Blue crab sur­vey re­sults are good

Maryland Independent - - Sports - Jamie Drake

Last week, Mary­land’s De­part­ment of Nat­u­ral Re­sources re­leased the re­sults of the 2016 Blue Crab Win­ter Dredge Sur­vey and the re­sults are good for the sec­ond year in a row.

The over­all crab pop­u­la­tion has in­creased for two years con­sec­u­tively, in­clud­ing the num­ber of spawn­ing-age fe­males. How­ever, the num­ber of fe­males still re­mains be­low the tar­get man­agers from Mary­land, Vir­ginia and the Po­tomac River Fish­eries Com­mis­sion are aim­ing for.

Ev­ery De­cem­ber to March, teams of sci­en­tists from Vir­ginia and Mary­land con­duct the sur­vey at 1,500 dif­fer­ent sites in the Ch­e­sa­peake Bay and its trib­u­taries. The crabs are dredged from the frigid bot­tom of the Ch­e­sa­peake Bay, where they lie mo­tion­less dur­ing the cold win­ter months. Work­ers dredge the bot­tom in spec­i­fied lo­ca­tions and the ma­te­rial is brought up to the sur­face. They sim­ply count the num­ber of crabs, which cre­ates an ac­cu­rate snap­shot of the crab pop­u­la­tion through­out the en­tire Ch­e­sa­peake Bay from year to year.

The win­ter dredge sur­vey has been taken an­nu­ally since 1990. Just look­ing at all the dips, blips and troughs on the line graph de­pict­ing the to­tal num­ber of crabs es­ti­mated in the Ch­e­sa­peake Bay the last 27 years is enough to give a per­son a se­ri­ous case of ver­tigo. The in­crease in pop­u­la­tion the last two years could be the start of a trend, but it’s too early to break out the cham­pagne (or crab knockers) yet.

Blue crabs have a com­plex life cy­cle. They are born in the bay and its trib­u­taries as mi­cro­scopic lar­vae that look more like wa­ter­borne aliens than the hard-shelled crus­taceans that end up on our pic­nic ta­bles each sum­mer.

They float out to the ocean on wind and cur­rents and re­turn sev­eral months later in much the same fash­ion to set­tle in the grass beds of the bay. They are tiny — not even a quar­ter of an inch from point to point in size — and they need those grasses for pro­tec­tion.

Th­ese tiny crabs are tasty morsels for a whole host of preda­tory crea­tures from sea tur­tles to herons, croaker to cat­fish. Even adult crabs are known for their can­ni­bal­is­tic predilec­tion for din­ing on ju­ve­niles. It’s a per­ilous life for a grow­ing crab.

Odds are lit­er­ally one in a mil­lion that a crab sur­vives to adult­hood (de­fined as over 2.4 inches by DNR for this study). A fe­male can spawn sev­eral times as an adult, but each time just a measly three eggs have a shot at sur­vival. This fact alone should make ev­ery­one want to pro­tect as many adult fe­male crabs as we can.

We’ve im­ple­mented new rules al­ready in the past few years to pro­tect fe­males. To­day, recre­ational crab­bers can’t take any fe­male crabs at all. The to­tal num­ber of crabs recre­ation­ally har­vested is dif­fi­cult to es­ti­mate and not in­signif­i­cant, but the ma­jor­ity of crabs har­vested each year aren’t taken by recre­ational fish­er­men. Re­stric­tions need to stay in place, or bet­ter yet get tougher for the whole crab pop­u­la­tion is still be­low ideal num­bers.

Just two years ago, the fe­male pop­u­la­tion was be­low the min­i­mum thresh­old of 70 mil­lion, in­di­cat­ing the fisher y was in grave dan­ger.

Thank good­ness the num­bers went up last year, to 101 mil­lion. And this year, the num­bers are even higher, 194 mil­lion. But 194 mil­lion is still 21 mil­lion crabs short of the goal of 215 mil­lion fe­male crabs rec­om­mended by sci­en­tists to sus­tain a strong fishery.

Mother Na­ture is ca­pa­ble of throw­ing us some se­ri­ous curve­balls that can chal­lenge even the sound­est fishery prac­tices. Nat­u­ral fluc­tu­a­tions in pop­u­la­tion are ex­pected. An over­abun­dance of preda­tory red drum in 2013 and a bad win­ter kill in

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