Social and Ecological Factors Affecting the Adoption of Aquaculture

Commercial fishermen in Maine are increasingly dependent upon the American lobster fishery, and this reliance on a single species poses a threat to working waterfronts. Aquaculture represents a potential opportunity for commercial fishermen to diversify their income. Literature on the adoption of innovation suggests that factors such as age, education level, fishing experience, diversification, and leadership are important predictors of early adoption of innovation. However, few studies have examined whether such factors affect the adoption of aquaculture by commercial fishermen. Our marine policy research studied fishermen enrolled in two pilot shellfish and seaweed aquaculture classes held in 2013 in Harpswell and Corea, Maine. Those enrolled in the classes can be considered early adopters of innovation. To better understand these early adopters and their perceptions of aquaculture as a means of income, we conducted a total of 33 semi-structured interviews before and after the course with fishermen who did and did not finish the course. Those who had broader experience and more years of experience, as well as those having demonstrated some form of leadership in fisheries cooperatives, were more likely to adopt. Potential barriers to the adoption of aquaculture were mostly related to risks associated with an uncertain return on investment. The results from this study will inform the structure of future aquaculture training courses as well as highlighting additional avenues of research on the adoption of aquaculture by commercial fishermen. Those starting aquaculture farms face many challenges, among them parasites such as the blister worm, Polydora websteri. This polychaete burrows into shells of several commercially important shellfish species, including the eastern oyster. As the oyster industry has grown, so has the impact of this worm. Oysters served on the half shell are not only less attractive when infested by worms, but mud and detritus can leak out during shucking and create off-flavors. Farmers are concerned about their reputation if blister worm-infested oysters are sent to market. Various kinds of chemical, fresh water, and brine baths have been used to treat blister worm infestations, but none has reliably eliminated worms in established burrows. The Bagaduce River Oyster Company (BROC) has developed the only known effective method of killing the worms without causing damage to the oysters. They place their oysters in cold storage for three weeks or more during the winter months – a method which is generally not harmful to the oyster but kills the adult blister worm. This treatment, however, is labor intensive and can result in lost production time. Our marine biology research explored whether periodic air-drying and pressure washing could reduce the settlement of larval P. websteri and block blister worm infestations before they occur. Oysters were air-dried for 4 h or 24 h, or air-dried and washed, every other week. Ten to twenty oysters were sampled from each treatment bimonthly from May through October 2014 and examined for the presence of newly constructed worm burrows. Additionally, plankton tows were taken on each side of the oyster farm to track the abundance of blister worm larvae in the plankton. Air-drying alone resulted in a substantial decrease in the formation of new blister worm burrows in experimental oysters. Although washing resulted in additional decreases in the number of new burrows, the impact of washing was not statistically significant. Our results suggest that regular air-drying and washing of oysters can reduce the impact of P. websteri at oyster farms in Maine that employ surface culture and reduces the need for complex treatments to rid oysters of blister worm infestations

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Integrative Biolog

Rancang Bangun Pengontrol Suhu dan Kelembaban di dalam Solar Dryer dengan Arduino

Alat otomatisasi buka tutup katup solar dryer berdasarkan nilai kelembaban yang dibaca dari sensor telah berhasil dibuat. Sensor pengukuran dikalibrasi dengan membandingkan nilai pada alat ukur standar (klimaloggpro) dengan nilai toleransi ukur suhu 1°C kelembaban 3%.  Rancangan hardware menggunakan kotak kayu dengan saklar buka tutup, arduino uno sebagai pengatur buka tutup dihubungkan dengan komputer dan sensor suhu dan kelembaban DHT22 sebagai sumber data pengukuran. Pengumpulan data dilakukan dengan tiga sistem solar dryer yaitu sistem tertutup, sistem terbuka dan sistem buka tutup. Sistem buka tutup diatur berdasarkan nilai kelembaban (%) yang dibaca di ruang pengering. Jika membandingkan ketiga sistem pengukuran yaitu sistem terbuka, sistem tertutup dan sistem buka tutup, sistem terbuka lebih baik dibanding sistem buka tutup dan sistem tertutup. Sistem terbuka dapat mengurangi massa air sebanyak 380 gram, sistem tertutup 229 gram, sistem buka tutup 337gram dengan nilai buka tutup 65%-90%

Ecology and co-existence of two endemic day gecko (Phelsuma) species in Seychelles native palm forest

In island ecosystems, reptiles play diverse ecological roles as a result of niche broadening, which increases potential niche overlap between species. Ecological niche partitioning is a means of reducing direct competition between coexisting species and differences in habitat use among island gecko species have been suggested as a by-product of specialization to feeding on certain resources. Here, we examine modes and drivers of niche partitioning of two endemic species of Phelsuma gecko (Phelsuma sundbergi and Phelsuma astriata) in relict native palm forest in the Seychelles to further understanding of congeneric reptile co-existence in native habitats. Phelsuma abundance, microhabitat use and habitat composition were quantified in different macrohabitat types. P. sundbergi showed a clear preference for habitat dominated by the coco de mer palm, Lodoicea maldivica and a strong association with male individuals of this dioecious species. P. astriata density increased significantly with arboreal biodiversity but did not display a relationship with a specific tree type. High levels of resource segregation were determined along the microhabitat axis, based on differential tree preference. Our results suggest that P. sundbergi and P. astriata may have evolved to co-exist in this habitat type through partitioning of microhabitat as members of a divergent specialist/generalist assemblage determined by consumption of L. maldivica pollen by P. sundbergi. Our findings concur with the hypothesis that differences in habitat use among island reptiles are a by-product of trophic specialization and support the conservation of native habitat for maintenance of reptile diversity

Niche partitioning in a sympatric cryptic species complex

Competition theory states that multiple species should not be able to occupy the same niche indefinitely. Morphologically, similar species are expected to be ecologically alike and exhibit little niche differentiation, which makes it difficult to explain the co-occurrence of cryptic species. Here, we investigated interspeci- fic niche differentiation within a complex of cryptic bumblebee species that co-occur extensively in the United Kingdom. We compared the interspecific variation along different niche dimensions, to determine how they partition a niche to avoid competitive exclusion. We studied the species B. cryptarum, B. lucorum, and B. magnus at a single location in the northwest of Scotland throughout the flight season. Using mitochondrial DNA for species identifica- tion, we investigated differences in phenology, response to weather variables and forage use. We also estimated niche region and niche overlap between different castes of the three species. Our results show varying levels of niche partitioning between the bumblebee species along three niche dimensions. The species had contrasting phenologies: The phenology of B. magnus was delayed relative to the other two species, while B. cryptarum had a relatively extended phenology, with workers and males more common than B. lucorum early and late in the season. We found divergent thermal specialisation: In contrast to B. cryptarum and B. magnus, B. lucorum worker activity was skewed toward warmer, sunnier conditions, leading to interspecific temporal variation. Further- more, the three species differentially exploited the available forage plants: In particular, unlike the other two species, B. magnus fed predominantly on species of heather. The results suggest that ecological divergence in different niche dimensions and spatio-temporal heterogeneity in the environment may contribute to the persistence of cryptic species in sympatry. Furthermore, our study suggests that cryptic species provide distinct and unique ecosystem services, demonstrating that morphological similarity does not necessarily equate to ecological equivalence