Readings Between the Spines: My Quest For the Best Crabbing Time

img_9520-002img_2038-002The crab I trapped overnight at Cornet Bay tap-scratched the inside of the blue bucket. That the foursome was a winter season record for me was great, but I dreaded what I needed to do next: kill ’em. The Washington State Department of Fish and Wildlife (WDFW) site’s section on Cleaning and Preparing Crab suggests either cooking (read “boiling alive”) then cleaning, or the reverse. Removing a crab’s shell while he’s still kicking (read “skinning alive”) seems cruel. It also says, “If handling live crabs proves to be a problem when removing the back, the crab can be killed quickly by a blow to the abdomen.” The method makes sense considering crustacean’s anatomy. Fig 5.3 illustrates its nervous system, a tiny brain between the eyes and a concentration of nerves along the central abdomen, like the root system of a tree.

nervous-system-1-3-2017-10-45-00-am-bmp

img_2202If you don’t think these creatures can feel pain, think again. A 2013 study in the Journal of Experimental Biology, Shock avoidance by discrimination learning in the shore crab (Carcinus maenas) is consistent with a key criterion for pain, indicates otherwise. Researchers placed shore crabs in a lighted tank with two darkened shelters, allowed them to choose one (or not), and subjected them (or not) to a mild shock, crabsshockexp-1-4-2017-1-47-21-pm-large“Those crabs not receiving shock in the second trial tended to persist with their choice of shelter; however, those receiving shock in the second trial were significantly more likely to switch choice of shelter… In this way the majority of crabs came to use the non-shock shelter (Fig. 1). These data show swift avoidance learning and discrimination that is consistent with expectations should these animals experience pain.”

At home, I tipped the bucket, slid the crab onto the pavement, flipped them onto their backs, and hatcheted each of them two or three times along the midline, first near the top, then the abdomen. Sometimes the legs twitch for up to a minute afterwards, but I think it’s more humane than boiling them alive.

img_2231-001Pulling a crab pot from the dock at Cornet Bay is like scratching the stuff off of a lottery ticket: more likely than not, you wind up empty handed. With many bait-filled traps vying for the attention of a few legal sized crab, everyone has a theory on the best tide, bait, and location along the dock to improve his or her chances of success. During the winter season there is less competition than in the busy summer months, so it’s a good time to go if you can handle wind, rain, cold, and occasionally, snow. My theory on optimizing your chance of catching crab from the dock at Cornet Bay is–no can do. If there are crab, you’re as likely to catch them as anyone else with whatever they are doing. WDFW recommends crabbing at slack tide because the tidal movement is reduced, allowing crab to forage for food, which is what most people do. Several have suggested that flood tide pulls crab into Cornet Bay. Others have mentioned that the water is less silty allowing crab better visibility during flood than slack tide; however, they have an excellent sense of smell.
crabsperiment-1-2-2017-8-42-42-pm-bmpThis December, I hypothesized, “I’ll catch more legal sized crab at high tide than low tide.” I also wondered whether the tidal coefficient and/or solunar activity might affect the amount of crab I could catch. I dropped a weighted yellow rope with knots at one foot intervals at several locations along the outside face of the dock, from which everyone crabs (except sometimes in the summer when it’s insanely crowded) and found that the water level variance from the shallowest (sw) end to the deepest (ne) end is only about 4.5 feet. I chose two spots near the center of the dock to place the pots and dropped them twelve times from December 12 through December 31, during which the average air temp (Oak Harbor) was 38°F and water temp was 47°F (Port Townsend).
img_2035-002img_2019Controlled variables:
Number of traps, location, quantity and type of bait, time in water (four hours)
Dependent variables:
Quantity and size of Dungeness and Red Rock crab trapped, legal-sized (6.25″ between the spines) male Dungeness crab trapped, aka “keepers.”Crab 1-2-2017 9-12-10 PM.bmp.jpg

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The results: with the two pots in the water for a total of (4 hours/time)x 12 times=48 hours, I trapped 107 crab. Of those, 9 were legal-sized males, but five were soft, leaving four keepers. The data shows that I caught most of the keepers (7 of 9) during low tide, which doesn’t support my hypothesis. Neither the solunar activity nor the tidal coefficient correlated with the quantity of crab trapped. I also caught several Red Rock keepers. Even though they taste delicious, they are small and less meaty, so most folks prefer Dungeness.

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During all that time I spent around crab, I observed some interesting behavior. Once, a hard-shelled, barnacled male pincered a soft-shelled’s leg…and tried to eat it. The Pacific States Marine Fisheries Commission Dungeness Crab Report 2014 claims, “cannibalism is prevalent among all age groups.” From the same report, I learned more about molting, “Growth is accomplished in steps through a series of discrete molts. Dungeness crabs of both sexes molt an average of six times during their first year and attain an average width of one inch. Six more molts are required to reach sexual maturity at the end of their second year, when they are approximately four inches across. Once maturity is reached, growth of females then slows as compared to males. Females molt at most once per year after reaching maturity and rarely exceed the legal size of males. Maximum female size is about seven inches. Male crabs usually molt twice during their third year and once per year thereafter. The average size of males three, four and five years of age is about six, seven and eight inches, respectively. Males may undergo a total of 16 molts during a lifetime, reaching a maximum size of nine inches and age of six to eight years.”

A bonus: the chance to see a female with eggs that a fellow crabber caught, “The smallest females carry about 500,000 eggs and the largest from 1.5 to 2 million.”

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At the Cornet Bay dock, scarcity of crab and competition from fellow crabbers are probably the biggest obstacles to catching keepers. Shellfish harvesting rules in our state are more strict than in Oregon or California.
img_5107-001WDFW
 allows a daily catch limit of:
5 male Dungeness crab greater than or equal to 6.25″ and 6 male or female rock crab greater than or equal to 5″
ODFW
12 male Dungeness crab greater than or equal to 5.75″ and 24 male or female red rock crab any size
CDFW
10 male or female Dungeness crab greater than or equal to 5.75″ and 35 male or female red rock crab greater than or equal to 4″
crabharvest-1-2-2017-10-07-07-pmcommercialcrabbingSince 1996, when WDFW began tracking the crab catch, the total (of recreational, commercial and tribal) caught increased by about 50% by 2012. With such strict laws in Washington state, you’d expect us to have the lowest catch total on the west coast, but we don’t. According to the Pacific States Marine Fisheries Commission (PSMFC) Dungeness Crab Report 2014, commercial fisherman in all three states abide by the same rules…Washington’s rules! Most were caught along the Washington coast (21.8 million pounds), then California (16.8), then Oregon (14.4). Total value for 2014, nearly $170,000,000 (that is not a typo). According to Don Velasquez, WDFW Fish and Wildlife Biologist, the difference in pounds caught between the two data sources is due to the fact that the PSMFC data includes only the crab caught along the Washington coast. Crab fisheries within Puget Sound are managed separately, and the harvest totals are typically not included in PSMFC data. Velasquez shared that Puget Sound crab is often sold live, to destinations inside and outside the United States, and so nets a higher price per pound than that caught outside the area, which are more often slated for processing. The most important thing he taught me was also the most surprising: placing crab in a bucket of water without an aeration device kills them! They will quickly run out of oxygen and die, particularly in warmer weather. The best way to keep crabs alive is to set them upright in a cooler or bucket and place burlap sacks or towels soaked in salt water over them. If the temperature is very cool, they can survive for days this way, which is why commercial crabbers use this method to keep their catch fresh.

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But back to my crabsperiment. In the end, I could only conclude: during the winter crabbing season, you might have better success during low than high tide. The data supports what I already knew, catching keepers from the Cornet Bay dock takes patience, persistence, and a little luck. In other words…it’s a crabshoot.

Note: Unless noted otherwise, information in quotes is from the Pacific States Marine Fisheries Commission Dungeness Crab Report 2014

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