Applied Osteology: Ghost Nets project

NOAA's "Ghost Nets" or "Derelict Fishing Gear Removal" Project

The negative effects incidental by-catch birds and mammals in commercial fishing gear are well-known, and have been extensively documented. What is less well-known is that many tons of commercial fishing gear are lost at sea every year, and that much of that lost, or derelict, gear continues to capture and kill fish, birds, and mammals.

Since 2002, a consortium of researchers headed by Tom Good (NOAA, Seattle) and Jeff June (Natural Resources Consultants, Seattle) has been conducting systematic surveys in Puget Sound and the Pacific coast of Washington to find and remove this derelict gear. The results are somewhat mind-boggling: in their first pilot study their divers found and recovered 27 acres of abandoned fishing gear! This gear included gill nets, trawls, and crab pots. Some of the gear is all balled up and not really a threat to any marine life. But depending on the type of gear and the degree to which it is deployed in the water column (which can change with every tidal cycle or with storms), these nets can continue "ghost fishing" for years after they were originally lost.

After a few weeks of recovery efforts, the divers asked if the PIs were at all interested in the piles of bones they were finding accumulated in and around the nets, some of which were 1-3 feet deep. Tom and Jeff responded with a resounding "YES!" and now I'm working with them to quantify the negative effects of these "ghost nets."

Since their first pilot season, their team has recovered 60 tons of nets and pots. In and around this gear, they have recovered nearly 6000 whole or partial carcasses of fish, birds, and marine mammals. Here are the summary data for the bird bones that I have examined so far:

Taxon	NISP (Number of Identified Specimens)
Aechmophorus sp. (Western or Clark's grebe)	8
Ardea herodias (great blue heron)	1
Gavia pacifica (Pacific loon)	1
Gavia sp. (common or yellow-billed loon)	4
Phalacrocorax auritus (double-crested cormorant)	7
Phalacrocorax pelagicus (pelagic cormorant)	72
Phalacrocorax penicillatus (Brandt's cormorant)	98
Phalacrocorax sp. (cormorant, indet.)	306
Uria sp. (common or thick-billed murre)	1

As the table shows pretty clearly, cormorants are the ones that are the most seriously affected by derelict fishing gear, making up nearly 93% of the total number of identified bird bones (NISP).

For more information on this project, contact Tom Good at NOAA.gov. A paper he presented last year at the ICES meetings should be available soon:

Thomas P. Good, Jeffrey A. June, Michael Etnier, and Ginny Broadhurst. 2007. Quantifying the impact of derelict fishing gear on the marine fauna of Puget Sound and the Northwest Straits. Proceedings of the ICES Annual Science Conference 2007.