Download Alice Mackay-cetacean interactions updated

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