Oxygen consumption of gill tissue of Hemigrapsus nudus and H. oregonensis has been measured at four levels of experimental salinity (35%, 75%, 100%, and 125% sea water), three levels of experimental temperature (5°, 12,5° and 20°C) in all combinations for both winter and summer animals. Summer animals of both species were found to have higher weight-specific oxygen consumption than winter animals when measured at the average summer (20°C, 35% sea water) and winter (5°C, 75% sea water) field conditions. At other experimental conditions respiration rates of summer-adapted animals were found to be higher for the majority of conditions, but there were examples of equal seasonal rates and examples of winter rates exceeding those obtained from summer animals. Winter animals were found to be less temperature-dependent than summer animals. No laboratory compensation to temperature of biological significance could be found in either species. Hemigrapsus nudus demonstrated a higher weight-specific oxygen consumption than H. oregonensis. Both species showed with minor differences, similar responses to the various factors investigated. The weight-specific oxygen consumption data present indirect evidence which indicate that the gills of both species are involved in regulating blood ions. The indications are that regulation of ions by the gills is more pronounced in summer than in winter. The regression coefficient of weight-specific oxygen consumption as a function of whole body weight was found to have a value of -0.169. This value was similar for both species and not affected by experimental conditions. The differences in physiological response between species indicate that the less variable Hemigrapsus nudus may be a select population which has migrated into this area from the outer coast and that H. oregonensis may be indigenous to this locality. / Science, Faculty of / Zoology, Department of / Graduate

Hemigrapsus nudus and H. oregonensis, the experimental animals, are subjected to a wide range of temperature and salinity in their natural environment. The influence of seasonal change, and laboratory acclimation to various temperature-salinity combinations in both summer and winter, on heat tolerance was determined. There was a seasonal change in the 50 per cent survival temperature for 12 and 24 hours when summer and winter base lines were compared. A definite species difference in thermal resistance was present, but both species reacted similarly to any particular temperature-salinity combination. Acclimation to a high temperature in the physiological temperature range generally increased the resistance to lethal temperatures and acclimation to low salinity generally decreased it. High temperature, high salinity was the most favourable acclimation combination to resist lethal temperatures. Gain in heat tolerance after a low temperature history was rapid, less than one week. The low tolerance found in winter animals at the low temperature series was not demonstrated in summer animals acclimated to these same conditions. Small animals appeared to be slightly more resistant than larger ones. Moulting at the test tolerance temperature adversely affected the resistance. A certain density was necessary to prevent death from overcrowding at lethal temperatures. There was no difference in tolerance between the sexes. / Science, Faculty of / Zoology, Department of / Graduate

When eyestalks are removed from Hemigrapsus nudus at least 10 days before ecdysis, linear growth of the destalked animals, measured as an increase in carapace width after ecdysis, is significantly higher than the linear growth of the unoperated control animals. The amount of water that control and destalked H. nudus absorb during ecdysis (stage E) is not significantly different; however, during early postecdysis the destalked animals show a significantly greater increase in wet weight than the controls. The greater linear growth calculated for destalked animals must be realized during early postecdysis. To investigate one possible mechanism to account for the large increase in wet weight characteristic of destalked animals during postecdysis, total osmotic pressure of the blood was measured throughout the molt cycle for control and destalked animals. The osmotic pressure measured from destalked animals is not significantly different from the measurements of osmotic pressure from control animals during the short period of ecdysis, however determinations of osmotic pressure from destalked animals during pro- and postecdysis are significantly lower than those from control animals. There is postulated a water balance-regulating principle located in the eyestalk which regulates the early postecdysial absorption of water. The absorbent surface of the destalked crab may become more permeable to water just after ecdysis, thus causing an increase in wet weight and an increase in size. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Also available in print.

Thesis (Diplome d'études approfondies de biologie animale)--Académie de Montpellier, Université des sciences et techniques du Languedoc, 1975. / Bibliography: p. [29]-[30]

Thesis (Ph. D.)--College of William and Mary. / Typescript (photocopy). Vita. Includes bibliographical references (leaves 231-240).

Thesis (Ph. D.)--University of Hong Kong, 1992.

Ip, Ho Yeung Brian. / Thesis M.Phil. Chinese University of Hong Kong 2014. / Includes bibliographical references (leaves 133-148). / Abstracts also in Chinese. / Title from PDF title page (viewed on 26, October, 2016). / Ip, Ho Yeung Brian.

Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaves : [44]-49).