Reuse of Fish Waste Yields Organic Liquid Fertilizer

By JOYCE ROWLEY/ecoRI News contributor

Spiny dogfish, an underutilized commercial fishery, are used in international markets for fish and chips. (NOAA)

Spiny dogfish, an underutilized commercial fishery, are used in international markets for fish and chips. (NOAA)

NEW BEDFORD, Mass. — With an expanding spiny dogfish catch, AMT BioProducts Inc. is beginning a $685,000 expansion from its current operations at 33 Cape St. into an adjacent 9,100-square-foot plant that is expected to double the company’s production capacity. But AMT BioProducts doesn't package fish, it processes fish waste into commercial-grade organic liquid fertilizer.

Last month, the City Council passed a five-year special tax assessment (STA) on the property of $47,918, as part of the city’s tax increment financing program. Although AMT BioProducts leases, the STA is passed through the property owner to the business.

The assessment is part of the state’s Economic Development Incentive Program (EDIP), which encourages businesses to stay and grow in Massachusetts. AMT BioProducts also will receive $31,336 in state tax credits for that same period.

“The STA is good for the city of New Bedford because it allows us to continue growing the support we give to the entire fishing industry; this protects and grows far more jobs than the five additional ones we will be adding,” said Jeffrey Young, the company’s co-founder and director.

Originally called Advanced Marine Technologies, AMT BioProducts began experimenting with the fish-waste reuse 20 years ago and relocated to its current location in 2005. The company has grown from four employees to 11. With the expansion into 39 Cape St., five new full-time jobs will be created over the next five years.

The company already complies with the new Massachusetts earned sick time law passed in November. The seven non-management employees receive a week of sick leave and a week of paid vacation, as will the five new employees. After three years, paid vacation time increases to two weeks. None of the employees receive health insurance, including management. But starting pay is well above minimum wage. Non-management employees earn between $25,000 and $35,000 a year.

The company’s expansion will rehabilitate a vacant seafood processing plant that has been empty for five years. Both properties share parking and a storage yard, making the expansion ideal, said Chawner Hurd, the company’s special projects director. AMT BioProducts hopes to have limited production in the new building up and running by the first quarter of this year.

The benefits of reusing fish byproduct are many. For one, with the recent Massachusetts ban on disposal of food waste in landfills or incinerators, some 10 million pounds of fish waste will have to go to a composting facility, Hurd said. Existing composting facilities in Dartmouth and Foxborough don’t have the capacity to handle that much material.

Instead, fish byproduct is enzymatically digested in a proprietary process, stabilized and packaged in bulk at the AMT BioProducts plant. The end product is relatively low in nitrogen, compared to chemical fertilizers, according to Hurd.

Organic Gem™ has a 3-3-0.3 nitrogen-phosphorus-potassium composition, and is certified by Organic Materials Review Institute (OMRI). Liquid fish waste fertilizer contains collagen and oils that bind the nitrogen to the soil, slowly releasing it.

“(The expansion) is also good for the environment because it enables us to double the amount of Organic Gem we produce," Young said, “thereby reducing use of an equivalent amount of harmful petrochemical fertilizers that would otherwise be gassing off into the atmosphere and leaching into sensitive waterways.”

Unlike petrochemical fertilizers, the liquid fish waste fertilizer is not a public-health risk nor a risk to groundwater supplies, according to the company’s material data safety sheet.

Dogfish stock
Although AMT BioProducts processes other fish byproduct, spiny dogfish is its primary feedstock. For several years, the spiny dogfish stock was considered depleted by the National Oceanic and Atmospheric Administration (NOAA). But a combination of factors led to a tripling of total allowable landings (TAL) in the past five years. After the stock was declared rebuilt in 2010, the TAL went from 15 million pounds to 49 million pounds in 2014.

Part of the increase resulted from a new stock assessment performed by NOAA in 2013. Scientists found that sample trawls showed an incredibly quick rebound in total biomass and female spawning biomass. Instead of taking 10 years to rebuild, the total biomass came back in under five years, according to NOAA research.

New science sponsored by the Commercial Fisheries Research Foundation, a Kingston, R.I.-based nonprofit led by fishermen and port-side business leaders, shed light on why spiny dogfish were more than plentiful by examining the species’ life-history patterns. That research helped inform the New England Fisheries Management Council and Mid-Atlantic Management Council in 2012 to eliminate seasonal allocations on the catch, which had at one time caused fishery closures.

Research by James Sulikowski, a professor at the University of New England’s Marine Science Center, showed that the spiny dogfish reproductive cycle was continuous, not annual, as previously thought, so biomass estimates for the stock were low. Among other things, Sulikowski found a “pupping” ground off the coast of Rhode Island while sample trawling. In one area off Block Island, the nets brought up all stages of the reproductive cycle in one net — pregnant females through young-of-year. This wide range of reproductivity occurring simultaneously may mean that dogfish don’t breed annually, but breed continuously, according to Sulikowski.

Both Sulikowski and scientist Roger Rulifson of Eastern Carolina University completed tagging studies that showed spiny dogfish don’t migrate up and down the coast, but instead have inshore-offshore migration patterns. So instead of population estimates that were based on a single group of dogfish traveling up and down the coast, scientists now realize that the dogfish seen up here weren’t necessarily the same dogfish seen in North Carolina.

Separate stocks north and south of Cape Cod meant there were far more dogfish than previously estimated, which helped explain why the stock quickly rebounded.