahigher reluctance to admit the negative eﬀects of illegal dragnets.
Subsequently, dragnets were identiﬁed as destructive to seagrasses
by a 100% of managers/scientists and trap ﬁshers, and 80% of dragnet
ﬁshers (93% of all ﬁshers, n = 100). Furthermore, only slightly fewer
respondents mentioned them to be the clearly most destructive from all
suggested gears (Fig. 5AB). This shows a high awareness about thedestructiveness of the illegal dragnets as well as a consensus among all
respondent groups, including dragnet ﬁshers themselves. A study from
Kenya showed similar results: a general agreement between ﬁshers,
managers and the government concerning discouraged beach seines,
but low compliance as beach seines were used to a high extent(McClanahan et al., 2005b). Factors contributing to the persistent use
are a lack of awareness about the socio-economic beneﬁts and sustainability of other gears, low costs associated to dragnet ﬁshing andthe general availability of dragnets (McClanahan et al., 2005b; Wallner4

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Fig. 3. Seagrass protection suggestions of managers/scientist(n = 13), trap ﬁshers (n = 60) and dragnet ﬁshers (n = 35).
In percent of respondent groups.

Hahn et al., 2016). Furthermore, strong cultural factors associated todragnet ﬁshing may also play an important role for the prevalentdragnet use in the study sites (de la Torre-Castro and Lindström, 2010).
At least 60% of all respondent groups thought that the suggested
management measures would have a positive eﬀect on seagrass ecosystems (Fig. 6A), with slight diﬀerences between managers/scientists
and trap users compared to dragnet users for education as well as
temporary closures. The same patterns can be seen in the answers
concerning the management measure with best eﬀect for seagrassecosystems (Fig. 6B), with managers/scientists as well as ﬁshers focusing on gear restrictions and education. Temporary closures ranked
on the third place for managers/scientists, while ﬁshers did not support
them as much. Instead, more ﬁshers thought that no-take zones would
be the best measure for seagrasses.

B)A)
dragnets
ringnets
traps
spearsspearguns
longline

managers & scientists
trap fishers

hook and line

dragnet fishers

gillnets
0

20

40

60

80

100 0

20

40

60

80

100

Fig. 5. A) Given ﬁshing gears mentioned to be destructive to seagrasses, yes/no question,
multiple answers allowed. B) Fishing gear mentioned to be the most destructive to seagrasses (only one answer allowed). In percent of respondent groups (managers/scientists:
n = 13; trap ﬁshers: n = 30; dragnet ﬁshers: n = 40).

3.4. Fishers' readiness to adopt diﬀerent management measures
The willingness of ﬁshers to adopt the suggested management
measures, as well as estimations of managers/scientists concerning it,
are shown in Fig. 7A. A majority of both gear groups were willing to

Fig. 4. A) Given seagrass threats conﬁrmed by the respondents. In percent of respondent groups (managers/
scientists: n = 13; trap ﬁshers: n = 60; dragnet ﬁshers:n = 41). B) The most serious seagrass threats according to
the managers/scientists (n = 13), trap ﬁshers (n = 60) anddragnet ﬁshers (n = 41). In percent of respondent groups,
only one answer allowed.

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Fig. 6. A) Given management measures with a positive effect on seagrasses conﬁrmed by the respondent groups,
multiple answers allowed. B) Management measures withthe best eﬀect on seagrasses, only one answer allowed. In
percent of respondent groups (managers/scientists: n = 12;
trap ﬁshers: n = 50; dragnet ﬁshers: n = 30).

dragnet ﬁshers (Fig. 7B), also followed by gear restrictions (under theterms to be compensated). This support for gear management comparedto other management measures was also found in earlier studies from
Kenya (McClanahan et al., 2004, 2005a; McClanahan et al., 2005b;
McClanahan et al., 2012). Furthermore, the dragnet ﬁshers' general
willingness to change gear has also been described in an earlier study
from Zanzibar (Wallner-Hahn et al., 2016). Such agreements as here on
gear management (the exclusion of illegal dragnets) are promising for
positive management outcomes and compliance and should be considered a window of opportunity for gear co-management attempts. The
latter study also describes that ﬁshers found the distribution of gears inan earlier exchange program unjust, as not all ﬁshers who were willingto stop using illegal gears were compensated (Gustavsson et al., 2014;
Wallner-Hahn et al., 2016). Further, ﬁshers complained that ‘friends ofthe government’ who were not ﬁshers themselves, had received gears,
and a group of over 20 dragnet ﬁshers complained that they had
handed in their illegal gear, but had only received one gillnet in return,which employs ﬁve people only.
We want to highlight the need to carefully assess which ﬁshers areaﬀected and to include all of them to equal and transparent terms, as it isof “major importance for the ﬁshers perception of the procedure being fair
and the regulation legitimate” (Jentoft, 1989). Previous experiences from
Zanzibar show that perceptions of justice have been low concerning different programs addressing ﬁsheries and gear exchange (Gustavsson et al.,2014). It should further be contemplated if also ﬁshers ﬁshing with legal
gears should be compensated or beneﬁt in any way, as it could be

agree to education (93% of all ﬁshes, n = 105), gear restrictions (91%of all ﬁshers) and mesh size regulations (87% of all ﬁshes). Most
dragnet ﬁshers emphasized, however, that they only would agree togear restrictions if they got compensated with legal alternatives, mostly
mentioning technologically more developed gears like gill nets, longlines or ring nets for pelagic ﬁshing, as well as motorboats. A compensation of ﬁshers in case of an implementation of gear restrictions isof highest importance, as many ﬁshers, often especially dragnet ﬁshers,
are among the poorest of the poor, lacking the economical means toinvest in legal gears (Silva, 2006; Cinner, 2009; FAO, 2011; WallnerHahn et al., 2016). Stricter enforcement and legal aftermath could
therefore have devastating consequences for ﬁshers and their families'
well-being.
All managers/scientists (n = 12) thought that there was a need for agear exchange program on Zanzibar. One of them highlighted that mostgears used were legal, but that they were used in an illegal way (e.g. theuse of pelagic ring nets in the intertidal zone or dragging), and that nets
only should be distributed to ﬁshers who for sure will use them oﬀshore.
Forty percent of the trap ﬁshers mentioned gear restrictions, followed by education as their favorite management type, which is not
surprising considering that they use traps which are institutionalized as
traditional and sustainable methods (RGZ (Revolutionary Governmentof Zanzibar), 2010) and conﬂicts with dragnet ﬁshers have occurred (dela Torre-Castro and Lindström, 2010).
Education was with 35% the most preferred management type forFig. 7. A) Willingness to adopt suggested management
measures (in percent of trap- (n = 60) and dragnet(n = 43) ﬁshers), and the managers/scientists' assumptionof ﬁshers' willingness to adopt these management measures(n = 10). Multiple answers allowed. B) Fishers' ﬁrst choiceof management possibilities. Only one answer allowed, inpercentages of trap- (n = 60) and dragnet ﬁshers (n = 60).

6

Marine Pollution Bulletin xxx (xxxx) xxx–xxx

S. Wallner-Hahn, M. de la Torre-Castro

were found due to the comparably fewer dragnet ﬁshers mentioning
their gear as destructive. However, nearly all dragnet ﬁshers acknowledged their gears to be destructive in a later question, as well asover 90% mentioning dragnets to be banned because of their destructiveness. It could thus be assumed that the diﬀerences in perceptions
concerning the destructiveness of dragnets between dragnet ﬁshers andthe other respondent groups can be neglected, as it may stem from an
unwillingness to admit the negative impacts of dragnets.
Close to all managers/scientists thought that seaweed farming is
destructive to seagrasses, but fewer ﬁshers of both gear groups, which
could, as described earlier, possibly be explained by kinship and loyalty. The same pattern was found for erosion, which could indicate aneed to communicate scientiﬁc knowledge to the communities.
Concerning the willingness to adopt diﬀerent management measures, diﬀerences were found on temporary closures, gear restrictions
and education. Fewer percentages of ﬁshers than managers/scientists
assuming, were willing to accept temporary closures. Surprisingly,
percentages over 77% for trap- and dragnet ﬁshers mentioned to bewilling to accept gear restrictions and education, compared to 50% of
the managers/scientists who expected a positive attitude. Among thegear groups, fewer dragnet ﬁshers (77%) than trap ﬁshers (97%) supported gear restrictions. This is not surprising as dragnet ﬁshers would
have to leave their gears in case of stricter implemented gear restrictions.
Positive examples from Kenya showing increases in catches andincome suggest that gear management is among the most suitable
management strategies for small-scale ﬁsheries with characteristics
such as those in Zanzibar (McClanahan et al., 2008; McClanahan andHicks, 2011; McClanahan and Abunge, 2014). In comparison to closed
areas, gear restrictions can be adapted to the requirements and thecontext of the ﬁshery in question without reducing local ﬁshinggrounds (McClanahan and Cinner, 2008). Consequently, the ﬁshers'
willingness to switch gears, including a cessation of dragnet ﬁshing, is
one of the areas which should be focused on for future management.
The results of this study show that there is already a considerable
support for just and transparent gear exchange under the conditions tocompensate current dragnet ﬁshers with more attractive gears. Tochange ﬁshers minds on gear use towards more traditional gears liketraps might however be a complex and long-term endeavor, as gear use
is rooted in traditions and norms (Wallner-Hahn et al., 2016). The same
pattern of diﬀerences between dragnet ﬁshers and trap ﬁshers wasfound for education, which might also indicate a general reluctance to
any management eﬀorts by certain individuals of the dragnet ﬁshers
participating in this study.

perceived as unjust to ‘reward’ only those who are using illegal gears,
while the ﬁshers already following the rules are missed out. Further biological studies on gear eﬀects on ﬁsh communities and habitats are needed
to be able to more accurately assess the eﬀects of gear-exchange endeavors. For seagrass and coral ecosystems, positive eﬀects could be expected from a cessation of dragnet ﬁshing, as dragnets are thought to havea considerable physical impact on seagrass- and coral habitats, as well as
indirect ones through ﬁshing of juveniles (Mangi and Roberts, 2006; FAO,
2011). Such indirect eﬀects connected to small ﬁsh body sizes are, forexample, a reduced grazing function on algae by herbivorous ﬁsh on coral
reefs (Lokrantz et al., 2008; Lokrantz et al., 2009), or a reduced predationpressure of e.g. triggerﬁsh on sea urchin populations feeding on seagrasses(McClanahan and Muthiga, 1989; McClanahan and Shaﬁr, 1990;
McClanahan, 1992).
3.5. Willingness to participate in monitoring and perceived beneﬁts ofseagrass management
Eighty-two percent of all ﬁshers (n = 108) said they would be
willing to partake in patrols and monitoring. This could be a favoring
factor for future management, as the direct involvement of ﬁshers ininstalling and enforcing of new regulations increases the chances ofthem to accept them as legitimate (Jentoft, 1989). Interestingly, also
56% (n = 43) of the ﬁshers currently using illegal dragnets answering
this question were willing to patrol. Totally 97% (n = 58) of thedragnet ﬁshers said they were aware about the general destructive effects of dragnets, and 93% said that that was the reason why they wereforbidden. These high degrees of awareness question whether it iseducation on gear eﬀects which is lacking, and rather shows a need forreminders and continuous education, information as well as communication on sustainable resource use.
Eleven out of 12 managers/scientists thought that ﬁshers generally
were aware about ﬁshing rules and regulations on Zanzibar, and nineout of ten thought that the ﬁshers were aware of the destructiveness ofdragnets, which conforms with the ﬁshers answers. Concerning eventual beneﬁts from implementing seagrass management, 72% of all
ﬁshers thought that they themselves and the associated communities
would beneﬁt the most, followed by 9% mentioning the government,
and 5% the marine ecosystem. These perceived beneﬁts could increase
the chances for participation and adoption of new rules (Jacobson andMarynowski, 1997). The managers/scientist group was asked thequestion if they thought the current system for monitoring and controls
was suﬃcient. Nine out of 10 respondents answering this question
thought that it was not suﬃcient and should be improved. Insuﬃcientmonitoring and controls have also been described in other studies fromthis area (de la Torre-Castro, 2006; de la Torre-Castro and Lindström,
2010; Wallner-Hahn et al., 2016), showing the need for an improved
system, which ﬁshers should be a fundamental part of.

4. Conclusions
The results of this study contribute to a better understanding ofareas of agreement as well as disagreement between ﬁshers' and managers' opinions on the management of seagrass-associated small-scaleﬁsheries in Zanzibar, from a pre-implementation point. The ﬁndings areof high value for small-scale ﬁsheries management as they provide
realistic and plausible grounds for mutual understanding and convergence among the diﬀerent actors in the system.
The main ﬁndings of this study are summarized as follows:

3.6. Analysis of diﬀering opinions
The statistical analysis of diﬀerences in opinions between the different respondent groups (managers/scientists and/or the two geargroups and/or all ﬁshers) showed eleven areas of diﬀerences between
respondent groups (Table 1): whether ﬁshing gear, seaweed farming
and erosion are threats to local seagrasses, if turbidity, sea-urchin
overgrazing and eutrophication are the most serious threats to seagrasses, whether dragnets are destructive and/or most destructive toseagrasses, and if temporary closures, gear restrictions and education
are management measures ﬁshers would adopt.
Concerning the suggested threats to seagrasses, fewer dragnet- thantrap ﬁshers mentioned ﬁshing gear as a potential threat. This is also
reﬂected in the subsequent questions about the perceived destructiveness of ﬁshing gears to seagrasses and the mention of the most destructive of them. Here, diﬀerences between trap- and dragnet ﬁshers
and hence also between trap-, dragnet ﬁshers and managers/scientistsi) seagrasses are important to all ﬁshers and managers/scientists,
more than half of all respondents perceive seagrasses as declining,with about half of them mentioning dragnets as a cause, and close
to all respondents think there is a need for seagrass speciﬁc management in Zanzibar.
ii) there is a consensus among the majority of ﬁshers and managers/
scientists, that dragnet use is the main threat to local seagrasses (butwith fewer dragnet ﬁshers agreeing on this), and that all suggested
management measures would have a positive eﬀect on seagrasses(with diﬀerences in proportions of ﬁshers and managers/scientists
7Marine Pollution Bulletin xxx (xxxx) xxx–xxx

S. Wallner-Hahn, M. de la Torre-Castro

Table 1
Questions where statistical diﬀerences in answers between the respondent groups were found. Compared were: a) managers/scientists
vs. trap ﬁshers vs. dragnet ﬁshers, b) managers/scientists vs. all ﬁshers and c) trap ﬁshers vs. dragnet ﬁshers. Statistical method: Fisher's
exact test. Only p-values < 0.05 were considered to be statistically signiﬁcant, numbers of respondents answering yes/no are given todescribe the diﬀerences.

Are the following threats to seagrasses (yes/no)?
fishing gear
seaweed farming
p-value 0.015
noyes
p-value 0.002
nomanagers&scientiststs
0
13
managers&scientiststs
1
trap fishers
060
trap fishers
23
dragnet fishers
536
dragnet fishers
21

yes
10
37
11

erosionp-value 0.006
managers&scientiststs
trap fishers
dragnet fishers

no
0
24
10

yes
13
35
30

p-value 1
managers&scientists
all fishers

0
5

13
96

p-value 0.021
managers&scientists
all fishers

1
44

10
48

p-value 0.009
managers&scientists
all fishers

0
34

13
65

p-value 0.009
trap fishers
dragnet fishers

0
5

60
36

p-value 0.016
trap fishers
dragnet fishers

21
23

11
37

p-value 0.133
trap fishers
dragnet fishers

24
10

35
30

Which is the most serious threat to seagrasses?
turbidity
sea-urchin overgrazing
p-value 0.004
noyes
p-value 0.059
noyesmanagers&scientists
130managers&scientists
110
trap fishers
58
1
trap fishers
53
7
dragnet fishers
31
8
dragnet fishers
41
0

eutrophication
p-value 0.015
nomanagers&scientists
11
trap fishers
58
dragnet fishers
35

yes
2
0
2

p-value 0.002
trap fishers
dragnet fishers

p-value 0.149
trap fishers
dragnet fishers

58
35

0
2

58
31

1
8

p-value 0.039
trap fishers
dragnet fishers

53
41

7
0

Would you adopt these management scenarios (yes/no)?
temporary closures
gear restrictions
p-value 0.002
noyes
p-value 0.010
nomanagers&scientists
08managers&scientists
2
trap fishers
29
31
trap fishers
2
dragnet fishers
26
15
dragnet fishers
8

yes
6
58
33

education
p-value 0.003
managers&scientists
trap fishers
dragnet fishers

no
0
0
7

yes
7
60
34

p-value 0.003
managers&scientists
all fishers

0
55

8
46

p-value 0.213
managers&scientists
all fishers

2
10

6
91

p-value 1
managers&scientists
all fishers

0
7

7
94

p-value 0.158
trap fishers
dragnet fishers

29
26

31
15

p-value 0.014
trap fishers
dragnet fishers

2
8

58
33

p-value 0.001
trap fishers
dragnet fishers

0
7

60
34

Are these gears destructive to seagrasses?
dragnetsp-value 0.0007
noyesmanagers&scientists
013
trap fishers
0
60
dragnet fishers
833
p-value 0.0005
trap fishers
dragnet fishers

no
0
8

yes
60
33

Which is the most destructive to seagrasses?
dragnetsp-value 0.0002
noyesmanagers&scientists
1
12
trap fishers
0
60
dragnet fishers
932
p-value 0.0002
trap fishers
dragnet fishers

0
9

60
92

controls, and most ﬁshers think that they themselves and theircommunities would beneﬁt the most from seagrass management.

concerning seaweed farming, eutrophication and erosion being
potential threats).
iii) gear restrictions and education are the favored management measures among all ﬁshers (with comparably fewer dragnet- than trap
ﬁshers willing to adopt them), while few managers/scientists predicted these measures to be favored. A majority of managers/scientists expected ﬁshers to adopt temporary closures, which is supported by smaller proportions of ﬁshers.
iv) a majority of ﬁshers are willing to participate in monitoring and

The agreement of all respondents on the need to speciﬁcally manage
seagrass ecosystems in Zanzibar, and a high willingness to participate inmonitoring as well as the perception of ﬁshers and local communities
beneﬁtting from it, might be good prerequisites for future management
eﬀorts. Areas of disagreement which would deserve more attention andeducation for ﬁshers would be seagrass threats (other than dragnets)
8

Marine Pollution Bulletin xxx (xxxx) xxx–xxx

S. Wallner-Hahn, M. de la Torre-Castro

manage small-scale ﬁsheries like these in Zanzibar in a more sustainable way, a seascape approach incorporating all associated habitats like
corals, seagrasses and mangroves is necessary (de la Torre-Castro et al.,2014). And, most importantly, in such closely interlinked social-ecological systems like the seagrass-associated small-scale ﬁsheries ofZanzibar, ‘people ought to be the means and the goals of the management process’ (de la Torre-Castro, 2012b). One promising step would be
the implementation of co-management concerning the exclusion of illegal dragnets and an associated gear exchange program.

and the beneﬁts of temporary closures, which were supported by mostmanagers/scientists. Poverty does not allow for longer periods of closures (McClanahan et al., 1997), but temporary closures have beenshown to have considerable positive social-ecological eﬀects in the
management of species with high turnover rates like octopus ﬁsheriesin Madagascar (Benbow et al., 2014). Further, eﬀorts should be made tocontinuously work with awareness raising on the destructiveness ofdragnets, and the beneﬁts of more sustainable gears in socio-economic
as well as ecological terms (McClanahan et al., 2005b; de la TorreCastro and Lindström, 2010; Wallner-Hahn et al., 2016). The identiﬁed
diﬀerences between ﬁshers and managers can be a starting point forincreased communication, discussions and mutual learning, that in turnenhance trust and the willingness to collaborate. One focus should beon gear management eﬀorts, with strong respect to the ﬁshers' willingness to participate and their need to be compensated for the loss of
their (illegal) gears, which are their main source of income. Management processes towards more sustainable social-ecological ecosystems
should be transparent, just and recognize and include existing local
ecological knowledge and traditional management as well as scientiﬁc
approaches (McClanahan et al., 1997; Tobisson et al., 1998). Further, toAcknowledgments
We would like to thank all ﬁshers, managers and scientists for their
participation in this study. We thank the Institute of Marine Sciences(University of Dar es Salaam) for support, the Department of Fisheries
Development and Marine Resources (Ministry of Fisheries andLivestock Development) and Department of Environment for sharedknowledge and experience. The Swedish Research Council partially
funded this research (project 344-2011-5448).

Appendix A
Compilation of the conducted statistical analyses and their results on diﬀering opinions. The Fisher's exact test was used to statistically test for
diﬀerences between the answers of respondent groups (managers & scientists; trap ﬁshers; dragnet ﬁshers; all ﬁshers). The presented results are pvalues. Only p-values < 0.05 were considered to be statistically signiﬁcant (italics).

Potential threat

Fishinggear

Are the following threats to seagrasses (yes/no)?
p-Value (Managers & scientists/trap −/ 0.015
dragnet ﬁshers)
p-Value1(Managers & scientists/all ﬁshers)
p-Value
0.009(Trap −/dragnet ﬁshers)

Trampling Seaweedfarming

Turbidity Sea-urchin
overgrazing

Pollution Eutrophication Erosion

0.266

0.002

0.301

0.151

0.734

0.113

0.006

0.249

0.021

0.264

0.529

1

0.056

0.009

0.308

0.016

0.419

0.101

0.532

1

0.133

0.095

0.298

0.004

0.0595No
0.015
mentions
No
0.070
mentions
No
0.149
mentions

Which is the most serious threat to seagrasses?
p-Value (Managers & scientists/trap −/ 0.255
dragnet ﬁshers)
p-Value (Managers & scientists/all
0.537
ﬁshers)p-value (Trap −/dragnet ﬁshers)
0.204

0.216

0.203

0.595

1

0.298

1

0.059

0.039

Gear

Gillnets

Hook & line

Dema

Dragnet Ringnet Spears Spear guns

Longline

0.621

0.469

0.350

0.007

0.359

0.769

1

1

1
0.515

1
0.4

1
0.192

0.55930.0005

0.717
0.203

0.593
1

1
1

1
1

No
mentionsNo
mentionsNo
mentionsNo
mentionsNo
mentionsNo
mentionsNo
mentionsNo
mentionsNo
mentions

0.0002

1

0.469

1

1

1

1

0.0002

1

0.4

No
mentionsNo
mentionsNo
mentions

Are these gears destructive to seagrasses?
p-Value (Managers & scientists/trap −/dragnet
ﬁshers)p-Value (Managers & scientists/all ﬁshers)
p-Value (Trap −/dragnet ﬁshers)
Which is the most destructive to seagrasses?
p-Value (Managers & scientists/trap −/dragnet
ﬁshers)p-Value (Managers & scientists/all ﬁshers)
p-Value (Managers/all ﬁshers)

Management typeNo-takezones

TemporaryclosuresGear
restrictions
9

Mesh size
restrictions

Minimum ﬁsh size
restrictions

0.546
1
0.391

1
1

Education

Marine Pollution Bulletin xxx (xxxx) xxx–xxx

S. Wallner-Hahn, M. de la Torre-Castro

Would you adopt these management scenarios (yes/no)?
p-Value (Managers & scientists/trap −/
0.417
0.002
dragnet ﬁshers)
p-Value (Managers & scientists/all ﬁshers) 0.322
0.003
p-Value (Trap −/dragnet ﬁshers)
0.687
0.158
Which of these managemet scenarios would you prefer?
p-Value (Managers & scientists/trap −/
0.466
0.218
dragnet ﬁshers)
p-Value (Managers & scientists/all ﬁshers) 1
0.157
p-Value (Trap −/dragnet ﬁshers)
0.269
0.712

0.010

0.665

0.331

0.003

0.213
0.014

0.627
0.776

0.715
0.216

1
0.001

0.414

0.366

1

0.651

0.420
0.399

0.243
0.754

1
1

1
0.399

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