What follows is a cautionary tale. A story about acting out in frustration; of letting passions get the better of our collective judgement. A yarn of life, economy, adventure, and...tourists.
Folks living in major coastal towns around the world know the story. As the days lengthen the sun's rays warm the air and the scent of dry grass drifts in the breeze. Locals finally get on the water as the rains and long dark of winter are left behind. But that's when they come: massive, constantly in the way, slowly moving in impassable groups, gorging themselves on an all you can eat buffet.
Folks living in major coastal towns around the world know the story. As the days lengthen the sun's rays warm the air and the scent of dry grass drifts in the breeze. Locals finally get on the water as the rains and long dark of winter are left behind. But that's when they come: massive, constantly in the way, slowly moving in impassable groups, gorging themselves on an all you can eat buffet.
Courtesy: Devin Braun via Flickr
I am, of course, talking about basking sharks (Cetorhinus maximus).
-"Hey, Kool-Aid"
Courtesy: jidanchaomian via Flickr
Basking sharks and cruise ship travelers may not seem to have much in common at first, but diving in (Ha! Ocean puns) to their life history reveals some surprising commonalities.
Baskers are the second largest fish species in the world, growing to average lengths of 15-20 feet, but they can get as long as 30. Because they're so big; a single flick of a basking shark's tail moves a lot of water and thus their streamlined bodies are propelled smoothly along with very little effort. This energy efficient movement allows basking sharks to travel great distances through temperate seas. One shark was tagged in late June of 2007 between Ireland and the UK, and had traveled all the way across the Atlantic to south of Greenland by early August. Like other related sharks that make long treks, basking sharks are cruising in search of food. But these massive fish aren't hunting for seals or other large prey; they're cruising along, mouths agape, straining plankton from the water. The filters on their gills are so good at collecting particles, yet remaining unclogged, that they're even inspiring engineers designing industrial and commercial water and air filters.
Basking sharks migrate seasonally across the ocean, and daily up and down in the water column following their favorite food: calanid copepods (pronounced: ko-peh-pods).
Copepods are rich in fats despite their constant failed attempts
at stealing the Krabby Patty secret formula.
Courtesy: DFO via WOrld Register of Marine Species
During the winter these planktonic crustaceans tend to hang out deeper in the water and farther out to sea, so baskers do the same. During the summer, copepod populations explode near shore as lengthening days cause massive blooms of phytoplankton for the copepods to graze on. Basking sharks head shoreward just ahead of this explosion of life to catch the bloom right as it begins and optimize their own feeding. Like most other zooplankton, copepods also participate in the planet's largest migration. During the day they descend to avoid active predators at the surface, and at night they come up to the phytoplankton rich layer that formed while the sun was high. Typically basking sharks do the same daily vertical migration, but occasionally tons of copepod predators called arrow worms will show up at the surface at night. This unexpected pulse of predators drives the majority of the copepods, and consequently the basking sharks, deep when we'd expect them to be shallow. So not only do basking sharks show up in the inland waters of the far north and south like cruise ships and their passengers, but they also predictably attend to the abundance of the buffet at the times of day it's most well stocked.
Basking sharks' feeding and travel habits aren't the only ways they jive with tourists. As their name implies, basking sharks often hang out in the sun not doing much. Since the sharks already have a pretty bitchin', deep-brown tan they must not be longing to soak up rays. Nope, it's that layer of copepods again. Because there's so much food at the surface, basking sharks don't have to move fast or far during the spring and summer blooms. The sharks are found in aggregations hundreds strong just lolling at the surface with their mouths open like they've fallen asleep sunbathing.
Okay I know there's a shark in this picture somewhere but...
Courtesy: candiche and Noodles and Beef via Flickr
These high concentrations of slow moving basking sharks occur in only a few places in the world. It's likely that these big shivers (the name for a group of sharks) show up in places like southern Chile, but we only know for sure that they happen in the Irish Sea, outside the Bay of Fundy, and historically in the Northwest Straits of the Salish Sea.
Just in case you're not from one of those places or didn't pay attention in geography
Now, you might have noticed that I said "historically" in the Salish Sea. In the past, basking sharks came to the region in droves every year to bathe in the Pacific Northwest sun and chow on the rich abundance of copepods in those waters. But like any pulse of summer tourists visiting a port; they were slow, in the way, and causing problems for traffic.
I'm lookin' at you; Pike Place!
Courtesy: Michael Munch via Flickr
As happens with anyone who deals with influxes of tourists too often; salmon fisher folk in British Columbia largely hated this yearly migration. The sharks were so numerous and slow that they frequently became entangled in salmon gill-nets. Basking sharks also have the same skin-teeth that other sharks possess, so when they thrashed to free themselves they often destroyed more of the net than just where they were caught.
Since much of the BC economy relied on salmon fishing at the time, basking sharks were listed as "Destructive Pests" by Canada's fisheries department in 1949. Six years later the department began an eradication program that, coupled with a commercial fishery for their skin and oil, did exactly as intended. Basking sharks were functionally extinct in the Salish Sea by the late 60s.
The Comox Post with its shark-slicing bow blade
was the pride of the program.
Courtesy: Popular Mechanics via Google Books
However attitudes towards basking sharks (and to a lesser degree cruise tourists) are changing. People better understand the role baskers play in the marine ecosystem as the massive end of a petite food chain. Ironically basking sharks now bring tourists to the Irish Sea and surrounding waters every year to watch their incredible shivers. Having basking sharks and cruise tourists around can greatly enhance the economies of northern port towns in the summer. And Lord knows we can use that extra cash for good beer and faux daylight to get us through the dreary mists of maritime winters.
There's also hope for the Salish Sea's population of basking sharks. They've been granted the protections that being listed as "endangered" under Canada's Species At Risk Act affords them since 2010. Baskers are also occasionally showing up in unexpected parts of the Salish Sea. In 2014 a basking shark gave a family out fishing a unique encounter when it basked about their boat for 15 minutes off of Edmonds, just 16 miles north of Seattle. No word on if the shark was planning to visit Pike Place.
" Excuse me, can you tell me how to get to the gum wall?"
Courtesy: Grace Coale via Q13 Fox
Baskers are the second largest fish species in the world, growing to average lengths of 15-20 feet, but they can get as long as 30. Because they're so big; a single flick of a basking shark's tail moves a lot of water and thus their streamlined bodies are propelled smoothly along with very little effort. This energy efficient movement allows basking sharks to travel great distances through temperate seas. One shark was tagged in late June of 2007 between Ireland and the UK, and had traveled all the way across the Atlantic to south of Greenland by early August. Like other related sharks that make long treks, basking sharks are cruising in search of food. But these massive fish aren't hunting for seals or other large prey; they're cruising along, mouths agape, straining plankton from the water. The filters on their gills are so good at collecting particles, yet remaining unclogged, that they're even inspiring engineers designing industrial and commercial water and air filters.
Basking sharks migrate seasonally across the ocean, and daily up and down in the water column following their favorite food: calanid copepods (pronounced: ko-peh-pods).
at stealing the Krabby Patty secret formula.
Courtesy: DFO via WOrld Register of Marine Species
During the winter these planktonic crustaceans tend to hang out deeper in the water and farther out to sea, so baskers do the same. During the summer, copepod populations explode near shore as lengthening days cause massive blooms of phytoplankton for the copepods to graze on. Basking sharks head shoreward just ahead of this explosion of life to catch the bloom right as it begins and optimize their own feeding. Like most other zooplankton, copepods also participate in the planet's largest migration. During the day they descend to avoid active predators at the surface, and at night they come up to the phytoplankton rich layer that formed while the sun was high. Typically basking sharks do the same daily vertical migration, but occasionally tons of copepod predators called arrow worms will show up at the surface at night. This unexpected pulse of predators drives the majority of the copepods, and consequently the basking sharks, deep when we'd expect them to be shallow. So not only do basking sharks show up in the inland waters of the far north and south like cruise ships and their passengers, but they also predictably attend to the abundance of the buffet at the times of day it's most well stocked.
Basking sharks' feeding and travel habits aren't the only ways they jive with tourists. As their name implies, basking sharks often hang out in the sun not doing much. Since the sharks already have a pretty bitchin', deep-brown tan they must not be longing to soak up rays. Nope, it's that layer of copepods again. Because there's so much food at the surface, basking sharks don't have to move fast or far during the spring and summer blooms. The sharks are found in aggregations hundreds strong just lolling at the surface with their mouths open like they've fallen asleep sunbathing.
Courtesy: candiche and Noodles and Beef via Flickr
These high concentrations of slow moving basking sharks occur in only a few places in the world. It's likely that these big shivers (the name for a group of sharks) show up in places like southern Chile, but we only know for sure that they happen in the Irish Sea, outside the Bay of Fundy, and historically in the Northwest Straits of the Salish Sea.
Now, you might have noticed that I said "historically" in the Salish Sea. In the past, basking sharks came to the region in droves every year to bathe in the Pacific Northwest sun and chow on the rich abundance of copepods in those waters. But like any pulse of summer tourists visiting a port; they were slow, in the way, and causing problems for traffic.
Courtesy: Michael Munch via Flickr
As happens with anyone who deals with influxes of tourists too often; salmon fisher folk in British Columbia largely hated this yearly migration. The sharks were so numerous and slow that they frequently became entangled in salmon gill-nets. Basking sharks also have the same skin-teeth that other sharks possess, so when they thrashed to free themselves they often destroyed more of the net than just where they were caught.
Since much of the BC economy relied on salmon fishing at the time, basking sharks were listed as "Destructive Pests" by Canada's fisheries department in 1949. Six years later the department began an eradication program that, coupled with a commercial fishery for their skin and oil, did exactly as intended. Basking sharks were functionally extinct in the Salish Sea by the late 60s.
was the pride of the program.
Courtesy: Popular Mechanics via Google Books
However attitudes towards basking sharks (and to a lesser degree cruise tourists) are changing. People better understand the role baskers play in the marine ecosystem as the massive end of a petite food chain. Ironically basking sharks now bring tourists to the Irish Sea and surrounding waters every year to watch their incredible shivers. Having basking sharks and cruise tourists around can greatly enhance the economies of northern port towns in the summer. And Lord knows we can use that extra cash for good beer and faux daylight to get us through the dreary mists of maritime winters.
There's also hope for the Salish Sea's population of basking sharks. They've been granted the protections that being listed as "endangered" under Canada's Species At Risk Act affords them since 2010. Baskers are also occasionally showing up in unexpected parts of the Salish Sea. In 2014 a basking shark gave a family out fishing a unique encounter when it basked about their boat for 15 minutes off of Edmonds, just 16 miles north of Seattle. No word on if the shark was planning to visit Pike Place.
Courtesy: Grace Coale via Q13 Fox
References:
Gore et al., "Transatlantic Migration and Deep Mid-ocean Diving by Basking Shark", Biology Letters: Marine Biology, Vol. 4 pg. 395-398, 2008.
Accessed via: http://rsbl.royalsocietypublishing.org/content/4/4/395
Lorch, Matt, "Close Encounter with Rare 25-foot Basking Shark in Puget Sound: "I didn't really feel scared, just excited", Q13 Fox News, Aug. 13th 2014
Pynn, Larry, "Rare B.C. Photograph of Endangered Basking Shark Shines Light on Change in Federal Attitudes", Vancouver Sun, Nov. 11th, 2013.
Accessed via:
Sanderson et al., "Fish Mouths as Engineering Structures for Cross-step Vortical Filtration", Nature Communications, Vol. 7, Article #11092, 2016.
Accessed via: https://www.nature.com/articles/ncomms11092
Siders et al., "Seasonal Variation in the Spatial Distribution of Basking Sharks (Cetorhinus maximus) in the Lower Bay of Fundy, Canada", PLoS ONE, Vol 8 Issue 12, 2013.
Sims et al., "Habitat-specific Normal and Reverse Diel Vertical Migrationin the Plankton-feeding Basking Shark", Journal of Animal Ecology, Vol. 74 pg. 755-761, 2005.
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