True, f. w. 



1904. The whalebone whales of the western North Atlan- 

 tic compared with those occurring in European waters, 

 with some observations on the species of the North Pa- 

 cific. Smithson. Contrib. Knowl. 33. 332 p. 



William J. Overholtz 

 John R. Nicolas 



Northeast Fisheries Center Woods Hole Laboratory 

 National Marine Fisheries Service, NOAA 

 Woods Hole. MA 02543 



entire low tide period, since only a single count 

 was made sometime between 90 min before and 90 

 min after low tide. 



This study was initiated in fall 1973 in an effort 

 to determine the availability of crabs and the 

 magnitude of intertidal harvest on one high-use 

 Puget Sound beach. From data collected, an esti- 

 mate was made of the total use of Puget Sound 

 beaches by sport crabbers for daylight low tides in 

 1974. 



Methods 



ESTIMATION OF INTERTIDAL HARVEST OF 



DUNGENESS CRAB, CANCER MAGISTER, ON 



PUGET SOUND, WASHINGTON, BEACHES' 



There are two major methods employed in the 

 sport fishery for the Dungeness crab. Cancer 

 magister, in Puget Sound, Wash. The first is a 

 passive method. A baited pot, trap, or ring net is 

 placed on a subtidal substrate, left for a period of 

 time, and retrieved. The second is an active 

 method. During periods of low minus tides, sport 

 crabbers seek crabs by sight. The crabbers usually 

 wade out into water between knee and waist level, 

 then walk parallel to the beach. A round metal 

 loop, about 1 ft in diameter, covered with wire 

 mesh and attached to a long handle, is generally 

 used to capture crabs. Beginners often bring fish 

 nets, but find it difficult to extricate the crabs 

 caught in the net. When a crab is seen, the crabber 

 maneuvers the hoop quickly under the crab. The 

 crab's legs go through the mesh, making escape 

 difficult, and the hoop is then pulled from the wa- 

 ter. Only male crabs may be taken, and they must 

 be a minimum of 152 mm (6 in) in width, as deter- 

 mined by a caliper measurement across the 

 carapace, directly in front of the 10th anterolat- 

 eral spines. The daily crab catch is limited to six 

 per person. 



Knowledge of the size and distribution of the 

 intertidal sport fishery was limited until 1969, 

 when the Washington Department of Fisheries 

 began aerial surveys to estimate low tide usage of 

 Puget Sound beaches for clam digging and crab- 

 bing. By summer 1973, enough data had been col- 

 lected to show which beaches were being used for 

 crabbing. However, the aerial surveys did not 

 reflect the total use of beaches by crabbers over the 



'Based on work submitted in partial fulfillment of the re- 

 quirements for the degree of Master of Science. 



FISHERY Bl'LLETIN VOL 77. NO I. 1979 



From preliminary aerial survey data. Mission 

 Beach, located 60 km north of Seattle and just 

 beyond the Port of Everett, was selected as the 

 study site (Figure 1). The beach is 3 km long, 

 shallow, and sandy, with eelgrass beds below the 

 mean lower low water (MLLW) level. This beach 

 had only one public access, cut through a 15-m 

 bluff. This location provided me with a good view 

 of the entire area and made it possible to interview 

 almost all crabbers using the beach. 



From October 1973 to October 1974 there were 

 19 low tide series with tides lower than -0.30 m 

 MLLW. These tidal series occurred in all months 

 of the year except March and September. I visited 

 Mission Beach during all tides lower than -0.30 

 m, except under adverse weather conditions in the 

 winter months. I arrived 2.25 h before low water 

 and walked to point 'a' ( Figure 1 ), where I entered 

 the water and moved toward the access at a depth 

 of 0. 15 to 0.85 m through the area most intensively 

 utilized by the sport crabbers. For all crabs ob- 

 served, I recorded the size to the nearest millime- 

 ter ( taken in a horizontal measurement directly in 

 front of the anterolateral spines on the carapace, 

 by means of a caliper) and sex. Sampling was by 

 the method used by most crabbers. 



Beginning 2 h before low tide, I made half- 

 hourly counts of the number of crabbers at the 

 beach, but continued beach sampling of crabs until 

 crabbers began to leave the beach, usually about 

 0.5 h before the low. At this time, I interviewed the 

 crabbers about their success and time spent crab- 

 bing. About 9(K of all crabbers using Mission 

 Beach, on tides checked, were interviewed. During 

 the interviews, I measured as many crabs as pos- 

 sible. From the interview data, I estimated the 

 number of crabbers on the beach at any time dur- 

 ing a period of 14 min before to 15 min after the 

 half-hourly counts. The average time spent crab- 

 bing was slightly over 1.5 h; thus, if all crabbers 



287 



