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The Monterey Bay National Marine Sanctuary (MBNMS) and partners are implementing a multi-year project to remove lost fishing gear from the deepwater habitats of the sanctuary using a remotely operated vehicle (ROV). The primary goals of the Lost Fishing Gear Project are to:
Lost fishing gear is identified as fishing nets, lines, pots, traps, and other commercial and recreational fishing gear that sits on the seafloor, gets caught on rocky reefs, or floats in the water column. The National Marine Fisheries Service and the MBNMS have documented lost fishing gear during Delta Submarine dives in 2003, 2004 and 2007. This gear includes long lines, gill nets, crab and fish traps, and trawling gear, which can become lodged or entangled on the seafloor and sometimes extending into the water column. Lost fishing gear is a concern for the following reasons:
The Lost Fishing Gear team has conducted two missions from the F/V Donna Kathleen during 2009 and 2010 to survey the deepwater habitats of MBNMS and test new methods to remove lost fishing gear from the seafloor. During this time, operations focused on the Monterey Bay proper region. A priority goal of these operations was to develop and refine methods for ROV retrieval of fishing gear from deepwater habitats between 100 – 300 meters. These depths are beyond traditional removal methods used in nearshore habitats such as recreational and technical SCUBA diving.
After locating the targets, the ROV was launched from the F/V Donna Kathleen along with a clump weight from the crane, boom and winch. The vessel was set up to drift with the wind and current toward the general target area. The ROV was lifted by the crane and boom, lowered into the water, released from the winch line, and swum out 40 meters from the vessel prior to launching the 600-pound clump weight attached to the winch cable and lowered into the water a few meters. At this point, the ROV tether was secured to the clump weight winch line, and thereafter every 3 meters until the clump weight reached 5 to 10 meters from the bottom to prevent contact with the seafloor. Depending on visibility, the ROV operated at 0.5 to 2 meters from the seafloor at speeds ranging from .5 to 1.5 knots. The ROV proceeded along a determined transect or search pattern, but its course was altered depending on the bottom relief and presence of lost fishing gear. Observations of gear were recorded and potential targets of interest carefully documented.
The following criteria were used to decide on removal of fishing gear: Impacts to animals and habitat with a high priority given to endangered or protected species and sensitive habitats; threats to fishing operations (increases risk for more gear to be snagged); impacts to habitat as a result of removal; and feasibility of removal. One of two retrieval methods was employed:
During the 2009 cruise, the team focused efforts within a state marine protected area in an effort to enhance its productivity by reducing the potential for entanglement of living marine resources. The team completed 22 ROV dives over 8 days. The majority of the dives (15) were conducted over Portuguese Ledge SMCA at depths ranging from 75 to 100 meters. The remaining dives were conducted in Carmel Bay (3) and off Cypress Point (1) at depths ranging from 45 to 260 meters. The total amount of removed fishing gear weighed over 500 pounds, and included a crab pot, a boat anchor, two 100-foot gillnets and a 40-foot rockfish gillnet fragment. Over 70 monofilament targets were marked while conducting an ROV transect in Portuguese Ledge State Marine Conservation Area.
In 2010, the team completed 19 ROV dives over 10 days. Dives were conducted along the edges of Monterey Canyon, at the edge of Soquel Canyon and at Point Lobos. Roughly half were in state marine protected areas while the others were in currently fished areas. Adding locations outside the state marine protected areas provided the opportunity to retrieve newer gear which is more likely to continue to trap fish and invertebrates. The team retrieved 450 feet of rockfish gill net in 250-300 meters depth, two crab pots in 225 meters, a spot prawn trap in 275 meters and 600 pounds of lead weights in 100 meters. During HD video surveys, additional gear found included a large, intact trawl net and a 50-foot sunken sailboat. The large trawl net, complete with headline, steel cabled footline and both doors, weighing approximately 2,200 pounds and located in a state marine conservation area, has been identified as a priority target for removal operations in 2011.
Retrieved gear can be either lightly or heavily encrusted, yet most did not appear to be actively fishing. Specimen collection and photo documentation for the net encrusting invertebrates has also been a goal during this project. Documented species included brittle stars, urchins, tube worms, bristle worms, octopi, brachiopods, nudibranchs, glass sponges, nipple sponges, shrimp, squat lobsters decorator crabs, cat shark egg cases, chitons, cup corals, cookie cutter stars, sun stars, metridium anemone sp, crinoids, flatfish, rockfish, and more. Next Steps Priority areas for retrieval operations in 2011 are sites in the Monterey Bay and the Point Sur region, and will include a combination of gear targets both inside and outside state marine protected areas, and include the large trawl net described above. Collaborative Partners The sanctuary funds this collaborative project within the MBNMS through a federal settlement that focuses on mitigating impacts to benthic habitats, and through a marine debris grant awarded to the UC Davis SeaDoc Society by the California Wildlife Conservation Board. Other key contributors to this effort include the California Department of Fish and Game, California State University Monterey Bay, Cordell Bank National Marine Sanctuary, the F/V Donna Kathleen, Marine Applied Research and Exploration, Monterey Peninsula College's MATE program, the National Marine Fisheries Service, and San Francisco State University's Romberg Tiburon Center. On Facebook For more information on this project contact: karen.grimmer@noaa.gov. A brief introduction of the Deepwater Lost Fishing Gear Recovery project led by MBNMS. Here we showcase some specialized GIS tools that were used to analyze the density of the lost fishing gear that we found using an ROV. A rockfish gill net is removed from 300 meters depth in Soquel Canyon SMCA using an ROV, a boat winch, and good, old fashioned elbow grease! |
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