August 2023 - MARMAM - devlists.uvic.ca

New publication: Unraveling the enigmatic type D killer whale (Orcinus orca): mass stranding in the Magellan Strait, Chile (Haro, Daniela)
by Daniela Haro 01 Aug '23

01 Aug '23

Dear MARMAM community, My co-authors and I would like to share our recently published paper on type D killer whales : Haro, D., Blank, O., Garrido, G. *et al.* Unraveling the enigmatic type D killer whale (*Orcinus orca*): mass stranding in the Magellan Strait, Chile. *Polar Biol* *46*, 801–807 (2023). https://doi.org/10.1007/s00300-023-03156-2 *Abstract* There are different ecotypes of killer whales (Orcinus orca) worldwide; type D killer whales are the least known. These killer whales have a globose head, an extremely small post-ocular patch and a falcate dorsal fin. We report the first stranding event of type D killer whales recorded in southern South America, in the Magellan Strait, Chile. The group consisted of four adult females, two juvenile females, and two females and one male of indeterminate age class. Total length of adult females averaged 572.8 ± 23.6 cm and juvenile females averaged 397.0 ± 24.0 cm. Dorsal fin height of adult females averaged 57.3 ± 8.5 cm and in juvenile females 30.5 ± 19.1 cm. No obvious signs of anthropogenic intervention were observed. The characteristic small post-ocular white eye patch of this killer whale ecotype measured 21.8 cm long and 5.9 cm wide in the freshest carcass found. All animals presented backswept dorsal fins and a dental formula of 11 to 13 maxillary and mandibular teeth. The length of the largest tooth in each individual ranged from 8.0 to 10.2 cm, suggesting that type D killer whales have smaller teeth. We suggest that the total length of type D killer whales is shorter than other killer whale ecotypes. After 67 years, we report the second known stranding of type D killer whales worldwide and we report for the first time body measurements, size, and number of teeth of this ecotype of killer whales. You can contact us with questions at dharod(a)santotomas.cl -- *Daniela Haro Díaz*

1 0

Workshop on social science techniques that could be applied to right whale conservation
by Andrew Wright 01 Aug '23

01 Aug '23

Dear Marmam, Apologies for cross posting. On 26th October, a 1-day workshop "Introduction to Available Tools for Exploring Human Behaviours Important for Addressing North Atlantic Right Whale Conservation Issues" will be held at Dalhousie University in Halifax Nova Scotia, in conjunction with the North Atlantic Right Whale Consortium. Participation at the Consortium meeting is not required for attendance, although it is preferred. The intent of this workshop is to gather a variety of social scientists with those currently involved in right whale conservation issues for an exchange of information and to develop a very loose roadmap for how social science might be applied to advancing this issue going forward. This meeting will not focus on changing any specific behaviour, nor will it develop an outreach plan for doing so, as these tasks would need to be undertaken two or three steps down the line of a full investigation by social scientists and then the applied efforts of conservation marketers. It is simply an opportunity to learn where there might be some benefit to trans-disciplinary collaborations going forward, and to provide a suitable forum for networking across the disparate disciplines. More details can be found here: https://www.narwc.org/2023-workshops.html. The intention is that this workshop will be free to all participants. If you are interested in participating, please email Andrew Wright ( marinebrit(a)gmail.com) by 31st August, as participation will be limited due to the size of the available room. Best, Andrew Wright, Kathleen Normal, Emma McKinley (Co-organisers)

1 0

New paper on fur seals' feeding habits in the South Atlantic
by Renan Lima 01 Aug '23

01 Aug '23

Dear MARMAM community, On behalf of my co-authors, I'm pleased to announce the publication of our new paper in Marine Mammal Science: Feeding habits of South American and sub-Antarctic fur seals during their nonbreeding season in the southwestern Atlantic Ocean de Lima RC, de Albernaz TL, ER Secchi, JD Cebuhar, S Botta https://onlinelibrary.wiley.com/doi/abs/10.1111/mms.13049 Abstract: Stomach contents of South American (*Arctocephalus australis*) (n = 219) (SAFS) and sub-Antarctic (*A. tropicalis*) (n = 37) (SFS) fur seals were opportunistically sampled from 1980 to 2021 to examine their feeding habits and resource partitioning in southern Brazil while in their nonreproductive periods. SAFSs mainly consumed abundant coastal pelagic species, such as Anchoa marinii and *Doryteuthis sanpaulensis*, resulting in high sexual trophic niche overlap. The frequency of occurrence (%FO) of fish prey, especially the overexploited *Micropogonias furnieri*, decreased between 1980–1992 and 2007–2021, while squid increased. For SFSs, offshore squids such as *Ommastrephes bartramii* and *Illex argentinus* were the most important prey considering both sexes in the long-term. The interspecific trophic niche overlap was low, but it is likely underestimated since it increased with the inclusion of scat samples from SFSs. This sample-size effect was also observed in Shannon's diversity index, which was lower for underrepresented SFSs. Marine debris ingestion was detected in both species (SAFS %FO = 2.7; SFS %FO = 8.3), with only flexible plastic material found. This study brings novel information on feeding habits of fur seal species in the extreme south of Brazil and unprecedented information about their ecology during the nonreproductive period. If you can't access the paper through the link, please contact one of my co-authors, Julieta (jucebuhar(a)gmail.com) Kind regards, Renan -- *Renan C. de Lima, PhD* Postdoctoral fellow Laboratório de Ecologia e Conservação da Megafauna Marinha - EcoMega Instituto de Oceanografia Universidade Federal do Rio Grande (FURG) Association of Polar Early Career Scientists - Brazilian Committee (APECS Brazil) - National Representative *Phone*: +55(53)99718994 | *e-mail*: renancdl(a)gmail.com *RG:* www.researchgate.net/profile/Renan-Lima-2 *ORCID*: https://orcid.org/0000-0002-9311-7085

1 0

New paper on bowhead whale gestation
by Nadine Lysiak 31 Jul '23

31 Jul '23

Dear colleagues, On behalf of my co-authors, I am pleased to share our new publication: https://royalsocietypublishing.org/doi/10.1098/rsos.230365 N.S.J. Lysiak, S.H. Ferguson, C.A. Hornby, M.P. Heidi-Jørgensen, and C.J.D. Matthews. 2023. Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales. Royal Society Open Science,10: 230365. DOI: https://doi.org/10.1098/rsos.230365 Abstract: Serial measurements of hormone concentrations along baleen plates allow for reconstructions of mysticete whale reproductive histories. We assessed gestation and calving interval in bowhead whales (Balaena mysticetus) by measuring progesterone, oestradiol, corticosterone and nitrogen stable isotope ratios (δ15N) along baleen of 10 females from the eastern Canada-west Greenland population. Three immature females (body size < 14.32 m) had uniformly low progesterone concentrations across their baleen, while seven mature females (body size ≥ 14.35 m) had repeated, sustained elevations of progesterone indicative of pregnancies. The mean duration of progesterone elevations (23.6 ± 1.50 months) was considerably longer than the approximately 14 month gestation previously estimated for this species. We consider several possible explanations for this observation, including delayed implantation or sequential ovulations prior to gestation, strategies that would allow females to maximize their fitness in variable Arctic conditions, as well as suggest modified criteria defining gestation as a shorter component of the entire progesterone peak. Calving intervals varied within and among individuals (mean = 3.7 years; range = range 2.8–5.7 years), providing population-specific reproductive estimates for growth models used in bowhead whale management and conservation. Please email me nadine.lysiak(a)gmail.com <mailto:nadine.lysiak@gmail.com> if you have any questions. Best wishes, Nadine

1 0