Browsing by Author "Slater, Matthew J."
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Item Co-culture of sea cucumber Holothuria scabra and red seaweed Kappaphycus striatum(John Wiley & Sons Ltd, 2014) Beltran-Gutierrez, Marisol; Ferse, Sebastian C.A.; Kunzmann, Andreas; Stead, Selina M.; Msuya, Flower E.; Hoffmeister, Thomas S.; Slater, Matthew J.Commercially valuable sea cucumbers are potential co-culture species in tropical lagoon environments, where they may be integrated into established aquaculture areas used for seaweed farming. In the current study, wild-caught juvenile sea cucumbers, Holothuria scabra, and red seaweed Kappaphycus striatum were co-cultured on Zanzibar, United Republic of Tanzania. Sea cucumbers (97 g 31 SD, n = 52) were cultured in mesh enclosures at initial cage stocking densities of 124 21 SD and 218 16 SD g m 2 under seaweed culture lines. Over 83 days, individual growth rate (1.6 g d 1 0.2 SD) of sea cucumbers at low stocking density was significantly higher (v2 = 8.292, d.f. = 1, P = 0.004) than at high-stocking density (0.9 g d 1 0.1 SD). Seaweed individual growth rates [6.27 ( 0.3 SE) g d 1] were highest in co-culture with sea cucumber at low density but did not differ significantly from high sea cucumber density or seaweed monoculture treatments (v2 = 3.0885, d.f. = 2, P = 0.2135). Seaweed growth varied significantly (v2 = 35.6, d.f. = 2, P < 0.0001) with sampling period, with the final sampling period resulting in the highest growth rate. Growth performance for seaweed and sea cucumbers (v2 = 3.089, d.f. = 2, P = 0.21 and v2 = 0.08, d.f. = 1, P = 0.777 respectively), did not differ significantly between monoculture and co-culture treatments, yet growth in co-culture was comparable with that reported for existing commercial monoculture. Results indicate H. scabra is a highly viable candidate species for lagoon co-culture with seaweed. Co-culture offers a more efficient use of limited coastal space over monoculture and is recommended as a potential coastal livelihood option for lagoon farmers in tropical regions.Item Effect of social and economic drivers on choosing aquaculture as a coastal livelihood(Elsevier, 2012-12-10) Slater, Matthew J.; Mgaya, Yunus D.; Mill, Aileen C.; Rushton, Steven P.; Stead, Selina M.Aquaculture is proposed as a means to income generation and food security in developing nations. Understanding drivers of attitudes and perceptions towards choosing aquaculture as a livelihood is essential to aid policy makers in promoting its development. This paper takes a new approach to establishing a baseline of these social and economic drivers. We used simple metrics familiar to policy makers collected in face-to-face semi-structured interviews – e.g. education level, time availability to work and income level – to predict willingness of individuals to adopt aquaculture as a livelihood. We compared modelling approaches ability to provide insights into effects of social and economic factors on willingness of 422 household decision-makers in coastal villages in Tanzania to participate in sea cucumber aquaculture as an alternative livelihood. Linear regression identified the factors; time available for a supplementary livelihood, gender, social network strength and material style of life as significantly predicting individuals' willingness to adopt aquaculture. A Bayesian Belief Network (BBN) model of community data created using logistic regression results, open response analysis and critical literature appraisal allowed intuitive manipulation of factors to predict the influence of aquaculture uptake drivers and constraints. The BBN model provided quantified predictions of the effect of specific policy interventions to promote aquaculture uptake within the modelled community. The analysis from the BBN model supports its broader use as an assessment tool for informing policy formulation by highlighting key areas of intervention to increase willingness to uptake aquaculture among target groups, such as low income households and women. BBNs provide a modelling approach that allows policy makers to visualise the influence of socio-economic factors on the success of introducing aquaculture in different local contexts.Item Growth performance of the sea cucumber Holothuria scabra and the seaweed Eucheuma denticulatum: integrated mariculture and effects on sediment organic characteristics(Inter Research, 2016) Namukose, Mary; Msuya, Flower E.; Ferse, Sebastian C.A.; Slater, Matthew J.; Kunzmann, AndreasDeposit-feeding sea cucumbers play a key role in marine ecosystems through bioturbation, burrowing and feeding on organic matter in marine sediments. Many deposit-feeding holothurians have therefore been recommended for integrated multitrophic aquaculture systems (IMTA). We set up an integrated mariculture system of sea cucumber Holothuria scabra and seaweed Eucheuma denticulatum in Bweleo, Unguja Island of Zanzibar, Tanzania, to investigate the effect of stocking density on the growth and survival of culture species, total organic matter (TOM) and total organic carbon (TOC) content in the sediment. Treatments that included a fixed stocking density (500 g, ca. 200 g m−2) of E. denticulatum and 4 sea cucumber stocking densities (monoculture, low, medium and high density; 0, 150 ± 5, 236 ± 24, 345 ± 48 g m−2, mean ± SD) of medium-sized H. scabra (114 ± 37 g) were established. Stocking density of H. scabra did not influence survival of either species. Seaweed cultured under high stocking density of H. scabra had a higher specific growth rate of 2.33% d−1 than that cultured at the medium or low densities or without sea cucumbers. Sea cucumbers cultured at low stocking density had a higher mean growth rate of 0.80 g d−1 compared to those cultured at medium or high densities. TOM and TOC in sediments decreased over the experimental period at medium sea cucumber stocking density, while at low and high stocking densities, organic matter accumulated. The study demonstrates that the integration of E. denticulatum and H. scabra at 200 g m−2 enhances seaweed growth and can reduce organic matter content in the sediments.Item Perceptions of rule-breaking related to marine ecosystem health.(2014-02-27) Slater, Matthew J.; Mgaya, Yunus D.; Stead, Selina M.Finding effective solutions to manage marine resources is high on political and conservation agendas worldwide. This is made more urgent by the rate of increase in the human population and concomitant resource pressures in coastal areas. This paper links empirical socio-economic data about perceptions of marine resource health to the breaking of marine management rules, using fisheries as a case study. The relationship between perceived rule-breaking (non-compliance with regulations controlling fishing) and perceived health of inshore marine environments was investigated through face-to-face interviews with 299 heads of households in three Tanzanian coastal communities in November and December 2011. Awareness of rules controlling fishing activity was high among all respondents. Fishers were able to describe more specific rules controlling fishing practices than non-fishers (t = 3.5, df = 297, p<0.01). Perceived breaking of fishing regulations was reported by nearly half of all respondents, saying “some” (32% of responses) or “most” (15% of responses) people break fishing rules. Ordinal regression modelling revealed a significant linkage (z = −3.44, p<0.001) in the relationship between respondents' perceptions of deteriorating marine health and their perception of increased rule-breaking. In this paper, inferences from an empirical study are used to identify and argue the potential for using perceptions of ecosystem health and level of rule-breaking as a means to guide management measures. When considering different management options (e.g. Marine Protected Areas), policy makers are advised to take account of and utilise likely egoistic or altruistic decision-making factors used by fishers to determine their marine activities