Marine Hagfish/Eel Traps Cause Devastating Impacts

By Carl Berg, PhD

Hagfish/eel trap parts can injure Hawaiian monk seals through starvation and infection. Photo by Carl Berg

Abandoned, lost and discarded fishing gear poses a major threat to the marine and coastal ecosystems of Hawai‘i. One of the most abundant and easily identifiable items of marine debris are the plastic, cone-shaped entrances of traps used to capture Pacific hagfish eels and Black hagfish off the Pacific coast of North America, and hagfish eels and conger eels off the east Asian waters of South Korea, Japan and China.

Kaua‘i Sperm Whale

Recently, the devastating impact of discarded hagfish/eel traps was brought home to us on Kaua‘i. A 56-foot-long adult male sperm whale washed up dead in nearshore waters off Lydgate Beach Park on Kaua‘i’s east shore. A necropsy conducted by the University of Hawai‘i Health and Stranding Lab found that the likely cause of death was blockage of the gastrointestinal tract by a number of manufactured items. Specifically, at least six plastic cone-shaped entrances of hagfish/eel traps were found in its stomach along with at least seven types of fishing net, at least two types of plastic bags, a light protector, fishing line and a float from a net.

Hawaiian Monk Seals

Surfrider Foundation is asking people to collect the cones and funnels whenever they see them, to prevent them to entrap monk seals or other marine mammals. Photo by Carl Berg

Young Hawaiian monk seals, a critically endangered species, are also injured by these hagfish/eel trap parts. Their snouts get caught in the funnel-shaped parts so they are unable to feed causing starvation, weakening, and predation by sharks. National Oceanic and Atmospheric Administration (NOAA) Fisheries data indicates that 15 seal pups and one yearling have been found entangled in the Northwestern Hawaiian Islands and had the trap part removed. That is an underestimation of total entanglements as researchers spend a very limited amount of time on these remote islands.

What Do Hagfish Traps Look Like?

Traps for conger eels and hagfish eels have two parts — a black cone/funnel is attached to a tube, a five-gallon bucket or a 50-gallon barrel — so that eels can enter the trap but not escape. The hagfish/eel traps are tied to a long-line and set on the ocean floor with bait inside. Often the cone/funnel come off and break apart, leaving only the cone portion as shown stuck on the snout of a monk seal pup. Thousands of hagfish/eel trap entrance parts get detached. Cones/funnels may float for decades in the North Pacific Gyre before ending up on our shores.

Although the cones generally look alike, there are many different models used in various fisheries in the North Pacific, mainly in the East China Sea and along the west coast of North America.

Help Remove These Trap Parts

Hagfish/eel trap parts found in the stomach of the sperm whale that washed ashore at Lydgate Beach Park. Photo by Daniel Dennison/DLNR

Surfrider Foundation is asking everyone to collect the cones and funnels whenever you see them. That way they can never entrap a monk seal pup or other marine mammals. And they cannot break up into smaller plastic pieces which other marine life could eat.

If you find any hagfish/eel trap parts, please photograph them and email the photos to hagfish@surfrider.org with the date and location. Photos should be taken straight down from the wide opening (flange), especially using a light-colored background so that the dark plastic stands out. Be sure the markings on the top of the flange are visible.

Report entanglement or ingestion of hagfish/eel trap parts to NOAA marine wildlife emergency response hotline at (888) 256-9840 and email a report to Dr. Berg at Cberg@pixi.com.

• Carl Berg, PhD, of Kaua‘i is the science advisor for Surfrider Foundation-Kaua‘i Chapter.