straps with the back strap. The harness pieces are joined together 

 with soft steel rivets so that if a released seal fails to return these rivets 

 will soon rust, allowing the harness to fall apart. 



Harness sizes and proportions vary, depending on the age and sex 

 of the seal. The dimensions of a harness for a juvenile male seal 

 weighing 65 kg (about 145 lb) are given in Figure 7. Note that the 

 belly straps are longer than the back strap to accommodate the large 

 chest muscles when the seal sits upright. No such accommodation is 

 necessary in harnesses for females. 



Neck strap 



33 cm 



Figure 7.— The dimensions of a nylon harness used to attach a time-depth 

 recorder to a 65 kg juvenile male fur seal. 



CAPTURE TECHNIQUES 



Adult Males 



Teamwork is more important in capturing adult males than in any 

 other kind of capture. One person should be responsible for deter- 

 mining which animals are to be captured, what efforts are needed to 

 keep the captures running smoothly, and what steps are necessary to 

 alleviate problems that arise (which rope to tighten, how to move an 

 animal into a better position, what direction to pull, who on the work 

 crew should move to another rope, etc.). The crew should be enthusi- 

 astic for the work to be done and have good rapport with the leader. 

 Before marking begins the leader should demonstrate how to move 

 around the animals, how to stop a charging male with a bamboo pole, 

 and generally what to expect. He should stress the need for concerted 

 group action, and the need for decisive individual action when some- 

 one is endangered. He should also stress that while there is no shame 

 in running from a charging adult male fur seal, the worker who runs 

 at the seal's first snort may abandon someone in a dangerous position 

 and undermine the confidence of the rest of the ere w. The leader must 

 anticipate that some workers, when excitement is high, or when there 

 has nearly been an accident, tend to vent their emotions through 

 excessive roughness to the animals. Such persons are not allowed to 

 work on our projects. In addition, we forewarn our workers that they 

 may respond to stress in these ways, and that such actions are inap- 

 propriate and unacceptable. 



Terrain is important to success in capturing adult territorial males. 

 Most of our 155 successful captures have been made on a broad flat 

 area measuring approximately 40 m by 100 m with a slight uphill 

 slope at one end. The surface is hard-packed dirt or bedrock littered 

 with fist- to man-size rocks. At another site, attempts to drag the ani- 

 mals up a narrow sloping beach of large boulders proved unsuccess- 

 ful. The animals were able to wedge themselves behind the large 

 rocks, and no amount of pulling would move them up the slope. 



Marking may begin soon after males start arriving in May, and 

 continue until the animals are too numerous to permit safe work, or 



until females begin arriving on the site. Optimum weather conditions 

 for marking are heavy overcast, no precipitation, and a moderate 

 wind. Rain makes both the ground and the animals slippery and 

 treacherous, and bleach marks often do not "take" on wet fur. Work 

 may be done on sunny days or warm days with no wind, but only 

 with considerable caution: the animals are easily overheated. 



The capture consists of getting two ropes (or lassoes) around the 

 animal, and quickly dragging it to the marking box. Typical ropes are 

 1 cm (3/8 in) hemp 12-15 m long. At this time of year male fur seals 

 are probably at their peak weight, and their necks are larger in diame- 

 ter than their heads. A noose around the neck of an animal will 

 merely slip off when the animal offers any resistance to being pulled. 

 Nooses must go around the neck of the animal and behind one front 

 flipper. When the two ropes are correctly applied each should pass 

 over the animal's back, one going behind each front flipper, and 

 crossing each otherat the animal's chest (like bandoliers) (Fig. 8) with 

 the two ropes emerging from the loops close together at or below 

 chest level. 



Figure 8.— An adult male fur seal showing the proper placement of two ropes 

 across the chest used to drag the animal into a box for marking. 



The animal should be approached by as few people as possible: 

 one person manipulates the noose, one maintains tension on the rope, 

 and one person assists in maneuvering the animal. A fourth person 

 may stand ready with a bamboo pole a meter or so behind the work- 

 ing crew to provide assistance if needed. This small number of peo- 

 ple seems to cause less disturbance, and the animals remain quieter 

 and easier to work with than with larger crews. The lasso is hung on 

 an 8 cm diameter hook at the end of a 4-5 m bamboo pole. The hook 

 can be tightly strapped onto the pole with fiber tape about 5 cm back 

 from the tip in the fashion of a boat hook. The lasso is not thrown 

 because the flying rope frequently alarms the animal. The rope loop 

 is dropped over the animal's head, and then arranged with the hook in 

 such a position that the seal may step through it with one front flipper 

 By staring or approaching to within 2-3 m (ready to jump back 

 quickly) one person can induce the seal to step forward into the loop, 

 or to make a short charge or boundary display. At this instant the per- 

 son controlling the end of the rope takes up the slack and pulls the 

 noose tight in position across the seal's chest and behind one flipper 

 Some experimenting will show how best to position the rope to 

 achieve this effect, and what sorts of noises or motions work best to 

 stimulate the animals to move forward. 



