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| Location | Gear | Catch | Technique | Bycatch Species | Type | |
|---|---|---|---|---|---|---|
Bay of Fundy |
na | Acoustic deterrent devices, Passive acoustic deterrents, Vessel noise reductions | Eubalaena glacialis (NA Right whale) | Field study in the wild | ||
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Summary: Risk factors involving ship strikes and North Atlantic right whales were investigated in this study. A multi-sensor digital acoustic recording tag (DTAG) was used to measure the responses of whales to four stimuli: vessel noise, social sounds of conspecifics, and a signal designed to alert whales. Silence was used as the control measure. Testing was conducted in the Bay of Fundy summer foraging region. The DTAGs are non-invasively deployed and record all sounds at a sampling rate of 32 kHz, a Nyquist rate of 16 kHz and records the pitch, roll, heading and depth of the whale at a sampling rate of 46 Hz. Whales showed a strong reaction to the alert signal, swimming strongly to the surface. Whales showed a mild response to social sounds and no response to sounds of an approaching vessel. The response to the alert signal would more likely result in an increased risk of collision and not a decreased risk. Effect on Bycatch: Whales showed a strong response to alert signals. |
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Northwest Atlantic |
Traps | N/A | Large Cetaceans (maximum length > 7.5 meters) | Summary study | ||
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Summary: Entanglements of 31 right whales (Eubalaena glacialis) and 30 humpback whales (Megaptera novaeangliae) in the western North Atlantic were analyzed to identify the parts and types of gear involved. The results indicated that a large number of specific gear types were involved in entanglements. Gear type could not be identified in 20% of entanglements. When gear type was identified, 89% of entanglements were caused by pot and gillnet gear. Pot gear was recovered from both species in equal amounts but gillnet gear was more frequently retrieved from humpbacks compared to right whales. For the 45 cases in which parts of the gear were retrieved, entanglements occurred in buoy line and/or groundline (49%), in float and surface system lines (11%), with 40% of cases in which the gear components were unknown. Right whales were most commonly entangled in the mouth (77.4%), while humpback whales were frequently entangled in both the mouth (43%) and tail (53%). Continued studies of entanglement are needed to provide additional insight. Effect on Bycatch: N/A |
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Australia |
N/A | Acoustic deterrent devices, Passive acoustic deterrents | Megaptera novaeangliae (Humpback whale) | Field study in the wild | ||
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Summary: A study was conducted with humpback whales to test their response to recordings of conspecific social sounds and an artificially generated tone stimulus. Experiments were conducted during humpback whales southward migration along the east coast of Australia. A total of 13 tone experiments, 15 social sound experiments and 3 silent controls were conducted during two field seasons (September/October 2004 and 2008). The results indicated that humpback whales respond differently, with respect to course traveled and dive strategy, to the two stimuli. Humpback whales responded to 'tones' by moving offshore and surfacing more often, perhaps trying to avoid the stimuli. These changes were related to the proximity to the source, the received signal level and signal to signal noise ratio. When social sounds were used the responses were very variable and dependent on the groups composition. This study indicates that behavioral responses of marine mammals to acoustic stimuli is complex and in need of additional research. Effect on Bycatch: Humpback whales responded to 'tones' by moving offshore and surfacing more often, perhaps trying to avoid the stimuli. Responses to social sounds were more variable. |
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Northwest Atlantic |
Traps | Lobster | Sub-surface bait setting | Large Cetaceans (maximum length > 7.5 meters) | Summary study | |
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Summary: The purpose of this project was to determine ways to enhance the performance of sinking groundline, involving three approaches: (1) Reviewing previous research and lobstermen’s experience with sinking groundlines; (2) Recording directly from lobster fishermen of the Gulf of Maine the practical challenges they encountered in converting to sinking groundline; (3) Producing visual observations of actively fished sinking groundline to gain insights into chafing and how it might be reduced. The outputs include recommendations from lobster fishermen in New England on mitigating the negative effects of using sinking groundline, and an identification of research priorities. Effect on Bycatch: N/A |
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Northwest Atlantic |
Traps | Lobster | At-call pop-up buoys | Large Cetaceans (maximum length > 7.5 meters) | Study in the lab | |
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Summary: This report describes a buoyless lobster trap that has an acoustic trigger mechanism. An existing lobster trap would contain all the components except for the transmitter, which consisted of a prototype developed using a Hummingbird Fish Finder. Effect on Bycatch: Not tested |
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Northwest Atlantic |
Non-specific | N/A | Weak links/ropes | Large Cetaceans (maximum length > 7.5 meters) | Summary study | |
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Summary: This supplement to a 2002 compendium of NOAA large whale entanglement prevention research provides an overview of recent NMFS gear research and testing of the time tension line cutter. Effect on Bycatch: N/A |
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Northwest Atlantic |
Non-specific | N/A | Weak links/ropes | Large Cetaceans (maximum length > 7.5 meters) | Summary study | |
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Summary: This supplement to a 2002 compendium of NOAA large whale entanglement prevention research has newer studies, including investigation of SAM gillnet gear, gillnet weak links and anchoring systems, evaluation of gillnet weak links, and a pilot study of options for reducing vertical line entanglements. Effect on Bycatch: N/A |
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Northwest Atlantic |
Traps | n/a | Quick-release gear, Weak links/ropes | Large Cetaceans (maximum length > 7.5 meters) | Summary study | |
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Summary: This supplement to a 2002 compendium of NOAA large whale entanglement prevention research includes newer studies, including evaluation of a time tension line cutter, and studies on neutrally buoyant groundline, load cell field work on gillnets, and recycling of polypropylene rope. Effect on Bycatch: n/a |
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Northwest Atlantic |
Traps | N/A | Buoy lines with reduced breaking strength, Quick-release gear, Weak links/ropes | Large Cetaceans (maximum length > 7.5 meters) | Summary study | |
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Summary: This is a compendium of various studies evaluating potential deterrents to large whale entanglements. Effect on Bycatch: N/A |
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| Gillnets | N/A | Acoustic deterrent devices, Passive acoustic deterrents | Large Cetaceans (maximum length > 7.5 meters), Small Cetaceans (maximum length < 7.5 meters) | Summary study | ||
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Summary: A summary study of methods used to reduce or eliminate marine mammal entanglements was conducted. The authors found little evidence on the effectiveness of the use of sound to reduce or eliminate marine mammal incidental capture. Substantial decreases in cetacean bycatch, due to the use of passive methods such as increasing fishing net reflectivity, were not evident through comparisons of catch rates in commercial fisheries or from observational deterrence studies. Net alarms have been shown to greatly reduce whale entrapment in Canadian fish traps but similar success has not been shown in reducing small cetacean bycatch in many gillnet fisheries. Few controlled studies on the use of sound to reduce or eliminate marine mammal interactions have been conducted. There is a need to additional basic research on echolocation behavior and behavioral interactions between marine mammals and fisheries. Effect on Bycatch: Net alarms do not appear ver effective in reducing small cetacean entanglements in gillnets |
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