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Cetaceans: summary of information presented in the final Report of the Expert Panel on a DCFA. Presentation to FRDC workshop on mitigating marine mammal interactions in the SPF Alice Mackay 25 June 2015 Introduction Summary of Report of the Expert Panel on a DCFA (Small Pelagic Fishery - SPF) in relation to cetacean species. 44 cetacean species identified as occurring, or likely to occur in the SPF area. The Expert Panel Report considers 21 of these cetacean species in terms of risks and likelihood of interactions with mid-water trawls in the SPF. Cetacean species identified in Expert Panel report Odontocetes (15) • • • • • • • • • • • • • • • Risso’s dolphin Fraser’s dolphin Hourglass dolphin Southern right whale dolphin Striped dolphin Indo-pacific bottlenose dolphin Bottlenose dolphin Shot-beaked common dolphin Spotted dolphin Spinner dolphin Dusky dolphin Short-finned pilot whale Long-finned pilot whale Killer whale Sperm whale Mysticetes (6) • • • • • • Southern right whale Humpback whale Bryde’s whale Sei whale Fin whale Blue whale Cetacean species richness in areas fished in the SPF using mid-water-trawl Cetacean species richness in relation to the total area of waters fished in the SPF using mid-water trawl during 2000-2013. Source: Report of the Expert Panel on a declared commercial fishing activity, October 2014. Overview Current information for 21 species considered by expert panel • Interactions with mid-water trawls in the SPF • Interactions with mid-water trawls in other fisheries (global) • Interactions with bottom trawls in other fisheries (Australia and global) • Overlap in species distribution with SPF For species identified as most likely to interact with mid-water trawls in the SPF, summary of current information on • Distribution • Population size • Ecology • Fisheries interactions Species Bycatch in MWT in SPF Risso’s dolphin Fraser’s dolphin Hourglass dolphin Southern right whale dolphin Striped dolphin Indo-pacific bottlenose dolphin Common bottlenose dolphin Short-beaked common dolphin Pantropical spotted dolphin Spinner dolphin Dusky dolphin Short-finned pilot whale Long-finned pilot whale Killer whale Sperm whale Documented interactions with pelagic trawls in other fisheries Documented interactions with bottom trawls in other fisheries Overlap of distribution with SPF ? High Low X Low X X High Low X X High X X X High X X X High ? X X X X Low Low Medium X X High X X X High High High X Species Bycatch in MWT in SPF Documented Documented Overlap of Conservation interactions with interactions with distribution pelagic trawls in bottom trawls in status with SPF other fisheries other fisheries Southern right whale Northern right whale bycaught in High off bottom or pelagic trawls Endangered Humpback whale Off bottom or pelagic trawls – bycatch and released alive High Vulnerable Bryde’s whale Partial Data deficient Sei whale High Vulnerable Fin whale Reports of feeding behind High codend – gear type not specified Vulnerable Blue whale High Endangered • Entanglement / bycatch reported for all species in a mix of gear types • Byrde’s whale feeds on pelagic schooling fish and are known to interact with purse seiners in Indian Ocean • All at risk of vessel collision Common bottlenose dolphin – Tursiops truncatus • Previously bycaught in mid-water trawls in SPF • High overlap in distribution with SPF • No Australian population estimate: • some estimates for localised subpopulations • Assessed Data Deficient • Inshore v offshore distribution • Resident v transient • Opportunistic foragers • Behavioural plasticity – multiple foraging strategies Tursiops truncatus – indicative distribution. Source: The Department of the Environment Species Profile and Threats Database Common bottlenose dolphin – Tursiops truncatus • Most common species reported interacting with bottom trawl fisheries – strong individual associations • Documented foraging in association with and also inside bottom trawls • (e.g. Moreton Bay, Pilbara, Gulf of Mexico) • Less information on interactions of this species with mid-water trawls • Within the area of the SPF bycatch recorded in • Gillnet sector of GHAT SESSF fishery • Anti-predator nets at aquaculture pens Short-beaked common dolphin – Delphinus delphis • Previously bycaught in mid-water trawls in the SPF • High overlap in distribution with SPF • Coastal and oceanic habitats • No Australian population estimate: • some estimates for localised subpopulations • Assessed Data Deficient • Can form large aggregations (1000’s) Delphinus delphis– indicative distribution. Source: The Department of the Environment Species Profile and Threats Database Short-beaked common dolphin – Delphinus delphis • Genetic differentiation across range • Six proposed management units based on sub-structuring • Seasonal migratory movement from southeastern to southern Australia • Feed primarily on small schooling fish and squid including epipelgaic species • Recorded foraging dives to 200m Location and approximate boundaries of 6 proposed management units of short-beaked common dolphins in southern and southeastern Australia. Source: Bilgmann et al. 2014. Multiple management units of short-beaked common dolphins subject to fisheries bycatch off southern and southeastern Australia. MEPS. 500:265-279 Short-beaked common dolphin – Delphinus delphis • High interaction rates with trawl fisheries globally • Documented interactions with mid-water trawl fisheries • Europe • New Zealand • Within area of SPF bycatch of this species has been recorded in • South Australian Sardine Fishery • Gillnet sector of GHAT SESSF fishery • Anti-predator nets at aquaculture pens Risso’s dolphin – Grampus griseus • High overlap in distribution with SPF • Outer shelf and slope habitat, areas of upwelling • No Australian population estimate • Group size 4-100, larger aggregations ~4,000 • Feed primarily on mid-water and bottom dwelling squid • Appear to feed mainly at night Grampus griseus– indicative distribution. Source: The Department of the Environment Species Profile and Threats Database Risso’s dolphin – Grampus griseus • Documented bycatch in mid-water trawls and off-bottom trawls in USA • Documented feeding associated with trawls • Bycaught (globally) in purse seine, driftnet and longlines (depredating) • No information on bycatch rates in Australia • Recent unusual high rate of strandings in NSW, VIC and TAS – investigation of possible causes ongoing Pilot whales – Long-finned pilot whale Globicephala melas Short-finned pilot whale Globicephala macrorhynchus • Coast to outer shelf and slope, underwater topography, seasonal movements • No Australian population estimate: • SFPW Data Deficient • LFPW Least Concern • Group size 20-40, larger aggregations ~1000’s • SFPW feed primarily on squid, cuttlefish, octopus and mix of fish species • LFPW feed primarily on squid, and small to medium fish like mackerel, herring and cod • SFPW recorded dives ~ 600m • LFPW recorded dives ~ 1000m • Diurnal diving pattern with vertical migration of prey (shallower dives at night) Globicephala melas – indicative distribution. Source: The Department of the Environment Species Profile and Threats Database Globicephala macrorhynchus – indicative distribution. Source: The Department of the Environment Species Profile and Threats Database Pilot whales – Long-finned pilot whale Globicephala melas Short-finned pilot whale Globicephala macrorhynchus • LFPW bycaught in mid-water and bottom trawls in midAtlantic of east coast of USA and west coast of Africa • LFPW have been observed feeding in association with trawls • Documented as bycatch (globally) in purse seine and driftnets, and depredating longlines • No information on bycatch rates in Australia Summary • SPF area overlaps with known distribution range of a number of cetacean species • Limited to no information on population abundance of species • Limited to no information on spatial or temporal distribution of species • Likelihood of interactions will vary with species: – Incidental v intentional • Risk of bycatch will increase with high spatial and temporal overlap and shared prey and target species • Population level impact of bycatches can only be assessed knowing – Size of population or sub-population size – Information on bycatch rates in all fisheries that overlap spatially with that population Information needs When assessing and mitigating bycatch need to know • What species are involved • What are patterns in bycatch (spatial, temporal, operational) Reason for interaction? • Spatial overlap • Shared target species • Incidental v intentional Is the bycatch rate sustainable? • What is the cumulative mortality for that population? • Is there mortality in other fisheries? • What age / sex class are being caught Species Documented Bycatch in interactions with MWT in pelagic trawls in SPF other fisheries Risso’s dolphin Fraser’s dolphin Overlap in distribution with SPF ? High Low Low X Hourglass dolphin Southern right whale dolphin Striped dolphin Indo-pacific bottlenose dolphin Bottlenose dolphin Short-beaked common dolphin Pantropical spotted dolphin Spinner dolphin Dusky dolphin Short-finned pilot whale Long-finned pilot whale Killer whale Sperm whale Documented interactions with bottom trawls in other fisheries High X X Low X X High X X X High X X X High ? X Low X X X Low Medium X X High X X High X High High X Bycatch in other fishing gears DN, PS, LL GN,DN,PS GN, DN GN GN,DN,PS GN, OH GN, PS, OH GN, PS, OH GN,DN,PS GN,DN,PS GN DN, PS, LL GN,DN,PS LL GN,DN, LL