Ken P. Findlay

A hydrodynamically active flipper-stroke in humpback whales

A central paradigm of aquatic locomotion is that cetaceans use fluke strokes to power their swimming while relying on lift and torque generated by the flippers to perform maneuvers such as rolls, pitch changes and turns [1]. Compared to other cetaceans, humpback whales (Megaptera novaeangliae) have disproportionately large flippers with added structural features to aid in hydrodynamic performance [2,3]. Humpbacks use acrobatic lunging maneuvers to attack dense aggregations of krill or small fish, and their large flippers are thought to increase their maneuverability and thus their ability to capture prey. Immediately before opening their mouths, humpbacks will often rapidly move their flippers, and it has been hypothesized that this movement is used to corral prey [4,5] or to generate an upward pitching moment to counteract the torque caused by rapid water engulfment [6]. Here, we demonstrate an additional function for the rapid flipper movement during lunge feeding: the flippers are flapped using a complex, hydrodynamically active stroke to generate lift and increase propulsive thrust. We estimate that humpback flipper-strokes are capable of producing large forward oriented forces, which may be used to enhance lunge feeding performance. This behavior is the first observation of a lift-generating flipper-stroke for propulsion cetaceans and provides an additional function for the uniquely shaped humpback whale flipper.

Humpback whale "super-groups" - A novel low-latitude feeding behaviour of Southern Hemisphere humpback whales (Megaptera novaeangliae) in the Benguela Upwelling System

Southern Hemisphere humpback whales (Megaptera novaeangliae) generally undertake annual migrations from polar summer feeding grounds to winter calving and nursery grounds in subtropical and tropical coastal waters. Evidence for such migrations arises from seasonality of historic whaling catches by latitude, Discovery and natural mark returns, and results of satellite tagging studies. Feeding is generally believed to be limited to the southern polar region, where Antarctic krill (Euphausia superba) has been identified as the primary prey item. Non-migrations and / or suspended migrations to the polar feeding grounds have previously been reported from a summer presence of whales in the Benguela System, where feeding on euphausiids (E. lucens), hyperiid amphipods (Themisto gaudichaudii), mantis shrimp (Pterygosquilla armata capensis) and clupeid fish has been described. Three recent research cruises (in October/November 2011, October/November 2014 and October/November 2015) identified large tightly-spaced groups (20 to 200 individuals) of feeding humpback whales aggregated over at least a one-month period across a 220 nautical mile region of the southern Benguela System. Feeding behaviour was identified by lunges, strong milling and repetitive and consecutive diving behaviours, associated bird and seal feeding, defecations and the pungent “fishy” smell of whale blows. Although no dedicated prey sampling could be carried out within the tightly spaced feeding aggregations, observations of E. lucens in the region of groups and the full stomach contents of mantis shrimp from both a co-occurring predatory fish species (Thyrsites atun) and one entangled humpback whale mortality suggest these may be the primary prey items of at least some of the feeding aggregations. Reasons for this recent novel behaviour pattern remain speculative, but may relate to increasing summer humpback whale abundance in the region. These novel, predictable, inter-annual, low latitude feeding events provide considerable potential for further investigation of Southern Hemisphere humpback feeding behaviours in these relatively accessible low-latitude waters.

Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales

Harvested to perilously low numbers by commercial whaling during the past century, the large scale response of Antarctic blue whales Balaenoptera musculus intermedia to environmental variability is poorly understood. This study uses acoustic data collected from 586 sonobuoys deployed in the austral summers of 1997 through 2009, south of 38°S, coupled with visual observations of blue whales during the IWC SOWER line-transect surveys. The characteristic Z-call and D-call of Antarctic blue whales were detected using an automated detection template and visual verification method. Using a random forest model, we showed the environmental preferences pattern, spatial occurrence and acoustic behaviour of Antarctic blue whales. Distance to the southern boundary of the Antarctic Circumpolar Current (SBACC), latitude and distance from the nearest Antarctic shores were the main geographic predictors of blue whale call occurrence. Satellite-derived sea surface height, sea surface temperature, and productivity (chlorophyll-a) were the most important environmental predictors of blue whale call occurrence. Call rates of D-calls were strongly predicted by the location of the SBACC, latitude and visually detected number of whales in an area while call rates of Z-call were predicted by the SBACC, latitude and longitude. Satellite-derived sea surface height, wind stress, wind direction, water depth, sea surface temperatures, chlorophyll-a and wind speed were important environmental predictors of blue whale call rates in the Southern Ocean. Blue whale call occurrence and call rates varied significantly in response to inter-annual and long term variability of those environmental predictors. Our results identify the response of Antarctic blue whales to inter-annual variability in environmental conditions and highlighted potential suitable habitats for this population. Such emerging knowledge about the acoustic behaviour, environmental and habitat preferences of Antarctic blue whales is important in improving the management and conservation of this highly depleted species.

Operation Phakisa and unlocking South Africa’s ocean economy

Operation Phakisa (www.operationphakisa.gov.za) is a South African Government delivery program initiated in 2014 to fast track the implementation of the country’s National Development Plan (NDP 2030) aimed at job creation, poverty alleviation and social equity (Zuma, 2014, October 15). ‘Phakisa’ is a Sesotho word for hurry and underscores the program’s urgency to deliver. The program, based on the Malaysian Government’s ‘big fast results methodology,’ follows a results-driven approach which includes the establishment of targets and associated public accountability in their attainment. Operation Phakisa is a broad multi-sectoral program that has initiatives in a number of South African sectors, including oceans economy, agriculture, health care and education, and is overseen by the South African Department of Planning, Monitoring and Evaluation (DPME) Operation Phakisa Delivery Unit (OP, 2015a, p. 1). In line with the expansion of ocean economies across the world, the South African government launched the Operation Phakisa ‘Unlocking the Oceans Economy’ (hereafter termed ‘Oceans Phakisa’) Initiative in 2014 to advance the benefit contribution of South Africa’s oceans economy (Potgieter, 2018, p. 50). The Oceans Phakisa Initiative initially reviewed eight industry sectors and an associated ocean governance sector for their potential in advancing the South African oceans economy through potential increases in GDP contribution and potential job creation opportunities (from a 2010 base levels to a 2033 target level) (OP, 2014a, p. 5). The reviewed sectors included Marine Transport and Manufacturing, Tourism, Offshore Oil and Gas, Construction, Renewable Energy, Fisheries and Aquaculture, Communication, Desalination and the Marine Protection Services and Governance Aspect (OP, 2015a). Three industry sectors (Marine Transport and Manufacturing, Offshore Oil and Gas and Aquaculture) and a Marine Protection Services and Governance were initially selected for advancement, with two further industry sectors (Tourism and Small Harbour and Infrastructural Development) selected thereafter (possibly to advance broader community rather than industry benefits) (OP, 2014b, 2014c, 2014d, 2014e, 2015a, 2015c). Whilst the overall Oceans Phakisa was mandated to South Africa’s Department of Environmental Affairs (DEA), each of the delivery areas were mandated to their respective government departments (Aquaculture to the Department of Agriculture, Forestry and Fisheries (DAFF) for example) and the Marine protection Services and Governance mandated also to the DEA. Over and above these six focused delivery areas, two enabling mechanisms were also established; the Department of Science and Technology (DST) to oversee research, innovation and technology and the Department