1. Prevalence of Lesions and Deformities Observed in Common
Dolphins (Delphinus sp.) in the Hauraki Gulf, New Zealand
Krista E. Hupman, Ophélie Humphrey, Matthew D. M. Pawley, Charli
Grimes, Sabrina Voswinkel, Wendi D. Roe, Karen A. Stockin
Introduction
Fig. 1 Common dolphin distinct body sectors
Methods
• Non-systematic photo-id surveys were conducted in the Hauraki Gulf from
2010–2013.
• For prevalence, the number of lesions and deformities were weighted by
the cumulative number of images taken for each body sector (Fig. 1).
• Lesions and deformities were grouped into 12 and 2 categories,
respectively [3–6] (Figs. 2,3).
Results
• A total of 233,624 images were taken during 1,411 encounters - 2,083
individuals were identified and catalogued.
• Of all individuals examined, 78% (n=1,624) displayed lesions and 0.5%
(n=11) exhibited deformities.
• Of all individuals with lesions and/or deformities, prevalence ranged
between 1–10 (mean=2.24, SE=0.03; Fig. 4).
• Most lesions were indentations & impressions (84.2%, n=1,368), whereas
raised & proliferative lesions were least observed (0.3%, n=5; Fig. 5).
• The highest percentage of lesions was observed on the anterior peduncle
(91.1%, n=1,118), whereas none were observed on the fluke.
• Cetaceans are subject to numerous natural pressures (e.g. inter- and intra-
specific interactions), in addition to anthropogenic threats (e.g. fisheries
interactions, commercial tourism, vessel strike and net entanglement) [1–
2].
• Photo-ID can be used to recognise distinct individuals and identify lesions
and deformities based on descriptive gross morphology (rather than
aetiology).
• For the first time, we examined the prevalence and type of lesions and
deformities recorded in common dolphins (Delphinus sp.) in the Hauraki
Gulf, New Zealand.
Conclusions
Fig. 3 Deformity categories
Fig. 4 Lesions/deformities per individual Fig. 5 Individuals per lesion type*
(*a-l as listed in Figure 2)
Literature Cited: [1] Bearzi, M., S. Rapoport, J. Chau, and C. Saylan. 2009. Skin lesions and physical deformities of coastal and offshore common bottlenose dolphins (Tursiops truncatus) in Santa Monica Bay and adjacent areas, California. Ambio 38:66–71; [2] Stockin, K. A., P. J. Duignan, W. D. Roe, L.
Meynier, M. Alley, and T. Fetterman. 2009. Causes of mortality in stranded common dolphins (Delphinus sp.) from New Zealand waters between 1998 and 2008. Pacific Conservation Biology 15:217–227; [3] Bardale, R. 2011. Principles of forensic medicine and toxicology. Jaypee Brothers Medical
Publishers, New Delhi, India. pp. 1–564; [4] Harrison, L. 2012. A standardised method for the comparison of skin lesions among bottlenose dolphin populations in coastal areas. BSc Thesis, Murdoch University, Perth, Australia. pp. 1–163; [5] Moore, K., and S. Barco. 2013. Handbook for recognizing,
evaluating, and documenting human interaction in stranded cetaceans and pinnipeds. National Oceanic and Atmospheric Administration Technical Memorandum, National Marine Fisheries Service, Southwest Fisheries Science Centre, NOAA-TM-NMFS-SWFSC-510, California, U.S.A. pp. 1–102; [6]
Luksenberg, J. 2014. Prevalence of external injuries in small cetaceans in Aruban waters, southern Caribbean. PLoS ONE 9:e88988. Acknowledgements: We thank Auckland Whale and Dolphin Safari and all research interns who have assisted with the data collection. Additional thanks to the Institute of
Natural and Mathematical Sciences, Massey University. Further Information: http://cmrg.massey.ac.nz
a) Deformed dorsal fin b) Spinal malformation
a) Scars b) Indentations & impressions
c) Cut-like Indentations d) Full thickness wounds*
e) Hyper-pigmented f) Hypo-pigmented
g) Targetoid h) Concentric rings
i) Tattoo-like j) Yellow/orange discolouration
k) Depressed & sunken l) Raised & proliferative
Fig. 2 Lesion categories (*only applies to the dorsal fin)
• A total of 78% of individuals exhibited lesions and deformities, highlighting
the natural and anthropogenic pressures faced by this population.
• Possible natural pressures included intra- or inter-specific interactions,
congenital malformations, environmental conditions and infectious origins.
• Possible anthropogenic pressures included fisheries/vessel interactions and
human induced environmental stressors.
n=203
n=1386
n=878
n=113
n=700
n=607
n=455
n=58
n=31
n=214
n=6 n=5
1
10
100
1000
10000
a b c d e f g h i j k l
Numberofindividuals
(logscale)
Lesion category
n=450
n=398
n=252
n=205
n=160
n=92
n=42
n=19 n=5 n=1
0
5
10
15
20
25
1 2 3 4 5 6 7 8 9 10
%ofindividuals
# Lesions and/or deformities