Saturday, April 11, 2015

Sea Lion Pulls Fisherman Off Boat, Whales Take Cod Off Lines. Following Loose Threads

It's hard to make sense of the news these days.  (Well maybe always.)  We get snippets, sometimes serious, sometimes not, that are often out of context.  Let's look at a couple of recent stories in the Alaska Dispatch:


1. Fisherman bitten, pulled off boat by sea lion in San Diego's Mission Bay

This man-bites-dog story seems to have been written for News of the Weird. Man holds up fish on boat for trophy picture and seal jumps out of the water and pulls the man in.  It's not clear what happened to the fish;  the article says the man was snatched by the sea lion "while attempting to
From old post on Seal Lfe Center Seward
snatch the large fish."  

What's missing from this story?  There have been a number of stories - including the Time magazine Feb. 18, 2015 story on the massive die-offs of sea lion pups in Southern California. 
"Experts at NOAA say that the culprit is rising ocean temperatures. (On a call with reporters Wednesday, a NOAA climate expert said that they do not believe the stranding increase is tied to climate change.) The warm temperatures are somehow affecting the squid, sardines and other animals that are the core diet of sea lions, perhaps driving the prey deeper into the water or farther offshore. So when mothers swim off to forage from the Channel Islands, where pups are weaned every year, they are having to stay away longer before they can come back.   .   . 

The root cause of the crisis, officials believe, is the odd wind patterns that aren’t cooling the ocean like they normally do. They aren’t certain of what’s behind the lack of cold winds, but they believe the patterns are creating a ripple effect through the food chain. The sea lions, at the top of that chain, are signaling that bigger things may be amiss among the larger marine food web. “There are a lot of puzzles here that we’re trying to put together,” says Nate Mantua, a NOAA climatologist. 'We don’t understand it. It’s a mystery.'”
Why are they dying?
"[T]hey do not believe the stranding increase is tied to climate change."  
But later on it says,
"We don't understand it.  It's a mystery."  
They think that
"warm temperatures are somehow affecting the squid, sardines and other animals that are the core diet of sea lions, perhaps driving the prey deeper into the water or farther offshore."

Is this related to climate change?  They think not, but they really don't know the cause.  But they believe there there's
"a ripple effect through the food chain."  

Was the sea lion that pulled the fisherman overboard particularly hungry because there's a sea lion food shortage?  The story never mentioned that.  And I don't know if this is affecting older sea lions or just the food they feed the pups.  But I suspect there's a bigger story we don't understand yet.

2.  Fish-stealing whales take bite out of black cod harvest in Gulf of Alask

This story goes into much more depth.  It's not a man-bites-dog story at all.  It's not a 'funny' one time event.  Rather it's come up at the North Pacific Fishery Management Council (which is currently meeting in the Hilton in Anchorage April 6-15 and whose agenda is here) and is being taken seriously because the whales are taking, according to federal surveys cited in the article
"under 10 percent of the annual harvest of the more than 360 Gulf of Alaska vessels that fish for black cod."  
They also report, 
"One study found that killer whales can reduce the catch by an average 65 percent."  
I'm guessing that the 65% figure could be for an individual boat, but the impact on the overall fishery is closer to the 10% level.  

Loose thread  (thoughts I want to raise, but don't have time to pursue in depth):  

1.   Seems to me that there's some sort of connection(s) between a hungry seal lion trying to snatch fish from a San Diego fisherman and whales  on cod hooked on long lines from Gulf of Alaska trawlers.  Both incidents involve mammals taking fish from humans.  What else might connect them?

2.  There's a clear human-centric bias here that pits the sea lion and the whales as the criminals, but to what extent does it make sense to ask how much fish are humans taking away from sea mammals and other sea creatures and how is that affecting their available food supply?  To be clear, the article says the sperm whales seem to be thriving and they've learned that the trawlers mean easy pickings.  

3.  Also not mentioned, is that the nearby pollock fishery's halibut by-catch for this year is predicted to be 92% of the allowable Bering Sea halibut for 2015. From an ADN opinion piece by David Bayes:
The International Pacific Halibut Commission has proposed a 70 percent reduction in halibut harvest for the central Bering Sea region, the most recent cut in a steady quota decline. In the meantime, halibut bycatch caps in the region's trawl fisheries have remained largely unchanged for decades. If these numbers hold true for the 2015 season, 92 percent of halibut harvested in the Bering Sea will go overboard as bycatch. You read that right, 92 percent of the allowable halibut catch is caught, smashed in the nets, and then shoveled back into the water. While some portion is allowed to be donated to food banks, millions of pounds each year are discarded. 
So, if you're not worried about starving sea lions or hungry whales (that may actually benefit from the bycatch going back into the sea), you might care about rural Alaskans who depend on halibut fishing for their living and much of their nutrition.

3.  Ocean acidification triggered devastating extinction, study finds

This one is from the LA Times and was republished today in the Alaska Dispatch News.  It looks at a huge marine die off
"the Permo-Triassic Boundary mass extinction event, happened some 252 million years ago, which over the course of about 60,000 years is thought to have wiped out more than two-thirds of land species and more than 90% of marine species on the planet."
[I tend to take explanations of what happened 252 million years ago with a grain of salt.  I have a lot of respect for what scientists can do, but they taking a few clear facts and project a possible story.  They could be spot on, but I can't find the 252 million year old archives on google to support it.] 

I know that ocean acidification is again a problem - this time human, not volcano caused - and it's possible there's a connection between the hungry sea lions and ocean acidification.

I know that when people find a lucrative and satisfying way to earn a living, they get pretty hostile to events that threaten that.  Their perception of the situation narrowly focuses on the personal impact they foresee.  Southerners saw the abolition of slavery as a threat to their way of life, and some are still fighting that battle.  But those of us not so directly affected need to be able to more rationally assess the situation and come up with options that are don't ignore those most impacted (fishers here), but that are best for society as a whole into the future as well as for the planet. 

There's a lot humans don't understand, but I do know that for every 'event'  there are usually many, many factors that play a role.  It's not a clear, A caused B relationship.  But there are a lot of C's, D's, E's, etc. that work, perhaps independently, to influence each other and the major events.  They may slow things down or speed them up.  Their combined impact may be to maintain the status quo, or to tip it in one direction or another. 

But the basic point I wanted to make is that there is usually much, much more to every news report  - whether it's about a shooting, an election, or a marine mammal-human conflict over fish - that doesn't get into the article.  And even when the media doesn't provide the details, readers should be asking for them. 

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