SEBASTICOOK TO THE SEA: ALEWIVES’ PERILOUS LIVES CRUCIAL TO ECOSYSTEM, ECONOMY

• watershed narratives

Sebasticook to the sea: Alewives’ perilous lives crucial to ecosystem, economy

By Matt Hongoltz-Hetling Staff Writer mhhetling@centralmaine.com | @hh_matt | 207-861-9287

 

  • Conserve forage fish. Small fish such as menhaden and sardines are a primary source of food for many species of birds, marine mammals, and large fish—including the striped bass, tuna, and salmon that support important commercial and recreational fisheries. However, forage fish populations are too often managed without adequate consideration of their vital role as prey, or not managed at all. Congress should require managers to protect forage fish with science-based catch limits that account for their unique role in the ecosystem.
  • Why did fishermen see a bounty while scientists in fact called it a bust? Researchers at the National Oceanic and Atmospheric Administration’s Northeast Fisheries Science Center say a change in the forage fish, or small prey species, the cod were eating offers an explanation.In the May 17, 2014, article published in the Canadian Journal of Fisheries and Aquatic Science, the authors say that around 2006 the dominant prey for cod switched from Atlantic herring to sand lance—small, eel-like fish that burrow in the sediment of the seafloor. Sand lance were abundant in an area known as Stellwagen Bank, and so cod, too, congregated there. Soon, cod fishermen focused so much effort on the bank that some 45 percent of the cod caught in a year came from just a 100-square-mile area in the region.

    While this study helps to explain the recent past, it also holds important lessons for the future of fishing. The switch in cod diet from herring to sand lance held major implications for one of the region’s most economically important fish. Over the years, through intensive fishing for prey species such as Atlantic herring and menhaden, plus the depletion of other historically important prey such as river herring and shad, the “menu” of forage fish available to cod and other predators has changed. We need a management system that better monitors and responds to the ways prey and predators interact.

    Such a system is available, and it’s called ecosystem-based fisheries management. Scientists have long known that simply measuring and managing one fish species at a time is insufficient. So they’ve put decades of work into developing the ecosystem-based approach to provide a much more accurate and useful picture of what’s occurring in the water.