Blue Crabs, Menhaden Showing Resurgence in Bay
By WAYNE CREED
Cape Charles Wave Columnist
May 18, 2015
This summer, my daughter Rachel will be spending her summer break from college working at the Cherrystone Campground Bait and Tackle shop. The job duties include monitoring the weather, marking the tides on the chalk board, recommending bait and tackle for the campers, and of course, running down the rules and size limitations when it comes to summer flounder and blue crabs.
For crabs, she is trained to remind the folks to always throw back sooks carrying a sponge, and that jimmys must be 5 inches point to point. You can use tape a measure, or just the railing at the end of the pier, which is 5 inches.
This season, the pier at Cherrystone may have a bit more blue crab action, as results of the winter dredge survey showed modest improvement in the Bay’s blue crab fishery. According to results released by Maryland DNR, “juvenile crabs increased 35 percent from 2014, and more than doubled from the record low in 2013. The 2015 juvenile abundance of 269 million crabs is just above the 26 year average of 261 million. The total abundance of crabs — which include juveniles, and adult males and females – was approximately 411 million.”
Going back to the results of the last few years, including the disastrous drop in populations recorded in 2013, the latest results show just how volatile the blue crab population is, and how vulnerable it can be to factors such as weather patterns (colder winters), changes in coastal currents, and of course fluctuations in levels of natural predators such as rockfish and red drum.
This year, the report estimates that 19% of the crabs died due to the severe winter temperatures. Given this amount of environmental variability, the task of managing this fishery is still a daunting one. According to Tom Miller of the University of Maryland Center for Environmental Science Chesapeake Biological Laboratory, “Managers acted to ensure the crab stock is no longer depleted as it was last year, and if we maintain exploitation rates close to the target the crab population will continue to increase over the long term.”
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According to DNR Secretary Mark Belton, “Despite the harsh winter temperatures, we are pleased that crab numbers increased.”
This May, the Chesapeake Bay Stock Assessment Committee will begin poring over the data and the analysis should be ready by June or July. The results of the analysis will determine next steps for managers in terms of how to manage the Chesapeake Bay blue crab.
Another important Bay resident, the Atlantic menhaden, is also showing signs of resurgence. After severe catch limits were put in place in 2012 as a means to slow the industrial harvest, the menhaden, a robust breeder, has responded well to the reduced fishing pressure. The SouthEast Data, Assessment, and Review assessment reveals an increase among fish in the oldest age classes, with more large adults than in previous estimates. This upward trend should continue if conservation measures remain in place.
Benchmark assessments for 2015 show that, according to ASMFS, Atlantic menhaden are “neither overfished nor experiencing overfishing. In a nutshell, fishing mortality has been decreasing, and is now “91% below the threshold and 73% below the target.”
But as has been a common theme around the fate of this oily little fish, there are still competing points of view. From the commercial side of things, the Menhaden Fisheries Coalition has a report that attempts to compile anecdotal evidence based on “observations of large schools of Atlantic menhaden by the media, fishermen . . . outside the fisheries management community.” Commercial entities, such as Omega Protein, which operates the largest (and only) reduction fishery on the east coast, offer that what people are seeing on the water points to “a healthy and plentiful stock.”
Some environmental groups, such as the Chesapeake Bay Ecological Foundation, aren’t buying it, and counter that the data still doesn’t take into account the various ecological factors, and that only looking at the population numbers severely oversimplifies the important role menhaden play in the larger ecological landscape — menhaden are feeder fish for predator species such as rockfish.
Presently, fisheries management is a decision-making process that deals with fish on a species-by-species basis. There is little if any discussion as to how one species may affect another, such as if the menhaden population crashes, how does that affect rockfish, weakfish, and bluefish?
That process is slowly beginning to change, as the ASMFC’s Multispecies Technical Committee has begun providing data, insight, and advice to managers about species interactions, and just how these interactions may “affect stock assessments and fisheries management.” According to the ASMFC website, the “MSTC has adopted a multispecies Virtual Population Analysis model to explore important predator-prey interactions among key ASMFC-managed species. The MSVPA produces annual estimates of natural mortality rates at age caused by predation for Atlantic menhaden.” These estimates are incorporated into the Atlantic menhaden single-species model. A multispecies statistical catch-at-age model “is also in the early stages of development.”
The fact that the MSTC and Atlantic Menhaden Technical Committee are working to create ecosystem-based reference points for menhaden is a good sign for the future. From their work, “Fisheries Ecosystem Planning for Chesapeake Bay,” the Chesapeake Fisheries Ecosystem Plan Technical Advisory Panel, provides a definition of a fisheries ecosystem as “the complex interactive community of organisms (including humans and their institutions) and their shared environment (including habitats and ecological processes) that contributes to, influences, or determines the fishing industry.”
For Menhaden, and all the species that need them, the ability to account for elements such as predation and how much menhaden biomass is required to meet the forage needs of their primary predators is a critical step forward.
As fishery managers move away from stove piped, single species approaches (easily manipulated by industry lobbyists), the implementation of Ecosystem based fishery management approaches, which weigh various sources such as pollution, coastal development, harvest pressure, predator/prey and other ecological interactions, will help manage and sustain healthy marine ecosystems and the fisheries they support.