A unique historical baseline uncovers harvesting impacts on intertidal molluscs at Inhaca Island, southern Mozambique

Sponges assemblages were sampled in four coastal study regions (Malindi, Kenya; Quirimba Archipelago, northern Mozambique; Inhaca Island, Southern Mozambique and Anakao, Madagascar) in the west Indian Ocean. Sponge species were counted in multiple 0.5 m2 quadrats at depths of between 0 and 20 m at a number of sites within localities within each region. Despite the relatively small areas sampled, sponge samples comprised a total of 130 species and 70 genera of the classes Demospongiae and Calcarea. Sponges are clearly a major taxon in these regions in terms of numbers of species, percentage cover or biomass, although their ecology in the west Indian Ocean is virtually unknown. Nearly half of the genera, e.g. Iotrochota, found were species with a so‐called Tethyan distribution. Most of the other genera were cosmopolitan, e.g. Clathria, but some were cold water (Coelosphaera), Indo‐Australian (Ianthella) or circum‐African (Crambe). Many of the species encountered in the present study occurred in at least two study regions, many in more and could occupy large areas of substratum. Some of these, e.g. Xestospongia exigua, are commonly found throughout the Indo‐west Pacific region where they also occupy much space. The endemicity of the shallow water sponge faunas in East Africa (20–25%) seem to be high within the Indo‐Pacific realm but are lower than northern Papua New Guinea. The tropical regions (Kenya and Northern Mozambique) were more speciose than subtropical regions (southern Mozambique and Madagascar) but not significantly more diverse (Shannon H′). Although latitude was not a major influence on sponge community patterns, hard substratum assemblages did form a cline from the tropics to Southern Mozambique, linked by Madagascar. Substratum nature (habitat) was most important in influencing the suite and number of species present. Sponge assemblages of soft substrata were much more dissimilar, both within and between habitats, than those on hard substrata. There was a predictable variability in species richness between hard substratum habitats: coral reefs being speciose and caves being less so. Our findings showed that both patterns and influences on species richness may be decoupled from those influencing diversity. In our data species richness, but not diversity, showed striking regional and bathymetric trends. In addition, sponge species richness mainly split at coral reef vs. non‐reef habitats, whilst diversity divided principally into assemblages on hard and soft substrata. We consider this dichotomy of findings between species richness and diversity values to be important, as these are two principal measures used for the interpretation of biodiversity.

Inhaca Island (southern Mozambique) is located in a high-latitude setting along the seaward margins of the estuarine Maputo Bay and is subject to fluctuations in temperature and salinity, and high sedimentation and turbidity levels. Coral reefs are developed sporadically along the margins of intertidal channels, but framework development is severely restricted. Coral growth is bathymetrically limited (never exceeding 6-m depth), and framework accumulation is only present in the upper 1–2 m. Massive Porites sp. produce a basic reef structure, with other coral genera (mainly Acropora sp., Favia sp., Platygyra sp., Pocillopora sp., and Montipora sp.) colonizing available substrata. Sediment samples also indicate restricted carbonate sediment production, with siliciclastics (mainly quartz) a major sediment contributor (often >90%) and carbonate grain assemblages differing from those normally associated with lower-latitude reefs. Although corals, molluscs and coralline algae (including rhodoliths) represent dominant grain constituents, Halimeda is absent and there is a low diversity (four species identified) of benthic foraminifera (mainly Amphistegina sp.). Grain associations are therefore somewhat transitional in character, comprising elements of both tropical (chlorozoan) and temperate (foramol) grain assemblages. These patterns of reef and associated carbonate production emphasize the marginal character of these reef environments, which form one end member in a broad spectrum of marginal reef systems that are now being identified in a range of both high- and low-latitude settings.

The effects of habitat characteristics (mangrove creek, sandflat, mudflat and seagrass meadow) water salinity, temperature, and depth on the density, spatial distribution and size distribution of juveniles of five commercially important penaied shrimp species (Metapenaus monoceros, M. stebbingi, Fenneropenaeus indicus, Penaeus japonicus and P. semisulcatus) were investigated during a high shrimp recruitment peak lasting from January to June 2002, in four contiguous habitats within a non-estuarine mangrove bay at Saco da Inhaca, Inhaca Island, Southern Mozambique. A total of 14,976 specimens representing the five species were collected by means of a 1m beam-trawl fitted with a 2 mm mesh net with a cod-end. Every two weeks corresponding with spring tides on three consecutive nights, three trawls of 50 meters each were carried out each night in each habitat at 1.40–2.15 a.m. after the daily spring tide high water peak. Species distributions among the four habitats during the six months sampled showed significant differences in habitat preference (p>0.001). Fenneropenaeus indicus, M. stebbingi and P. japonicus dominated the catches in sand flats with densities of 27 ± 0.94, 18 ± 0.98 and 7 ± 0.76 shrimp /50 m2, respectively. Metapenaeus monoceros dominated catches in mudflats at a density of 21 ± 0.78 /50 m2, followed by M. stebbingi with 13±1.2 /50 m2. Penaeus semisulcatus was almost exclusively captured in seagrass meadows at densities of 8± 0.57 /50 m2. Only the Metapeneaus species showed a wide range of habitat utilization. The differences in habitat preference emphasises spatial partitioning between shrimps, reducing competition. Multiple linear regressions of juvenile shrimp densities for each species with water depth, salinity and temperature showed some significant effects. Fenneropenaeus indicus density showed a significant negative relationship with salinity and water depth and a positive relationship with temperature and turbidity. Metapenaeus stebbingi numbers showed a significant positive correlation with increasing salinity and temperature, but a negative one with depth. Penaeus japonicus numbers were significantly related to decreasing salinity and depth. Penaeus semisulcatus abundance was significantly related to decreasing temperature, and increasing turbidity and depth. More than 50% of the total shrimps captured had carapace length of ≤ 3 mm, substantiating the nursery function of the different habitats sampled in the study. Keywords: penaeid, shrimps, juveniles, distribution, habitats, mudflats, sandflats, mangrove creek, seagrasses, Inhaca Island, Mozambique West Indian Ocean Journal of Marine Science Vol. 3 (2) 2004: pp. 163-178

The hypervariable carbonic anhydrase 3/550 intron marker was sequenced in order to ascertain the levels of genetic variability and connectivity within and between reefal populations of the hard coral, Acropora austera, on the south-east African coastline. Populations were sampled from (north to south) Bazaruto and Inhaca islands (Mozambique), Rabbit Rock, Two-mile and Red Sands Reefs and Leadsman Shoal (Maputaland, South Africa). Populations at Inhaca Island contained two private alleles, part of the only monophyletic clade with fixed differences between populations in this study. Haplotype and nucleotide diversity were higher in the north of the study area. Indices of migration and haplotype sharing supported significant connectivity between populations in South Africa and Mozambique, which may be important in sustaining genetic diversity in the down-current South African A. austera populations. Measures of population subdivision indicated a significant amount of fixation of allele frequencies amongst populations. Although fine, such differentiation in a marker from the nuclear genome of a hard coral is consistent with some demographic isolation between A. austera populations in southern Mozambique and South Africa. Populations at Rabbit Rock and Inhaca Island were found to be significantly isolated from, and thus less connected to, A. austera populations at other reefs.

Oysters are important resources for the daily diet, a source of economic income for many coastal communities and a delicacy for the tourism industry. In this study, the oysters (Pinctada capensis and Saccostrea cucullata) were investigated with the aim to assess the catch per unit effort, density and size composition. The study was conducted over a three-year period on Inhaca Island, Southern Mozambique. For both species, perception of fishery trends from collectors was carried out through habitat censuses and interviews. Transects, quadrats and daily fisheries catches approaches were used. Results show that P. capensis is the most exploited on the island. A total of 72.1% of respondents pointed that the oyster P. capensis is decreasing, due to excessive catching (75.4%) followed by natural death (24.6%), while 20.9% affirmed that the resource is stable and 7.0% are unaware about the resource trend. Oyster densities, sizes and catches per unit effort were higher in less accessible areas only for P. capensis. The present study provides valuable baseline information to recommend best practices to improve the exploitation, and access the need for introduction of aquaculture, towards the sustainable management and conservation of oysters, and ultimately to ameliorate people’s livelihoods.

This study examines changes in frigate tuna populations in southern Sri Lanka, based on reports from fishers in three age classes. Significantly higher values for best day's catch and largest specimen ever caught were obtained by older fishers than younger ones. Values were also significantly higher during early years, providing clear evidence of a decrease in the resource over time (1951–2007). Older fishers reported best catches further inshore and in shallower waters which, on becoming depleted, forced younger generations to fish in less exploited areas further offshore. Heavy harvesting is also evident from the significantly greater number of sites reported by older fishers as being depleted, compared with observations of younger fishers. These findings contrast markedly with catch and catch per effort patterns from statistics for frigate tuna and bullet tuna (combined) in southern Sri Lanka (1994–2004). No stock decline is evident, and at least one report in the early 1990s advocated increasing exploitation rates by 40% to maximize yields. Although not a primary research objective, fisher observations on frigate tuna populations were also analysed to help evaluate possible effects of the 2004 tsunami. Most fishers reported post‐tsunami decline, but mainly from a larger new generation of fishers, rather than extra boats provided by aid money or (direct or indirect) biophysical impacts from the tsunami. Reliance on fishery statistics, especially for mixed species and over a limited period, can be risky and easily mask true stock status. Evidence of harvesting effects on frigate tuna in southern Sri Lanka is evident using questionnaire data over a longer time scale. This study provides another compelling case of the ‘shifting baseline syndrome’, whereby fishers of different ages have altered perceptions/experiences of their environment. This may be its first reported occurrence in Sri Lanka. Traditional knowledge from this and similar surveys may provide national fishery management with valuable insights and help improve conservation prospects for frigate tuna and other marine resources. Copyright © 2009 John Wiley & Sons, Ltd.

Ocean acidification presents a major threat to marine life, and a large body of evidence has documented its negative effects on various marine species and ecosystems. Recent meta-analyses highlight the key role of local adaptation and have linked species’ sensitivity to extremes of the present range of pH variability. More specifically, ‘physiological tipping points’ can be correlated with the lowest experienced pH where the organisms live. We verified this hypothesis by comparing the responses of larvae of the collector urchin Tripneustes gratilla originating from two neighbouring seagrass meadows at Inhaca Island in southern Mozambique. The two seagrass meadows experience different conditions: the site at the Inhaca Marine Biology Research Station (Estação de Biologia Marítima de Inhaca, EBMI) is subtidal, and the site at Banguá is intertidal. Larvae of adults collected from the two sites were cultured in the laboratory under four different target pH treatments (8.04, 7.67, 7.46 and 7.29) for 7 days. The results showed an overall negative effect of lower pH on survival and growth as well as on an index of symmetry. Larvae originating from the intertidal seagrass habitat at Banguá which experiences large pH fluctuations were more sensitive to a lower pH than those from the subtidal seagrass habitat at EBMI. This finding suggests that different mechanisms for pH tolerance and local adaptation may apply in subtidal versus intertidal environments. Consequently, the unifying principle that physiological tipping points are correlated with the extreme low pH in the present range of variability, may reach its limit in increasingly extreme environments under natural conditions.

Nine seagrass species were identified around Inhaca as well as a more narrow form of Thalassodendron ciliatum (Forsk.) den Hartog occurring in rocky pools at the north east coast. Seagrasses were mapped and grouped in seven distinct community types (in order of areas covered): Thalassia hemprichii/Halodule wrightii, Zostera capensis, Thalassodendron ciliatum/Cymodocea serrulata, Thalassodendron ciliatum/seaweeds, Cymodocea rotundata/Halodule wrightii, Cymodocea serrulata and Halophila ovalis /Halodule wrightii; with the ninth species Syringodium isoetifolium occurring in three of these communities. A dichotomous identification key is presented. Seagrasses covered half of the whole intertidal area around Inhaca Island and diversity was also high at community level. Transects at macro and micro scales showed zonation of species which may be due to tidal gradients or topographic variation. Cluster analysis indicated ecological dissimilarities between co-dominant species. A decline of Zostera capensis has recently been seen outside the local village. Baseline studies like this are important for coastal zone management in developing countries, where large future changes in seagrass cover can be expected.

Inhaca Island, southern Mozambique, is located towards the southerly latitudinal limits of coral reef growth. Reef development is restricted to the margins of channels which dissect intertidal flats on the Maputo Bay side of the island, and to depths of around 6 m. In contrast to lower latitude reefs, reef development is therefore both spatially and bathymetrically restricted (largely due to high turbidity levels). These natural stress levels were exacerbated, via increased freshwater and sediment discharge, during the severe floods of late 1999/early 2000. Flood impacts varied but were most significant on reefs on the inner (western) side of the island where live coral cover (LCC) decreased from 60.5% (1999) to 24.0% (2001). This is attributed to freshwater-induced bleaching. Dead in situ coral cover increased from 18.6% (1999) to 51.3% (2001). Reefs on the southern tip of the island, by contrast, were relatively unaffected. It is suggested that this largely reflects a closer proximity to the open Indian Ocean which mitigated the effects of freshwater dilution.

A study to estimate the relative importance of mangrove primary carbon and nitrogen sources to five commercial penaeid shrimps species was done at Saco da Inhaca, a non-estuarine mangrove-fringed bay on Inhaca Island, southern Mozambique. Carbon and nitrogen stable isotope ratios were determined in a variety of primary producers (mangroves, epiphytes, phytoplankton and seagrasses), sediments and in five penaeid shrimp species (Penaeus (Fenneropenaeus) indicus, P. japonicus, P. semisulcatus, Metapenaeus monoceros and M. stebbingi), collected within the bay in different habitats and during two different periods. The penaeid shrimps showed ∂ 13C values ranging from –13 to –19 ‰, (average of –15.6 ± 0.4 ‰, n=19) which is highly enriched compared to the mean value for mangrove leaves (average - 27.6± 3.6 ‰, n=3) which varied from –20 to –32‰. The results shows that some shrimps may derive their carbon either from detritus, plankton remains or from benthic organisms. Overall, the carbon isotopic signal shifted as the shrimps got bigger, suggesting a change of diet with growth. No significant differences were found between ∂ 15N isotope values among the shrimps studied, indicating that they may belong in the same trophic position (except P. semisulcatus, which occupies a higher level). There is some evidence that sampling period influences the carbon isotope ratios for sediment and shrimps. Keywords: stable isotopes, penaied shrimps, mangrove bay, Inhaca island, Mozambique West Indian Ocean Journal of Marine Science Vol. 3 (2) 2004: pp. 151-162

Highlight Research The COVID-19 pandemic has caused an increase in the price of marine resources and the income of coastal communities has been affected. The government and the authorities need to come out with several incentives to control this condition and the request for fish markets can be met customarily without rising prices and declining marine resources. Malaysian Fisheries Development Authority (LKIM) a body that has a direct link to the fishing industry needs to ensure that all fishermen's associations participate in the purchase and marketing of fishermen's catch. Adaptation of fish producers will pave the way for all coastal communities to develop more organized fishing systems and sufficient food sources Abstract COVID-19 has a significant impact on the fishery industry, economy, and food supply. The government of Malaysia imposes a Movement Control Order (MCO) to curb the spread of COVID-19 infection. Although the MCO implementation has benefits in terms of public health, it has affected the fishery industry and the livelihood of coastal communities in Malaysia. This study aimed to identify the impact of the COVID-19 pandemic on the fishery industry and their livelihoods during that period of calamity. Qualitative research and thematic analysis were employed to seek deeper information on the real situation that retards the fishing activities to the opt stage. COVID-19 has already revealed gaps in health care, the economy, and food systems. The findings obtained can provide recommendations to the government to provide initiatives to fishermen to help them maintain and improve their livelihood. However, this study has limitations as the number of respondents is relatively small due to the restrictions of movement allowed by the government. Future studies could be further enhanced in terms of the impact of COVID-19 after movement restrictions have been loosened and could use a quantitative approach to obtain significant data.

Monthly plankton sampling was carried out at three stations on the west coast of Inhaca Island, southern Mozambique, from August 1994 to August 1995. Sampling included water mass physical parameters, nutrients, chlorophyll and zooplankton with nets of 125 and 330 µm pore aperture. Nutrient concentration has shown maxima during the summer months, where rain provides the maximum outflow of rivers discharging into Maputo Bay. Following the nutrient peak, chlorophyll a has shown maxima around the month of April, with another minor peak in September, when temperature begins to increase. Zooplankton densities followed closely the phytoplankton peaks, especially small herbivorous taxa and larval stages, such as gastropod and bivalve larvae.

—Litter fall and decomposition of mangrove leaves were compared for different seasons, species (Avicennia marina and Rhizophora mucronata) and sites in southern Mozambique. Mangrove leaf litter fall and decomposition was estimated using small mesh collecting-baskets and litter bags respectively in 2006 and 2007 at two sites of Maputo Bay: an urban dwarf mangrove at Costa do Sol (Maputo City) and a rural well-developed mangrove at Saco (Inhaca Island). A. marina at Saco produced more litter (dry season 10.6 g m-2 and wet season 14.2 g m-2) than R. mucronata (dry season 4.6 g m-2 and wet season 14.1 g m-2), and leaves contributed more to total litter fall in the dry season (February/March) compared with the wet season (September/October) for both species. Decomposition by means of loss of ash free dry weight (AFDW) from leaves maintained in the subtidal was best described by double exponential models which showed loss rates of leaves along the time. Field experiments at Saco showed that submerged leaves of A. marina decomposed faster than R. mucronata. For A. marina, the average time required to lose half of the initial AFDW (t0,5) was 96 days and 78 days for the dry and wet season respectively, whereas for R. mucronata leaves it took 151 days in the dry and 476 days in the wet season. At Costa do Sol, A. marina leaves took 171 and 48 days for the dry and wet seasons respectively to lose half AFDW; whereas R. mucronata took 98 days in the dry and 25 days in the wet season. The results showed that breakdown of leaf litter was season and species dependent. Litter decomposition in the wet season was faster than the dry season and A. marina had the fastest decomposition rates, appearing to act as a principle pioneer species for enrichment of the fringing mangrove habitats of sub-tropical eastern AfricaKeywords: Litter fall, leaf decomposition, sub-tropical, southern Mozambique

The level of biodiversity in Indonesia as a tropical country is very high, the potential of marine biological resource makes the sea of Indonesia called as Marine Mega-Biodiversity region in the world. Therefore it was expected especially in coastal communities can take and utilizing of marine biological resource optimally, especially for conventional and traditional for health. However basical knowledge and attitude of coastal communities about coastal and marine resources primarily for its management is still lack. The lack of the basical knowledge can affect the inability of society to engage in the use of coastal and marine resources, especially the utilization of marine biological resources in health. The aim of this research was to determine the relationship between knowledge and attitude to the utilization of marine biological resource for health on coastal communities area of Soropia wich one of coastal areas in Southeast Sulawesi with high potential of marine biological resorces. The research method used observational design with cross sectional approach. The subjects of the research were coastal communities in Soropia located in three villages, namely Tapulaga, Leppe and Bajoe. This research was conducted for January 2016, with 292 respondents of population. The sample were selected by using stratified random sampling technique that obtained 167 respondents. Bivariate analysis was performed by Chi square and Fisher test.The result of bivariate analysis showed that there was significant relationship between knowledge (p=0,000) and the utilization of marine biological resource for health and there was significant relationship between attitude (p=0,014) and the utilization of marine biological resource for health. This research concluded that there were significant relationship between knowledge and attitude to the utilization of marine biological resource for health in the coastal community area of Soropia. The present research suggested that there would be further research that investigated the efficacy of Enhalus acoroides root as the alternative treatment to resolve Diabetes disease, Semele cordiformis as the alternative medication to cure Hepatitis disease and Siganus sp. bile as the alternative analgesic medication to wounds caused by fish bone. Keywords: marine biological resource,health, knowledge, attitude, coastal community

The blue economy concept that gained popularity after the 2012 UN Conference on Sustainable Development (Rio+20) has since been advocated by public and private actors as well as environmental non-governmental organisations. Defined as “the sustainable pursuit of economic activities resulting from the exploitation of coastal and marine resources” (Germond-Duret and Germond, 2022) the blue economy concept has raised both hope and concerns: hope that environmental protection will be at the heart of (economic) activities at sea; and concerns that it will facilitate further unsustainable exploitation of coastal and marine resources. It can be seen as being part of a wider “blue acceleration” process, “a race among diverse and often competing interests for ocean food, material, and space” (Jouffray et al., 2020).The academic literature as well as policy and legal documents on the blue economy, almost non-existent a few years ago, is now burgeoning. However, it remains an ambiguous and contested concept, and further work is needed to address the place of environmental protection within the blue economy, the role of communities in this process, and the potential human and social costs of additional economic activities at sea. As research on the blue economy expands and as stakeholders further exploit coastal and marine resources, it is critical to deepen our understanding of how the blue economy can be just and fair.Deploying corpus linguistic analysis this paper will examine the existing academic literature as well as policy and legal documents on the blue economy published by governments, civil society, regional and international organisations to investigate:(1) to what extent traditionally overlooked stakeholders, such as coastal communities, are represented in the academic literature, policy and legal documents related to blue economy?(2) are the economic, social and cultural justice implications of blue economy activities addressed?(3) what checks and balances mechanisms are put in place to support inclusive participation of Indigenous Peoples, local communities, small-scale fishers, women, children and young people at the heart of the process?UN databases such as the Food and Agriculture Organization of the UN’s SSF-LEX, the UN Division for Ocean Affairs and the Law of the Sea’s Maritime Zones and Maritime Delimitation database, and the International Seabed Authority’s national legislation database will be used to collate various governments’ documents related to the blue economy.The findings from the paper will identify trade-offs and inequities that surface as blue economies rapidly develop and provide pathways to integrate transdisciplinary action research approaches, processes, and innovation that are needed to unlock the potential of science to develop sustainable blue economies (Heidkamp et al., 2021). Transdisciplinary research implies working with ocean experts from varied disciplines, different knowledge holders and stakeholders in the co-design of solutions (Febrica, 2021).