246 
THE CORAL TRIANGLE: HEARST BIODIVERSITY EXPEDITION 
400 
* 350 - 
I 3W - 
^ 250 - 
200 
150 
100 
50 
l.l J.2 1.3 1,4 1.5 
2.1 2.2 2.3 2.4 2.5 2.0 2.7 2 .^ 2.9 2.11) 
24-May-11 
T9-Nt>v-12 
Collection Date 
Figure 6: Longevity data from both groups of Amphioctopus marginatus 
collected in the Philippines. Black bars are 24 May 2011; grey bars are 19 
November 2012. Longevity was highly variable, but the second collection 
lived longer on average (206.3 + 116.0 days, as compared to 173.6 + 126.9 
days). So far, our longest-lived specimen (1.5) was 375 days post collection. 
of 126.9 days), while the animals 
from our seeond eolleetion lived 
an average of 206.3 days (± stan¬ 
dard deviation of 116.0 days). A 
t-test was performed on the data 
set, and there was no statistieal 
differenee between the longevity 
from the two eolleeting trips 
(independent samples, unequal 
varianee, p = 0.642). The longest 
lifespan that we witnessed at 
Steinhart Aquarium was 375 
days following eolleetion (speei- 
men 1.5, eolleeted May 24, 2011, 
death on June 2, 2012). 
Seneseenee was observed in 
both large and small animals and 
followed the general pattern seen 
in other oetopuses: lethargy, 
unwillingness to leave a den, spi¬ 
raling arm tips, dulling of skin 
eolor, refusal to feed. Like other speeies of small, warm-water oetopuses, it is likely that in the 
wild, A. marginatus grows very rapidly, is semelparous (breeds a single time), and then dies with¬ 
in 1 to 2 years (Wells and Wells 1977). 
Display Techniques. — Steinhart Aquarium at the California Aeademy of Seienees has been 
sueeessful in displaying Amphioctopus judged on the basis that (1) the animals are living to their 
presumed natural lifespan (> 1 year post eolleetion), and (2) we are aehieving positive edueation- 
al engagement with aquarium visitors. Guests are often erowded around the exhibit to observe the 
oetopus. Our displays are simple and are based on the environments where we eolleeted Amphioc¬ 
topus. They aeeurately represent the animals native habitat: soft, sandy substrate with a small 
amount of roek and stemmed algae, and ineluded various items to be utilized as dens. Periodieally 
we have added “toys”, sueh as legos, and plastie squid or oetopus figures, but none of the animals 
showed much interest in these items. 
Initially, the octopuses were given pvc fittings, flowerpots, and coconut shells to use as dens. 
The display of Amphioctopus was further enhanced by giving the animals clear glass bottles to use, 
so that they are visible even when they retreat into their dens. Steinhart Aquarium Senior Biologist 
Richard Ross created several hand-blown glass dens of different sizes and shapes. We have found 
that a den slightly larger than the octopus, with an inner fold (a lip of glass that projects inside the 
den) seems to be preferred by these animals (Fig. 7). These hand blown glass dens have also been 
used with other species of octopus (larger Pacific striped octopus, an undescribed species) with 
great success for both the animals and the viewing public. We are planning further research to 
determine what makes one type of artificial den more preferable to another. 
At Steinhart Aquarium, Amphioctopus were only displayed singly. Given the natural popula¬ 
tion density of these animals, research on displaying multiple animals in larger exhibits (750 liters 
or more) might yield interesting results, including successful mating or observations of other social 
behaviors. 
Captive Behavior. — Amphioctopus is a very visible display animal, usually nestled in some 
