Wolffish: Preying for Help, by Rachel Villalobos

You would think having a name like “wolffish” would mean to stay away at all costs, but the Atlantic Wolffish (Anarhichas lupus) is actually not aggressive towards people and generally sedentary in nature. Their name can be attributed to the large canine teeth that protrude from their powerful jaws, used for hunting and eating hard-bodied invertebrates, including crabs, sea urchins, and snails (Figure 1). Consequently, wolffish play a vital role in the regulation of these prey species, namely sea urchins and green crab. Because the Atlantic Wolffish is generally sedentary, they prefer specific rocky habitats that allow them to hide and catch prey (Keith and Nitschke, 2008). 

 

Figure 1. Atlantic Wolffish (Anarhichas lupus) eating a sea urchin. Source 

 The fish are historically found in the deep, cold waters of the north Atlantic Ocean, and in U.S. waters throughout the Gulf of Maine and as far south as New Jersey (Rountree, 2002). Unfortunately, the range of habitat has diminished greatly over the past few decades due to habitat destruction, and the Wolffish is now only found clustered in three different areas of refuge in the Gulf of Maine, Georges Bank, and the Great South Channel (Nelson and Ross, 1992). Despite this fact, many conservation organizations and agencies list the conservation status of the Atlantic Wolffish under least concern. NOAA has denied the addition of the species onto the Endangered Species Act due to their high numbers in Canadian waters (Cosgrove, 2009). However, this is due to the fact that Canada began protecting the Atlantic Wolffish several years ago under their Species at Risk Act. Shouldn’t the U.S. then list the Atlantic Wolffish under the Endangered Species Act? Regardless of what these organizations and agencies say about the status of the Wolffish, there is solid evidence of a need for protection that is not being met by the U.S. The Atlantic Wolffish should be listed under the Endangered Species Act because it plays a vital role in the marine ecosystem and the population has been in steady decline for the past 30 years.

Although it may not be the most widely known fish in the sea, the Atlantic Wolffish is considered by many ecologists as a keystone species in the north Atlantic Ocean food webs (Dowdell, 2015). When left unchecked, sea urchins, a major prey of wolffish (Keats, 1986), create what’s known as an urchin barren. An urchin barren is an area that was once a flourishing kelp bed or kelp forest that has been grazed bare and results in hundreds of sea urchins left on the rocky platform (Andrews, 2013). Once the sea urchin population has reached this size, it’s much harder to regulate and reverse the damage that has been done, so it’s best to control the numbers before they can cause an issue as damaging as an urchin barren. By keeping the sea urchin population low, kelp forests can thrive which provides numerous benefits to marine life (Just, 2012). Many species seek shelter in the kelp forests and feed on the seaweed. Kelp also is very important to carbon sequestration, the regulation of CO_2, not only in the ocean but in the atmosphere as well (Weatherall, 2014). In the face of climate change and rising atmospheric carbon dioxide levels, we can’t afford to lose such beneficial seaweed. However, if the Atlantic Wolffish population is unable to prey upon sea urchins and control their population size, kelp forests will be wiped out and negatively impact the surrounding marine world. In order to keep this from happening, the wolffish needs to be properly protected and thus should be listed under the Endangered Species Act. 

 

Figure 2. U.S. Wolffish landings from 1950-2011  Source

The Atlantic Wolffish has found itself in the middle of a sadly ironic situation; not only are humans the key to the population’s stability, but we are also the main cause of its decline. Over 1,200 metric tons (900,000 lbs) of wolffish were caught in 1983, which was the peak for U.S. landings of the Atlantic Wolffish (Figure 2). Since then, U.S. landings have decreased 97% to about 31.6 metric tons. Although there has been such a large decline in the commercial catch of wolffish, they still face a large threat by being unintentionally caught as bycatch, primarily in the otter trawl fishery (Keith and Nitschke, 2008).  They are also impacted by trawling and dredging, which tears up the seafloor and destroys their rocky habitat (Anderson, 2009). This specific habitat is important for hunting and protection for their young. Eggs are hidden in clusters under rocks and guarded by the male for 9-10 months (Fairchild, 2013). Without this specific rocky habitat they are susceptible to predation and have a decreased chance of survival. It was even estimated that practically every inch of the seafloor off the coast of New England was impacted by this form of modern fishing gear between 1984 and 1990 (Barth, 2009). While it is prohibited from being brought to shore and sold, the Atlantic Wolffish is still caught as bycatch and often thrown back into the water dead and uncounted (Keledjian, 2014). Despite being classified as a Species of Concern in 2004, and a total ban on the possession of Atlantic Wolffish by the New England Fishery Management Council (Anderson, 2009), populations are still declining due to bycatch and habitat destruction.

The only chance the Atlantic Wolffish has for survival is if the government decides to take matters into their own hands. They have allowed the decline of such an important species to go on for far too long, and it’s time that they took some responsibility for it. Current population estimates do not exist, and without stock structure studies our ability to manage the declining population is significantly impaired (Dowdell, 2015). Why there is a lack of current data on the population size is truly baffling. All we have to go on is how often the species is caught in trawl surveys, which has steadily been declining since the 1980s (Figure 3 and Figure 4). 

 

Figure 3. Decline in number of Wolffish caught in trawl surveys of the Western Gulf of Maine.  Source

If the Atlantic Wolffish population continues to decline, as last seen in 2009, then the negative impacts will become too big to ignore. The sea urchin population will exponentially increase, kelp forests will be depleted and CO₂ levels will rise, just to name a few. Without more strict governmental regulations, the wolffish will continue to be affected by modern fishing techniques, specifically otter trawls, to a point that recovery may no longer be viable. There is no longer a question of whether or not the Atlantic Wolffish is a species of concern or if it should be listed under the Endangered Species Act. With all the evidence that surrounds us, we can’t ignore the foreseeable outcome as to the fate of this keystone species. The Atlantic Wolffish needs to be listed under the Endangered Species Act due to the crucial role it plays in the north Atlantic Ocean food web and the fact that population numbers have been steeply declining over the past couple decades.

 

Figure 4. Positive tows (Wolffish caught) from NEFSC bottom trawl surveys in the fall. Source.

References

Anderson, J., et all. 2009. Status Review of Atlantic Wolffish (Anarhichas lupus). National Marine Fisheries Service. NOAA.

Andrews, K. 2013. Sea urchins and  biodiversity. Explore the Seafloor. ABC Science and Integrated Marine Observing System (IMOS).  http://exploretheseafloor.net.au/the-science/urchins-biodiversity/  {accessed June 13, 2016}

Barth, B. 2009. Federal Officials Begin Official Review of Endangered Listing for Atlantic Wolffish: Announcement Marks Major Step Forward in Protection for One of New England’s Most Threatened Species. Conservation Law Foundation. http://www.clf.org/newsroom/federal-officials-begin-official-review-of-endangered-listing-for-atlantic-wolffish-announcement-marks-major-step-forward-in-protection-for-one-of-new-englands-most-threatened-fish-species/ {accessed June 13, 2016}

Cosgrove, S. 2009. Wolffish Protection Delayed is Wolffish Protection Denied. Conservation Law Foundation. http://www.clf.org/blog/wolffish-protection-delayed-is-wolffish-protection-denied/  {accessed June 13, 2016}

Dowdell, S. 2015. Fish Friday: The Atlantic Wolffish – Antifreeze Included. New England, Ocean Odyssey. http://newenglandoceanodyssey.org/fish-friday-the-atlantic-wolffish-antifreeze-included/ {accessed June 13, 2016}

Fairchild, E., et al. 2013. Spring feeding of Atlantic wolffish (Anarhichas lupus) on Stellwagen Bank, Massachusetts. Fishery Bulletin 113:191-201

Just, R. 2012. Atlantic Wolffish: A Face only a Mother Could Love? New England, Ocean Odyssey. Conservation Law Foundation.http://newenglandoceanodyssey.org/atlantic-wolffish-a-face-only-a-mother-could-love/ {accessed June 13, 2016}

Keats, D., et all. 1986.  Atlantic wolffish (Anarhichas lupus L.; Pisces: Anarhichidae) predation on green sea urchins (Strongylocentrotus droebachiensis). Canadian Journal of Zoology 64(9): 1920-1925

Keith, C. and P. Nitschke. 2008. Atlantic wolffish. Northeast Data Poor Stocks Working Group Meeting, Northeast Fisheries Science Center. http://www.nefsc.noaa.gov/publications/crd/crd0902/wolffish/origwolffish.pdf {accessed June 13, 2016}

Keledjian, A., et all. 2014. Wasted Catch: Unsolved Problems in U.S. Fisheries. Oceana, Inc.

Nelson, G. A., and M. R. Ross. 1992. Distribution, growth and food habits of the Atlantic wolffish (Anarhichas lupus) from the Gulf of Maine-Georges Bank region. Journal of the Northwest Atlantic Fishery Science 13:53-61.

Rountree, R. A. 2002. Wolffishes: Family Anarhichadidae. In Bigelow and Schroeder’s fishes of the Gulf of Maine. Smithsonian Inst. Press, Washington D.C.

Weatherall, G. 2014. Ocean Plants Part 3: Kelp and Climate. New England, Ocean Odyssey. Conservation Law Foundation. http://newenglandoceanodyssey.org/ocean-plants-part-3-kelp-and-climate/  {accessed June 13, 2016}