Mitigating Seabird Mitigating Seabird Interactions with Interactions with Trawl Nets Trawl Nets Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Objectives Objectives • Characterise the nature and extent of • Characterise the nature and extent of interactions of seabirds attracted to trawl interactions of seabirds attracted to trawl nets (NIWA Report 2008) nets (NIWA Report 2008) • Identify ways to avoid or reduce these • Identify ways to avoid or reduce these interactions (Workshop 6 May 2008) interactions (Workshop 6 May 2008) • Trial methods with potential to reduce these • Trial methods with potential to reduce these interactions (focus of today's presentation) interactions (focus of today's presentation) Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Trial Methods Trial Methods • Trial two methods with potential to • Trial two methods with potential to reduce seabird net captures by reduce seabird net captures by reducing volume of netting on the water reducing volume of netting on the water surface surface 1. Turning the vessel while hauling 1. Turning the vessel while hauling 2. Net binding when shooting 2. Net binding when shooting Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Please note: No seabirds were Please note: No seabirds were harmed during these trials! harmed during these trials! Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Turning while hauling Turning while hauling Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Net binding Net binding Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Net binding Net binding Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Sea Trials Completed Sea Trials Completed • FV Taimania – Hoki Fishery Cook • FV Taimania – Hoki Fishery Cook Strait September 2008 Strait September 2008 • FV Aleksandr Buryachenko – Jack • FV Aleksandr Buryachenko – Jack Mackerel Fishery West Coast North Mackerel Fishery West Coast North Island December 2008 Island December 2008 Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
FV Taimania FV Taimania Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
FV Taimania FV Taimania Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
FV Aleksandr Buryachenko FV Aleksandr Buryachenko Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
FV Aleksandr Buryachenko FV Aleksandr Buryachenko Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Trial Areas Trial Areas Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Turning the Vessel Turning the Vessel • These vessels must turn 5° to 10° helm when • These vessels must turn 5° to 10° helm when hauling to get the net onto deck correctly hauling to get the net onto deck correctly • This does close up the volume of mesh – but • This does close up the volume of mesh – but the turn is not continuous – the net must be the turn is not continuous – the net must be hauled straight at times especially at start hauled straight at times especially at start • Couldn’t complete trial on either vessel – as • Couldn’t complete trial on either vessel – as both must turn vessel every haul, no control both must turn vessel every haul, no control treatment was possible treatment was possible Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
FV Taimania (see video) FV Taimania (see video) • Fleeted onto net roller • Fleeted onto net roller Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
FV A Buryachenko FV A Buryachenko • Two nets fleeted on each side of deck • Two nets fleeted on each side of deck Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Net Binding Net Binding • Net binding can be competently and safely • Net binding can be competently and safely carried out onboard using midwater nets carried out onboard using midwater nets • The ties have to have the correct holding • The ties have to have the correct holding force – different holding force for different force – different holding force for different parts of the net parts of the net • Could not bind head of trawl – too much • Could not bind head of trawl – too much force force • Gave up on breaking binds • Gave up on breaking binds Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Net bind Net bind • Fixed twine bind with twist knot • Fixed twine bind with twist knot Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Net with binds being shot away Net with binds being shot away Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Net without binds being shot away Net without binds being shot away Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Show videos Show videos Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Net Binding - issues Net Binding - issues • Need a balance between holding • Need a balance between holding netting long enough vs not releasing netting long enough vs not releasing • May not release because: • May not release because: • Binding too tight / too many twists • Binding too tight / too many twists • Frayed rope not coming undone • Frayed rope not coming undone Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
FV Taimania FV Taimania • Trawl net still closed on haul • Trawl net still closed on haul Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Frayed rope Frayed rope • The culprit • The culprit Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Results of Net Binding Results of Net Binding FV A. Taimania Binding Information Performance Tow # Bind Type Diameter Twists in Bind Intervals between binds (m) Held Loose Let Go Broken/Failed/Held Net Closed 3 Mussel lash 4 3 15-20 3 1 5 Cotton 4 Tied 15 0 0 4 (all broke) 6 Mussel lash 4 3 4 15 10 Mussel lash 4 3 15 4 12 Mussel lash 4 3 15 3 1 Net Failed to open during tow FV A. Buryachenko Binding Information Performance Tow # Bind Type Diameter Twists in Bind Intervals between binds (m) Held Loose Let Go Broken/Failed/Held Net Closed 4 Mussel lash 8 3 10-12 6 2 6,10,12 Mussel lash 10 3 10 8 1 1 Mussel lash 5 3 13 10 10 PPE 5 4 Mussel lash 5 3 16 9-10 10 PPE 6 4 Mussel lash 5 3 19 8-10 10 2 PPE 7 4 Mussel lash 6 3 21 8-10 10 1 Sisal 6 4 1 Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Bird Behaviour – FV Taimania Bird Behaviour – FV Taimania Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Bird Behaviour – FV Taimania Bird Behaviour – FV Taimania FV Taimania 180 160 140 Number of Seabirds 120 100 Hauling Shooting 80 60 40 20 0 Small Albatross Cape Petrel Other Seabirds Types of Seabirds Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Bird Behaviour – FV A Buryachenko Bird Behaviour – FV A Buryachenko Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Bird Behaviour – FV A Buryachenko Bird Behaviour – FV A Buryachenko FV Aleksandr Buryachenko 30 25 Number of Seabirds 20 Hauling 15 Shooting 10 5 0 Small Albatross Cape Petrel Other Seabirds Types of Seabirds Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Can Turning the Vessel Reduce Can Turning the Vessel Reduce Seabird Captures? Seabird Captures? • Both vessels must turn to get net • Both vessels must turn to get net onboard onboard • The net must haul headline straight on • The net must haul headline straight on (30% of haul time) (30% of haul time) Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Can Turning the Vessel Reduce Can Turning the Vessel Reduce Seabird Captures? Seabird Captures? Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Can Turning the Vessel Reduce Can Turning the Vessel Reduce Seabird Captures? Seabird Captures? • Turning the vessel does reduce • Turning the vessel does reduce exposed netting on rest of trawl exposed netting on rest of trawl Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
Can Net Binding Reduce Seabird Can Net Binding Reduce Seabird Captures? Captures? • Obviously only on shooting • Obviously only on shooting • More seabirds about on hauling • More seabirds about on hauling • Cleaning net of stickers before shooting may • Cleaning net of stickers before shooting may be more effective be more effective • Bottom trawls not tested • Bottom trawls not tested • Apparent that at times not required • Apparent that at times not required • Would be good contingency measure • Would be good contingency measure Clement & Associates Ltd FISHERIES ADVISORS & ANALYSTS
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