[MARMAM] Sperm whale departure from the central portion of the Gulf of California publication!

[Hector Perez]

Dear colleagues,

Hola, my co-authors, and I are pleased to share with you our latest
publication on the sperm whale departure from the central portion of the
Gulf of California, particularly in the Midriff Islands Region, which is
open access on the section Life and Environment PeerJ journal.

Title: The departure of sperm whales (*Physeter macrocephalus*) in response
to the declining jumbo squid (*Dosidicus gigas*) population in the central
portion of the Gulf of California.

Pérez-Puig H, Arias Del Razo A, Ahuatzin Gallardo D, Bolaños J. 2024. The
departure of sperm whales (*Physeter macrocephalus*) in response to the
declining jumbo squid (*Dosidicus gigas*) population in the central portion
of the Gulf of California. PeerJ 12:e18117
https://peerj.com/articles/18117/

Abstract:

As sperm whales are important predators that control energy flux in the
oceans, changes in their population can be used as a sentinel to measure of
ecosystem health. The present study conducted a sperm whale survey of the
eastern Midriff Islands Region in the Gulf of California over the course of
nine years, recording sightings and collecting photographs of the fluke of
sperm whale individuals. A photo-identification catalog was compiled, while
individual recapture data were used to estimate the population size in the
central portion of the Gulf of California, using a Jolly-Seber POPAN open
population model. The results obtained show a yearly population of between
20 and 167 sperm whales, with a super population of 354 sperm whales
observed between 2009 and 2015. However, from 2016 to 2018, no sightings of
the species were recorded, which coincides with the decline observed in
landings of their main prey, the jumbo squid, in the region. General
additive model conducted on sperm whale sightings per unit of effort vs
jumbo squid landings obtained an adjusted R2 of 0.644 and a deviance
explained of 60.3%, indicating a good non-linear relationship between
sightings of this odontocete and its prey availability. This evidence
suggests that sperm whales departed the region between 2016 and 2018, due
to a documented fishery collapse alongside changes of their main prey into
its small phenotype, possibly as the result of increase warming conditions
in surface and subsurface waters in the Gulf of California in the last
three decades.

Saludos!
-- 
MC. Héctor Pérez Puig.
___

Programa de Investigación y Conservación.
Centro de Estudios Culturales y Ecológicos.
Prescott College A.C.
Bahía de Kino, Sonora, México.
e-mail: hector.pe...@prescott.edu
teléfono: (01662) 242-0024.
http://www.prescott.edu/kino-bay-center/index.html
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[MARMAM] New paper on Northernmost Habitat Range of Guadalupe Fur Seals in the Gulf of California.

[Hector Perez]

Dear MARMAN colleagues,

On behalf of my co-authors, we are pleased to announce our recent short-note in 
Aquatic Mammals Journal about ¨Northernmost Habitat Range of Guadalupe Fur 
Seals (Arctocephalus townsendi) in the Gulf of California, México¨.

Citation:
Gálvez, C., Pérez-Puig, H. and F. R. Elorriaga-Verplancken. (2022). 
Northernmost Habitat Range of Guadalupe Fur Seals (Arctocephalus townsendi) in 
the Gulf of California, México. Aquatic Mammals, 48(3):223-233, DOI 
10.1578/AM.48.3.2022.223 Short223

You can have access to the short-note here:  
https://www.aquaticmammalsjournal.org/index.php?option=com_content&view=article&id=2200:northernmost-habitat-range-of-guadalupe-fur-seals-arctocephalus-townsendi-in-the-gulf-of-california-mexico&catid=207&Itemid=326

Here is the absctrat:

In this short-note, we provided information on an apparent increase in the 
Guadalupe fur seal’s (Arctocephalus townsendi) (GFS) habitat expansion range, 
involving the potential establishment of the first bulls haul-out site located 
in the Midriff Islands Region of the Gulf of California. We highlight the 
relevance of increase research efforts in this area to determine their 
potential colonization, which is relevant due to haul-out site is located in a 
region where important anthropogenic activities (e.g, fishing) are performed, 
representing a potential risk forindividuals welfare and survival during their 
post-breeding migration period along the Gulf of California.

Please feel free to contact us with any questions/comments or request a pdf 
copy.

Best regards,

Héctor.
___


M.C. Héctor Pérez Puig
Coordinador - Programa de Mamíferos Marinos

Centro de Estudios Culturales y Ecológicos Prescott College A.C.


Coordinator - Marine Mammal Program

Prescott College Kino Bay Center for Cultural and Ecological Studies

   w. 
www.prescott.edu/kino-bay-center/index.html
   e. hector.pe...@prescott.edu
   t. (01662)-242-0024
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[MARMAM] New publication: First Leucistic Bottlenose Dolphin (Tursiops truncatus) Sighting Registered in the Gulf of California, Mexico.

[Hector Perez]

Dear MARMAM colleagues,

On behalf of my co-authors I'm excited to announce our publication (short note) 
in Aquatic Mammals, which describes the first leucistic event of Bottlenose 
Dolphin (Tursiops truncatus) registered in the Gulf of California.

Pérez-Puig, H., Heckel, G., & Meltzer, L. (2019). First Leucistic Bottlenose 
Dolphin (Tursiops truncatus) Sighting Registered in the Gulf of California, 
Mexico. Aquatic Mammals, 45(5), 507–512. 
https://doi.org/10.1578/AM.45.5.2019.507


Short summary: As with all mammals, coloration patterns of the skin, and of the 
eyes in cetaceans, depends almost entirely on the quantity of melanin in the 
organism. Leucism can result when the production of melanin is minimal but not 
completely absent; the deficiency of pigmentation of the skin results in an 
abnormally white appearance, while the eyes maintain a normal color. Abnormal 
pigmentation has been recorded in at least 25 cetacean species, including 
bottlenose dolphin Tursiops truncatus. Few sightings of those cetaceans with 
abnormally white pigmentation have been recorded in Mexico. The majority of 
bottlenose dolphin sightings with this abnormally white pigmentation have been 
recorded on the Atlantic coasts from Texas to North Carolina. Therefore, the 
sighting reported and described herein represents the second odontocete in 
Mexico and the first confirmed sighting of a leucistic bottlenose dolphin in 
the Gulf of California. This atypical coloration has never been reported in 
other studies on this species in the same or adjacent regions in the Gulf of 
California.


For more information, the article is now available to the public on The Aquatic 
Mammals Web site using the following link:

https://www.aquaticmammalsjournal.org/index.php?option=com_content&view=article&id=1954:first-leucistic-bottlenose-dolphin-tursiops-ttus-sighting-registered-in-the-gulf-of-california-mexico&catid=177&Itemid=326

For a PDF copy, please you can also send a email: hector.pe...@prescott.edu

Best regards,

Héctor.
___


M.C. Héctor Pérez Puig
Investigador Residente - Programa de Mamíferos Marinos

Centro de Estudios Culturales y Ecológicos Prescott College A.C.


Resident Researcher - Marine Mammal Program

Prescott College Kino Bay Center for Cultural and Ecological Studies

   w. 
www.prescott.edu/kino-bay-center/index.html
   e. hector.pe...@prescott.edu
   t. (01662)-242-0024
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[MARMAM] New Publication: Abundance estimation of gray whale calves from shore-based surveys.

[Hector Perez]

Dear colleagues from MARMAM community,

My co-authors and I are pleased to announce the following publication through 
Marine Mammal Science:

Pérez-Puig, H., Heckel, G. and Breiwick, J. M. (2017), Abundance estimation of 
gray whale (Eschrichtius robustus) calves from shore-based surveys undertaken 
near Ensenada, Baja California, Mexico, 2004–2006. Mar Mam Sci, 33: 593–610. 
doi:10./mms.12401

Abstract:

Gray whale calf abundance was estimated from shore-based surveys near Ensenada, 
Baja California, during their northbound migration. Over the course of 129 
effort-days (756.5 observation hours), 162 calves were counted, comprising 42, 
41, and 79 calves in 2004, 2005, and 2006, respectively. To estimate the number 
of undetected calves during the observation periods in 2006, detection 
probabilities were estimated by simultaneous and independent counts using a 
Huggins model. The detection probabilities ranged from 0.655 to 0.997. The 
number of calves estimated during effort periods were divided by their 
estimated detection probabilities, while the total number of calves were 
estimated by fitting a generalized additive model (GAM) to the passage rate 
(whales/h) and effort (time) data. The final gray whale calf abundance 
estimates were 451 (95% CI = 430, 513), 253 (95% CI= 245, 308), and 442 (95% CI 
= 396, 510) calves for 2004, 2005, and 2006, respectively. The estimates were 
lower than those reported for Piedras Blancas, California, during the same 
years, with one possible reason being that an important number of cow/calf 
pairs migrate too far from shore (>10 km) to be detected from the observation 
site used in this research.

The article can be downloaded here: 
http://onlinelibrary.wiley.com/doi/10./mms.12401/full. If you would like a 
pdf copy or have any further inquiries please email to 
ghec...@cicese.mx or myself 
hector.pe...@prescott.edu


Best regards,


MC. Héctor Pérez Puig.

___

Programa de Investigación y Conservación - Programa de Mamíferos Marinos
Centro de Estudios Culturales y Ecológicos
Prescott College A.C.
Bahía de Kino, Sonora, México.
e-mail: hector.pe...@prescott.edu
teléfono: (01662) 242-0024.
http://www.prescott.edu/kino-bay-center/index.html
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