[MARMAM] New publication - Histomorphological stratification of blubber of three dolphin species from sub-tropical waters

Natasha Roussouw nroussouw at gmail.com
Mon Sep 19 05:41:41 PDT 2022


Dear MARMAM Subscribers,



On behalf of myself and my co-authors, I am pleased to share our new
publication on the ‘Histomorphological stratification of blubber of three
dolphin species from subtropical waters of Kwa-Zulu Natal, South Africa”:



Roussouw, N., van Vliet, T., Naidoo, K., Rossouw, G., Plön, S. (2022).
Histomorphological stratification of blubber of three dolphin species from
sub-tropical waters. *Journal of Morphology*.
https://doi.org/10.1002/jmor.21511



*Abstract*

Blubber is a highly specialized and dynamic tissue unique to marine mammals
and presents a reflection of the individuals' nutrition, environment, and
life history traits. Few studies have investigated the histomorphology of
cetacean blubber in subtropical environments. The aim of this study was to
investigate the blubber histomorphology of three different dolphin species
off the subtropical KwaZulu‐Natal coast, South Africa, using adipocyte cell
size, number, and density. Blubber tissue samples from the saddle area of
43 incidentally bycaught animals (four *Sousa plumbea*, 36 *Tursiops
aduncus*, and three *Delphinus delphis*) were used to compare cell
parameters between blubber layers. Samples were divided into the upper
third (corresponding
to the superficial layer closest to the epidermis), middle third, and lower
third (corresponding to the deep layer). For *T. aduncus*, factors
potentially affecting blubber histomorphology, such as sex, age class, and
season, were also assessed. Our results showed that no stratification was
present in *S. plumbea*, which could be ascribed to the species' warmer
inshore habitat, large body size, and apparent lower mobility. For *T.
aduncus* and *D. capensis*, however, blubber stratification was determined,
characterized by a gradual transition of cell size, number, and density
between layers rather than clearly defined layers. Significant differences
in adipocyte cell number and density were found for different sexes and age
classes of *T. aduncus*. However, there were no significant differences
between seasons, which was attributed to the small temperature differences
between seasons. This study represents the first investigation of
odontocete blubber histomorphology in subtropical waters. It is recommended
that future studies investigate blubber lipid content, while also taking
into consideration the reproductive status of the females and the
temperature range of their study area. It is hoped that our results, in
conjunction with histopathology and other health indicators, could assist
in assessing health and body condition.



You can access the full-text (read online only) for free at the following
link:

https://onlinelibrary.wiley.com/doi/epdf/10.1002/jmor.21511



Alternatively, please feel free to e-mail me for a pdf copy or if you have
any queries.


Kind regards,


Natasha Roussouw (MSc)
Bayworld Centre for Research and Education (BCRE)
Port Elizabeth
South Africa
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