244 
THE CORAL TRIANGLE: HEARST BIODIVERSITY EXPEDITION 
cally used as a scavenger to keep uneaten food from degrading water quality. Live algae, Cauler- 
pa prolifera (Lamouroux, 1809), was grown in the exhibit to assist with maintaining high water 
quality and guest visual interest. 
Feedlng. — At Steinhart Aquarium, Amphioctopus are fed live freshwater ghost shrimp 
enriched with CYCLOP-EEZE (Argent Chemical Laboratories, Redmond, WA, USA), live Cran- 
gon shrimp, frozen Crangon shrimp, locally collected crabs (Hemigrapsus spp.), and live Manila 
clams { Venerupis philippinarum). Crangon shrimp are commonly used as bait for recreational fish¬ 
ing, and are purchased from a fishing supply store. Manila clams are purchased from a restaurant 
seafood industry supplier. In the rare instances that live shrimp were not available, frozen prawn 
was accepted and eaten by the octopus. Food was often given in jars (see below) and inside wiffle 
balls as part of a fonnal behavioral enrichment program. 
Attempts to Acquire Specimens Through Commercial Sources. — As the animals 
from our May 2011 collecting trip began to get old and undergo senescence, we made several 
attempts to obtain replacement octopuses through the normal public aquarium channels of com¬ 
mercial collectors and suppliers. None of these attempts were successful. Instead of receiving 
Amphioctopus, we received several shipments of Abdophus or Macropus. The second author has 
experienced this trend for the last 10 years. We postulate that because octopus are rarely collected 
for the marine aquarium trade, it is very difficult to find collectors that can tell the difference 
between the various octopus species. Also, Amphioctopus occur in areas that are not often visited 
by commercial collectors, and most are unwilling to do special trips to selected areas for only one 
kind of animal as such trips are not cost effective. It is unknown Amphioctopus are target¬ 
ed or opportunistically caught in traps used by traditional fishers, or whether this method could be 
used to collect specimens without requiring SCUBA. 
On our November 2012 collecting trip, we invited a commercial collector working for Aquas- 
capes Philippines to join us on the expedition to learn how to identify the species, where to find it, 
and to learn appropriate collecting teclmiques. This was an attempt to create a reliable source for 
future acquisitions of Amphioctopus marginatus. The fishennan joined us on the boat, saw the col¬ 
lecting sites and snorkeled with us while we collected the specimens. Challenges here revolved 
around a language barrier (all communication was through a translator) and limited access to 
equipment (everything from SCUBA equipment and underwater flashlights to the plastic collect¬ 
ing jars). It remains to be seen whether or not this will be an effective strategy for future acquisi¬ 
tions of coconut octopus. 
Results and Discussion 
Collecting and Shipping. — On May 24, 2011, as part of the Hearst expedition, Steinhart 
Aquarium biologists collected a total of 14 specimens exhibiting a range of sizes from 0.75 cm to 
5.0 cm ML. During collection, three larger octopuses died of what we now call “rigor”: a stiffen¬ 
ing of arms and mantles. These thi*ee individuals were all larger animals. Two died almost imme¬ 
diately (before the collection dive was over). The third specimen was inactive but still alive when 
we returned to our holding area; this individual died during the night. 
The cause of this sudden mortality is unknown, but we postulate that this may be a “fear” 
reflex, and is perhaps a result of collecting larger animals without dens and placing them in clear 
plastic bags. An alternate explanation is that the larger specimens experienced a sudden decrease 
in water quality while enclosed in the plastic bags for the duration of the collecting dive. This rapid 
decrease in water quality could be caused by increased physiological activity resulting from the 
stress associated with collecting, or perhaps due to the animal inking in the bag. A drop in dissolved 
oxygen or an accumulation of carbon dioxide or ammonia could cause sudden mortality in the min- 
