[MARMAM] Abstracts - Journal of Cetacean Research & Management, 13(1)

Dagmar Fertl dagmar_fertl at hotmail.com
Thu Jan 29 10:35:05 PST 2015


Dear Marmam and ECS-mailbase subscribers,
 
Apologies to those of you who will receive duplicate emails due to cross-posting.  The following are abstracts from one of the most recent issues (Volume 13, issue 1, 2013) of the Journal of Cetacean Research and Management. The following is posted on behalf of the IWC and the journal editor.
 
The International Whaling Commission (IWC) publishes the Journal of Cetacean Research and Management thrice yearly (Spring, Autumn, and Winter), with at least one supplement that will contain the full report of the IWC Scientific Committee. This is one of the final issues of JCRM to be published in hard copy format. The IWC is delighted to inform you that the Journal of Cetacean Research and Management will be available free of charge online from Volume 14 (https://iwc.int/jcrm). Back copies will also be available free of charge on the IWC website. Some back copies of the Journal of Cetacean Research and Management are available in hard copy format, and these are available for the cost of postage only. For further details, please contact secretariat at iwc.int.
 
Contact information is provided for the corresponding author for each article. Please do not contact the listserve editors or me for pdfs. Thank you for your continued interest in the journal and abstract postings. 
 
A guide for authors is included at the website.
 
With regards,
 
Dagmar Fertl
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Brodie, P., K. Ramirez, and M. Haulena. 2013. Growth and maturity of belugas (Delphinapterus leucas) in Cumberland Sound, Canada, and in captivity: evidence for two growth layer groups (GLGs) per year in teeth.  Journal of Cetacean Research and Management 13(1):1-18.
 
Contact e-mail: p.brodie at icloud.com
 
The beluga (Delphinapterus leucas) is one of the few cetaceans to adapt, year-round, to an Arctic environment, one of the most challenging marine habitats, incorporating shallow estuaries, high turbidity, shifting pack-ice and extreme tidal ranges. Adaptation is attributed in part, to year-round herd integrity and synchrony, occupying a sequence of restricted seasonal habitats and calving sites, which are reflected in tooth laminae. Field research, 1966–1969, led to the conclusion that females are sexually mature at 5.75 years and males at 8.75 years, gestation is 15–16 months, reproductive cycle 3 years, with a lifespan of 30–35 years. Newborn and the first four year-classes are recognisable by length, body colour and morphology. The two-year nursing period results in rapid growth, coincident with a training period to acquire social, feeding, and crucial under-ice navigational skills. Belugas in Cumberland Sound had been reduced through exploitation, thus it is unlikely that present numbers are food limited, reflecting maximum rate of increase. We examine growth indices for captive belugas, either captured as calves, or first and second generations born in captivity, to compare known-age animals. Onset of sexual maturity in males and females is similar to findings for Cumberland Sound, which was based on two growth layer groups per year in the teeth, or GLG/2. We analyse studies where previous oral doses of tetracycline, as well as bomb radiocarbon 14C from 1958 were used to argue for single annual GLGs or GLG/1. Dedicated field studies, using appropriate dosage of intramuscular tetracycline, provide evidence for GLG/2. The 14C study appears to have been compromised by preparation technique and burdens sampled in the 1990s may have been of maternal origin, transferred during foetal growth and nursing, or from recent fallout to 1980. Fundamental to the issue of growth-at-age: arguments for GLG/1 are based on back-calculation from adults of unknown age, while GLG/2 is based on projection from newborn to known-age young and adults. Direct observations and cross-referenced parameters do not substantiate GLG/1, which requires halving the growth rate, thus doubling the age of sexual and physical maturity as well as lifespan, resulting in a 40% reduction of the intrinsic rate of natural increase, substantially lower than the present rate of recovery observed.
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Bassos-Hull, K., R.M. Perrtree, C.C. Shepard, S. Schilling, A.A. Barleycorn, J.B. Allen, B.C. Palmer, W.E. Pine, and R.S. Wells. 2013. Long-term site fidelity and seasonal abundance estimates of common bottlenose dolphins (Tursiops truncatus) along the southwest coast of Florida and responses to natural perturbations .  Journal of Cetacean Research and Management 13(1):19-30.
 
Contact e-mail: kbhull at mote.org
 
Information characterising site fidelity and abundance for common bottlenose dolphins (Tursiops truncatus) along the southwest coast of Florida is important for defining stock structure for management purposes. Long-term site fidelity and ranging patterns of bottlenose dolphins in Charlotte Harbor and Pine Island Sound, Florida were investigated using photo-ID data collected during 566 boat-based surveys from 1982 through 2007. Seasonal abundance estimates were generated from seven multi-week field seasons during 2001 through 2006, before and after a major hurricane and red tide event occurred in the area. In total, 1,154 distinctive dolphins were identified up to 34 times each with 84% of individuals resighted on more than one day. Multiple year residency rates were high with 81% of dolphins sighted in at least two years and 30% over ten or more years. Seventy-six percent of individuals with sightings on two or more days were observed in both summer and winter. Of 249 dolphins sighted on ten or more days in the study area, 83% were never observed outside the study area, indicating strong site-fidelity. Two years after a devastating Category 4 hurricane in 2004 and following two years of Karenia brevis harmful algal blooms, 94% of dolphins were observed in the same region within the study area and abundance estimates remained stable. Documenting range and site fidelity patterns of individuals over long periods of time is helpful for characterizing population structure and for examining changes attributable to environmental factors and perturbations such as hurricanes, harmful algal blooms and climate change.
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Martien, K.K., D.P. Gregovich, and A.E. Punt. 2013. Defining the appropriate ‘Unit-To-Conserve’ under the International Whaling Commission’s Revised Management Procedure. Journal of Cetacean Research and Management 13(1):31-38.
 
Contact e-mail: Karen.Martien at noaa.gov
 
Identifying the appropriate ‘Unit to Conserve’ (UTC) is critical to the success of any management scheme. While the need to define the UTC appropriate to the IWC’s Catch Limit Algorithm (CLA) has long been recognised by its Scientific Committee, little progress has been made on this issue. The CLA was rigorously tested prior to its adoption. However, most of those original performance trials focused on single-population scenarios or two-population scenarios with no ongoing dispersal. None of the trials considered the performance of the CLA across a range of dispersal rates. In this study, the performance of the CLA under a variety of population structure scenarios is examined. This is the first study to investigate the levels of connectivity (i.e. dispersal rate) for which populations require separate management to meet the conservation goals of the CLA. All the trials consisted of two populations that were managed as a single stock for 100 years. Both historical and modern hunts were spatially-biased so
that population 1 was the primary target of hunting. Parameters that varied among trials were the relative carrying capacities (K) of the populations, the dispersal rate between them, maximum sustainable yield rate (MSYR1+), and the precision in simulated abundance estimates. All of these parameters had strong effects on the conservation performance of the CLA. Trials with a low MSYR1+ (1%) generally ended with the abundance of population 1 below 0.54K, regardless of the dispersal rate or relative carrying capacities of the two populations. The same was true of trials in which the carrying capacity of population 1 represented only 10% of the total landscape carrying capacity and the CV of the abundance estimates was low, even when dispersal between populations was high (5 × 10–3yr–1) and MSYR1+ was 4%. The results suggest that the appropriate UTCs under the RMP are likely to exchange dispersers at high enough rates that they will be difficult to delineate using existing methods. These results also highlight the value of spatially-diffuse hunting patterns that avoid potential overhunting of unrecognised stocks.
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Bertulli, C.G., M.H. Rasmussen, and M.J. Tetley. 2013. Photo-identification rate and wide-scale movement of common minke whales (Balaenoptera acutorostrata) in the coastal waters of Faxaflói and Skjálfandi Bays, Iceland. Journal of Cetacean Research and Management 13(1):39-45.
 
Contact e-mail: ciarabertulli at yahoo.it
 
Information on movement and site fidelity is important for conservation and management. Photo-ID of common minke whales (Balaenoptera acutorostrata) was conducted from whalewatching vessels within the coastal waters of Faxaflói (a bay on the southwest coast of Iceland) and Skjálfandi (a bay on the northeast coast) between 2007–10 and 2001–10 respectively, to examine fidelity to the sampling locations and movement between them. Images of 292 individual minke whales were obtained in Faxaflói and 61 in Skjálfandi, with an overall ‘annual re-capture proportion’ of 23.3% in the former and 16.4% in the latter. Most (about 80%) of the resighted animals in each bay were re-sighted in one year only. The total number of identified whales has increased in both Faxaflói and Skjálfandi Bays since 2007 and 2001 respectively, suggesting the existence of an open population in both bays. One match was found between the two bays, eight years apart; the distance was approximately 600km between southwest and northeast Iceland. This study shows the value of photo-ID studies from platforms of opportunity such as whalewatching vessels. More data are required from broader geographic areas before firm conclusions can be drawn about movements and site fidelity within Icelandic waters.
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Vermeulen, E. 2013. Abundance estimates of southern right whales (Eubalaena australis) in Bahía San Antonio, Patagonia, Argentina.  Journal of Cetacean Research and Management 13(1):47-51.
 
Contact e-mail: elsvermeulen5 at gmail.com
 
The abundance of southern right whales (Eubalaena australis) was estimated by the means of aerial line-transect surveys for the area of Bahia San Antonio, a bay located in the north-western region of the San Matias Gulf (40°50’S 64°50’W), Rio Negro, Patagonia Argentina. In total, seven aerial surveys were conducted in the first week of August and September 2009, September, October and November 2010, and August, September 2011. Survey effort equalled a total flight time of 12.4h, during which 200 whales were counted in 119 whale groups. Half of the encounters were solitary animals and 17% were mating groups. Corrected abundance estimates showed the highest amount of whales present in the bay during the month of September, with 85+71, 207+108 and 117+55 animals in 2009, 2010 and 2011 respectively. In adjacent months, less than half the amount of whales seemed to be present. The correction factor g(0)availability resulted 0.392+0.456. Perception bias was not accounted for. These aerial surveys resulted in the first estimates of southern right whale abundance in this north Patagonian bay and indicated a rather abrupt peak during the month of September. This being the peak month for right whale presence is consistent with data from other regions in the Southwest Atlantic, but data obtained in the other months remained scarce and thus results should be interpreted carefully. The complete absence of whales in the area during November 2010 and August 2011 raises further questions on the predictability of the whale’s presence in the area. Overall, more consistent aerial surveys should be conducted to accurately determine the annual and interannual evolution of southern right whale abundance in the study area.
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Silberg, J.N., J.M.V. Acebes, A.M. Burdin, E.G. Mamev, K.C. Dolan, C.A. Layusa, and E.Q. Aca. 2013. New insight into migration patterns of western North Pacific humpback whales between the Babuyan Islands, Philippines and the Commander Islands, Russia. Journal of Cetacean Research and Management 13(1):53-57.
 
Contact e-mail: joshsilberg at gmail.com
 
The population structure of humpback whales (Megaptera novaeangliae) in the North Pacific has received significant attention in recent years through the collaborative Structure of Populations, Levels of Abundance, and Status of Humpback whales in the North Pacific (SPLASH) study. However, the analysis of humpback whales in the western North Pacific Asian population was limited in the SPLASH study, due to small sample size. Much of the Asian population summers off Kamchatka, Russia and spends the winters in breeding grounds in Okinawa and Ogasawara, Japan and the Babuyan Islands in the northern Philippines. Prior studies grouped the Commander Islands feeding ground in Russia, with the eastern Aleutian Islands as part of the central humpback whale stock. This paper uses additional years of photo-ID data from both the Philippines (160 whales from 2000–12) and the Commander Islands (531 whales from 2008–10) to establish a previously unreported migratory connection by matching four animals between the two sites. The new migratory linkage found in the present study suggests that a small portion of humpback whales hypothesised to be migrating to a ‘missing’ breeding ground in the central North Pacific are actually migrating to the Philippines. However, additional studies on a wider geographical scale are required.
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Ivashchenko, V.Y., P.J. Clapham, and R.L. Brownell, Jr. 2013. Soviet catches of whale in the North Pacific: revised totals. Journal of Cetacean Research and Management 13(1):59-71.
 
Contact e-mail: yulia.ivashchenko at noaa.gov
 
The USSR conducted a global campaign of illegal whaling beginning in 1948. Catch records for Soviet pelagic operations in the Southern Hemisphere (and the northern Indian Ocean) have been largely corrected, but major gaps have remained for the North Pacific. Here, using newly discovered whaling industry reports, corrected figures for Soviet catches in this ocean are provided. During the period 1948–79, a minimum of 190,183 whales were killed by the USSR in the North Pacific (195,783 if one includes an estimate for sperm whales taken in years for which there are no true data); of these, only 169,638 were reported to the IWC, a difference of 20,568 whales (26,168 including the sperm whale estimate). Figures were falsified for 8 of 12 hunted species, with some catches over-reported to camouflage takes of illegal species. Revised catch totals (caught vs. reported) are as follows: blue whale – 1,621 vs. 858; fin whale – 14,167 vs. 15,445; humpback whale – 7,334 vs. 4,680; sperm whale – 153,686 vs. 132,505; sei whale – 7,698 vs. 11,363; North Pacific right whale – 681 vs. 11; bowhead whale – 145 vs. 0; gray whale – 172 vs. 24. Bryde’s, minke, killer and Baird’s beaked whale catches were reported correctly. Of all the hunted species, sperm and North Pacific right whales were the most heavily impacted. Major falsifications for sperm whales involved figures for both total catch and sex ratio.
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Lammers, M.O., A.A. Pack, E.G. Lyman, and L. Espiritu. 2013. Trends in collisions between vessels and North Pacific humpback whales (Megaptera novaeangliae) in Hawaiian waters (1975-2011). Journal of Cetacean Research and Management 13(1):73-80.
 
Contact e-mail: lammers at hawaii.edu
 
Injury from collisions with vessels is a growing threat worldwide for many species of whales. Thirty seven years of historical records were examined for evidence of vessel collisions with humpback whales in the main Hawaiian Islands. Between 1975 and 2011, 68 collisions between vessels and whales were reported including 59 witnessed collisions and 9 observed whale injuries that were consistent with a recent vessel collision. No collisions were immediately lethal. The waters between Maui, Molokai, Lanai and Kahoolawe, which are known to have one of the highest concentrations of humpback whales in the Hawaiian Islands, had the highest incidence of collisions. Over 63% of the collisions involved calves and subadults, suggesting a greater susceptibility towards collisions among younger animals. The rate of collisions increased significantly over the final twelve breeding seasons of the study and was greater than predicted by the estimated annual increase in the whale population, suggesting that the rising number of reported collisions cannot be explained solely by the annual increase in whale abundance. Although the total number of registered vessels and shipping traffic in Hawaii remained relatively constant between 2000 and 2010, there was a significant increase in the number of vessels between 7.9m and 19.8m in length. Vessels within this size range were also the most commonly involved in collisions during the study period, accounting for approximately two thirds of recorded incidents. It is concluded that from 1975 2011, there was a significant increase in reports of non-lethal collisions between vessels and humpback whales, especially calves and subadults, in the main Hawaiian Islands that likely reflects a combination of factors including the recovery of the population of North Pacific humpback whales, increases in traffic of particular vessel types, and increased reporting practices by operators of vessels.
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Brandon, J.R., and A.E. Punt. 2013. Testing the Gray Whale Strike Limit Algorithm (SLA): allowing environmental variability to influence population dynamics . Journal of Cetacean Research and Management 13(1):81-88.
 
Contact e-mail: jbrandon at u.washington.edu
 
The performance of the Gray Whale SLA is evaluated based on an operating model conditioned on available information for the eastern North Pacific stock of gray whales including: survey estimates of 1+ abundance; calf counts; strandings data; and the extent of sea-ice in the feeding grounds in the Bering Sea in the early season. Multiple scenarios are considered in the analyses to explore the impact of different sources of environmental variation, including scenarios in which future environmental forcing and episodic events are driven by the relationships between reproductive success and survival to sea ice. A variety of sources of uncertainty are considered, including parameter uncertainty, the uncertainty about the relationship between the extent of sea-ice and population dynamics, and observation error. The impact of these sources of uncertainty on the performance of the Gray Whale SLA is small. For all scenarios considered in the simulations, application of the SLA results in the stock being at or near carrying capacity at the end of a 92 year projection period for which sea-ice cover forecasts are available, while still satisfying the needs of aboriginal whalers 		 	   		  
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