{"title":"Establishing historical benthic cover levels for coral reefs of the Western Indian Ocean","authors":"Mishal Gudka, Swaleh Aboud, D. Obura","doi":"10.4314/wiojms.v22i1.11","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.11","url":null,"abstract":"Data on coral reef health prior to large-scale disturbances are unavailable in most parts of the world including the Western Indian Ocean (WIO). Robust coral reef health baselines could improve the understanding of changes occurring to reefs in the 21st century and prevent the “shifting baseline” phenomenon, enabling researchers and managers to evaluate the success of management measures, and set achievable targets for new interventions. To make this data accessible to the WIO coral reef community, a literature review was conducted to identify and compile data collected prior to 2008 for two principal measures of reef health; hard coral and fleshy algae cover. Baseline hard coral and algae cover levels were calculated using data from selected sites that were known to be in healthy condition prior to (or just after) the 1998 bleaching event. Mayotte had the highest mean hard coral cover with 80.9 % (95 % bootstrap confidence interval (95 % CI) =65.8-95.9 %), followed by Comoros with 62.1 % (95 % CI=53.2-78.8 %) and Madagascar with 55.6 % (95 % CI=49.8-62.5 %). Mean fleshy algae cover varied from 8.4 % in Mayotte (95 % CI=2.4-17.4 %) to 35.4 % in Mozambique (95 % CI=20.6-50.8 %). At a regional scale, mean baseline hard coral cover is estimated to be between 41 and 47 %; reefs were in a coral-dominant state, with more than double the amount of coral compared to algae.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122708601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Marcelino, A. Macia, M. Mafambissa, Diego Castejón, Carlos Andrade
{"title":"Combined effects of salinity and temperature on survival and growth during the early life cycle of the rock oyster Saccostrea cuccullata (Born, 1778)","authors":"J. Marcelino, A. Macia, M. Mafambissa, Diego Castejón, Carlos Andrade","doi":"10.4314/wiojms.v22i1.10","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.10","url":null,"abstract":"Temperature and salinity are among the critical factors affecting the survival and growth of bivalve larvae. The combined effects of temperature and salinity on the embryonic and larval development of the rock oyster Saccostrea cuccullata (von Born, 1778) in culture conditions were investigated in a laboratory study on Inhaca Island, Mozambique. A factorial experimental design tested three temperatures (24, 30 and 34 ºC) and three salinities (30, 35 and 40 parts per thousand) over a seven-day period. Larval survival and growth (in height and length) were assessed by regular sampling by counting and measurement of larvae under an optical microscope equipped with a micrometric scale. Significantly higher larval survival was observed at the combination of 30 °C and 35 salinity. However, the mid-range temperature (30 ºC) and highest salinity (40) resulted in faster growth of the larvae. The lowest temperature (24 ºC) negatively affected growth regardless of salinity level and survival decreased linearly with increasing salinities. The present results will aid in the understanding of the environmental factors behind the natural recruitment of spat of S. cuccullata and contribute to the optimization of rearing protocols for the larval culture of this oyster species.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133182327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A new report of the stenopodid shrimp Stenopus devaneyi Goy, 1984 from the Western Indian Ocean","authors":"Gabriel Barathieu, Olivier Konieczny, J. Poupin","doi":"10.4314/wiojms.v22i1.8","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.8","url":null,"abstract":"The rare stenopodid shrimp, Stenopus devaneyi Goy, 1984, is reported for the first time in the Western Indian Ocean (WIO), at 60 m depth at Mayotte Island. No specimens were collected but the species is recognized confidently on photographs based on its characteristic colour pattern: two large red spots on the sides of the second abdominal somite. Selected colour photos are presented. Former Indo-West-Pacific records are listed with an updated map for the geographic distribution of this shrimp. A few ecological observations are made.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116880492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Susana W. Kihia, J. Uku, Sarah Ater, Moses Kioko, N. I. Kadagi, N. Wambiji
{"title":"Billfish in coastal visual art in Kenya: a resource for ocean science communication","authors":"Susana W. Kihia, J. Uku, Sarah Ater, Moses Kioko, N. I. Kadagi, N. Wambiji","doi":"10.4314/wiojms.v22i1.7","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.7","url":null,"abstract":"Approaches to marine conservation and management issues has often been limited to using scientific research to propose technical and policy interventions. However, communicating outputs as scientific publications and policy briefs has limited reach and impact for non-academic audiences. Art markets in Mombasa and Kilifi Counties in Kenya were sampled to determine how the creative arts can be used to communicate ocean science. Artwork with terrestrial themes was popular and increasingly available to buyers compared to ocean art. Billfish as a representative species was popular in ocean art culture, underscoring its potential in a niche market for ocean art. Our study highlights opportunities for active collaboration between scientists and artists in communicating messages from scientific work to non-academic audiences. Engagement of Western Indian Ocean countries in the UN Decade of Ocean Science for Sustainable Development will benefit from the use of ocean art in science communication and enhance ocean literacy in the region.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134599567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Rumisha, Rehema J. Simwanza, A. Nehemia, R. Mdegela, M. Kochzius
{"title":"DNA barcoding reveals threatened and protected elasmobranchs in Tanzanian fish markets","authors":"C. Rumisha, Rehema J. Simwanza, A. Nehemia, R. Mdegela, M. Kochzius","doi":"10.4314/wiojms.v22i1.6","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.6","url":null,"abstract":"Western Indian Ocean countries have banned elasmobranch finning and enacted legislation to protect endangered elasmobranchs, however finned and morphologically deformed specimens are still landed and traded on Tanzanian fish markets. Such specimens are difficult to identify morphologically, and it is possible that protected elasmobranchs are among these. This study used DNA barcoding to uncover protected elasmobranchs in 102 specimens traded on Tanzanian fish markets. The sampled specimens revealed 23 elasmobranch species, 12 of which (52.1 %) were classified as endangered (EN) or critically endangered (CR) on the IUCN Red List. Three of the identified species (great hammerhead Sphyrna mokarran, oceanic whitetip shark Carcharhinus longimanus, and pelagic thresher Alopias pelagicus) are protected by Tanzanian laws. Hence, it is advised that steps be taken to strengthen law enforcement at landing sites and fish markets in the country. Furthermore, the Third Schedule of Fisheries (Amendment) Regulations of 2009 should be updated to include 11 EN and CR elasmobranchs that are not on the list. Additionally, national and regional elasmobranch conservation plans should be developed to prevent the exploitation of endangered elasmobranchs.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130772190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nancy Iraba, S. Yahya, Jerry Mang'ena, Fadhili M. Malesa
{"title":"Comparison of growth and survival rates of big blue octopus (Octopus cyanea, 1849) fed on natural and formulated diets in captivity","authors":"Nancy Iraba, S. Yahya, Jerry Mang'ena, Fadhili M. Malesa","doi":"10.4314/wiojms.v22i1.5","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.5","url":null,"abstract":"Comparative studies on growth and survival rates of Octopus cyanea fed on natural and formulated diets in captivity have never been conducted in Tanzania. This study aimed to investigate the growth and survival rates of O. cyanea using natural and formulated diets. The three formulated diets were made up of a mixture of sardines, fish waste, and alternating ratios of crab paste content across the different diet treatments. Treatment B had 75 % crab paste content, Treatment C had 50 % crab content and Treatment D had 0 % crab content while Treatment A was based on a natural diet of frozen crabs (Scylla serrata) and was used as a control. After five weeks of feeding, the effect of each diet was analyzed on growth performance and survival rates for the octopus. Results showed that there was a significant difference in growth rate in all the diet treatments (H=13.243, p=0.004, DF=3). Specific growth rates (SGR) were higher in octopuses fed in feed treatment A and lowest in feed treatment D. The survival rates were 100 % for treatment A and feed treatment B and 75 % for treatments C and D respectively. More research is needed to develop optimal nutritional diets for faster growth rates of O. cyanea in captivity.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126705041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Willingness and drivers of community participation in mangrove conservation in the Rufiji Delta, Tanzania","authors":"Loyce N. Ntibona, M. Shalli, M. Mangora","doi":"10.4314/wiojms.v22i1.4","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.4","url":null,"abstract":"Promoting local community participation in recognition of their indigenous knowledge is important for effective resource conservation. The aims of this study were to evaluate local community willingness and drivers of participation in mangrove conservation activities in the Rufiji Delta. Data were collected through focus group discussions, key informant interviews, semi-structured household interviews and participant and non-participant observations, across three designated management blocks - Northern delta (ND), Central delta (CD) and Southern delta (SD). Qualitative data were analysed using content analysis while quantitative data were analysed for descriptive and inferential statistics. Overall, the majority of respondents (88 %) agreed that it was important for the community to participate in mangrove conservation activities and 50 % of them expressed immediate readiness to participate if called upon. Zone wise, 50 % of respondents in ND and CD, and 42 % in SD indicated a moderate level of community willingness to participate in conservation. Age of household head, education level, source of income and awareness of mangrove governing laws were the most significant drivers positively associated with community willingness to participate in conservation activities. These findings suggest that for long-term management of mangroves, local communities should be adequately recognized as partners rather than as foes.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117166980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Seagrass cover reduction in Zanzibar from 2006 to 2019","authors":"Daniel W. Purvis, N. Jiddawi","doi":"10.4314/wiojms.v22i1.1","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.1","url":null,"abstract":"Seagrass meadows are abundant in Zanzibar, Tanzania and provide essential ecosystem services, yet they have been less researched or protected than other marine ecosystems. Evidence suggests that anthropogenic impacts, such as seaweed farming, small-scale fishing, and tourism, are their greatest threats. Using geographic information systems (GIS) to estimate seagrass cover, this study conducted Spearman’s rank correlation analyses to estimate correlations between the scale of seaweed farming, fishing, and tourism or the implementation of marine protected area (MPA) management plans, and the change in percent of seagrass cover from 2006 to 2019. On average, seagrass cover decreased by 10.98 % over this period. The scale of tourism was negatively correlated with seagrass cover (rs (9) = -0.64, p = 0.044). No other variables were correlated with declines, though seaweed farming had a weak protective effect on seagrass cover (rs(9) = 0.28, p = 0.426). To improve the management of seagrass meadows, plans must identify seagrasses as critical ecosystems, expand seagrass restoration projects, and address harmful practices in the tourism industry.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130531526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"New record of the Bluntnose scorpionfish, Neomerinthe erostris (Alcock 1896) (Teleostei: Scorpaenidae) from Mayotte, southwestern Indian Ocean","authors":"R. Fricke, T. Mulochau, Gabriel Barathieu","doi":"10.4314/wiojms.v22i1.3","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.3","url":null,"abstract":"The Bluntnose scorpionfish Neomerinthe erostris is recorded for the first time from Mayotte, southwestern Indian Ocean, based on a specimen photographed in November 2022, at a depth of 115 m. The live colour pattern of this species is described for the first time.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129260283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The first attempts made towards the domestication of sea cucumbers in Kenya","authors":"Esther W. Magondu, Gladys M. Holeh, J. Munguti","doi":"10.4314/wiojms.v22i1.2","DOIUrl":"https://doi.org/10.4314/wiojms.v22i1.2","url":null,"abstract":"The potential for culture of sandfish Holothuria scabra in Kenya was investigated based on a sample of 1000 wild individuals with an average weight of 40-80 g. This experiment was conducted to identify suitable methods of collection, transportation, acclimatization, and growth at different stocking densities. Packing methods tested during collection were oxygen filled plastic bags and open basins. For method 1, Sample 1 sandfishes were carried individually in oxygen filled plastic bags with sea water. Sample 2 included a total of five sandfishes per bag, and Sample 3 had a maximum of ten sandfishes. Under method 2 specimens were transported using open basins containing sand and aerated sea water in densities of 10, 20 and 30 individuals per basin. The mean (±SD) percentage evisceration rate during transportation in method 1 was 0 for a density of 1, 3.33 ± 5.77 % for a density of 5, and 20 ± 10 % for a density of 10. In method 2 evisceration occurred at all the three densities; 23.3 ± 15.28 % for the low density, 23.33 ± 2.8 % for the middle density and 36.6 ± 3.33 % for the higher density. The findings of this study provide information to contribute to the development of marine aquaculture of sea cucumber in Kenya.","PeriodicalId":200681,"journal":{"name":"Western Indian Ocean journal of marine science","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124537140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}