Intertidal gleaning fisheries: Recognising local-scale contributions and management scenarios

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Introduction
Small-scale fisheries (SSF) are globally important for livelihoods, food security and nutrition [21].Effective and equitable management of SSF is key to harnessing these contributions and enabling pathways towards sustainable fisheries.Effective and equitable management often requires inclusion of the diversity of actors participating across SSF value chains [52,65].In particular, there are growing calls to recognise the participation of women in SSF, who have historically been absent in SSF monitoring, statistics and analyses [30,31,36].Accordingly, building our understanding of how women contribute to the small-scale sector, and devising means of mainstreaming women and gender into SSF management is a priority [17,31,36,37].In the case of women who directly engage in capture roles, there needs to be a better understanding of aspects including fishing methods, grounds and targeted species [32,36].Importantly, contextual understanding is needed to inform tailored management based on place-specific social and ecological factors.
Gleaning is one such fishing activity, which globally provides a livelihood means for women in coastal communities [31], particularly within the tropics [60].The activity involves walking through intertidal zones during low tide, with little-to-no gear, in search of species that can be consumed, sold or used as bait.Tropical intertidal zones constitute a range of productive, easily accessible habitats which support a large variety of maritime activities [43].Gleaning can be conducted in various intertidal habitats, including rocky or sandy substrates, mud flats, seagrass, reefs and mangroves [2,4,43,58].The activity typically targets sessile or slow-moving invertebrates such as bivalves and gastropods, however, more mobile organisms, including cephalopods and crustaceans, are also commonly encountered [26,42,61].Studies involving catch surveys typically report diverse and species rich catch compositions [1,24,26,54].Gleaning characteristics may differ across spatial and temporal scales though, with this being an important aspect to explore for effective management [27,55].
Gleaning fisheries tend to be data-poor, and underrecognised or absent within SSF management [31].This lack of representation is problematic on several accounts.First of all, a seemingly important source of income and food sustenance remains largely unregulated and undocumented [50,61].Secondly, unmanaged populations of targeted invertebrates risk decline, which may cause detriment to the wider intertidal ecosystem [1,6,24].Habitat degradation is also possible from unregulated gleaning [2,3,44].Finally, gleaners' contributions to the small-scale sector remain overlooked, meaning our overview of human activities within such coastal areas is incomplete [7,64].Accordingly, investigating means of building effective management for gleaning, as well as mainstreaming the fishery into the overall management of the small-scale sector is imperative.
Gleaning management exists in some regions worldwide, however issues related to compliance, enforcement and displacement are reported [5,15,51].For example, minimum catch-size limits are utilised for managing trochus (Rochia nilotica) fishing in Samoa.However, regulation of this is poor [48].Rotating no-take zones have also been trialled in Zanzibar, Tanzania, but enforcement was low except in one site (Bweleo) which had nearby naval presence [15].More successfully, temporal closures in gleaned areas have demonstrated higher catch rates and invertebrate abundances than continuously-open areas in the Solomon Islands [4,14].Similarly, temporal closures of octopus fishing that includes gleaning within East Africa, has reported net economic benefits from increased catch sizes and income generated [46,53].An effective co-governance system has also been reported in Spain, through local gleaner organisations who have implemented permit-type schemes and minimum catch size limits [23].Whilst these successful management examples exist, they are relatively uncommon with working concepts for sound management remaining limited to few contexts.Particularly missing is perspectives from gleaners themselves on managing the fishery, and what enabling or hindering factors they perceive as important within their own contexts and experiences.
The overall aim of this study was to further the understanding of gleaning fisheries and explore how management of this fishery could be effectively approached.To do this, individual interviews and focus group discussions (FGDs) were undertaken in Zanzibar, Tanzania.Two sites on Unguja island's west coast (Nyamanzi and Unguja Ukuu) were investigated.Specifically, the study aimed to, (i) investigate how gleaning fisheries contribute to income and food sustenance in two nearby villages through interviews with gleaners, including how the sites differ; and (ii) explore different management strategy scenarios in FGDs with the gleaners.The study discusses the importance of sitespecific investigations and provides management suggestions that have been discussed and locally anchored by gleaners.Using the insight collectively gained from the interviews and FGDs, recommendations are discussed and presented in order to further mainstream gleaning into SSF management and sustain important contributions from the fishery into the future.

Study area
Zanzibar is situated 40 km off the coast of Tanzania in the Western Indian Ocean, comprising an archipelago of two larger islands and 50 smaller islets.The largest island, Unguja, is commonly referred to as Zanzibar, and is the island being referred to as Zanzibar henceforth.Zanzibar has a highly productive seascape with habitats including coral reefs, seagrass, macroalgae, and mangroves [8].Tides are semidiurnal and have a substantial range, from 3-4 m during spring low tides to approximately 1 m during neap tides.A large proportion of the population engages in maritime livelihoods, particularly within small-scale fisheries [34,35].
Data was gathered in two locations, Nyamanzi and Unguja Ukuu (Fig. 1) on the west coast of Zanzibar, over a ten-week period between October-December 2018.The sites were selected based on guidance from the Institute of Marine Sciences, University of Dar Es Salaam, informing that there were a large number of gleaners in the two sites.The intertidal zones in the two sites also represent different dominant substrate types, with softer sand and mud substrates being more abundant in Unguja Ukuu, and harder rock substrates more abundant in Nyamanzi (Fig. 2).Both sites are seagrass dominated.The populations according to recent census (2022) in Nyamazi was 2547 and in Unguja Ukuu was 2330 [57].Through observations during the interviews, typically 50-60 gleaners were participating in each site during spring low tide on a given day.These numbers may differ with the weather and seasons.
Two approaches were used to further the understanding of gleaning fisheries and explore how management of this fishery could be affectively approached.The first step was to arrange initial FGDS in each of the sites.Thereafter, individual interviews were conducted with gleaners.Lastly, follow-up FGDs were held.

Individual interviews
Forty-six interviews, consisting of structured questionnaires were conducted with gleaners across the two sites, Nyamanzi (n=24) and Unguja Ukuu (n=22) (Table 1).Interviews were conducted during spring low tide periods, in landing sites.Interviews were only done during daytime low tides, as this is when gleaning typically occurs (as opposed to night time).The interview format was done following the gleaning landing survey protocol established by the Indo Pacific Seagrass Network (https://indopacificseagrass.network/); a complete layout of the questionnaire can be found in the supplementary material (S1).The interviews were conducted in Swahili, with the assistance of a translator, who had prior experience interviewing fishers.The interviews aimed to solicit information on the following factors: (i) motivations for gleaning, for example, acquiring food for home consumption, cash income through markets at various scales or within the curio trade; (ii) time dedicated to gleaning, as well as the typical number of gleaning days in a month; (iii) gear usage; (iv) preferences for different intertidal habitats/substrates, (v) intended use with the current catch, and (vi) should an income be generated, the estimated monetary value of the catch based on approximation.The questions were structed with multiple-choice questions (i.e. the questions related to motivations, habitats, gears and intended uses), as well as open-ended questions (i.e.time spent gleaning and estimated monetary value).The responses were compiled and analysed by comparing percentages in response frequencies between the sites for the multiple-choice questions.For the open-ended questions, mean values and ranges were compared for the estimated earnings and time spent gleaning.

Focus group discussions
To obtain more in-depth information on gleaning and the potential for its management, two separate FGDs were done in both sites.Overall, two FGD sessions were organised in each site; an initial session and a follow-up session, arranged following the completion of the interviews (Table 1 changed over time and whether they consider these spaces to be affected positively or negatively by gleaning iii.Management of Gleaning: How well participants feel represented by current intertidal management institutions; whether the introduction of management strategies would be positively or negatively received; suggestions for increasing sustainability of gleaning and/or providing further protection of habitats used for gleaning grounds; how participants regard different managerial scenarios (spatial and/or temporal closures, minimum catch sizes, education schemes, limitations on certain gear choices and beach recorders).The strategies were selected by the authors based on existing usage elsewhere in the Zanzibar SSF management sector.This meant the strategies had feasibility in the local context and gleaners may already have familiarity and knowledge of them.

Table 1
Method overview, including the number of gleaners partaking in the interviews and FGD sessions, within each site.Regarding the FGDs, one of each session was held within each site.For example, one initial session, and one follow-up session within each site.Follow-up sessions were done to discuss the initial findings from the individual interviews, as well as to give participants the opportunity to request any further discussions points or information from the team.Some of the themes from the initial sessions were also followed up, and further discussed when needed.Each group consisting of 12-14 participants (Table 1).The participants were all local to the area and regularly participating in gleaning activities, aside from this no other participant criteria was necessary.
FGDs were designed with semi-structured questions and preprepared discussion points that permitted interaction, open dialogue, and deviation to other themes that were raised by participants.The sessions were transcribed, categorised and thematically analysed based on the above described discussion points.If there wasn't consensus on certain discussion points, the level of dissent was noted through recording numbers with differing viewpoints.The sessions were organised during neap tide periods.This was to ensure that the sessions didn't conflict with the gleaning done typically in the spring tides.All sessions were conducted in Swahili, with assistance from a female translator.In some cases, background information was presented to the groups (i.e.examples of successful gleaning management implementations from Fiji and Costa Rica, as well as the management strategy scenarios) and a discussion was initiated following this input.
The follow-up sessions held a second component where management aspects were further discussed in response to the initial discussions held in the first session.Two international management scenarios from Fiji [56] and Costa Rica [22] were presented in the follow-up sessions.International case studies were selected, as opposed to more local examples, as this was requested by the participants, The case studies were selected based on being relevant to Anadara antiquata, sometimes referred to as cockles or ark clams and locally known as Korobwe, which is one of the most important species within the sites based off the initial FGDs.The case studies also had contextual similarities to Zanzibar in the form of tropical and rural settings.In both case studies, gleaning was predominantly being undertaken by women in intertidal areas, in a methodically similar way to the two Zanzibar study sites.The Fiji case study involved the successful establishment of a temporal closure system for Anadara cockle gleaning management [56].With support from the Department of Fisheries and The University of the South Pacific, the gleaners established 'taboo' areas; traditional temporal closures of fishing areas in the event of the death of a high chief.The community was facilitated with monitoring techniques to assess the efficacy of the taboo areas as replenishment zones and thus were informed on the concepts underlying the strategy.The second case study originating from Costa Rica, where Anadara cockles were being heavily gleaned in mangroves.A minimum legal harvest size of 45 mm was established by the Costa Rican government to encourage the stock to reach reproductive maturity before collection [22].

Gleaning characteristics
General gleaning characteristics including earnings, time spent gleaning and gear usage were investigated through the interviews.The 46 interview respondents across the sites were women, with ages ranging between 18 and 56.An overview of the interview responses is shown in Table 2.A summary of the average earnings is also shown in Table 3 in both Tanzanian shillings (TZH) and US dollars (USD). Across both sites, the average time spent gleaning on a typical day was 3.28 hours (± 0.53 hrs).Income for those selling at least part of their catch ranged between 2000 and 25,000 TZH).Overall, 37% (n=17) of the respondents reported using gears whilst gleaning, which included knives, sticks and rakes.No one was found to be using traps, nets (mosquito nets or otherwise) or fishing rods in either site.
In Nyamanzi, a total of 24 gleaners were interviewed.Respondents were typically gleaning for 10 days within a monthly period, averaging 3.25 hours (± 0.1 hrs) on a typical day.Income for those utilising their catch for market commodities ranged between 4000 and 25,000 TZH, with an average selling price of 10,912 TZH (± 6213 TZH).Those with catches selling at the higher price range (>25,000 TZH) were using boat transport to reach intertidal areas inaccessible by walking, where a greater density of invertebrates was available due to lower gleaning pressure compared to the walking-accessible gleaning grounds.The majority of respondents were not using gears (92%, n=22); out of those who were, the only gear mentioned was knives.In Unguja Ukuu, 22 gleaners participated in the interviews.Respondents were typically gleaning an average of 10 days per month, with a typical gleaning day consisting of 3.32 hours (± 0.1 hrs).Those who were selling parts, or all of their catches were earning within a range of 2000-25,000 TZH, with an average selling price of 6358 TZH (± 5852 TZH).Only one participant earned above 25,000 TZH and did so by selling a catch exclusively consisting of the sea cucumber, sandfish (Holothuria scabra).Gear usage was fairly commonplace, with 68% (n=15) reporting utilising during gleaning.This included wooden and metal sticks, knives, and in one person's case a rake.

Motivations for gleaning
The motivations behind gleaning were discussed in the interviews, with the contributions to livelihoods discussed in the initial-session FGDs.In the follow-up sessions, the preliminary results from the interviews on gleaning motivations were discussed, alongside reasoning for which species held importance for income and sustenance.Overall reasons given for gleaning, across both sites in the interviews were selling in local markets (83%, n=38), home consumption (59%, n=27) and selling in larger, town markets (39%, n=18).In Nyamanzi, the most popular reason given in the interviews for gleaning was selling in the local markets as food items, with 92% (n=21) of respondents reporting doing so.Fifty-eight percent (58%, n=14) were accessing larger town markets and 46% (n=11) were gleaning to acquire food for home consumption.In Unguja Ukuu, 77% (n=17) of interview respondents were gleaning for home consumption, 73% (n=16) were selling in local markets and 18% (n=4) were selling in larger town markets.
The initial-session FGDs were also asked to elaborate on the relative importance of gleaning in terms of household income and food sustenance.In Nyamanzi, 83% of the participants felt that the activity was more important for their household income, and 17% felt that gleaning was more important for food sustenance.In Unguja Ukuu, 67% reported household income, and 33% reported food sustenance.Women in both sites described gleaning as being one of very few livelihoods available to them.Other coinciding forms of income were farming, firewood collection (possibly for sale or subsistence), small-scale businesses, and work within local kiosks.These activities were often being undertaken in neap tides when the intertidal zone isn't passable.In Nyamanzi, seaweed farming was an available option and was now a more commonplace livelihood for women in the area, compared to gleaning.However, in Unguja Ukuu the seaweed farming sector had collapsed and was no longer a viable option.The two don't tend to be done in conjunction, as both must be done during spring low tides.

Habitat and species preferences
Preferences on habitats for gleaning grounds, as well as habitats with high monetary value associated were investigated through the interviews.In the initial-session FGDs, the motivations for these preferences were discussed, alongside changes to the intertidal zone over time.Responses were similar across both sites.Overall, 89% (n=41) of the interview respondents had been gleaning in seagrass on the day of interview.Fifty seven percent (57% n=26) had been gleaning in sand substrates, 9% (n=4) in mud substrates, and 4.3% (n=2) in coral reefs.When asked about which habitat/s were their favourite for gleaning purposes, the most popular response was seagrass (91%, n=42), followed by sand (54%, n=25) and then mud and coral reefs (6.5%, n=3 respectively).Habitats in which catches could be obtained with the highest monetary value were seagrass (88%, n=40), sand (57%, n=26), mud (9%, n=4), coral reefs (4% n=2) and deep water (2%, n=1).Participants were able to respond with more than one habitat for each question, with most participants opting to select multiple habitats.
During the initial-session FGDs, when asked about which intertidal habitats entailed the most important gleaning grounds, respondents in both sites unanimously agreed it to be seagrass meadows.This was on account of these areas possessing the highest invertebrate abundances.No preference in particular seagrass species was expressed in either group.In Nyamanzi, they also mentioned sand and mud substrates as being important habitats for gleaning.The group reasoned that although there were more invertebrates available in seagrass meadows, they were easier to find in unvegetated sand and mud areas.In Unguja Ukuu, the group preferred tide-exposed reef flats as they provide good substrates for harvesting octopus and cockles.
During the follow-up session FGD participants were asked to further elaborate on which species were important for generating income, and which were important for acquiring food for home consumption.Both sites considered cockles (Swahili: korobwe) to be the most important species of cash value, due to their high abundance and high market demand.Black-lipped oysters (Pinctada margaritifera, Swahili: chaza) were also mentioned, along with the gastropods' ramose murex (Chicoreus ramosus, Swahili: Kome dike) and tulip shells (Pleuroploca spp, Swahili: Kome dume).For the latter two, it was the opercula which possessed economic value.Neither group considered key species in the tourist trade, such as tiger cowries (Cypraea tigris) or spider conches (Lambis lambis) to be important for income.Generally, men fishing in deeper intertidal areas were selling their catches of tiger cowries and spider conches, whereas women would utilise these for home consumption.The highest value species available through gleaning was sandfish.Cockles (Cardiidae spp) of various species (not included A. antiquata) were agreed to be the most important items for home consumption.In Unguja Ukuu, pen shells (Pinna muricata and Atrina vexillum) were important for home consumption, as well as for fish bait.However, in Nyamanzi these species were not commonly caught due to the small quantity of meat available, and an associated risk of food poisoning.

Temporal changes to usage of intertidal resources
Temporal changes to the gleaning fishery and usage of intertidal resources were investigated during both the initial-and follow upsession FGDs.The participants were encouraged to discuss how the gleaning fishery has changed over time, as well as to provide their observations on general changes to coastal areas.Both sites stated that gleaning had become steadily more difficult over time due to a decline in available invertebratesalthough no specific timeframe could be provided, the participants described the changes as occurring over several decades.However, it was agreed in Nyamanzi that it was approximately 10 years ago that they were able to fill an entire bucket with their catch (mostly between 10 and 15 L).As a reference, the participants described being able to fill only one-quarter of that amount at present.When asked whether they had observed specific species decreasing over time, the Nyamanzi group reported that horse mussels (Modiolus spp.), were a species that had particularly become less available despite being abundant in the past.The Unguja Ukuu group did not report any particular species as having declined over time.In the follow-up FGDs, the participants were asked for their views on temporal trends regarding the market value of target species.Both sites explained that black-lipped pearl oysters were previously the most lucrative species, however, they have now been surpassed by Anadara cockles which have experienced an increase in popularity for use in celebratory events, such as wedding ceremonies.Accordingly, the market price of the oysters has declined, whereas the price for cockles has increased.Unguja Ukuu also mentioned an increase in demand for sea cucumbers and the ramose murex, with the price of the latter's operculum increasing.

Perspectives on management scenarios
The final section of the initial-session FGDs aimed to encourage an open discussion on the participants' views and ideas relating to the management of gleaning.Both sites reported an absence of management schemes regarding gleaning in their localities.However, the participants were open to the scenario provided there was minimal government intervention, preferring a community-based approach.In Nyamanzi, the participants agreed that a management scheme would be most successful if it entailed rotating no-take zones enacted through by-laws and a watchman system.One person also suggested a system entailing cards being distributed by local authorities which would permit individuals to glean in the area.Also important was the creation of alternative livelihoods for the upcoming generation; for example, by generating financial support for small-scale businesses.Resources required to implement a management scheme included loans for small-scale businesses and watchmen to guard the no-take zones.In Unguja Ukuu the participants also suggested no-take zones, rotating on a 2-3-month basis.The participants also emphasised a need for alternative livelihoods to counteract the increasing numbers of gleaners, resulting from the collapse of local seaweed farms.Resources stated as needed for the strategy included financial support and net supplies for cordoning off no-take zones, as well as awareness raising schemes to ensure a universal understanding of the introduced changes.When asked about the potential foreseen obstacles to a management scheme, Nyamanzi felt that a lack of understanding of the new rules and the encroachment of gleaners from neighbouring communities into no-take zones would be problematic.Unguja Ukuu also mentioned these obstacles, and raised conflicts with other resource-users, including other groups of fishers regarding the notake zone boundaries.After an open discussion within the FGDs about views and ideas relating to the management of gleaning, several different management strategies (Table 4) were detailed to the initialsession groups and generated similar responses in both locations.Amongst those positively received were the beach recorders, education workshops, gleaner committees, and the aforementioned temporal or spatial closures.The most negatively received were minimum catch size limits and having limits on total allowable catch.Both groups argued that rules necessitating gear limitations were inconsequential as the use of damaging gears was not widespread.

Management case studies
During the initial-session FGDs, participants were asked if they wished to receive more information on gleaning related topics.Both sites requested more information on how the activity is managed elsewhere in the world.Therefore, during the follow-up FGDs, the participants were presented with two international case studies from Fiji and Costa Rica, where rural communities were gleaning Anadara cockles for sustenance and economic commodities, in a parallel scenario to Zanzibar.
In Nyamanzi, the participants expressed that the Fiji model would not be suitable for Zanzibar, due to the very high numbers of gleaners present.This was in contrast to the initial sessions where no-take zone strategies were discussed in a more positive light.They also reiterated that poaching would prevent the success of such a strategy.Rather, they were more inclined towards the Costa Rica example with size limits.They felt it was a fair concept, which to be effective would need to be inaugurated across Zanzibar.However, they felt strongly that those enforcing the rule would need to be externally sourced, as a member of the community would too often make allowances based on kinships.In Unguja Ukuu, the participants also felt that the taboo approach would be vulnerable to poaching issues.To overcome poaching, they felt a security system would need establishing, alongside largescale meetings with gleaners in the area to ensure understanding of the concepts behind the strategy thus encouraging compliance.They also agreed that the Costa (þ) Temporal rotating notake zones were agreed as the most popular strategy, with groups describing pre-defined ideas on how to enact the strategy in their areas Rica strategy would be preferable.As with Nyamanzi, they explained that enforcement authorities could not be sourced from within the community on account of allowances being made.

Discussion
Gleaning fisheries constitute an important direct contribution of women to the harvest sector globally [30,45,61].Despite the widespread nature of gleaning in the tropics, there is a clear pattern of under recognition and under regulation within management, despite important local-scale contributions such as those found in this study.Within the FGDs, there was an evident willingness amongst gleaners for management of the fishery.There were also suggestions for how management could be materialised, alongside substantial awareness and knowledge surrounding the resource status within gleaning.These insights, based on local knowledge about the specific contexts and factors that may help or hinder management, would be invaluable for inclusion within SSF and wider coastal management as demonstrated in other gleaning contexts [27].
In Zanzibar, gleaning has historically been categorised as a sustenance fishery, which also provides income [10,15,24,42].However, from those who participated in this study, the motivation lent more towards financial gain, rather than food sustenance.In a study by [42], interviews with gleaners in a different location on Zanzibar (Nungwi), concluded that gleaning was first and foremost a sustenance activity, however, had been more commonly a social activity alongside sustenance in the past.There is a possibility that gleaning has experienced a temporal shift towards more commercial endeavours in recent times.It could be the case that gleaning is becoming more profitable due to the increasing commercialisation of cockles, and growing market demand for the opercula of commonly gleaned gastropod species (C.ramosus and Pleuroploca spp.) [15].From a more global perspective, the importance of gleaning as a social activity in Timor-Leste was emphasised by [28], highlighting a need to move beyond the sustenance narrative.More recently in Unguja Ukuu, cultural values were highlighted within gleaning fisheries [54].Gleaning has also been described as an important means of fishing bait in the UK and Kuwait [2,63].Bait fisheries tend to be under recognised [63], so this may also be more widespread.Increasingly clear is that gleaning motivations can differ spatiotemporally, and can contribute to coastal livelihoods through numerous important aspects.An important finding in this study is that even with two sites of relatively close proximity (~12 km) we found differences in gleaning motivations and habits highlighting the diverse nature of the fishery beyond its sustenance typecast.
In terms of the ecological components which support local-scale contributions, habitats and species were explored regarding the roles in both income generation and food sustenance.Seagrass was found to be the preferred habitat for gleaning, as well as the habitat where catches of highest monetary value are obtainable.From a wider perspective, seagrass has been reported as an important gleaning habitat in other tropical regions [45,61], including Indonesia [26], Malaysia [11], Kenya [1], the Philippines [49], Mozambique [13] and Timor-Leste [58].Gleaning was also being performed in various other shallow habitats, particularly sand substrates as invertebrates were easier to find with the lack of vegetation.Through the FGDs, the species most relevant to income and home consumption avenues were explored.Cardiidae cockles were agreed to be the most important for food sustenance.Anadara cockles, the ramose murex and tulip shells were reported as the species most important for income.An important finding was that although participants were catching potentially valuable ornamental gastropods, such as tiger cowries and spider conches, they were not selling these.Additionally, the FGD participants mentioned that fishermen were regularly collecting tiger cowries in deeper waters and accessing the tourist trade through these catches.It is possible that traditional views on gender roles prevent women from so easily accessing the tourism trade [10,25].Inequitable access to a lucrative market can create an income disparity between men and women fishers, and is a means by which benefit distribution from a natural resource is gender differentiated [19].With market values driving changes to species targeted through gleaning in this study (i.e.changes in favour from black-lipped oysters to cockles), how gleaning fisheries respond to market changes, and the drivers of inaccessibility to profitable economic sectors needs further investigation.
The FGDs also contended several issues with gleaning activities that could be tending the fishery towards overexploitation.Firstly, all participants agreed that invertebrate availability was declining in the intertidal zone, and catch volumes had been gradually decreasing over an extended period of time.The notion that invertebrate availability and catch volumes have decreased over time has been reiterated in several Zanzibar-based studies [24,42,54], and more globally across gleaning fisheries in other regions [1,6,62].Importantly, there was a unanimous reliance on gleaning as a livelihood means, with all participants agreeing that few alternatives are available to women in their localities.Both groups also reported increasing numbers of gleaners, especially in Unguja Ukuu where there had been a collapse in the seaweed farming sector.Seaweed die-offs and production declines due to stressors, such as climate change, has been occurring more frequently in Zanzibar over the last two decades [12,33,40].With climate change ongoing, there may be increasing numbers of people entering gleaning fisheries if seaweed farming becomes inviable.This situation was perceived as ongoing by the FGD participants in Unguja Ukuu, and holds importance for future management.Empirical studies may be helpful to further confirm the link between seaweed farming exits and gleaning entries, as well as implications for the long-term viability of the fisheriesan issue which was reiterated several times throughout the FGDs.
Much of this study's focus was placed on gathering insight from gleaners on potential management strategy scenarios.Within the initial session FGDs, there was a clear emphasis on rotating no-take zones being an appropriate tool for increasing invertebrate abundances.A similar strategy of temporal closures was also positively perceived with participants in a Brazilian gleaning fishery [16].No-take zones serve important conservation and management strategies worldwide, with widely reported positive effects on fish/invertebrate biomass, abundances and species richness [29,38].However, there is some debate over how well no-take zone designs translate from fin fisheries to invertebrate fishery contexts.There are several examples of successful usage of no-take zones in managing bivalve and gastropod stocks, on account of larval export increasing recruitment within adjacent areas [9,39,47].However, an adult spill-over effect is unlikely due to the sessile and low mobility nature of gleaning landed species, and if not managed properly, areas can become crowded causing reduced reproductive output and stunted growth [15,43].Furthermore, it isn't clear whether the rotation period of 2-3 months suggested in the Unguja Ukuu FGDs would yield the wanted results.We currently have insufficient knowledge regarding the life histories of many commonly gleaned species in the region, and more globally [43,61].A Philippines-based study on the gametic cycle of the cockle, A.antiquata, has a reported duration of 1-2 months and persists throughout the year, with spawning peaking in warmer periods [59].However, information on the age or size of reproductive maturity currently remains inadequate to implement informed management plans.Furthering knowledge of seasonal availability and peak spawning periods may also help to inform no-take zones.Generally gleaning can be done year-round, although catch composition may vary across seasons [54].
An attempt at establishing a no-take zone for gleaning has previously been attempted in Zanzibar's Fumba Peninsula within four locationsincluding Nyamanzi.The project performed poorly in Nyamanzi as a result of seasonal sand movements inducing high mortality within the stocks [15].Other sites also experienced compromised results on account of poachers encroaching from neighbouring communities.The most successful project occurred in Bweleo, within which the closed areas were established in close proximity to a navy compound which proved effective at deterring poachingalthough this can't be replicated in sites without the presence of naval compounds or similar.During the follow-up FGDs, no-take zones were discussed in a more negative light, with poaching being the most pertinent reason why the strategy would be unlikely to succeed.No-take zones have considerable potential as a gleaning management strategy [16,20,41], however means of enabling compliance and poaching prevention are necessary to explore.A possible option could be gleaning committees as a co-governance system to distribute licence type systems as done successfully in a Spanish gleaning fishery [23], this reflects suggestions made from the FGDs both in the positive sentiment towards gleaner committees as well as distributing permit cards.
There were some further hindering aspects discussed in the FGDs which could hold implications for gleaning management.Both villages concurred that individuals fulfilling authoritative or monitoring roles could not be members of the community due to the likelihood of allowances being made based on kinships.[18] previously described this issue in an analysis of the beach recorder system for fishery management in Zanzibar.Secondly, both FGDs brought forward conflict between neighbouring communities and encroachment into no-take zones as a substantial hindrance.In Zanzibar, the intertidal zone is open-access and tends to span numerous communities which creates issues relating to customary marine tenure.This is one of the most challenging elements concerning management of gleaning, especially no-take zone strategies, as communities do not have exclusive rights to intertidal areas.For success with this strategy, a level of cross-community cooperation may be necessary.Cross-community communication was a success factor within Malagasy periodic octopus fishery closures; a similar strategy in which successful community management was implemented within open access gleaning grounds [46].Furthering understanding of the conditions that foster such cross-community co-operation is an important consideration with the suggested rotating no-take zone strategy.
Within this study, we appreciate that the investigation of two sites results in some limitations in how representative the findings are to Zanzibar as a whole.As we found substantial differences in two sites of close proximity, the potential for spatial variation in all aspects of the study may vary across the region.There was also some indication of temporal variation in for example the shift in importance of the fishery from sustenance motivated to income motivated.This study therefore provides a snapshot overview of the two sites' gleaning fisherieswith emphasis that the characteristics and status of the fishery's potential to differ spatially and temporally.

Conclusions
This study shows that local context and knowledge is very important both to understand the drivers and the potential for management of gleaning.The study showed an indication that gleaning may becoming an increasingly income-driven activity, possibly resulting from increasing market values for commonly landed species, including Anadara cockles, the ramose murex and tulip shells.Whilst contributing food to households remains an important component of the fishery, gleaning should be recognised as an important income generator for women.A possible avenue to explore for initiatives aiming to increase income could include investigating means of increasing accessibility into tourism markets so that catches of ornamental gastropods can be sold.
The study also explored different management strategies and case studies within the FGDs, aiming to gather insights on preferences and perceptions for how management may be materialised within the local contexts.In the initial session FGDs, a rotating no-take zone strategy was perceived positively.However, more hindering factors were discussed in the follow-up sessions after a Fijian case study has been presented.These hindering factors included encroachment from neighbouring communities and allowances being made based on local kinships.This highlights a potential need for cross-community cooperation and means of deterring poaching, possibly through a license-type system as suggested by the FGD participants.Furthermore, greater understanding of the life histories of important species is needed to inform effective rotation periods.Finally, we highlight the importance of gleaner insights, knowledge and suggestions, which could have high value within overall intertidal and fishery management within Zanzibar.

Fig. 2 .
Fig. 2. Images of the intertidal zones at low tide in Nyamanzi (left) and Unguja Ukuu (right), representing the two gleaning grounds used as study sites.

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. Pike et al.

Table 2
Summary of responses from the interviews with gleaners in Nyamanzi (n=24) and Unguja Ukuu (n=22).Forty-six interviews were conducted in total within landing sites.All questions, besides question 3, could be answered with more than one answer category.

Table 3
Approximated average income for selling the day's catch across the sites.Income is shown in Tanzanian shillings and US dollars (conversion rate: 1 TZH = 0.00043726 USD).

Table 4
Common fishery management strategies presented and discussed within the follow-up session FGDs in order to gain perspective on the different strategies' applicability to gleaning.