171
10 Nautilus
successful reproduction may in fact be the sex ratio of nautiluses housed in one
system. It is unlikely that captive rearing of nautiluses is a viable process, so close
monitoring of wild populations and fishing limits are critical to their survival.
10.6 Disease and Anesthesia
Successful maintenance of captive cephalopods depends primarily on excellent water quality but also on constant monitoring (Oestmann et al. 1997). While physical
signs of health deterioration should be monitored, behavioral abnormalities may
be more telling of health problems. Nautilus disease is not very well understood
for a myriad of reasons. Most often, it is difficult to detect the problem before it
is terminal and the specimen has expired. However, there are several common reports of health abnormalities. Perhaps the most common are the problems regulating
buoyancy. Positive buoyancy occurs in many specimens received from the wild;
however, the best treatment regimen appears to be the “sit and wait” approach. Most
specimens with positive buoyancy resolve the problem on their own. Animals with
positive buoyancy do not seem to suffer any other ill effects, at least in captive populations. Cases of negative buoyancy are less common and even less understood. One
case of negative buoyancy in the literature correlated the condition with a severe
bacterial infection and a parasitic infestation; however, the treatments were not successful and the specimen expired (Barord and Henderson 2008). Mucodegeneration
is perhaps the most common infection in captive nautiluses that appears to be the
result of an internal bacterial infection that manifests as significant mucus production around the eyes and tentacles. All reports of this disease had shown it to be fatal
until a recent treatment regime of oxytetracycline and iodine on a single N� pompilius (Barord et al. 2012). Fungal infestations have been reported, and in one case,
the fungus was identified as a Fusarium sp. (Scimeca 2006) though no treatment
was employed. Anesthetic use in nautiluses is necessary for certain veterinary procedures, such as hemolymph withdrawal, and may also be necessary for specific research methods. Urethane was commonly used as a nautilus anesthetic (Ward et al.
1977) though its inherent carcinogenic effects render this method not viable. Recent
trials with ethanol have proven it to be effective in inducing anesthesia for both hemolymph withdrawals and radiographic procedures (Barord and Henderson 2008).
10.7 Conclusions
The large-scale, continuous process of nautilus culture systems does not appear to be
feasible at this point. The proxies for captive mating, reproduction, egg laying, egg
development, and hatchling survival are not well understood. Therefore, it is difficult
to understand what methods should be modified for future success. However, given
the declining populations in several areas of the Indo-Pacific (del Norte-Campos
2005; Dunstan et al. 2010; Dunstan et al. 2011c; De Angelis 2012) and that most of
10 Nautilus
successful reproduction may in fact be the sex ratio of nautiluses housed in one
system. It is unlikely that captive rearing of nautiluses is a viable process, so close
monitoring of wild populations and fishing limits are critical to their survival.
10.6 Disease and Anesthesia
Successful maintenance of captive cephalopods depends primarily on excellent water quality but also on constant monitoring (Oestmann et al. 1997). While physical
signs of health deterioration should be monitored, behavioral abnormalities may
be more telling of health problems. Nautilus disease is not very well understood
for a myriad of reasons. Most often, it is difficult to detect the problem before it
is terminal and the specimen has expired. However, there are several common reports of health abnormalities. Perhaps the most common are the problems regulating
buoyancy. Positive buoyancy occurs in many specimens received from the wild;
however, the best treatment regimen appears to be the “sit and wait” approach. Most
specimens with positive buoyancy resolve the problem on their own. Animals with
positive buoyancy do not seem to suffer any other ill effects, at least in captive populations. Cases of negative buoyancy are less common and even less understood. One
case of negative buoyancy in the literature correlated the condition with a severe
bacterial infection and a parasitic infestation; however, the treatments were not successful and the specimen expired (Barord and Henderson 2008). Mucodegeneration
is perhaps the most common infection in captive nautiluses that appears to be the
result of an internal bacterial infection that manifests as significant mucus production around the eyes and tentacles. All reports of this disease had shown it to be fatal
until a recent treatment regime of oxytetracycline and iodine on a single N� pompilius (Barord et al. 2012). Fungal infestations have been reported, and in one case,
the fungus was identified as a Fusarium sp. (Scimeca 2006) though no treatment
was employed. Anesthetic use in nautiluses is necessary for certain veterinary procedures, such as hemolymph withdrawal, and may also be necessary for specific research methods. Urethane was commonly used as a nautilus anesthetic (Ward et al.
1977) though its inherent carcinogenic effects render this method not viable. Recent
trials with ethanol have proven it to be effective in inducing anesthesia for both hemolymph withdrawals and radiographic procedures (Barord and Henderson 2008).
10.7 Conclusions
The large-scale, continuous process of nautilus culture systems does not appear to be
feasible at this point. The proxies for captive mating, reproduction, egg laying, egg
development, and hatchling survival are not well understood. Therefore, it is difficult
to understand what methods should be modified for future success. However, given
the declining populations in several areas of the Indo-Pacific (del Norte-Campos
2005; Dunstan et al. 2010; Dunstan et al. 2011c; De Angelis 2012) and that most of