Anthony F. Amos

DISTRIBUTION OF KRILL ( EUPHAUSIA SUPERBA ) AND THE HYDROGRAPHY OF THE SOUTHERN OCEAN: LARGE-SCALE PROCESSES

ABSTRACT This paper is a review of the large-scale features of distribution of krill (Euphausia superba) and the hydrography of the Southern Ocean, as determined from the major oceanographic research expeditions of the 20th century. It is intended for the biologist interested in the physical oceanographic literature of the Southern Ocean and includes some of the basic krill literature for the oceanographer engaged in multidisciplinary research programs. The broad features of krill distribution from an oceanographers viewpoint are described, followed by a general account of the hydrographic methods and their possible application to krill research. A sector-by-sector excursion around Antarctic circumpolar waters describes the hydrography of each sector. The literature is primarily from those studies where basic physical oceanography was the major impetus for the study.

Environment aspects of manganese nodule mining

The authors describe the environmental baseline conditions in the ‘nodule zone’, with emphasis on those parameters that might be affected by nodule mining. They consider the impact of full-scale mining operations on that environment and, finally, Put forward recommendations to minimise adverse impacts and so to make deep-sea mining environmentally acceptable.

Phytoplankton distribution and abundance as related to a frontal system north of Elephant Island, Antarctica

During January-March, 1991, the distribution and floristic composition of the phytoplankton around Elephant Island, Clarence Island and the northern end of King George Island were determined in relation to physical oceanographic conditions and to proximity of the shelf-break and continental slope. The study area included 180 stations, and c. 5400 km of transects providing continuous measurements of salinity, temperature, beam attenuation, and chlorophyll a (chl a) concentrations in surface waters. The richest phytoplankton areas (2-4 pg chl a 1.l) were generally found associated witha strong salinity front, extending north of King George Island to north of Elephant and Clarence Islands. Data on the phytoplanktoncommunity suggest that shelf waters were characterized by low biomass and a nanoplankton population, while in and just north of the front the biomass increased and there was a shift to a diatom-dominated microplankton population. This is thought to be related to increased stability of the water column just north of the front. The salinity front ran more or less parallel to the continental shelf-break, but its exact position varied during the period of study. It was generally associated with transition water (Type 11) or with Weddell-Scotia Confluence water (Type 111).

Antarctic krill stock distribution and composition in the Elephant Island and King George Island areas, January–February, 1988

Information is provided on the distribution, size and maturity composition of Antarctic krill (Euphausia superba) stocks in the Elephant Island and King George Island areas, and at repeatedly sampled sites to the north of each island, during January–February, 1988. The overall distributional patterns of different sizes and maturity stages demonstrated a seasonal progression of those observed in the Antarctic Peninsula region during November–December, 1987 by Siegel (1989). The krill sampled at each island site represented different size-maturity groups and demonstrated different horizontal and vertical distributional characteristics. These distributional differences may be related to the demographic differences and/or hydrographie differences between the two sites.

PHENOLOGY OF SIX MIGRATORY COASTAL BIRDS IN RELATION TO CLIMATE CHANGE

Abstract The migration phenology of six species of coastal birds on Mustang Island, Texas, USA was examined for a 27-year period (1978–2005). First arrival date, last date of departure, and duration of stay were quantified for three winter and three summer residents. These three variables were analyzed for changes over time and correlation with local, regional, and global temperature indices. Mean local summer temperature increased 0.03° C/year (0.74° C overall), while mean local winter temperature increased 0.10° C/year (2.76° C overall). The three winter residents had a trend for increasingly later arrival, increasingly earlier departure, and decreased duration of stay over the 27-year period. These trends reflect a shortening of the winter season for these birds and are consistent with expected responses due to warming temperatures. The three terns representing summer residents had less homogeneity in temporal trends than the three winter residents. Correlations of local temperature with arrival and departure dates, and duration of stay yielded few significant results and no overall pattern. Only Double-crested Cormorant (Phalacrocorax auritus; a winter resident) and Least Tern (Sterna antillarum; a summer resident) had significant correlations between arrival date and arrival temperature.

Identification of Fibropapillomatosis in Green Sea Turtles (Chelonia mydas) on the Texas Coast

ABSTRACT Nine green sea turtles, Chelonia mydas, were presented to two rehabilitation facilities on the Texas coast with cutaneous growths consistent with fibropapillomatosis. Complete blood counts, radiographs, and computed tomography were performed for further evaluation. No evidence of internal tumors was present using either imaging modality. Treatment included surgical excision of the cutaneous tumors. Histopathologic analysis and polymerase chain reaction (PCR) were performed with the tissue samples collected. Histopathology revealed characteristic inclusions in only three (33%) individuals, and PCR results for fibropapilloma-associated turtle herpesvirus were positive for eight (89%) of nine individuals submitted. To our knowledge, this is the first report of fibropapillomatosis in a green sea turtle on the Texas coast.

Hypothermic stunning of green sea turtles in a western Gulf of Mexico foraging habitat

Texas waters provide one of the most important developmental and foraging habitats for juvenile green turtles (Chelonia mydas) in the western Gulf of Mexico, but hypothermic stunning is a significant threat and was the largest cause of green turtle strandings in Texas from 1980 through 2015; of the 8,107 green turtles found stranded, 4,529 (55.9%) were victims of hypothermic stunning. Additionally, during this time, 203 hypothermic stunned green turtles were found incidentally captured due to power plant water intake entrapment. Overall, 63.9% of 4,529 hypothermic stunned turtles were found alive, and 92.0% of those survived rehabilitation and were released. Numbers of green turtles recorded as stranded and as affected by hypothermic stunning increased over time, and were most numerous from 2007 through 2015. Large hypothermic stunning events (with more than 450 turtles documented) occurred during the winters of 2009–2010, 2010–2011, 2013–2014, and 2014–2015. Hypothermic stunning was documented between November and March, but peaked at various times depending on passage of severe weather systems. Hypothermic stunning occurred state-wide, but was most prevalent in South Texas, particularly the Laguna Madre. In the Laguna Madre, hypothermic stunning was associated with an abrupt drop in water temperatures strong northerly winds, and a threshold mean water temperature of 8.0°C predicted large turtle hypothermic stunning events. Knowledge of environmental parameters contributing to hypothermic stunning and the temporal and spatial distribution of turtles affected in the past, can aid with formulation of proactive, targeted search and rescue efforts that can ultimately save the lives of many affected individuals, and aid with recovery efforts for this bi-national stock. Such rescue efforts are required under the U.S. Endangered Species Act and respond to humanitarian concerns of the public.