Life in the World's Oceans

Diversity, Distribution, and Abundance

Alasdair McIntyre

• Publisher: Wiley-Blackwell
• Year: 2011
• ISBN:
  9781444348095
• Edition: 1
• Topic: Tecnología e ingeniería
• Subtopic: Pesca y acuicultura

Life in the World's Oceans: Diversity, Abundance and Distribution is a true landmark publication.

Comprising the synthesis and analysis of the results of the Census of Marine Life this most important book brings together the work of around 2000 scientists from 80 nations around the globe.

The book is broadly divided into four sections, covering oceans past, oceans present, oceans future and a final section covering the utilisation of the data which has been gathered, and the coordination and communication of the results.

Edited by Professor Alasdair Mcintyre, Marine Life is a book which should find a place on the shelves of all marine scientists, ecologists, conservation biologists, oceanographers, fisheries scientists and environmental biologists. All universities and research establishments where biological, earth and fisheries science are studied and taught should have copies of this essential book on their shelves.

• A true landmark publication
• One of the most important marine science books ever published
• Contributions from many world leading researchers
• Synthesis of a huge amount of important data
• Represents the culmination of 10 years' research by 2000 scientists from 80 countries

PART I

Oceans Past

Chapter 1

Marine Animal Populations: A New Look Back in Time

Poul Holm¹, Anne Husum Marboe², Bo Poulsen², Brian R. MacKenzie³

1.1 Introduction

Since around 1980, marine-capture fisheries have stagnated at around 90 million tonnes per year, despite massive technological investments and the opening up of distant and deep waters in the Southern hemisphere. The oceans will simply not yield more. In fact catches are of increasingly smaller fish of less economic value and total returns on investments are dwindling. On a global scale, capture fisheries are doomed to be of less importance as a source of protein to a growing human population, while the fishing pressure remains extremely high. There is no sign that the rise of aquaculture in recent decades has eased the pressure on wild resources. The fisheries crisis is part of a general health alert for the oceans. Marine habitats are under severe pressure as a side effect of trawling and directly by dredging, harbor development, the concretization of large stretches of coastline, and especially from eutrophication caused by both agriculture and aquaculture (Lotze & Worm 2009).

But what is the scale of change? What used to be in the sea before humans began impacting marine ecosystems and habitats? What are the major long-term effects of human extractions of marine life? Are the impacts of recent or ancient origin? In other words what are the baselines against which we may evaluate some of the findings of the Census of Marine Life field projects by 2010? Can we talk with confidence about the history of the sea, can we gauge how much has changed – and with what consequences to us humans? This was the grand challenge that was put to the scientific community some ten years ago when the Census endorsed the History of Marine Animal Populations (HMAP) Project to assess and explain the history of diversity, distribution, and abundance of marine life (Box 1.1). Although the history of marine animal populations has long been one of the great unknowns, recent advances in scientific and historical methodology and new applications of existing methodology have enabled the HMAP teams to expand the realm of the known and the knowable (Holm 2002).

The analytical framework of HMAP embraces two basic premises, one concerning data, one concerning methodology. First, much of what we can know about the history of the oceans will be in the “human edges” of the ocean, those in the near shore and coastal zone. This is where humans most directly interacted with the sea in the past and therefore most historical records relate to these activities. However, in both the human edges and in the central oceanic waters there have been extensive fisheries for larger organisms, and the value of the organisms encouraged the creation and maintenance of archival material. As HMAP has evolved, new and unexpected data sources have been discovered, and we know now that vast repositories are still untapped.

Second, historical analysis must combine with ecological analysis in a truly interdisciplinary way. New insights are due to the introduction of established marine science methodology to historical data, notably standardizing fishing effort (catch per unit effort) (see, for example, Poulsen & Holm 2007), biodiversity counts of historical fisheries (Lotze et al. 2005), statistical modeling of historical data (Klaer 2005; Rosenberg et al. 2005), etc. Perhaps the most surprising results have come simply from the data– mining effort in itself, which has revealed a wealth of documentation for historical fisheries previously neglected by historians. Examples of this are of catch records spanning two to four centuries (Holm & Bager 2001; Starkey & Haines 2001; Lajus et al. 2005; B. Poulsen 2010). HMAP has provided inspiration to glean important information from surprising and sometimes unlikely sources such as restaurant menus (Jones 2008) and snapshots of sports fishermen’ s catches (McClenachan 2009). Archaeological techniques have been deployed in conjunction with historical methods and stable isotope analysis to explore the character and composition of fish catches during early medieval times (Barrett et al. 2008), and many more unconventional approaches could be cited.

Box 1.1

Regional and Species Focus of HMAP

HMAP is a collaborative effort by some 100 researchers around the globe participating in several region- or species-specific research teams. Twelve are based on marine areas, as follows: southeast Australian Shelf; New Zealand Shelf; Caribbean Sea; Gulf of Maine; Newfoundland and Grand Banks; Baltic Sea; North Sea; Mediterranean Sea; Black Sea; White and Barents Seas; southwest African Shelf; and the biodiversity of nearshore waters. Three case studies focus on the following species: whales, cod, and mollusks and one on Northern European fish bone assemblages. In addition, several smaller case studies have been undertaken in areas such as the Philippine Seas, the Wadden Sea, and the seas of Indonesia and northern Australia.

In many ways the complicated interplay between man and nature calls for a new type of historical research. Science is a challenge to historians who have had little statistics, not to speak of modeling, as part of their training. Historical source-criticism is a challenge to scientists who are used to hard data. Although academic history through the 1990s concentrated on narrative and deconstructing skills, environmental history also demands command of both statistical and scientific methods.

The need for historians and scientists to work together is not uncontroversial. Some historians assert that history would carry no lessons for the future as events are never repeated in exactly the same form. Some scientists doubt the validity of historical data that are by definition “dirty data” in the sense that they are relics of events, not signals of a recurrent phenomenon, or experiment, established in a controlled environment such as a laboratory. In the early part of the Census some skeptics doubted the role of environmental history in this mega-science program. Would such a program not by default perpetuate the divide between science and the humanities? Indeed, as one critic put it, would the marriage of history and science not lead to scientists simply appropriating data for their own use (Van Sittert 2005)?

HMAP is founded on the belief that the divide between history and science needs to be bridged. History will never repeat itself but like the child learns to walk based on experience so does society base decisions and preferences on past experience. The historian may indeed detect trends and patterns of behavior behind diverse and unique events. Emphatic statements on the validity of and need for the HMAP approach have been made by some historians (Anderson 2006; Bolster 2006, 2008). Conversely, if we reduce science to controlled experiments we would never understand the fundamental principles of natural selection. More urgently, contemporary concerns about global climate change, biodiversity, and scarcity of resources are based on perceived changes of nature and availability of natural resources. Therefore, the history of nature itself – and the dependency and impact of human society on nature – has become a prime social, economic, and political concern, and scientists and historians need to address these very real issues, or decisions will be based on assumptions.

Environmental historians do not have to become biologists, nor do biologists need to become historians. However, we do need to understand enough of each other’ s language to exchange information and insight. Our experience of dialogue across the current divide of humanities and science has led to the emergence of the new scientific community of marine environmental history and historical marine ecology (Box 1.2).

Box 1.2

HMAP Outreach

HMAP has paved the way to establishing several new academic posts and trained graduate students at several participating universities. Marine environmental history and historical ecology is now taught at the undergraduate and doctoral level at universities in the USA (New Hampshire, Connecticut, Old Dominion (Virginia), Scripps Institution of Oceanography (California)), in Canada (Dalhousie (Halifax), Simon Fraser (Vancouver)), in Europe (Roskilde (Denmark), Hull (UK), Trinity College Dublin (Ireland), Södertörn (Sweden), Tromsø (Norway), Bremen (Germany), the St. Petersburg State University (Russia)), and in Australia (Murdoch (Perth)).

A total of 205 books and papers have been published up to September 2009 and the HMAP database (www.hull.ac.uk/hmap) holds approximately 350,000 records, with some 80% available through OBIS (see Chapter 17). By late 2010, it is anticipated that up to 1,000,000 records will be available on the HMAP website. With such a massive output it is obvious that any overview of major findings will be highly selective. In the following, we shall establish first the state of knowledge before the beginning of the Census in 2000, then focus on some of the highlights from the HMAP case studies. By way of conclusion, the chapter closes with observations on what we do not know, how we may get to know it, and why some questions will remain unanswerable.

1.2 The Background

Marine ecology was born as a scientific discipline by the late nineteenth century and derived often from a strong interest in the fisheries (Smith 1994). The question of human impact on marine life was central not only from the perspective of economic interest (for example where are the fish and how do we catch them?) but from the perspective of human impact (for example what is the effect of extracting thousands of tonnes of fish and what damage to the seabed may be caused by certain fishing technologies?).

The central question of the possibility of overfishing was raised at the World Fisheries Exhibition in London in 1884 and drew two opposing answers. One came from one of the leading scientific figures of the day, Thomas Henry Huxley, who concluded that “… probably all the great fisheries are inexhaustible; that is to say that nothing we do seriously affects the number of fish” (Huxley 1883). A more conservative note was struck by Ray Lankester, a young professor of zoology, that “the thousands of apparently superfluous young produced by fishes are not really superfluous, but have a perfectly definite place in the complex interactions of the living beings within their area” (Lankester 1890). To the credit of both men and to the academic community at the time the question of the possibility of harmful overfishing was put to the test. A rigorous series of trawls were undertaken in Scottish waters and were at first understood to support Huxley’ s view. In 1900, however, the tests were reanalyzed and further data from observations of commercial operations out of Grimsby were scrutinized. The conclusion by Walter Garstang was clear and had far-reaching implications: “… the rate at which sea fishes reproduce and grow is no longer sufficient to enable them to keep pace with the increasing rate of capture. In other words, the bottom fisheries are undergoing a process of exhaustion” (Garstang 1900; cf. Smith 1994, pp. 106–108).

This fundamental observation is at the heart of the question of human interaction with the oceans. Garstang established beyond scientific doubt that extractions might have an impact. Through the twentieth century, fisheries science concentrated on identifying optimal sustainable yields that would not extract more from the sea than marine life would be able to replenish. By the second half of the century, fisheries science had become highly sophisticated, equipped with research ships and advanced computer models. Scientific organizations like ICES, the International Council for the Exploration of the Sea, established in 1902 for the North Atlantic (Rozwadowski 2002), and a plethora of similar organizations for other ocean realms and migratory species, struggled to get both the science right and deliver management advice. Characteristically, fisheries studies were often based on very short time-series, although scientists were aware of long-term changes. The centennial variability of the Swedish Bohuslen herring fisheries provided a textbook example that fisheries may change dramatically over the long term. Nevertheless, perhaps because of the strong link with policy advice, the focus of cutting-edge science tended to be on recent data often obtained with new equipment, which by the very fact obliterated longerterm perceptions. Data observations over the long term were often discontinued for financial reasons. Few observation series are maintained today that span more than a few decades, the best-known of which is the Continuous Plank-ton Data Recorder survey, which has been maintained for the North Atlantic and North Sea since 1931 (Continuous Plankton Recorder 2009).

Marine science separated from fisheries science through the twentieth century as scientists developed the concept of ecology as a study of biodiversity, food webs, and biological processes and functions as a separate line of inquiry. To ecologists the ultimate question is not what is in nature for us, the humans, but how do we understand nature on its own, with the humans left out. Interest focused on biodiversity, the awesome richness of nature, and the exhilaration of understanding intricate and ingenious life-forms. By the 1960s ecologists did realize that ecosystems rarely remain steady for long, and “fluctuations lie in the very essence of the ecosystems and of every one of the … populations” (Margalef 1960 cited in Smith 1994, p. 33). Marine ecologists, however, perceived little or no need for history, with the exception of a few studies of correlations between contemporary and historical observations of animal populations and key environmental variables (Cushing 1982; Alheit & Hagen 1997; Southward 1995). Things were about to change, however, as demonstrated in a programmatic statement on the need to determine the historic structure of exploited ecosystems (Pitcher & Pauly 1998).

In a seminal study of the Caribbean ecosystem, Jeremy Jackson criticized ecologists for assuming that the natural or original condition is equal to the first scientific description of a phenomenon (Jackson 1997). Jackson turned to a concept developed a few years earlier by a fisheries scientist, Daniel Pauly, for a diagnosis of the problem, which was termed the shifting baseline syndrome (Pauly 1995). Pauly observed that equilibrium or steady-state models are based on a given dataset, often established by scientists within the past generation. However, what happens to equilibrium if older data are introduced? We cannot know from recent information the extent of the losses that have happened.

Jeremy Jackson, himself an American ecologist, son of a historian, used the British Empire trade statistics of the eighteenth century to learn of the trade in turtles from the Caribbean. When working out the numbers – hundreds of thousands of turtles killed in a single year – he realized that the ecosystem of the Caribbean would have looked very different to what conservation biologists supposed based on information from the past couple of decades (Jackson 1997). The lesson to ecologists of Jackson’ s historical analysis of Caribbean coral reefs was that textbook descriptions of reef ecosystems were limited by the fact that the systematic description by modern biology only began in the 1950s.

Jackson put the case squarely to the ecologists: they needed to turn to historical sources and rediscover the world.

Another influential development in reinstating the historical dimension in science was the development of paleoecology and archaeoichthyology in the past 30–40 years. The preservation of fish scales in anoxic bottom sediments off the coast of California provided scientists the opportunity to reconstruct 1,600 years of pelagic abundances (Soutar 1967; Baumgartner et al. 1992; Francis et al. 2001). The field of paleozoology provided one of the first clear examples of scientists working across the cultural divides of historical and ecological analysis. Analysis of fish remains from archaeological sites provided a possible avenue to understanding biodiversity distribution and abundance. In the 1960s the Swedish scientist H ö glund analyzed fish bones excavated from eighteenth century production sites for train oil and found that the Bohuslen herring was spent (namely post-spawning) herring from the sub-population of the North Sea Buchan herring (H ö glund 1972). In the 1990s studies clearly demonstrated the potential of bringing the different lines of inquiry together (Muniz 1996; Enghoff 1999).

What about the historians? Environmental history has been a growth field in the USA since the 1970s and a little later in Europe, Asia, and Australia, and indeed, despite institutional problems, also in South America and Africa. However, the focus by leading American environmental historians was strongly on human agency and perception whereas ecological factors were rarely allowed to play an explanatory role. On top of that, the discipline developed out of a strongly narrative and qualitative approach to history that had little rapport with the quantitative approach of ecologists. The focus was very much on frontier cultures of the prairies, bushlands, savannahs, and steppes, whereas the oceans were strangely disregarded. Maritime historians on the other hand were firmly embedded in economic and social history with a preoccupation for naval and shipping matters and had little regard for environmental issues. The few fisheries historians often found their subject of marginal interest to mainstream historians and a bit fuzzy as the ecological context of fishing could not be disregarded but on the other hand was little understood. The few substantial overviews of fisheries published generally adopted a national, regional, or port perspective whereas environmental considerations were accidental at best. It was only as late as 1995 that the North Atlantic Fisheries History Association was established, but even then few papers dealt with the impact of harvesting on the seas (Holm & Starkey 1995 – 99).

Signs were in the air, however, that things were about to change. In the North Atlantic, Holm & Starkey (1998) reported the results of a workshop titled “Fishing Matters” that brought together his...

Table of contents

• Cover
• Title page
• Series page
• Copyright
• Foreword
• Introduction
• Acknowledgment
• Contributors
• The Scientific Steering Committee of the Census of Marine Life
• PART I: Oceans Past
• PART II: Oceans Present - Geographic Realms
• PART III: Oceans Present - Global Distributions
• PART IV: Oceans Present - Animal Movements
• PART V: Oceans Future
• PART VI: Using the Data
• Index