In 1888, the Tasmanian Parliament placed a 1-pound bounty on the world’s largest carnivorous marsupial – the thylacine (Thylacinus cynocephalus), better known as the Tasmanian tiger. The rapid subsequent extinction of the thylacine following the death of the last captive animal in 1936 is now regarded as an irreplaceable loss for humanity. Yet decisions leading to extinction continue to be made with little thought today, despite their negative impact on all future generations.

Extinctions in the marine realm typically go unnoticed. Several shallow-water handfish species, for example, have not been seen for decades, while the red handfish (Thymichthys politus) has apparently declined to about six individuals on one small reef. If these were mammals, birds, reptiles or amphibians then some attempt at population recovery would be underway. However, as marine fishes living out-of-sight, they have not been considered for the IUCN Red List, let alone for dollars allocated to facilitate survival.

This general lack of data on marine species extends to whole ecosystems; analysis of dated shell fragments indicates marine biodiversity can collapse catastrophically across regions with no public or scientific recognition. Recent studies also indicate substantial global losses of coral reefs, seagrass beds, mangroves, shellfish reefs, kelp forests, plankton production, and populations of large fishes, higher vertebrates and sea stars.

We believe that many such losses could have been avoided with better information. If the public could see the magnitude of harmful environmental change occurring underwater, then better resources and improved intervention would be demanded. Destructive practices such as bottom trawling, which would cause a public outcry if on land, would no longer be accepted.

To bridge the knowledge gap for marine species, we sought assistance from volunteers as the best means to undertake rigorous quantitative surveys of marine species across scales impossible for dedicated scientific teams to cover. We joined with recreational divers and marine conservation agencies in setting up the not-for-profit Reef Life Survey Foundation.

Initial efforts received pilot funding from the Australian Government through a Commonwealth Environment Research Facilities grant. Consequently, data collection efforts have been most concentrated around Australia, but with surveys also completed in 41 other countries. Unlike other marine citizen science organisations, we focused principally on data quality rather than wide public engagement. We headhunted the best and most enthusiastic volunteer divers (about 200 to date), trained them in scientific underwater survey methods, and then supported them in ongoing survey efforts, particularly in locations of greatest importance to management agencies.

While many researchers remain skeptical of the quality of data provided by citizen scientists, we found no detectable statistical difference between data generated by volunteers and professional biologists. As is also the case for keen birders, volunteers with sufficient enthusiasm to memorize whole field guides should be expected to produce data of the highest quality, provided they are given sufficient scientific direction, appropriate training and testing.

Our fundamental challenge at Reef Life Survey is to make the distribution and population trends of tens of thousands of marine species visible for the first time. While not there yet, RLS has achieved much in its 6-year lifetime. Divers have now completed surveys encompassing over 3,000 marine species at over 2,000 sites. On the scientific level, we have compiled abundance data for over 50 threatened marine species, improved impact assessments for threats related to climate change, invasive species, wild fishing, aquaculture, pollution and foreshore development, distinguished new global hotspots of marine biodiversity, and identified the most critical features needed for marine protected area efficacy. Our data have provided the basis for numerous scientific papers, including two in Nature – an outcome probably unprecedented for a grassroots organisation with no paid employees and minimalistic budget of around $50,000 per year. [Scientific American is part of the Nature Publishing Group.]

The ecological data and an accompanying Data Descriptor underlying the two Nature papers were released last week for general scientific application with the launch of the new open access publication Scientific Data. These data cover greater geographic and taxonomic scales than previous quantitative ecological datasets with standardised methods. For the initial release, the dataset contains 134,759 separate abundance counts of 5,746,960 individual fishes belonging to 2,367 taxa, from 1,879 sites in coral and rocky reefs distributed worldwide. The data will be updated through the future, offering new opportunities to assess broad-scale spatial patterns in community structure, and as a basis for modelling studies and testing ecological hypotheses. The Data Descriptor in Scientific Data provides a detailed description of the data, enabling discovery, search and reuse of the underlying primary datasets, and linking to the resulting data files which are stored in the public repository figshare and on the Reef Life Survey website.

The decision to release the data was not a difficult one, regardless of potential costs seen by many field ecologists in distributing raw data. These include the extra effort required to prepare and format data to a standard suitable for public presentation, and potential flaws in the data that may be identified when scrutinised closely. Given the scale of the Reef Life Survey dataset, some transcription and identification errors are inevitable. However, we would prefer to hear of such errors and update the dataset accordingly, rather than keep them obscured. Through various quality checks, we are confident that the proportion of such errors is low and any effect on broad-scale analyses would be trivial.

For many data gatherers, the biggest apparent cost when publicly releasing raw data is forfeiture of repayment for the personal effort expended. We certainly recognize this concern, noting that significant time spent in the field by young ecologists is rarely the most effective means to build a research career when compared to spending similar time statistical modelling. Professional recognition, in ecology at least, is heavily weighted towards ideas. In this, we share the collective frustration of field ecologists when modellers demand access to data, as if months or years gathering data in trying field conditions are considered to be no different than obtaining data from a mechanical logger.

Scientific recognition of the importance of comprehensive data is, however, increasing. Leading journals such as Nature (with Scientific Data) and Ecology now recognise that some datasets are of equivalent importance to theory and warrant publication status in their own right. Theoreticians will also hopefully recognise the importance of collaborating with data providers to better understand idiosyncrasies when interpreting the natural world.

For the Reef Life Survey dataset, public release is fundamental to its conservation aims and values and the reason that volunteer divers contribute so generously to its development and expansion. In contrast to the limited life of most research projects, the value of a quantitative set of standardized data on marine biodiversity will increase with every year as an irreplaceable scientific benchmark against which changes in ecosystem condition can be assessed. Divers commit so enthusiastically to Reef Life Survey because they see their efforts contributing in a real way to improved management, with a legacy that will endure forever.