Comparison of Marine Spatial Planning Methods in Madagascar Demonstrates Value of Alternative Approaches

The Government of Madagascar plans to increase marine protected area coverage by over one million hectares. To assist this process, we compare four methods for marine spatial planning of Madagascar's west coast. Input data for each method was drawn from the same variables: fishing pressure, exposure to climate change, and biodiversity (habitats, species distributions, biological richness, and biodiversity value). The first method compares visual color classifications of primary variables, the second uses binary combinations of these variables to produce a categorical classification of management actions, the third is a target-based optimization using Marxan, and the fourth is conservation ranking with Zonation. We present results from each method, and compare the latter three approaches for spatial coverage, biodiversity representation, fishing cost and persistence probability. All results included large areas in the north, central, and southern parts of western Madagascar. Achieving 30% representation targets with Marxan required twice the fish catch loss than the categorical method. The categorical classification and Zonation do not consider targets for conservation features. However, when we reduced Marxan targets to 16.3%, matching the representation level of the “strict protection” class of the categorical result, the methods show similar catch losses. The management category portfolio has complete coverage, and presents several management recommendations including strict protection. Zonation produces rapid conservation rankings across large, diverse datasets. Marxan is useful for identifying strict protected areas that meet representation targets, and minimize exposure probabilities for conservation features at low economic cost. We show that methods based on Zonation and a simple combination of variables can produce results comparable to Marxan for species representation and catch losses, demonstrating the value of comparing alternative approaches during initial stages of the planning process. Choosing an appropriate approach ultimately depends on scientific and political factors including representation targets, likelihood of adoption, and persistence goals

Nitrogen uptake kinetics of freshly isolated zooxanthellae

83-88Zooxanthellae freshly isolated from the coral host Pocillopora damicornis exhibited substrate-saturable uptake kinetics for ammonium, nitrate and urea. Maximum uptake velocity for ammonium [10. 1 nmol. (mug chl-a).-1h-1] was greater than that for nitrate [2.8 nmol.(mug chl-a).-1h-1] and urea [0.37 nmol. (mug chl-a).-1h-1]. Half-saturation constants for uptake of the three nitrogen compounds were in the range of 10-15 mumol.l-1. Generally, uptake of any one nitrogen substrate appears to be inhibited by the other 2 substrates when the latter are present in higher concentrations. The observed interactions can be explained by the uncompetitive model. These results are interpreted as indicative of a simultaneous uptake of all 3 nitrogen compounds by the zooxanthellae

Carbon Fixation and Excretion in Symbiotic Algae (Zooxanthellae) in the Presence of Host Homogenates

43-46Rates of carbon fixation and excretion in zooxanthellae, isolated from the massive coral Favia pallida, were found to decrease with time. In the presence of host homogenate, the two rates were enhanced. Zooxanthellae responded to tissue homogenate of other species of corals also, but the responses were of different degrees. Excretion of carbon continued both in the light and darkness. Tissue homogenate from F. pallida stimulated carbon fixation in zooxanthellae even after 4 hr which is longer than the reported duration of 3 hr regarding the effectiveness of the homogenate. Probably the property of zooxanthellae to excrete photosynthetically fixed material in the presence of host homogenate is to provide a source of nutrition to corals

Energy pathways in the Laccadive Sea (Lakshadweep)

242-246Energy components of the Laccadive Sea include phytoplankton, zooplankton and detritus. Of these, the detritus contributes most of the energy (97%). Large quantities of detritus, may this greater than phytoplankton and zooplankton in the upper 250 m layer, include microbial flakes, organic aggregates, remains of phytoplankton and zooplankton and faecal pellets. Caloric content of suspended detritus is fairly high and similar to that of other water masses. Annual harvestable yield of the Laccadive Sea has been estimated from the total energy contributed by phytoplankton and zooplankton and it is concluded that Laccadive Sea can support fishery many times greater than what is exploited

Biological Productivity of Coastal Waters of India - From Dabhol to Tuticorin

84-93Biological productivity of coastal waters of India, from Dabhol to Tuticorin was studied during the 17th cruise of RV Gaveshani in March 1977. Within 50 m depth from the coast, data on chlorophyll a, 14C uptake and zooplankton biomass were collected at 55 stations. Larger phytoplankton organisms (microplankton) contributed greater spatial variations in primary productivity than nannoplankton. Maximum primary production was recorded in areas adjoining Karwar and Calicut. production at the primary level of the food chain for the entire coastal area measuring 43x 103 km2 was at the rate of 0•33 gC/m2/day or 122 tonnes C/km2/yr or 5 million tonnes of carbon/yr. Of the 18 major components constituting the zooplankton biomass, copepods formed the dominant group. Caloric value of different components ranged from 0•5 to 6•4 kcal/g dry weight. The average production of zooplankton in the total area was 125 mgC/m2/day which amounted to 2•5 million tonnes of carbon/yr or 60 tonnes of carboni km3/yr. Mean transfer coefficient was found to be 10% and the average tertiary production, calculated from both primary and secondary production rates, was approximately 2 million tonnes of live weight/yr. The average sustainable yield per year has been estimated as 0•8 million tonnes of fish. The annual harvestable yield calculated from the energy budget in terms of calories for the entire coastal area agreed with that estimated from the primary and secondary production rates. The present exploited yield from the coastal waters is of the order of 0.6 million tonnes. The existing yield of pelagic, demersal and crustacean resources from the Kerala region appears to be greater than the annual sustainable yield and hence the stock in this area requires conservation. In the other coastal regions, further increase in the exploitable yield of the order of 0•2 million tonnes seems possible

Growth performance, carcass characteristics and internal organ weights of weaner rabbits fed replacement levels of sun-dried soyabean milk residue

This study evaluated the growth performance of weaner rabbits fed diets containing sundried soybean milk residue meal (SSMR) at five levels of inclusion. Forty weaner rabbit with an average initial weight of 520±1.04g arranged in a completely randomized design (CRD) were used. SSMR was used at 0, 25, 50, 75 and 100% levels to replace soya bean meal. The result of the growth performance showed progressive increase in parameter evaluated as the level of SSMR increases in the diets. Rabbits fed (100% SSMR) recorded significant higher final body weight 1351.73g which was similar to rabbits fed 25, 50 and 75% SSMR while those on T1 (0% SSMR) had the least value of 1194.50g. However, carcass characteristics and internal organ weights measurements were also not influenced by the treatment diets. It was therefore concluded that 100% SSMR can be used in compounding weaner rabbits without deleterious effect on growth performance, carcass characteristics and internal organ weights.&#x0D;  &#x0D;  &#x0D; Cette étude a évalué le rendement de croissance des lapins sevrés nourris selon des régimes contenant des résidus de lait de soja séchés au soleil (RSSS) à cinq niveaux d'inclusion. Quarante lapins sevrés d'un poids initial moyen de 520±1,04 g disposés dans un modèle complètement randomisé (CRD) ont été utilisés. SSMR a été employé aux niveaux de 0, 25, 50, 75 et 100% pour remplacer le repas de haricot de soja. Le résultat de la performance de croissance a montré l'augmentation progressive du paramètre évalué comme le niveau des augmentations de SSMR dans les régimes. Les lapins nourris (100% SSMR) ont enregistré un poids corporel final plus élevé significatif 1351.73g qui était similaire aux lapins nourris 25, 50 et 75% SSMR tandis que ceux sur T1 (0% SSMR) avaient la valeur la moins élevée de 1194.50g. Cependant, les caractéristiques de carcasse et les mesures internes de poids  d'organe n'ont pas non plus été influencées par les régimes de traitement. Il a donc été conclu que 100% SSMR peut être utilisé dans la composition des lapins sevrés sans aucun effet sur la performance de croissance, les caractéristiques de la carcasse et le poids interne des organes.</jats:p

Removal of bacteria and nutrient dynamics within the coral reef framework of Curaçao (Netherlands Antilles)

The authors studied removal rates of bacteria and the regeneration of inorganic nutrients in coral reef cavities in the reef slope of Curaçao, Netherlands Antilles. We found that in cavities the hard substratum surface area (=ca 68% of cavity surface area) is 65% covered with sessile filter feeders. The cryptic cavity surface area exceeds the projected surface area of the reef by 1.5–8 times. Consequently, the organisms living in these cryptic habitats have potentially a large impact on pico- and nano-plankton densities and are important in reef water nutrient dynamics. We closed cavities (±70 l volume, 15 m depth) in seven experiments to study changes in bacterial densities and dissolved inorganic nutrients (DIN, DIP, and silicate) over time. Water samples were taken from the middle of the cavity at 5-min intervals, for 30 min, and analyzed for heterotrophic bacterial abundance and nutrient concentrations. After closure, bacterial abundance dropped rapidly. Of the initial bacterial concentration in the cavities, 50–60% had disappeared after 30 min, an average disappearance rate of 1.43×104 bacteria ml−1 min−1 (0.62 mg C l−1 d−1; or 30.1 mg C m−2 cavity surface area d−1). NOx concentrations increased significantly during the time of closure. Efflux rates varied between 1.02–9.77 mmol m−2 cavity surface area d−1. NH4 + and PO4 3− concentrations were variable and did not show a consistent change over time in the experiments. Comparison of bacterial organic nitrogen disappearance rates and DIN (NOx+NH4 +) release rates suggests that on average only 30–40% of additional sources of N besides bacteria were required to balance the nitrogen budget. This highlights the importance of heterotrophic bacterioplankton as food for cryptic filter feeders on coral reefs. Silicate concentrations significantly decreased after closure with 0.50 mmol m−2 cavity surface area d−1, suggesting the net deposition of SiO4 2− in spicules of cryptic filter feeding sponges. We conclude that coral reef cavities are a major sink for heterotrophic bacteria, a sink for dissolved silicon (DSi), and a source for NOx. That reef cavities are a source for NOx suggests strong remineralization and nitrification in cavities with a potential role for sponge-symbiotic microbial nitrification