Southern right whale (Eubalaena australis) mortalities and human interactions in Australia, 1950-2006

Abstract

A total of 44 records of southern right whale mortalities and non-fatal anthropogenic interactions have been documented in Australia by museums, wildlife agencies and researchers since 1950. Sixteen of the events involved whales that apparently survived. Events were recorded in all months except January and 65% occurred in the period July to October. Mortalities were more numerous in the western half of the continent where southern right whales are more frequently observed. Events were classified according to their outcome and nature: carcasses (with no evidence of human interaction) n=25, fatal entanglements n=1, non-fatal entanglements n=12, fatal vessel collisions n=2, non-fatal vessel collisions n=3, non-fatal shooting n=1. No live strandings were recorded. The number of both mortalities and non-fatal anthropogenic incidents has increased 4-fold since the mid 1970s. More calves than ‘non-calf’ whales were present in the carcass category, whereas the opposite was the case for events involving human interaction. Lines, nets and buoys used in fishing crustaceans (rock-lobster, crab) were associated with several entanglements (n=5). A longline entanglement of a 14m female resulted in a chronic injury, debilitation and death. As a proportion of the total records for each region, there were fewer vessel collisions of right whales in Australia (11%) than in South Africa (16%) or the North Atlantic (35%).

A global review of protected species interactions with marine aquaculture

“…High‐performance netting materials are often used in offshore aquaculture environments to contain fish, exclude predators, and prevent predation. Some netting materials and their related hardware pose potential entanglement risk, resulting in injury, stress, or death to marine mammals, sea turtles, birds, and sharks 25,26,48,53–59 . Finfish operations can attract some piscivorous animals because wild fish aggregate to the structural habitat provided by cages or are attracted to excess feed loss from the cages 25,55,60,61 …”

“…From 1990 to 1999, fatal entanglements of 17 short‐beaked common dolphins ( Delphinus delphis Linnaeus, 1758) and 11 Indo‐Pacific bottlenose dolphins ( Tursiops aduncus Ehrenberg, 1833) in southern bluefin tuna ( Thunnus maccoyii Castelnau, 1872) ranching operations using large mesh (>15 cm) antipredator nets have been documented in South Australia 53,60 (Table 3). In 1993, a humpback whale broke through the walls of a tuna ranching operation and was trapped in the net pen for 2 days before it was successfully released 53,60 (Table 3). In an International Whaling Commission Scientific Committee National Progress Report, 138 the fatal entanglement of a bottlenose dolphin in a yellowtail kingfish ( Seriola lalandi Valenciennes, 1833) cage in 2008 was documented with no further information (Table 3).…”

“…Some netting materials and their related hardware pose potential entanglement risk, resulting in injury, stress, or death to marine mammals, sea turtles, birds, and sharks. 25,26,48,[53][54][55][56][57][58][59] Finfish operations can attract some piscivorous animals because wild fish aggregate to the structural habitat provided by cages or are attracted to excess feed loss from the cages. 25,55,60,61 3 | PROTECTED SPECIES AND MARINE AQUACULTURE…”

“…Marine mammals can be excluded from their habitats depending on the size and concentration of farms, farm operations (including vessel traffic), and behaviour of a particular marine mammal species. 43,53,58,60,65,[76][77][78] While some marine mammals may not be spatially excluded from farm areas, limited mobility in the vicinity may result in individuals being forced into suboptimal foraging habitat. Species may alter their behaviour, and be deterred from traversing or feeding if aquaculture structures present a navigation obstacle.…”

“…From 1990 to 1999, fatal entanglements of 17 short-beaked common dolphins (Delphinus delphis Linnaeus, 1758) and 11 Indo-Pacific bottlenose dolphins (Tursiops aduncus Ehrenberg, 1833) in southern bluefin tuna (Thunnus maccoyii Castelnau, 1872) ranching operations using large mesh (>15 cm) antipredator nets have been documented in South Australia 53,60 (Table 3). In 1993, a humpback whale broke through the walls of a tuna ranching operation and was trapped in the net pen for 2 days before it was successfully released 53,60 (Table 3).…”