Conservation & Sustainable Management

Are we really protecting North Atlantic right whales?

With its common name originating from whalers who, because of their tendency to float on the surface once dead, decided that they were the ‘right whale’ hunt, the North Atlantic right whale (Eubalaena glacialis) has had a somewhat difficult past with people.  By 1530s Basque whalers where happily taking these whales (and others too) off Labrador and Newfoundland in the Northeast Atlantic.  By the mid-1600s, shore-based whaling took off down the east coast of the USA.  Between 1634 and 1951, it is estimated that somewhere between 5,500 and 11,000 right whales were killed by hunters.  1935 saw the introduction of the Convention for the Regulation of Whaling – the first protection afforded to these critters but many – but not all – whaling nations (Japan and the then Soviet Union being the exceptions).  Protection was bolsters in 1949 with the International Convention for the Regulation of Whaling (IWC), which banned signatories from hunting them for commercial purposes.  In the US, they were listed under the Endangered Species Conservation Act in 1970, and the subsequent Endangered Species Act of 1973.  Canada, who is not a signatory of the IWC, has listed them under their Species At Risk Act (SARA) as Endangered.  Today it is estimated that there are somewhere between 300 – 400 individuals left, and whilst commercial whaling has ceased, they are still under threat primarily from ship strikes or entanglement in shipping gear.

To help tackle the ship strike threat, Seasonal Management Areas (SMAs) were introduced off the east coast of America in 2008.  The rules are fairly straight forward, limiting speeds to under 10 knots (18.5 km/hour) for commercial vessels larger than 65 feet (20 meters) long.  There are currently 10 SMAs, which become active seasonally to capture when right whales are actually in the area, and then deactivate when the whales should have moved off.  Alongside the SMAs, Dynamic Management Areas (DMAs) were also brought it.  These zones are implemented when aggregations of the whales are detected in areas outside the SMAs.  For 15 days after detection, mariners are asked to avoid DMAs.  If they do pass through, they are asked to voluntarily reduce their speeds.  So do these zones work to reduce ship strikes on the right whales – and indeed any other large whale population that may find itself inside these zones?  According to this latest study lead by Julie van der Hoop from Woods Hole Oceanographic Institution… sort of.

Julie and her fellow researchers obtained confirmed mortality data for a whole host of whale species – not just right whales – that were reported along the American east coast between 1990 and 2012, alongside cause of death (if identified).  They also obtained sighting data from North Atlantic Right Whale Consortium database from 1990 to 2008.  This, the team report, will help them assess the whales’ occurrence inside – and indeed outside – the SMAs.  Some statistical, spatial, and temporal analysis later, and the team were able to tell us a little more about the effectiveness of these SMAs.

First to the mortalities.  Between 1990 and 2012, 1,198 confirmed mortalities were reported along the US east coast.  Most of the whales species were identified too – good news for the researchers, but cause of death was only confirmed with certainty in 458 cases.  In line with other study findings, entanglement was the leading cause of death, followed by vessel strikes.

The sightings data indicated that just 17% of the right whale sightings between 1990 and 2008 were outside the areas that would become SMAs.  In other words, when the SMAs were implemented in 2008, they were located in areas where 83% of sighting had previously occurred.  Not bad – its tricky to capture every individual in a management zone when those individuals tend to move around a lot.  So what of the strikes themselves… are they reduced?  Well the good news is that over the years right whale ship-strikes have shown a decline… though not directly coincident with the introductions of the SMAs (the decline started from 2007, the zones were implemented in 2008).  The researchers also note that active SMAs only encompass 36% of historical right whale strikes.  32% of the historical strikes occurred when the SMAs were active, but not in the areas the SMAs covered.

So whats going on here?  Well the team believe that the decline is right-whale strikes is likely down to a combination of measures introduced earlier – like voluntary and mandatory routing changes in the Bay of Fundy.  They also suggest that the SMAs themselves may not be as effective as they could be because of low vessel compliance (estimated to be around 21 – 33% between 2009 & 2011).  They also suggest that there is insufficient monitoring to detect just how effective these management areas are…meaning the management strategy could never adapt to be ‘better’ because no one knew that there was a potential issue.  The last major issue the researchers highlight is the timing and location of the SMAs.  The SMAs cover critical habitat and calving areas for the right whales but they are missing in the ‘migratory corridor’ that run along the east coast.  It is in this corridor where whales are most often sighted, and it in this corridor where strikes were frequent outside the active SMAs.  In essence, the SMAs are “spatially insufficient in certain seasons”.

Because the researchers only included records of animals found dead (either at sea or on shore) and not those found with serious injuries that most likely lead to death, actual mortality could be underestimated…and likely is – not all dead whales end up on shore, or float on the surface until spotted.  Which brings up another point.  Where the dead whales were spotted is not necessarily where they died (especially on shore).  The researchers recognise this, but note that drift data dead whales that were struck by ships is limited, and that drift would differ with location, making it difficult to determine where the whales actually died.

The paper which was published in Conservation Letters , and has been made open access.  You can have a read of it here http://dx.doi.org/10.1111/conl.12105

 

Image: North Atlantic Right Whale.  Credit Florida Fish and Wildlife Conservation Commission/Flickr (CC BY-NC-ND 2.0)

Conservation & Sustainable Management, Marine Life

Whale Watch Out (ship strikes on whales)

Humans have always had an impact on whales.  From prehistoric times, whaling was a key feature of many human communities.  Meat, skin, and organs provided food.  Bones became tools, and baleen a strong fibrous material for fishing lines, roofs, and baskets.  With the industrialization of an unregulated commercial whaling industry, whale numbers plummeted across the globe.  On 2nd December 1942 the International Convention for the Regulation of Whaling which was signed.  The International Whaling Commission (IWC) was established to ensure “the proper conservation of whale stocks and thus make possible the orderly development of the whaling industry”.  Today, whaling has largely declined, undertaken by just a handful of countries and whale-dependent communities.  Never-the-less the human impact on this enigmatic group has not ceased.  Like many marine species, whales can be impacted through overfishing their prey, ocean warming and acidification, noise pollution, toxins in the water, and loss of essential habitat.  Perhaps most noticeable to the public is when whales come into contact with vessels, seemingly often with fatal results.

 

A number of cases of whale strikes have made the news.  In September 2010 a blue whale was found on a cargo ship bow in the Port of Oakland.  April 2014, a fifty-five foot fin whale was found on a container ship bow in New York Harbour.  It’s not just commercial shipping that poses a strike risk to whales.  Going through historical reported strikes on humpback whales in Hawaiian waters, researcher Dr Marc Lammers from the Hawaii Institute of Marine Biology discovered that 61% of the strikes involved tour boats – whale watchers, snorkelers, and divers.  This only reflects reported strikes, with “The lack of incidents reported involving large ships [being] somewhat curious“.  Not everyone reports strikes, even when they are supposed to do so.  With the data we do have, the impact of strikes on some whale populations appears somewhat minimal.  The endangered North Pacific humpback population, Dr Lammers notes, is currently experiencing an estimated 6% annual increase in population size.  More recently, University of Washington Doctoral student Cole Monnahan noted that the endangered eastern North Pacific blue whale population has also experienced an increase, with ship strikes having little impact on their recovery.  More so, Cole and colleagues estimate that an 11-fold increase in strikes would result in a 50% change that the long-term population would drop below ‘depleted’ levels.   Not all whale populations have experienced recovery though.  Despite commercial whaling of the Antarctic blue whale ceasing in 1972, analysis lead by aquatic and fisheries scientist Dr Trevor Branch of the University of Washington estimated that the population continues to remain just under 1% of its pre-hunted abundance.  For such populations, strikes may impede population recovery.

 

Regardless of population status, strikes are undesirable.  “Nobody wants to hit a whale” states John Berge, Vice President of the Pacific Merchant Shipping Association, “for the same reasons that nobody driving down the highway wants to hit a deer, or a possum, or a skunk”….

The full article was published and can be read in The Marine Professional – a publication of the Institute of Marine Engineering, Science & Technology (IMarEST)

Image: By Pier Nirandara/Flickr (CC BY-NC-ND 2.0)

Conservation & Sustainable Management

How not to hit a whale:  Move the shipping lane

Coming in at around 170 tonnes The blue whale (Balaenoptera musculus) is the heaviest animal known to have existed on Earth.  This huge critter feeds on some of the smallest, filtering zooplankton through its baleen plates that hang from its upper jaw.  The blue whale as a group (there are several sub-species) is unfortunately listed as Endangered on the IUCN Red List.  Commercial whaling certainly took its toll on the global population and was, without a doubt, the most threatening of human activities to these large enigmatic creatures.  With commercial whaling now largely ended, the human threat to their persistence has declined greatly.  But there are still incidents between humans and the blues, like entanglement in fishing gear and marine litter, noise pollution that can hamper their communication, and ship strikes.  Certainly the recovery of the blues in the eastern North Pacific isn’t as good as we would expect, but the reasons for this somewhat lacklustre comeback are much harder to pin down.  Many avenues need to be explored – including seemingly infrequent events like ship strikes.

Ladd Irvine of Oregon State University and a team of researchers wanted to take a closer look at blue whale movements off California, an area which also contains a great deal of shipping activity.  When looking at movement of any population, it’s really important to get as much historical data as possible because animals can vary their movements year on year.  The team used 15 years’ worth of data collected from 171 tagged whales.  These satellite monitored radio tags are pretty nifty pieces of kit, collecting the time and location of the whales at the surface and transmitting to satellites.  With this wealth of data, the team set to work figuring out which areas of the Californian coast are particularly important to blue whales.  Sure enough, some rather interesting patterns emerged.

Blue whales are attracted to the west coast of the US during the summer months to feast on the large numbers of krill found in the California Current System.  The krill are super-abundant during this time as a result of upwellings that increase productivity in the region, and by currents and the bathymetry (equivalent to topography – how the sea floor looks) of the area that concentrate the krill into certain areas.  As you might expect, the blue whales concentrated in areas where krill was most abundant.  Early in the summer the whales tended to stay in the more southerly sections, where upwelling intensity (and thus productivity) is fairly moderate.  During October and November the northern section of California experiences much stronger upwellings, and sure enough that’s exactly where the whales tended to hang out.  The whales don’t just head up north around the same time every year though.  Because the tracking data spanned 15 years, the researchers were able to compare movements over multiple years.  The timing of the more intense northerly upwelling varies year on year, and it was quite apparent that the whales tailored their northerly migration in line with this variation.  With variation in krill availability, you might expect that the whales would stay in California waters as long as krill abundance was high enough to give a decent meal.  Interestingly, the whales didn’t really alter when they continued on their migration out of California in line with productivity timings.  There was only one notable time when they did leave significantly later – in 2004.  What’s so special about 2004?  Well not much.  There was a weak  El Niño, but the researchers note that it didn’t really have an impact in the California Current System.  1999 was a super-productive year in the California Current System and no doubt prey was super-abundant.  Did the whales hang out there for longer than usual?  Nope!

So far so good, but the tracking data also revealed some potential issues.  The blues tended to be most concentrated alongside areas where human population is high, and where there are busy ports.  Busy ports means busy shipping lanes, which run straight through the places where the whales can be found.  Now remember that ship strikes are thought to be relatively infrequent, but the question is how do we know if there has been a ship strike?  Well first of all we have to know we have hit a whale.  Sounds daft, but if you’re in a huge freight vessel you might not notice.  You might also hit a whale and injure it (with unknown survival), or you might fatally hit a whale, and just not report it.  We do have evidence that on the whole ship strikes are on the increase, and this paper makes a seemingly simple suggestion to reduce the likelihood of a strike on a blue whale: move the shipping lane during the months when the whales are migrating through.  Of course such a move is an economic, political, and social minefield, but it’s not impossible – and there is a prescient.  Twelve years ago shipping lanes in the Bay of Fundy, Canada were moved just 6 km away from a key North Atlantic right whale feeding ground.  Since then, the right whale population has shown a small increase.  Of course correlation doesn’t imply causation, but it is food for thought.

This paper is published in the open access journal PLoS ONE.  Have a read of it here http://dx.doi.org/10.1371/journal.pone.0102959

Image:  Blue whales aren’t the only whale species to be susceptible to ship strikes.  This image shows an North Atlantic right whale (Eubalaena glacialis) who died after colliding with a vessel and suffering significant propeller cuts.  Credit: NOAA National Marine Sanctuaries/Center for Coastal Studies (Public Domain Licence)