scholarly journals Prey selection of Dall's porpoise Phocoenoides dalli on the continental slope off the Pacific coast of Sanriku in winter

2010 ◽  
Vol 76 (1) ◽  
pp. 54-61 ◽  
Author(s):  
RYOSUKE OKAMOTO ◽  
HIROSHI OHIZUMI ◽  
KAZUHISA UCHIKAWA ◽  
MASAKI ITO ◽  
TOSHIHIDE IWASAKI ◽  
...  
2016 ◽  
Vol 4 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Michael Glassow ◽  
Elizabeth A. Sutton ◽  
Carola Flores Fernandez ◽  
Heather B. Thakar

AbstractArchaeologists studying shell assemblages from prehistoric sites along the Pacific coast of North America have been interested in the influences of collecting intensity and environmental variability on California mussel (Mytilus californianus) size. To determine the variation in mussel size within a shell assemblage, researchers have developed a variety of proxies of mussel valve length based on measurements of morphological features occurring at or near the valve’s umbo. We propose four additional measurements that can serve as proxies and evaluate their correlation with valve length using regression analysis. Of the four, anterior adductor scar length has the strongest correlation, and we present two examples of its application. We also evaluate a popular visual technique based on a set of outline drawings of valves of varying lengths, and we found that it systematically underestimated valve length but could be useful under certain circumstances. We conclude that the selection of a particular proxy of mussel valve length depends on the nature of the mussel shell assemblage being studied and the research context.


2010 ◽  
Vol 76 (5) ◽  
pp. 747-754 ◽  
Author(s):  
Tsutomu Hattori ◽  
Takehiro Okuda ◽  
Yoji Narimatsu ◽  
Masaki Ito

2005 ◽  
Vol 56 (7) ◽  
pp. 1037 ◽  
Author(s):  
Verónica Castañeda-Fernández de Lara ◽  
Mark Butler ◽  
Sergio Hernández-Vázquez ◽  
Sergio Guzmán del Próo ◽  
Elisa Serviere-Zaragoza

The habitat requirements of early benthic stage juveniles of California spiny lobster Panulirus interruptus are known only from studies conducted near its northernmost geographic range, where environmental conditions differ markedly from those along the Pacific coast of the southern Baja California Peninsula (Mexico). We determined the natural habitat of this stage of P. interruptus in the central portion of their range from sampling the available dominant vegetated habitats included various seagrasses and macroalgae. Additionally, experiments on habitat selection by early benthic juvenile P. interruptus were performed under laboratory conditions to test natural substrate selection and whether selection of substrata is affected by odour signals. Despite the abundance of different macrophytes as habitat, 93% of the juvenile lobsters were found at the base of the blades of Phyllospadix spp. in the intertidal zone at 0 to 3 m. The highest juvenile densities were found in September at both sites. In laboratory experiments, juvenile lobsters preferred, in order of preference, Gelidium robustum, Phyllospadix, Plocamium pacificum, and holdfasts of the kelp Macrocystis pyrifera. A second laboratory experiment showed that these preferences were affected by odour signals. Results indicate that the ecology of juvenile P. interruptus off the coast of the Mexican Baja is similar to that observed off the coast of southern California.


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