169
10 Nautilus
10.4.2 Water
All cephalopods, including nautiluses, require excellent water quality. The epidermis
of cephalopods is made up of microvilli that facilitate the uptake of contaminants in
their surrounding seawater environment. Nautiluses accumulate trace elements in the
wild (Bustamante et al. 2000; Pernice et al. 2009) and are thus susceptible to toxic
elements in captive conditions. Water quality can be maintained through the use of
strong mechanical, biological, and chemical filtration. The principal parameters to
monitor are levels of nitrogenous waste which should be kept between accepted ranges of < 0.10 mg L
−1
ammonia, < 0.10 mg L
−1
nitrite, and < 20.00 mg L
−1
nitrate (Spotte
1979). However, these parameters can and should be maintained near 0.00 mg L
−1
using adequate filtration methods and consistent water changes. In closed systems,
UV scrubbers should be used, as they remove many key bacteria that can cause serious health problems in nautiluses. Nautiluses are sensitive to warm temperatures, so a
chilling unit must be installed on the system to maintain temperatures between 15 and
27 °C. Specimens housed in 28 °C for 4 h have shown poor survival (Carlson 1987).
In some cases, a rhythmic day/night temperature cycle has been set on aquariums so
that the temperature changes throughout the day, from 18 to 21 °C (Carlson 1987), to
mimic normal migration patterns in the wild. The use of supplements, such as calcium
carbonate and magnesium, has been applied in some systems but there do not appear
to be any data to support positive effects in nautiluses. The pH should be maintained
at 8.20 through the use of a buffering system or effective water changes. Nautiluses
are stenohaline, requiring a small salinity range which should be maintained between
34 and 36 psu (Boyle 1991). When moving nautiluses (for experiments or to another
tank, etc.), it is important to keep them submerged in water during transit. Nautiluses
are susceptible to mantle infections with repeated exposure to air.
10.4.3 Housing
There is little information to suggest the proper size, shape, and stocking densities
of captive nautiluses. However, based upon the vertical migrations of wild nautiluses, nautilus-holding systems should be higher rather than wider to support the
vertical movements, as shown in Fig. 10.2. Adding texture to the wall of the tank
will make it more attractive to the animal. The average life span of nautiluses in
captivity is approximately 3 years though there are occasions of nautiluses living
5–6 years in captivity (Carlson 1987).
10.4.4 Feeding
The gut content from wild nautiluses contains many different prey items, including fish and crustaceans, and crustacean molt shells (Ward and Wickstein 1980).
10 Nautilus
10.4.2 Water
All cephalopods, including nautiluses, require excellent water quality. The epidermis
of cephalopods is made up of microvilli that facilitate the uptake of contaminants in
their surrounding seawater environment. Nautiluses accumulate trace elements in the
wild (Bustamante et al. 2000; Pernice et al. 2009) and are thus susceptible to toxic
elements in captive conditions. Water quality can be maintained through the use of
strong mechanical, biological, and chemical filtration. The principal parameters to
monitor are levels of nitrogenous waste which should be kept between accepted ranges of < 0.10 mg L
−1
ammonia, < 0.10 mg L
−1
nitrite, and < 20.00 mg L
−1
nitrate (Spotte
1979). However, these parameters can and should be maintained near 0.00 mg L
−1
using adequate filtration methods and consistent water changes. In closed systems,
UV scrubbers should be used, as they remove many key bacteria that can cause serious health problems in nautiluses. Nautiluses are sensitive to warm temperatures, so a
chilling unit must be installed on the system to maintain temperatures between 15 and
27 °C. Specimens housed in 28 °C for 4 h have shown poor survival (Carlson 1987).
In some cases, a rhythmic day/night temperature cycle has been set on aquariums so
that the temperature changes throughout the day, from 18 to 21 °C (Carlson 1987), to
mimic normal migration patterns in the wild. The use of supplements, such as calcium
carbonate and magnesium, has been applied in some systems but there do not appear
to be any data to support positive effects in nautiluses. The pH should be maintained
at 8.20 through the use of a buffering system or effective water changes. Nautiluses
are stenohaline, requiring a small salinity range which should be maintained between
34 and 36 psu (Boyle 1991). When moving nautiluses (for experiments or to another
tank, etc.), it is important to keep them submerged in water during transit. Nautiluses
are susceptible to mantle infections with repeated exposure to air.
10.4.3 Housing
There is little information to suggest the proper size, shape, and stocking densities
of captive nautiluses. However, based upon the vertical migrations of wild nautiluses, nautilus-holding systems should be higher rather than wider to support the
vertical movements, as shown in Fig. 10.2. Adding texture to the wall of the tank
will make it more attractive to the animal. The average life span of nautiluses in
captivity is approximately 3 years though there are occasions of nautiluses living
5–6 years in captivity (Carlson 1987).
10.4.4 Feeding
The gut content from wild nautiluses contains many different prey items, including fish and crustaceans, and crustacean molt shells (Ward and Wickstein 1980).