lifted so that the seal can be carried about. Large seals cannot stand 

 up in this device because they push against the board rather than the 

 ground. Milk samples can be taken from restrained females through a 

 sliding door under the teats. 2 



Hold-Down Fork (Fig. 2c) 



This is a 2 m long metal pole with a U-shaped fork at one end. The 

 prongs of the fork are about 15 cm long and about 15 cm apart. The 

 entire device can be constructed from galvanized plumbing pipe and 

 pipe fittings. It is used to pin the head of a small animal to the ground. 

 It may be used in place of a hold-down bar in situations where the 

 animal must be held in position at the location of capture. It is best 

 applied when the animal must be restrained for only very short peri- 

 ods of time. Restraint with the hold-down fork is not nearly as secure 

 as with the restraint bar 



Nets 



Large hoop nets (Fig. 3) have been used successfully in various 

 applications. The basic hoop, fabricated of 3.75 cm (1 1/2 in) alumi- 

 num tubing is 0.75 m (30 in) in diameter, and has a 4 m handle. Two 

 30 cm long diagonal braces extend from the handle to the rim of the 

 hoop (not quite tangent to the perimeter). 



3.75cmO.D. 3.75 cm 1.0. 



\ -A 



m deep with little or no taper Into the foot of this net is sewn a bag of 

 canvas or fiber-reinforced plastic. The purpose of the bag is to restrict 

 the animal's vision, which encourages it to rest more quietly while 

 under restraint. Without this restriction the animal will continue to 

 struggle, and males of this size are too strong to be restrained by force 

 alone. Instead of a bag, a sleeve may be used with grommets installed 

 along its border on the deep end. A strong purse string may be woven 

 through these grommets and the ends of the net outside the bag. The 

 capture is made with the net pursed. The bag is 60-75 cm deep and 

 the same diameter as the inside of the net. The bag should be sewn 

 into the net deeply enough so that when a captured animal pushes 

 against the bag, the force is restrained by the strong net and not by the 

 bag within the net. The bag is deep enough to go over the animal's 

 head and part way down it shoulders. 



Transport Boxes (Fig.4) 



These are small lightweight boxes with wire mesh tops used for 

 transporting small animals that two people can carry. Dimensions are 

 60 cm x 60 cm x 80 cm (24 in x 24 in X 32 in) and allow comfort- 

 able posture and some movement for an adult female, with space for 

 her pup. The boxes are small enough to be loaded easily on a small 

 aircraft. "Stretcher" type handles are removable to save space. 



Figure 3.— A hoop net with a handle of aluminum tubing inserted inside a piece 

 of aluminum pipe welded and braced to the hoop. 



Figure 4. — A transport box with removable handles used to carry fur seal 

 females and small males. 



Proper construction of this hoop will greatly reduce its weight 

 without loss of strength. Our most satisfactory design combines alu- 

 minum pipe (thick walled) and aluminum tubing (thin walled). The 

 circular hoop and diagonal braces are made of tubing. Into a short 

 "handle" (about 30 cm) of aluminum pipe attached to the hoop is 

 inserted a longer (3 m) handle of aluminum tubing. This arrangement 

 weighs little but provides sufficient strength at the point of maximum 

 stress where the handle meets the hoop. 



Nets of varying dimensions and weights are attached to this hoop 

 depending upon the size of animals to be caught. The most frequendy 

 used net type is nylon or polypropylene fishing net with roughly 10 

 cm mesh openings. 



For capturing adult females and small subadult males, a net with a 

 slight taper and a depth of 1.25-1.5 m is appropriate. Pups may be 

 caught with this net also, but if numerous pup captures are to be 

 made, a smaller hoop and net will be less cumbersome. 



For capturing large subadult males weighing 135-160 kg (300-350 

 lb), just smaller than adult territorial males, the net should be about 2 



; Daniel Costa. PRL. Scripps Institution of Oceanography, La Jolla. CA 92037. 

 pers. commun. July 1981. 



Boxes are built with 1 cm (3/8 in) plywood and 5 x 5 cm (2 x 2 in) 

 lumber. Galvanized hardware cloth (0.6 cm mesh) is used for the top. 

 Completely removable tops are more versatile than hinged tops. The 

 plywood cross braces on the tops provide rigidity, safe handholds, 

 and some visual screening of the animals from the box carriers. A 

 simple, quick-acting latch mechanism is advantageous. For long 

 journeys a raised false bottom of slats may be added to reduce contact 

 of the animals with their own excrement. See illustration for con- 

 struction details. 



Adult Male Marking Box (Fig. 5) 



This apparatus has been described in detail previously (Gentry and 

 Johnson 1978); basic information about the device will be repeated 

 here. The principle on which the box operates is physical immobili- 

 zation through downward pressure. The top of the box can be low- 

 ered until the animal is pressed between the top and a false bottom. In 

 that position small doors in the top provide access to various parts of 

 the seal's body for tagging and marking. Also the top and false bot- 

 tom with the seal sandwiched between can be hoisted as a unit for 

 weighing. 



