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Captive Pinniped Eye Problems, We Can do Better!

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Captive Pinniped Eye Problems, We Can do Better!

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While many advances have been made in husbandry practices, nutrition, medicine, and life support system designs for marine mammals, a large percentage of captive pinnipeds still suffer from ocular conditions such as corneal disease, premature cataracts, and lens luxations (1,2,3). (Figures 1 and 2) Recent studies have identified a number of causative factors for this including some that can be corrected in captive settings such as exhibit designs, water quality and water additives (2,3). The environmental challenges that are imposed on captive pinnipeds as compared to those living in the wild must always be considered. Wild pinnipeds swim and dive in oceans and bays to capture their prey. The sandy ocean floor is relatively non-reflective, especially as the animals move to deeper water, so diving mammals do not experience significant light reflected from the bottom back into their eyes. Wild pinnipeds
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Captive Pinniped Eye Problems, We Can do Better!
Laurie J. Gage, DVM, Dipl ACZM
1
1
Big Cat and Marine Mammal Specialist USDA APHIS Animal Care Center for Animal Welfare
While many advances have been made in
husbandry practices, nutrition, medicine, and life support
system designs for marine mammals, a large percentage
of captive pinnipeds still suffer from ocular conditions
such as corneal disease, premature cataracts, and lens
luxations (1,2,3). (Figures 1 and 2) Recent studies have
identified a number of causative factors for this
including some that can be corrected in captive settings
such as exhibit designs, water quality and water
additives (2,3).
The environmental challenges that are imposed
on captive pinnipeds as compared to those living in the
wild must always be considered. Wild pinnipeds swim
and dive in oceans and bays to capture their prey. The
sandy ocean floor is relatively non-reflective, especially
as the animals move to deeper water, so diving
mammals do not experience significant light reflected
from the bottom back into their eyes. Wild pinnipeds
Received December 9, 2011; Accepted December 31, 2011
Correspondence: Laurie J. Gage
Phone: 707-251-5523
Email: Laurie.J.Gage@aphis.usda.gov
Journal of Marine Animals and Their Ecology
Copyright © 2008 Oceanographic Environmental Research Society
Vol 4, No 2, 2011
Printed in Canada
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Invited Commentary
Figure 1 - Moderate corneal opacity in a California sea lion. Many
captive pinnipeds develop mild to severe corneal lesions,
subluxated lenses and cataracts as a result of chronic exposure to
excessive oxidants, UV light or both.
Figure 2 - More severe corneal pathology in a sea lion likely
caused by exposure to excessive oxidants in the water. This animal
was exposed for years to city water with chlorine levels exceeding
2.5 PPM.
rarely have access to shade in their environment nor do
they seek it. When on land they spend most of their time
interacting with other animals or sleeping or resting
with their eyes closed. They have little reason to gaze
skyward. However, captive pinnipeds are frequently
housed in pools painted a light blue color which is very
effective at reflecting most of the UV light energy back
towards the animals as they dive and swim. As well,
captive pinnipeds are often housed in deep grottos or
pools where they must look up frequently to see out of
the exhibit or to catch fish (Figure 3). When keepers,
trainers, or members of the public feed the animals they
may inadvertently force the animals to look directly into
the sun to get their fish reward. These conditions may
cause damage to the eyes of captive pinnipeds because
they are forced to be exposed to far more UV light than
their wild counterparts. This is supported by studies
such as a recent publication that identified pinnipeds
with no access to shade were 10 times more likely to
develop cataracts or lens luxations (2). In another 6-year
study conducted on captive otariids, keratitis or
keratopathy was identified in 142 eyes of 113 sea lions
(62.8%) (1).
A surprising percentage (21% ) of young
animals under the age of 10 years were affected.
Further supporting the premise that UV light is a key
causative factor, flare-ups occurred primarily during
seasons when the sunlight exposure increased or became
more intense. Flare-ups were also seen in northern
latitudes in the winter on bright sunny days when snow
was continuously on the ground. Interestingly, animals
housed indoors had less severe corneal disease for their
age and fewer flare-ups of keratitis. Clearly, exhibit
design issues such as pools and surrounding colors that
are overly reflective coupled with a lack of shade are
critical to eye health issues.
byproducts formed by the combination of organic mate-
rials with oxidants added to purify the water may cause
or contribute to pinniped eye disease (1,5).
Most ma-
rine mammal water quality experts make every effort to
maintain total chlorine levels below 1 PPM in marine
mammal pools. In less sophisticated systems the chlo-
rine levels may frequently spike above 1 PPM. Some
pools are filled with fresh municipal water where the
total chlorine frequently exceeds 2.5 PPM. In some in-
stances 100% of the pinnipeds housed in these pools
suffer from obvious corneal damage (personal observa-
tion, Figures 1 and 2).
Bromine used either as the primary disinfectant or
by its presence in source water may combine with or-
ganic material to form many undesirable byproducts.
The noxious byproducts of these compounds such as
halogenated methanes (chloroform, bromoform,
bromodichloromethane or dibromochloromethane) are
often overlooked and rarely measured (5). These
compounds have been shown to be toxic to liver and
kidney cells. The mechanism of toxicity involves the
initial oxidation by the cytochrome p450 enzyme
systems which are present in ocular tissues at about 5%
of the concentration in liver cells (4). These enzyme
systems will begin the breakdown of drugs or toxins
present in ocular tissues thereby producing free radicals,
peroxide, or other intermediates in the process.
Antioxidants are important in managing these damaging
intermediates. Ozone is a powerful oxidant and a popu-
lar disinfectant for marine mammal life support systems.
If residual ozone enters the animal pools it may cause
eye discomfort or damage. Animals exposed to residual
ozone in the pools will exhibit epiphora and blepharo-
spasm (Personal observation). If animals are exhibiting
eye discomfort and the life support system staff can rule
out chlorine or other oxidant spikes, ozone may be the
cause. Ozone test kits are commercially available and
inexpensive. Some kits simply measure the presence of
ozone in the pool water with a test involving a color
change. Efforts should be made to ensure ozone is not
present in the water where the animals live.
It has long been thought that housing pinnipeds in
fresh water would certainly contribute to eye damage.
However, I have not found this to be true in all cases.
For example, I have observed sea lions housed in one
northern latitude fresh water exhibit where the pool was
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Vol 4, No 2, 2011
Printed in Canada
Figure 3 - Pinnipeds held in captive situations are often fed from
above their pools by the staff or by the public, forcing them to look
skyward far more frequently than their wild counterparts.
Water quality issues may also play a causative role
in pinniped ocular disease, therefore water quality in
pinniped pools is important to eye health (3). While it is
important to maintain clean water for the animals living
in captive situations, the use of excessive oxidants to
sterilize the water may in turn be harmful to the eyes of
the animals living in those pools. Chlorine or bromine
may cause corneal damage themselves. In the more so-
phisticated life support systems these chemicals are care-
fully monitored, however oxidant spikes may still occur.
Spikes in oxidant levels or exposure to noxious chemical
Captive Pinniped Eye Problems
JMATE
exhibit and back areas. They have elaborate filtration
systems with sophisticated monitoring of chemicals to
prevent oxidant spikes in the water. The addition of oxi-
dants to the pool must be carefully monitored and
chemical or oxidant spikes quickly mitigated in animal
pools. Levels of chlorine in city water should be meas-
ured and when elevated above 1 PPM, the water should
be treated with sodium thiosulfate or allowed time in
open holding tanks for the chlorine to dissipate to reduce
the amount of chlorine entering animal pools. Including
daily antioxidants known to protect ocular tissue such as
carotenoids, lutein and zeaxanthin, in the diet may help
to prevent or minimize damage to ocular tissues (2,3).
These improvements will allow pinnipeds with existing
eye disease to be more comfortable and may be instru-
mental in preventing painful or premature eye disease in
the next generation of captive pinnipeds.
To sum up, pinnipeds housed in captive settings
are dependent on the choices we make for them. They
have no choice of the color of their surroundings or the
depth or size of their pools. We select the food they eat
and the manner in which it is distributed to them. We
have a responsibility to ensure their diet is wholesome
and their environment is appropriate. The choices we
make for housing and feeding these animals should be
based on what is optimal for their needs, and should not
contribute to, or cause pain or discomfort. Ocular
disease in captive pinnipeds is commonplace but I
believe it is preventable if they were provided with more
natural (and less reflective) pools and surroundings,
strategic areas of shade, clean water without excessive
oxidants or other irritating byproducts, appropriate
feeding practices, and wholesome diets that include
protective anti-oxidants.
When we commit to housing and exhibiting wild
animals in captive settings we should commit to doing it
properly or not do it at all.
References
1. Colitz CMH, Renner MS, Manire CA, Doescher B
et al. Characterization of progressive keratitis in
otariids. Vet Ophthalmol 13:47-53, 2010.
2. Colitz CMH, Saville WJA, Renner MS, McBain
JF et al. Epidemiological survey of risk factors
associated with cataracts and lens luxations in
captive pinnipeds in the United States and the
27
painted black (non-reflective) and the source water was a
constant flow from an underground fresh water aquifer.
No chemicals were added to the water, and none of the
animals exhibited corneal lesions. In contrast, at a more
southern latitude facility, the animals were housed in
natural salt water with no chemicals added but the pools
were painted a light blue color (very reflective) and
many of these pinnipeds had evidence of corneal damage.
What can we do to solve these problems?
For years most pinniped exhibits have been
painted a light blue color. While the color does allow
the darker-colored animals to be more easily seen by the
public, it has considerable drawbacks. Substantial
evidence is mounting to support the notion that these
light blue pools cause or exacerbate ocular damage.
Underwater UV light meters have been employed in
some instances in an effort to quantify the amount of UV
light reflected from the pool and exhibit walls. “Google
Earth” offers an opportunity to view facility pools and
subjectively assess the amount of visible light reflected
from the animal pools and beamed back to space.
Rough comparisons of the reflective properties of pool
color on visible light may be made this way between
facility exhibits and also at different institutions and
may aid in the decision of what colors for exhibits and
pools will afford the animals the most ocular comfort.
When exhibits are designed or refurbished, ensure that
pools and surrounding areas are coated or painted with
colors that are not considered UV or light-reflective such
as earth tones. The addition of shade in parts of the
exhibit or holding pools will also reduce the amount of
UV light reflected into the eyes of the resident
pinnipeds. Trainers and keepers should be aware of their
position when attending to the animals and never force
an animal to look directly towards the sun when it is be-
ing fed or trained. At facilities where the public feeding
of the animals is allowed, position shade structures be-
hind the public or designate feeding areas for the public
to stand at different times of the day to prevent the ani-
mals from being forced to look directly towards the sun
while being fed. A number of zoos and aquariums have
already refurbished their exhibits or have built new ones
that utilize earth tone colors for the pools and surround-
ings and have provided shade in some areas of the
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Bahamas. J Am Vet Med Assoc 237:429-436, 2010.
3. Gage, LJ. Ocular disease and suspected causes in
captive pinnipeds. In Fowler, ME, Miller, RE,
editors: Zoo and wild animal medicine. 7th Edition.
St. Louis, 2011, Elsevier. pp. 490-494.
4. Forrester J.V., A.D. Dick, P.G. McMenamin, W.R.
Lee. 2002. The Eye: Basic Sciences in Practice,
2nd Edition. Elsevier Health Sciences.
5. Latson, E., Byproducts of disinfection of water
and potential mechanisms of ocular injury in
marine mammals. What you can’t see might
hurt them, in Proceedings. 40th Ann. Meeting
International Association Aquatic Animal
Medicine 2009: pp. 186-188.
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Captive Pinniped Eye Problems
... Eye diseases are quite common in pinnipeds, both in wild or under human care population [1][2][3][4]. Among the ocular disorders more frequent in these marine mammals there are certainly those of the cornea, with a wide range of clinical presentations from keratitis localized and not complicated to more or less deep or infected ulcers [5,6]. Corneal alterations in pinnipeds, as in other animal species, can be cause of severe pain and the intensity of discomfort can vary in the affected subjects. ...
... The results confirmed the literature [1][2][3][4]. Comparing with other authors [5], a lower incidence of the phenomenon in our population resulted (46.6% versus 64.6% of individuals affected), but it is important to consider how in her study, Colitzalso includes individuals with localized corneal opacities and signs of ocular discomfort but without ulceration. The prevalence of bilateral presentations was high (34 of 76 episodes). ...
... It can cause a thickening of the cornea such as to alter the perception of the real depth of the lesionand, at times, a certain degree of conjunctival pigmentation with extension in the cornea can be present. Mostly in these species the vascularization is necessary for the resolution of deeper lesions to avoid delayed or and stunted healings (Figure 1c) [5]. The cornea ulcers therapy includes topical antibiotics in the form of eyedrops. ...
Article
Full-text available
Background: Despite limited information, topical drug combinations are being routinely used for the treatment keratitis in pinnipeds.Corneal alterations in pinnipeds, as in other animal species, can be cause of severe pain and the intensity of discomfort can vary in the affected subjects. Late diagnosis or untimely treatment can lead to dramatic developments even in case of minor corneal diseases, with sometimes disastrous consequences for the globe up to loss of vision. Methods: During five years a small population of different species, age and sex, kept under human care, was submitted to a complete daily ophthalmological evaluation and to a treatment when necessary. Results: The ulcerative keratitis was a relatively frequent pathology (seven of 15 subjects for a total of 76 episodes). Six of 7 patients (85.7%) showed lesions simultaneously in both eyes at least once. The average time elapsing between the ulcer diagnosis and the healing of the same was about 32 days (σ=±18 days) with a minimum of 3 and a maximum of 74 days. In cases where the therapy has been conducted, the onset ulcer until its resolution, with the same drug (n = 6), were obtained average values of 28.6 days (σ=±17.07 days) in the case of netilmicin, 27.5 days (σ=±6.56 days) for tobramycin, and 41.95 days (σ=±9.69 days) for gentamycin. The difference between these values was statistically not significant (p = 0.9) for netilmicin and tobramycin while for the group treated only with gentamycin, the difference was detected statistically significant compared with netilmicin and tobramycin (p=0.048 and p=0.042 respectively). In two cases (n=2) it was considered necessary to associate local therapy with systemic therapy using doxycycline and non-steroidal anti-inflammatory drugs. In these cases the resolution has taken place in 31 days (σ=±16.65 days). In four cases (n=4) autologous plasma has been added to local therapy. In eleven cases (n=7) it was necessary to use local osmotic agents (sodium chloride 5%, glucose 35%) to solve the edema. Conclusions:Due to the anatomical and physiological characteristics of the pinnipeds eye, the best medical treatment for corneal lesions in our experience was the use of antibiotic collyrium associated with hyperosmotic solution in case of edema and platelet rich plasma (PRP) to support the healing, considering an administration frequency 3-4 times/day at least. Keywords: Pinnipeds, ulcerative keratitis, incidence, management, Shapiro-Wilk test
... Another pressing health topic is ocular health; eye conditions are prevalent in sea lions and seals, are known to cause function loss and pain, and are considered a welfare issue that needs urgent attention (Colitz et al., 2010;Gage, 2011). Research on eye problems reports that a large percentage of captive pinnipeds suffer from ocular conditions, such as corneal disease, premature cataracts, and lens luxations (Colitz et al., 2010;Gage, 2011). ...
... Another pressing health topic is ocular health; eye conditions are prevalent in sea lions and seals, are known to cause function loss and pain, and are considered a welfare issue that needs urgent attention (Colitz et al., 2010;Gage, 2011). Research on eye problems reports that a large percentage of captive pinnipeds suffer from ocular conditions, such as corneal disease, premature cataracts, and lens luxations (Colitz et al., 2010;Gage, 2011). Causative factors such as exhibit design, water quality and water additives, and suggestions on how to correct them can be found in these papers and related references. ...
... Causative factors such as exhibit design, water quality and water additives, and suggestions on how to correct them can be found in these papers and related references. Access to UVprotective shade should be readily available and the preferred colour of the pool should be earth tones, tan or brown colours to avoid glare and reflections (Colitz et al., 2010;Gage 2011). Suggestions on feeding and training during sunny conditions are also offered, such as not throwing the fish while animals stare up into the sun (Gage 2011). ...
Article
Marine mammals include cetaceans, pinnipeds, sirenians, sea otters and polar bears, many of which are charismatic and popular species commonly kept under human care in zoos and aquaria. However, in comparison with their fully terrestrial counterparts their welfare has been less intensively studied, and their partial or full reliance on the aquatic environment leads to unique welfare challenges. In this paper we attempt to collate and review the research undertaken thus far on marine mammal welfare, and identify the most important gaps in knowledge. We use 'best practice case studies' to highlight examples of research promoting optimal welfare, include suggestions for future directions of research efforts, and make recommendations to strive for optimal welfare, where it is currently lacking, above and beyond minimum legislation and guidelines. Our review of the current literature shows that recently there have been positive forward strides in marine mammal welfare assessment, but fundamental research is still required to validate positive and negative indicators of welfare in marine mammals. Across all marine mammals, more research is required on the dimensions and complexity of pools and land areas necessary for optimal welfare, and the impact of staff absence for most of the 24-hour day, as standard working hours are usually between 0900-1700.
... The design of current and future marine mammal pools, including characteristics and surroundings, as well as water quality and additives, needs attention. Recent research on eye problems report that a large percentage of captive pinnipeds still suffer from ocular conditions such as corneal disease, premature cataracts, and lens luxations (Colitz et al., 2010b;Gage, 2011). Causative factors such as exhibit designs, water quality and water additives, and suggestions on how to correct them can be found in these papers and related references. ...
... Causative factors such as exhibit designs, water quality and water additives, and suggestions on how to correct them can be found in these papers and related references. Access to UV-protective shade should be readily available, and the preferred color of the pool should be earth tones-tan or brown colors -to avoid glare and reflections (Colitz et al., 2010b;Gage, 2011). Suggestions on feeding and training during sunny conditions are also offered (Gage, 2011). ...
... Access to UV-protective shade should be readily available, and the preferred color of the pool should be earth tones-tan or brown colors -to avoid glare and reflections (Colitz et al., 2010b;Gage, 2011). Suggestions on feeding and training during sunny conditions are also offered (Gage, 2011). ...
Article
In 2012, two marine mammal welfare and well-being workshops were held: one from 19-21 March 2012 at the Harderwijk Dolfinarium in the Netherlands, and the other from 9-11 November 2012 at Hubbs-SeaWorld Research Institute in San Diego, California. Well over 150 international participants attended, from Europe as well as North America. Herein, we present a summary of the presentations. The aim of the workshops was to discuss topics relevant to marine mammal welfare and well-being from a holistic perspective, including training, enrichment, nutrition, habitat choice, social behavior, anatomy and physiology, acoustics, and cognition. Presenters were asked to apply knowledge and information gained from research on wild and captive animals in order to strengthen, improve, and build on existing marine mammal care programs. Many of these topics require more research for us to make evidence-based decisions on animal needs and preferences-what promotes the reduction of negative welfare and/or what in-creases positive welfare and well-being.
... Ocular diseases in marine mammals, such as pinnipeds, are often caused by water-related and environmental factors. 21,22 Water quality, including abnormal dissolved oxygen, carbon dioxide, ammonia, nitrate, nitrite, water pH levels, and water additives, as well as exhibit design F I G U R E 5 A histologic image of a normal giant Pacific octopus eye. The ciliary papillae (black arrow) with its attachment to the lens can be appreciated. ...
... and excessive sunlight have a major impact on marine species welfare, and have been reported to cause keratitis and cataracts in otariids. [21][22][23][24] Chlorine, which was not specifically measured in any of the three octopuses' water systems, is a known cause of "cloudy eyes" in fish due to corneal edema secondary to corneal epithelial damage. 25 Also, ozonated artificial seawater systems can cause alternations to specific substances in the water. ...
Article
Purpose: Review octopus ocular anatomy and describe the histopathologic findings in three octopuses diagnosed with phakitis and retinitis. Animals: Two common octopuses (Octopus vulgaris) and one giant Pacific octopus (Enteroctopus dofleini) with a history of ophthalmic disease. Methods: A literature search was performed for the ocular anatomy section. Both eyes from all three octopuses, and two control eyes, were submitted for histopathologic evaluation. Hematoxylin and eosin stain was used for standard histopathologic evaluation; GMS stain was used to screen for fungi, gram stain for bacteria; and Fite's acid fast stain for acid fast bacteria. Results: Anatomically, the anterior chamber of the octopus has direct contact with ambient water due to an opening in the dorsal aspect of a pseudocornea. The octopus lens is divided into anterior and posterior segments. The anterior half is exposed to the environment through the opening into the anterior chamber. Neither part of the lens has a lens capsule. The retina is everted, unlike the inverted vertebrate retina, and consists of just two layers. Histopathology revealed inflammatory phakitis and retinitis of varying severity in all six eyes of the study animals. No intraocular infectious organisms were recognized but one common octopus eye had clusters of coccidian parasites, identified as Aggregata sp., in extraocular tissues and blood vessels. Conclusion: We describe inflammatory phakitis and retinitis in two species of octopuses. The underlying cause for the severe intraocular response may be direct intraocular infection, water quality, an ocular manifestation of a systemic disease, or natural senescence.
... Today many different species of marine mammals are trained using positive reinforcement techniques to enable the animals to collaborate in their own daily care, (for example the treatment of health issues such as sea lions and seals trained to accept eye drops to treat cataracts: Colitz et al. 2010;Gage 2011), in research, education and conservation programmes (for a review see Kuczaj and Xitco 2002;Brando 2010). Initially the training of marine mammals was motivated by the entertainment industry to present animals performing and participating in movies and TV series. ...
... However, APHIS should establish a minimum requirement to provide substrate that is colored to minimize heat stress, particularly during summer months. Highly reflective surfaces are also a problem for ocular health in pinnipeds (Colitz et al. 2010;Gage 2011); therefore, requiring less reflective surfaces for temperature control would address two significant health concerns simultaneously. ...
Chapter
A recent increase in collaborative and independent studies on sea lions, seals and walruses has advanced our knowledge and interest in pinniped welfare. Nevertheless published discussions of the welfare of pinnipeds, and secondly of potential measures to assess their welfare, are, respectively, very few and non-existent. This chapter aims to make first steps in the discussion on assessing pinniped welfare, with the goal of stimulating future welfare investigations. Pinniped species are able to thrive in two opposing environments, the land/ice margin at the coast and in the sea, and these animals use these two ‘domains’ for different functions. Welfare measurement is concerned with the outcome of an animal’s internal and external responses to its environment, and pinniped species’ evolutionary biology may be especially important in this respect, in terms of our understanding of the animals’ responses and interactions within their two domains. Pinnipeds are being directly impacted by serious anthropogenic disturbances in the wild, including human interference at established feeding and breeding grounds, hunting, entanglement and climate change, and are also often kept in captive collections. Feasible evaluations of welfare can therefore be assumed to have potential widespread utility, including applications benefitting the animals themselves.
Article
To characterize a form of progressive keratitis that occurs commonly in otariids. One hundred and thirteen captive otariids were evaluated by ophthalmologic examination and digital photography. Forty-six females and 67 males were in the reference population, average age of 14 years. California sea lions predominated (n = 100); there were also six Steller sea lions, five brown fur seals, one Guadalupe fur seal and one northern fur seal. Three stages of progressive keratitis are described. Overall, 64.6% animals and 142 eyes from 113 animals (62.8%) were affected with one of three stages. The mildest form, Stage 1 keratitis, occurred in 78 of 226 eyes (34.5%); the intermediate Stage 2 keratitis occurred in 30 of 226 eyes (13.3%); and the most severe, Stage 3 keratitis, occurred in 34 of 226 eyes (15%). All but six animals had bilateral disease. Animals with Stage 1 keratitis were significantly younger than those in more advanced stages. 'Otariid Keratitis' occurs in all populations of eared seals evaluated. A large-scale epidemiological study is ongoing to identify the risk factors that contribute to this disease. Exposure to chronic sunlight appears to be an important risk factor as shade diminishes clinical signs; animals kept out of sunlight the majority of the time have less severe clinical signs. Age may be important since exposure accumulates with aging. Progression of the disease is also associated with secondary opportunistic bacterial and fungal infections. The surface immune system may be imbalanced contributing to these infections and progression.
Byproducts of disinfection of water and potential mechanisms of ocular injury in marine mammals. What you can't see might hurt them
  • E Latson
Latson, E., Byproducts of disinfection of water and potential mechanisms of ocular injury in marine mammals. What you can't see might hurt them, in Proceedings. 40th Ann. Meeting International Association Aquatic Animal Medicine 2009: pp. 186-188.