Posted on May 22 2018
Nature is messy. There are a billion sub-systems within an ecosystem, and there are so many variables that things don’t run like clockwork. However, the wonder of nature is that while excesses and scarcities of resources and populations continually occur, the overall function is to pull the operation back toward balance. The concept of homeostasis in a population says that there may be rises and falls in the numbers of individuals, but that in the longer run, there is a middle number around which the species in question will oscillate. This results in people remarking that it was a good year for salmon, or that the deer hunting was plentiful, or not so good. The supply swells and wanes, but it’s always out there. A famous case where they seemed to disappear altogether was seen decades ago on the California coast.
Monterey Bay has always offered a wealth of fishing. Early Chinese immigrants made good use of the resources of this rich pocket of the Pacific as far back as the mid-1800s. Monterey the town, thanks to its scenic setting and the establishment of rail service, began to draw tourist attention in the latter part of that century. Some rather upscale hotels and houses were built as this traffic increased. Fishing continued, however, and was spurred to greater heights by the needs of soldiers in World War I. Canneries that had started up in the early 1900s supplied portable protein in the form of canned sardines for doughboys fighting in Europe, and the increasing use of purse seine fishing boats meant large catches and greater efficiency in landing them. Somehow, the sardines just kept on coming, no matter the volume of the take. The jobs provided by plentiful fish remained a valuable engine of commerce during the Depression years, though a large percentage of the enormous tonnage went into fertilizer rather than human mouths. The Second World War brought the need for yet more expansion of the fisheries and the canneries—the sardines were pulled from the sea in staggering numbers to once again feed the troops. About this time, author John Steinbeck wrote his famous stories of Cannery Row and the quirky characters who inhabited this outpost of fish production, but the boom was just about over. The mid-1940s saw the last peak of sardine catches, and the numbers dropped precipitously thereafter. Returns in the early ‘50s were terrible, and a few years later, there was no sardine fishery left in Monterey Bay, or anywhere else on the West Coast.
What had caused the collapse? It was the subject of endless speculation. Overfishing was the most obvious culprit to point to, but many fishermen refused to believe it, and searched for alternative explanations: the atomic bomb explosions in the Pacific, submarines and torpedoes, an exodus of sardines to a safer home away from fishing boats—and some even blamed the huge Alaskan earthquake of 1964. The fish, and therefore the industry, were gone, and Monterey had to find its way to a new economy, once again centered around tourism. But the purse seiners hadn’t fished every single last sardine out of Monterey Bay. With the pressure off the sardine population, the fish that were left had a chance to regroup. Numbers slowly grew, but well short of commercial viability, for a long time. Not until the mid-1980s did a resurgence begin and a sardine fishery become re-established. But further dips and climbs made for an uneven recovery. The last big peak was in 2007, and since then it has been downhill to zero catch today, even as a ban on sardine fishing goes into its fourth year. The fishery has been managed for decades, unlike in the boom years and the 1950s crash days, so why do the fish keep disappearing? As before, speculation abounds, but so does good science. Many studies have been conducted trying to find the answer.
Among several possible causes is cyclical ocean temperature swings. There is no one-for-one correlation between colder water and fewer sardines, but there is some similarity in the fluctuations. Sardines are partial to relatively warmer waters. When the ocean along the West Coast chills, sardines generally grow scarcer and anchovy numbers rise, and the return of warmer water makes for improved sardine conditions. But the influence is still in dispute, and the fish may be varying their numbers due to different factors. Some suggest that because sardines are relative newcomers—evidence of their occurrence on the Pacific coast goes back to no further than 7,000 years ago—they may still be adjusting their numbers in response to a “new” environment. Their populations definitely go through cycles of boom and bust over periods of decades, and have done so for many hundreds of years, as seen in fish-scale evidence taken from ocean-floor coring. There is no doubt that fishing is a factor in their decline, but it may be something of a coup de grace when their numbers are on a natural downturn. Careful management is therefore crucial to keeping them out of critical danger. More than just humans depend upon a healthy sardine population. Seabirds, seals, and other marine mammals suffer when forage fish like sardines crash—it’s the small creatures in an ecosystem that form the broad base of the food chain, and their loss is significant.
We know a lot more about ocean systems than we did decades ago, but our knowledge is still painfully scant, and the number of variables in the depths make it very challenging to point to a cause, or to devise a solution. The new normal of climate change means old assumptions may be fairly worthless, and the picture seems to change faster all the time. The current flatline of fishable sardine populations along the West Coast may be simply the bottom of one cycle’s downturn, or a catastrophic collapse. Scientists will be pressing on with studies to try and understand which one it is.
The California Coast—maybe not so much for sardines lately, but still a great place to visit! Get a beautiful wall map of that long coastal strip featuring regional highlights, made by National Geographic and available from Maps.com.
caption: Sardines—small and silvery.
source: Flickr: Rockyeda (CC by 2.0)
caption: They really like each other’s company.
source: Wikimedia Commons: TANAKA Juuyoh (CC by 2.0)
caption: Basic purse seine technology caught a lot more fish.
source: Wikimedia Commons: Historic American Engineering Record, Tim Whitely (Public domain)
caption: Womens’ flying fingers packed millions of tons of sardines into little cans on Monterey’s Cannery Row.
source: Wikimedia Commons: Jim G from Silicon Valley, CA, USA (CC by 2.0)
caption: The Monterey Bay Aquarium is a big driver of the economy on old Cannery Row.
source: Wikimedia Commons: Eigenes Werk (Public domain)
caption: Now sardines school over the heads of Monterey Bay Aquarium visitors.
source: Wikimedia Commons: Rhododendrites (CC by SA 4.0)