Mysids were sampled seasonally from the intertidal zone of the beach to a depth of 61 m offshore along the mid-Oregon coast. The seven mysid species collected occurred in characteristic bathymetric zones, with members of different genera occupying overlapping zones while members of the same genus occupied largely different zones. The distribution of one mysid species, Archaeomysis grebnitzkii was examined in greater detail. Adult and juvenile A. grebnitzkii were found to occupy different zones. Juveniles occurred in the inner surf zone and beach in high densities while adult animals were normally found from the seaward edge of the surf zone to 30 m in much lower densities. The mean brood size of A. grebnitzkii was found to be 47.2, with larger brood sizes occurring in early spring and summer corresponding to larger body sizes of the breeding females. / Graduation date: 1983

This project had three main aims. The first aim was to investigate the metabolic physiology of the mysid Mesopodopsis wooldridgei. Secondly, the study examined the contribution of the mysid to the zooplankton community. Finally the study attempted to clarify the primary sources of carbon utilised by the mysid using stable carbon isotope analysis. The study was conducted in the freshwater dominated permanently open Great Fish Estuary (33°30’S; 27°08’E) located along the south-eastern coastline of southern Africa. Mass specific oxygen consumption rates of Mesopodopsis wooldridgei ranged between 0.11 and 8.38 ml O2 mg ww-1 h-1 and increased with an increase in water temperature. There were no significant differences in the respiration rates between the male and female mysids (P > 0.05). At a constant temperature (20°C), the oxygen consumption rate of M. wooldridgei decreased with an increase in salinity. Salinity tolerance of the mysid was strongly modified by temperature. At 5‰ and 30°C, mysids exhibited mass mortality. The Q10 value for M. wooldridgei at 15, 25 and 35‰ was estimated at 2.34, 1.44 and 2.14, respectively. Results of the study suggest that M. wooldridgei is well adapted to surviving in environments characterised by variations in temperature and salinity. Within the Great Fish Estuary, total chl. a concentration ranged between 2.68 μg L-1 and 31.12 μg L-1 and was always dominated by large phytoplankton cells (>5 μm). Average zooplankton abundance ranged between 62 and 28 917 ind. m-3 and biomass between 10 and 203 mg Dwt m-3. The zooplankton community was numerically dominated by the calanoid copepod Pseudodiaptomus hessei, which comprised up to 100% (range between 12 and 100%) of the total zooplankton counted. Total zooplankton biomass during the day was dominated by copepods and by mysids during the nighttime. Among the mysids, M. wooldridgei was the most numerically abundant mysid and comprised <10% of the total zooplankton abundance. Numerical analysis found no seasonal pattern in the total zooplankton abundance (including mysids). The lack of any seasonality could be attributed to the continuous freshwater inflow into the estuary due to the inter-basin transfer of water from the Gariep Dam to the Fish River system. A distinct spatial pattern in the zooplankton community structure was evident with the upper stations almost entirely dominated by the copepod P. hessei, while at stations occupied in the lower reaches of the estuary, the zooplankton community comprised a mixture of freshwater, estuarine and marine breeding zooplankton species. The mysids also demonstrated a distinct spatial pattern in their distribution. Mysids were generally absent from the upper reaches, while in the middle reaches Rhopalophthalmus terranatalis and M. wooldridgei were numerically dominant. Gastrosaccus brevifissura dominated in the lower regions of the estuary. Stable isotope analysis (δ13C) indicated that the dominant source of carbon utilised by the numerically dominant copepods and juvenile M. wooldridgei within the estuary was derived from the extensive phytoplankton stocks within the system. In contrast, sub-adult and adult mysids (R. terranatalis, M. wooldridgei and G. brevifissura) appeared to consume a combination of phytoplankton and copepods. The contribution of the various sources of carbon to the total carbon intake of the mysid remains unknown.

No description available.

The rate of oxygen consumption of an organisms is influenced by rush factors as temperature, activity, body rise, Salinity, and time of day (Prosser and Brown, 1961). Temperature andsalinity are considered to be the most important environmental l factor in the liver of aquatic invertebrates (Kaune, 1564). In general, aquatic invertebrates are thermo Comforters, and their ratio of metabolics and activity are decisively affected by water temperature. The capacity to regulate ray increase or decrease as a function of temperature, and it is usually greatest at a near-optimum temperature (Kinne, 1963).

No description available.

Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2017-08-15T18:09:12Z No. of bitstreams: 1 838399.pdf: 16942201 bytes, checksum: 9076f743b0138fdf664b4ddf01613ea0 (MD5) / Made available in DSpace on 2017-08-15T18:09:12Z (GMT). No. of bitstreams: 1 838399.pdf: 16942201 bytes, checksum: 9076f743b0138fdf664b4ddf01613ea0 (MD5) Previous issue date: 1977 / CAPES / Apresenta os estudos sistemáticos e zoogeográficos de onze espécies de Misidáceos que ocorreram nas amostras coletadas pelo Navio Oceanográfico "Almirante Saldanha" na comissão Norte / Nordeste I no período de 14/9 a 16/12/1967. Inicialmente apresentámos o material e os métodos utilizados tanto a bordo do Navio quanto no Laboratório de Plâncton do Departamento de Zoologia do Instituto de Biologia da UFRJ. A seguir fizemos um resumo do histórico da ordem com as ocorrências no Brasil, posteriormente redescrevemos as espécies com sua ocorrência e distribuição geográfica conhecida. Apresentamos ainda uma listagem da situação atual da ordem no Brasil e, a partir dos resultados, sugerimos mais pesquisas sobre o grupo. / Presents the sistematic and zoogeographical studies of eleven species of mysids, found in the samples collected by the "Almirante Saldanha" Oceanographic Ship in the North/Northeastern I Expedition during the period from 14/9 to 16/12, 1967. First we presented the material and methods used inboard and at tho Plankton Laboratory of the Zoology Department - UFRJ Biology Institute; then we wrote an abstract of the historical of the order with the brazilian occurrences. Further we rediscribed the species, given their occurrences and known geographical distribution. Yet we presented a list of the actual situation of the order in Brazil and based upon the results we suggest more researching studies about the group.

No description available.

In this study, I present a new approach to prey quantification in the context of the predator-prey relationship between an apex marine predator, the gray whale, (Eschrichtius robustus) and one of its primary prey, mysids (Family Mysidae) in a tertiary foraging area, in Clayoquot Sound, on the west coast of Vancouver, Island, British Columbia. With the use of a remote acoustical sounder, I first quantify mysid patches in the presence of foraging gray whales. Second, I address the biomass in those patches using a new approach to quantification. By creating an estimate of total biomass of mysids in the study area concurrently with the presence of gray whales, I demonstrate the effect that the foraging whales have on their prey. Tracking the changes of the number of whales and the number of patches, including the overall biomass of the patches provides evidence for this relationship. As the number of gray whales in the study area increases steadily from May to July, 2004, the number of mysid patches and biomass decrease during the same period. The number of foraging whales located in the study area ranged from only five in May to thirty-one on July 18th, in a region covering only 25 km of the southwest coast of Flores Island. After this period of foraging, the whales deserted the study area completely, and only one whale was seen during the month of August. The mysid population regroups slightly after the pressure of foraging whales is released, the number of patches and biomass increase a small amount, exhibiting the expected behavioral response of the prey to re-aggregate into tight swarms. The acoustic method for prey quantification is described in detail as this is a first application of this technology to the mysid-gray whale relationship. In this approach, l demonstrate that the Distorted Wave Borne Approximation model (DWBA) is useful to estimate mysid populations. This study provides a key piece in the progression of eight years of ongoing research on the foraging ecology of gray whales in Clayoquot Sound, British Columbia.

No description available.

No description available.