Fishing about and about fishing

 

A wise man said once: a people without history is a people without future. I'd paraphrase: science that ignores former studies and historical data cannot produce reliable predictions. This is also true for all those who attribute to fishing being the single or predominant cause for all trends and variations in fish populations. 

 

I’m often wondering how references quoted in so many learned articles on fisheries related subjects reach only 5 or 10 year back. Fisheries science has started developing towards the ascent of the last century and has flourished throughout its mid. Long term data series and historical information on fish yields fluctuations and on climatic variations, as well as biological/ecological knowledge on life history and behaviour of the main commercial species have been long available. Unfortunately, this cache of wisdom has been rarely consulted by the model-addicted fishery science and fisheries management in most Western countries. 

 

As Einar Hjorleifsson, a noted Icelandic fishery scientist recently posted on the FISHFOLK Internet List: “Too few of us, stock assessment biologists, check the old books, looking at how things were in the old days. Sometimes (I) wonder if I should not switch totally into the history of fisheries rather than trying to stay in the predictive world. E.g. the likelihood of a comeback of cod in Greenland can in part be judged on (the basis of) the available historical archives. History in one sense repeats itself. At minimum history is never constant“. Hear, hear!

 

In October, I received a long-awaited book by L.B. Klyashtorin and A.A. Lyubushin, recently published in Russian by the Moscow VNIRO (the All-Russian Scientific Institute for Fisheries and Oceanography). Its title is “Cyclic Climate Changes and Fish Productivity”.  The authors show that multi-annual and multi-decadal variations in fish yields have been documented far back.

 

In Japan, there's a 400-year history of fluctuating abundance of sardine with a 50-70 years periodicity and consequent boom-and-bust coastal economy. There's also written documentation for over 1,000-year history of rises and falls of the herring fishery in the Skagerrak, first analysed in 1880 by Ljuingman, who found that "rich" and "poor" periods lasted each for some 55 years, with the whole cycles lasting 110-120 years each. In parallel, more recent studies show 60-70-year cyclic climate fluctuations, both global and hemispheric; Greenland ice cores analysis extends this periodicity to at least 1,500 years back, while more recent studies associate the “herring cycles” with long-term meteorological and oceanographic processes.  The book proceeds with many examples of how such variations are associated with climatic fluctuations.

 

Up to 100-year records show 55-60 year oscillations of populations of the most important Atlantic and Pacific commercial fish species that form about 50% of total landings in their respective areas: Atlantic and Pacific herring, Atlantic cod, European, South African, Peruvian, Japanese and Californian sardine, South African and Peruvian anchovy, Pacific salmon, Alaska pollock, Chilean jack mackerel and some others. 

 

Time series of several environmental indicators ranging back to 1,500 years ago suggested similar periodicity. Off California, for the last 1,600 years sardine and anchovy interchange every 50 to 70 years, and there’s a significant coherency of climate and long-term stock dynamics of Atlantic-Scandinavian herring and Arcto-Norwegian cod with time series of 85 and 93 years, respectively. 

 

Graphs in the 8-chapters, 334 p. book, illustrate how much of the past and present overfishing-collapses of stocks are "bottoms" of historic fluctuations, which the authors correlate with climatic cycles.

 

In August 2002, I wrote here that the late 20th century recovery of the Icelandic herring fishery was not owing to the introduction of ITQ system, although two local economists, who claimed that thanks to the ITQs at the end of the 20th century occurred an almost ten-fold increase of herring catches, and its biomass was greater than at any time since the 1950s.   This was a lame claim, for the herring’s recovery was rather due to a favourable shift from a bust period towards an upward trend of a cycle, which fitted the climate-fisheries fluctuation pattern, as outlined some years before in L.B. Klyashtorin's FAO Fish.Tech.Pap . (410). 

 

Klyashtorin indicates that the Atlantic-herring biomass projection based on climate index shows a downward trend in the nineteen fifties and an upward one in the 1970s. The Icelandic economists simply took a piggy-back ride on an ignored natural fluctuation. But, quota system or not, the herring will slide again on the downward slope of its climate-forced cycle.

The Russians are not alone. I just came across a paper published in Journal of Climate, Volume 19, Issue 20 (October 2006) by P.Lehodey and 12 other scientists from France, the U.K., Canada, S.Africa, Mexico, Norway, Germany and the USA, entitled “Climate Variability, Fish and Fisheries”. It says approximately the same thing as the Russian book, and concludes with a call for collaborative work between climatologists, oceanographers, and fisheries scientists to resolve some of the outstanding problems in the management of fisheries.

One can only conclude that ignoring regime shifts and other climatic fluctuations can lead to misunderstanding of the role of fishing on marine fish populations and their ecosystems, and consequently to their mismanagement. While overfishing is a fact in many cases, it alone doesn’t explain the boom-and-bust fishing reality. Neither can management steps “recover” fish stocks to their former state, if those are on a downward section of their natural cycle. 

The 2005 Russian book represents the most authoritative and-up-to-date analysis of the effect of climatic and planetary factors on fishery resources, in particular, and fishery ecosystems, in general.  To make it accessible to the rest of the world, it should soonest be translated to English, for It would open the eyes of fishery scientists and managers to the bitter truth that they cannot “recover” a stock, which is on the downward slope of its multi-annual variation. Neither should they depress fishing of a stock that’s half way up on the upwards slope of its cycle. Hopefully, it will help in so much needed overhauling of the prevailing fisheries science-cum-management system.