238 



GARTH, HAIG, AND KNUDSEN 



The windward algal ridge receives the largest waves 

 which supersaturate incoming water with oxygen. Algae 

 grow here in a profusion of species and mass. Initially we 

 used pry bars to loosen slabs from the algal ridge. These 

 were placed in plastic bags or buckets while another team 

 member attempted to secure all free decapods. Slabs were 

 carried to the nearest island for cracking and collecting of 

 decapods. Subsequently, a rigid, heavy-welded pip>c crack- 

 ing table with a car-decking top was designed and built for 

 the purpose of cracking coral or slabs at any site including 

 the algal ridge (Fig. 1). Buckets, hammers, and other 

 equipment were secured to the table. A marker allowed 

 note taking (even under water), so station numbers were 

 issued and recorded as needed. Naturally someone held 

 the table when very large waves were running. The yield 

 of species was dramatically increased by the use of the 

 cracking table. 



Illuminated by a Coleman lantern, the reef-flat and algal 

 ridge were also collected at night with excellent success. 

 The algal ridge off Enewetak Island was also collected dur- 

 ing waveless doldrums — until two large tsunamic waves 

 came shoreward, throwing Knudsen 30 feet back onto the 

 reef flat. 



Small amounts of formaldehyde were applied full 

 strength to the reef flat at low-low tide. The preservative 

 diluted in patches of water and entered worm burrows, 

 evicting numerous decapods which otherwise would have 

 been impossible to collect. Behind the reef flat, formal- 



dehyde was injected 6 inches deep in coral rubble. Soon 

 afterwards, decapods that resembled chips of coral worked 

 up to the surface and were captured with a guppy net. 



On our first trip, we snorkeled every day and averaged 

 about 5 to 10 miles of swimming per day in local areas. 

 Always new corals or new formations, new wave patterns, 

 reef drainage currents, etc., provided new records. Plastic 

 bags were placed over corals or crinoids, and the coral 

 and/or crinoid was removed with decapod species intact. 

 The author was towed by our slow moving outboard skiff 

 to survey miles of lagoon margin. A hand signal meant 

 new coral formation — or possible shark attack. We 

 snorkeled down to about 60 feet in quest of some crinoids 

 and corals. 



Collecting was successfully attempted with a dredge 

 built and outfitted at Pacific Lutheran University (PLU). 

 We used the dredge, powered by a skiff, in shallow water 

 (to 30 feet). In deep)er lagoon water, we used an M-boat in 

 reverse, with the dredge ropw and buoy ready to go over- 

 board when fouled. Markers placed and recorded to allow 

 work to continue the next day were never found again. 

 However, many rare and some new records of crabs were 

 worth the effort. A cable and winch, as opposed to pulling 

 the cable by hand, would have greatly facilitated lagoon 

 studies. 



Islands possessed many species of decapods on land 

 and even in trees. Since islands are scattered around much 

 of the reef, and refracting waves strike islands differently, 



f^ 



Fig. 1 Cracking table on the algal ridge at Enewetak, about 1000 ft from land. 



