Foraging behavior of fish‐eating sperm whales in the Gulf of Alaska in the presence and absence of fishing vessels

2005 ◽  
Vol 118 (3) ◽  
pp. 1909-1909 ◽  
Author(s):  
Aaron Thode ◽  
Jan Straley ◽  
Kendall Folkert ◽  
Victoria O’Connell ◽  
Christopher Tiemann
Keyword(s):  
Foraging Behavior ◽  
Gulf Of Alaska ◽  
Sperm Whales ◽  
Fishing Vessels ◽  
Presence And Absence

Acoustic and foraging behavior of tagged sperm whales under natural and depredation foraging conditions in the Gulf of Alaska

2013 ◽  
Vol 134 (5) ◽  
pp. 4008-4008
Author(s):  
Delphine Mathias ◽  
Lauren Wild ◽  
Aaron Thode ◽  
Jan Straley ◽  
John Calambokidis ◽  
...  
Keyword(s):  
Foraging Behavior ◽  
Gulf Of Alaska ◽  
Sperm Whales

scholarly journals Southeast Alaska Sperm Whale Avoidance Project (SEASWAP): a successful collaboration among scientists and industry to study depredation in Alaskan waters

2015 ◽  
Vol 72 (5) ◽  
pp. 1598-1609 ◽  
Author(s):  
Janice Straley ◽  
Victoria O'Connell ◽  
Joe Liddle ◽  
Aaron Thode ◽  
Lauren Wild ◽  
...  
Keyword(s):  
Sperm Whale ◽  
Gulf Of Alaska ◽  
Global Studies ◽  
Sperm Whales ◽  
Catch Per Unit Effort ◽  
Southeast Alaska ◽  
Vessel Area ◽  
Stock Assessments ◽  
Presence And Absence ◽  
Successful Collaboration

Abstract In Alaskan waters, depredation on sablefish longline gear by sperm whales increases harvesting cost, negatively biases stock assessments, and presents a risk of entanglement for whales. The Southeast Alaska Sperm Whale Avoidance Project (SEASWAP), a collaborative effort involving industry, scientists, and managers, since 2003 has undertaken research to evaluate depredation with a goal of recommending measures to reduce interactions. Prior to 2003, little was known about sperm whale distribution and behaviour in the Gulf of Alaska (GOA). Although fishers were reporting increasing interactions, the level of depredation varied with no apparent predictor of occurrence across vessels. Between 2003 and 2007, fishers were provided with fishery logbooks and recorded information on whale behaviour, whale presence and absence, during the set, soak, and haul for 319 sets in the GOA. Data were evaluated for a vessel, area, and seasonal (month) effect in the presence and absence of sperm whales. Using catch per unit effort (cpue) as a metric, in kg/100 hooks, results indicated that depredation depended on both the vessel and the area. More whales associated with vessels from April to August. Sperm whales were also likely to be present when cpue was high, revealing that whales and fishers both knew the most productive fishing areas, but confounding the use of cpue as a metric for depredation. Using a Bayesian mark-recapture analysis and the sightings histories of photo-identified whales, an estimated Nˆ=135 (95% CI 124, 153) sperm whales were associating with vessels in 2014. A spatial model was fitted to 319 longline sets and quantified a 3% loss in cpue, comparable to other global studies on sperm whale depredation. Through all phases of SEASWAP, our understanding of depredation has gained significantly. This successful collaboration should be considered as a model to create partnerships and build collaborations between researchers and fisherpeople encountering marine mammal interactions with fishing gear.

Field trials of an acoustic decoy to attract sperm whales away from commercial longline fishing vessels in western Gulf of Alaska

2017 ◽  
Vol 196 ◽  
pp. 141-150 ◽  
Author(s):  
Lauren Wild ◽  
Aaron Thode ◽  
Janice Straley ◽  
Stephen Rhoads ◽  
Dan Falvey ◽  
...  
Keyword(s):  
Gulf Of Alaska ◽  
Field Trials ◽  
Sperm Whales ◽  
Fishing Vessels

scholarly journals Exploring variability in the diet of depredating sperm whales in the Gulf of Alaska through stable isotope analysis

2020 ◽  
Vol 7 (3) ◽  
pp. 191110
Author(s):  
Lauren A. Wild ◽  
Franz Mueter ◽  
Briana Witteveen ◽  
Janice M. Straley
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Sperm Whale ◽  
Gulf Of Alaska ◽  
Mixing Models ◽  
Sperm Whales ◽  
Potential Prey ◽  
Squid Species ◽  
Fishing Vessels

Sperm whales interact with commercially important groundfish fisheries offshore in the Gulf of Alaska (GOA). This study aims to use stable isotope analysis to better understand the trophic variability of sperm whales and their potential prey, and to use dietary mixing models to estimate the importance of prey species to sperm whale diets. We analysed tissue samples from sperm whales and seven potential prey (five groundfish and two squid species). Samples were analysed for stable carbon and nitrogen isotope ratios, and diet composition was estimated using Bayesian isotopic mixing models. Mixing model results suggest that an isotopically combined sablefish/dogfish group, skates and rockfish make up the largest proportion of sperm whale diets (35%, 28% and 12%) in the GOA. The top prey items of whales that interact more frequently with fishing vessels consisted of skates (49%) and the sablefish/dogfish group (24%). This is the first known study to provide an isotopic baseline of adult male sperm whales and these adult groundfish and offshore squid species, and to assign contributions of prey to whale diets in the GOA. This study provides information to commercial fishermen and fisheries managers to better understand trophic connections of important commercial species.

scholarly journals Acoustic tracking of sperm whales in the Gulf of Alaska using a two-element vertical array and tags

2013 ◽  
Vol 134 (3) ◽  
pp. 2446-2461 ◽  
Author(s):  
Delphine Mathias ◽  
Aaron M. Thode ◽  
Jan Straley ◽  
Russel D. Andrews
Keyword(s):  
Gulf Of Alaska ◽  
Sperm Whales ◽  
Vertical Array ◽  
Acoustic Tracking

scholarly journals White-capped albatrosses alter fine-scale foraging behavior patterns when associated with fishing vessels

2011 ◽  
Vol 428 ◽  
pp. 289-301 ◽  
Author(s):  
LG Torres ◽  
DR Thompson ◽  
S Bearhop ◽  
S Votier ◽  
GA Taylor ◽  
...  
Keyword(s):  
Foraging Behavior ◽  
Behavior Patterns ◽  
Fine Scale ◽  
Fishing Vessels

From clicks to counts: Applying line-transect methods to passive acoustic monitoring of sperm whales in the Gulf of Alaska

2014 ◽  
Vol 136 (4) ◽  
pp. 2246-2246
Author(s):  
Tina M. Yack ◽  
Thomas F. Norris ◽  
Elizabeth Ferguson ◽  
Brenda K. Rone ◽  
Alexandre N. Zerbini
Keyword(s):  
Gulf Of Alaska ◽  
Acoustic Monitoring ◽  
Line Transect ◽  
Sperm Whales ◽  
Passive Acoustic Monitoring ◽  
Passive Acoustic

scholarly journals Cues, creaks, and decoys: using passive acoustic monitoring as a tool for studying sperm whale depredation

2015 ◽  
Vol 72 (5) ◽  
pp. 1621-1636 ◽  
Author(s):  
Aaron Thode ◽  
Delphine Mathias ◽  
Janice Straley ◽  
Victoria O'Connell ◽  
Linda Behnken ◽  
...  
Keyword(s):  
Low Frequency ◽  
Field Tests ◽  
Sperm Whale ◽  
Acoustic Monitoring ◽  
Sperm Whales ◽  
Passive Acoustic Monitoring ◽  
Long Distance ◽  
Fishing Activity ◽  
Fishing Vessels ◽  
Passive Acoustic

Abstract Since 2003, a collaborative effort (SEASWAP) between fishers, scientists, and managers has researched how Alaskan sperm whales locate demersal longline fishing activity and then depredate sablefish from gear. Sperm whales constantly produce relatively low-frequency biosonar signals whenever foraging; therefore, over the past decade, passive acoustic monitoring (PAM) has become a basic tool, used for both measuring depredation activity and accelerating field tests of potential depredation countermeasures. This paper reviews and summarizes past published PAM research on SEASWAP, and then provides a detailed example of how PAM methods are currently being used to test countermeasures. The review covers two major research thrusts: (i) identifying acoustic outputs of fishing vessels that provide long-distance “cues” that attract whales to fishing activity; and (ii) validating whether distinctive “creak” sounds can be used to quantify and measure depredation rates, using both bioacoustic tags and statistical comparisons between visual and acoustic depredation estimates during federal sablefish surveys. The latter part of the paper then provides an example of how PAM is being used to study a particular potential countermeasure: an “acoustic decoy” which transmits fishing vessel acoustic cues to attract animals away from true fishing activity. The results of an initial 2011 field trial are presented to show how PAM was used to design the decoy signals and monitor the efficacy of the deployment. The ability of PAM to detect both whale presence and depredation behaviour has reduced the need to deploy researchers or other specialists on fishing cruises. Instead, volunteer fishers can deploy “user-friendly” acoustic recorders on their gear, greatly facilitating the testing of various deterrents, and providing the industry and regulators a convenient and unobtrusive tool for monitoring both the scale and long-term spread of this behaviour across the Alaskan fishery.

scholarly journals Depredating sperm whales in the Gulf of Alaska: local habitat use and long distance movements across putative population boundaries

2014 ◽  
Vol 24 (2) ◽  
pp. 125-135 ◽  
Author(s):  
JM Straley ◽  
GS Schorr ◽  
AM Thode ◽  
J Calambokidis ◽  
CR Lunsford ◽  
...  
Keyword(s):  
Habitat Use ◽  
Gulf Of Alaska ◽  
Sperm Whales ◽  
Long Distance ◽  
Local Habitat

scholarly journals Experimental fishing with an “umbrella-and-stones” system to reduce interactions of sperm whales (Physeter macrocephalus) and seabirds with bottom-set longlines for Patagonian toothfish (Dissostichus eleginoides) in the Southwest Atlantic

2010 ◽  
Vol 68 (1) ◽  
pp. 228-238 ◽  
Author(s):  
Sabine Goetz ◽  
Martín Laporta ◽  
Julio Martínez Portela ◽  
M. Begoña Santos ◽  
Graham J. Pierce
Keyword(s):  
Environmental Variables ◽  
Economic Loss ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Southwest Atlantic ◽  
Fishing Vessels ◽  
Visual Evidence ◽  
Patagonian Toothfish ◽  
Dissostichus Eleginoides ◽  
Modelling Data

Abstract Goetz, S., Laporta, M., Martínez Portela, J., Santos, M. B., and Pierce, G. J. 2011. Experimental fishing with an “umbrella-and-stones” system to reduce interactions of sperm whales (Physeter macrocephalus) and seabirds with bottom-set longlines for Patagonian toothfish (Dissostichus eleginoides) in the Southwest Atlantic. – ICES Journal of Marine Science, 68: 228–238. Depredation, i.e. the damage or removal, of Patagonian toothfish (Dissostichus eleginoides) from longlines by sperm whales (Physeter macrocephalus) can cause considerable economic loss for Spanish fishing vessels in the Southwest Atlantic. The fishery also suffers high bycatch rates of seabirds. The main goal of the study was to assess the extent of depredation and seabird bycatch and to test the potential of the so-called “umbrella” system, coupled with attached stones for faster sinking, for minimizing both. Moreover, we investigated the relationships between sightings of sperm whales, depredation, catches, and environmental variables using generalized additive modelling. Data were collected during 297 hauls on a longliner in 2007/2008 in international waters of the Southwest Atlantic. Sperm whales were sighted during 35% of the hauls, always during gear retrieval, and their presence was positively related to fish damage. The overall depredation rate (0.44% of the total catch) was low, but is assumed to be underestimated because sperm whales were suspected of also taking fish without leaving visual evidence. The “umbrella-and-stones” system was highly effective in preventing bycatch and appeared to restrict depredation, but significantly reduced the catches. The results demonstrate that there is still some way to go to solve the problem of depredation.

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