Invertebrates

Restoring a vast, complex ecosystem like the Salish Sea costs money — that long green stuff with the short future. With politicians and public opinion involved, tough fights often break out over spending on improvements that, to some, appear subjective: Is it worth $100,000 to remove a certain bulkhead or replant a certain eel grass bed? Maybe… And that’s where good science can inform great policy.

One of the best examples of science coming to the rescue of a dollar-and-cents conservation issue occurred when the SeaDoc Society recently got caught up in the question of abandoned fishing nets. In partnership with the Northwest Straits Initiative, SeaDoc developed a predictive model that clearly shows the cost of these ghost nets that continue to trap and kill marine life for decades.

Northwest Straits Initiative-funded researchers made multiple dives on derelict nets, counting trapped critters, studying decomposition rates, and determining how much of the dead marine life fell out of the nets as they were recovered (Over 17% of the catch never made it to the surface, showing how critical it is to have underwater scientists on the job). SeaDoc then dove into the data, actually inventing a statistical model to predict each cast-off net’s killing capacity.

The results? Abandoned nets catch and kill more than 1,000 invertebrates (mainly crabs), 150 fish, and nearly 80 birds every year, year after year after year – and most of these silent killers have been doing their dirty work since the 1970s. Run that data through the seafood value calculator and it quickly adds up, with each net wasting $19,656 in Dungeness crab alone, every 10 years. The one-time cost to retrieve a derelict net? $1,358. It doesn’t take an accountant to do that cost-benefit analysis.

Only through funding from private donors like you was SeaDoc able to do this ground-breaking (and net-cutting) science, which has led to clear policy and, more importantly, vital and measurable improvement in the Salish Sea ecosystem. Thank you.

To view the manuscript just published in Marine Pollution Bulletin, click here (pdf).

For more about SeaDoc's derelict fishing gear project, see our lost fishing gear page.

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