Ocean Biodiversity

What Matters?

At some point the only reason we really care about threats such as acidification, plastics, toxins or over-harvesting is either a) a direct threat to the health of our own species (humans), or b) the loss of biodiversity. Bio diversity is about both the abundance of individuals and richness of species on the planet. It is about both raw quantity of life, and the number of types. This is what makes a monoculture of exotic marine seaweed (e.g. Caulerpa taxifolia) in the Mediterranean, dramatically less important and valuable than a healthy coral reef. The reef may have less actual mass of life, but it is far richer in specific types of life…and therefore DNA. While we may not like to see marine debris in the water per se, it really matters if it either harms us, or diminishes life on earth.

An important new project is pulling together a global network of research teams to assess marine life at all levels and locations. This Global Ocean Census is an unprecedented resource for marine conservation.

The Threats

Marine life is under intense pressure on multiple fronts. These run the range of direct harvesting and killing to weakening effects that increase susceptibility to other threats. Most common on the list are:

  1. Over-harvesting- this is about decades, or centuries of catch beyond any sustainable rate. Marine life is harvested, numbers decrease and may in some cases collapse in the same manner that caused the extinction of the Passenger Pigeon in North America. This is especially difficult in the sea as we rarely have anywhere near the population data or transparency to know where things stand.
  2. Habitat destruction- often tied to the above, the physical deterioration of ocean habitats has a major and long lasting effect on the ability of the sea to support life. Trawl lines dragging like field plows, silting, land reclamation, sea wall construction, dynamite fishing- even ship wrecks in certain cases can dramatically undermine the ability to support life.
  3. Bio-pollution- this is principally about invasive species or long-term shifts in the ecosystem that make it extremely difficult for native species to survive. A great example is the explosion of long-spined sea urchins  (Diadema) in the Canary Islands. Likely arriving as stowaways in ship ballast, these urchins have exploded in local waters- literally consuming the once rich and productive algae community. We now see scoured lava rock amidst thousands of urchins and very few fish.
  4. Acidification is a direct threat to all marine life that builds carbonate shells- lobsters, clams, most plankton, coral… The higher pH frustrates formation of these calcium shells and therefore slows the growth of the animals.
  5. Temperature rises- Ocean temperature rises through either natural phenomenon like El Nino or climate change can knock out major chunks of local biodiversity. Ocean water changes have always occurred- its the sudden nature that is a problem here
  6. Pollution is a broad ranging threat that includes physical harm like an Albatross swallowing discarded toothbrushes, or a sea turtle in a net…all the way down to long term persistent chemicals. Toxin pollution is particularly disturbing and dangerous because it can be so hard to detect and understand. Rarely is this a simple case of “fish dying”… it can just as easily be a long-term reduction in fish health, smaller size, or reduced breeding success. While we are shocked about oil spills in the Gulf, few people understand how our own heavy doses of pharmaceuticals passing into local waters create perhaps much more serious threats to marine life.

These threats do not exist in isolation, but strongly interact- mostly in ways that we understand very poorly. A population of giant bluefin tuna that has been over harvested to 5% of its natural level (threat 1), that is swimming across seafloor subject to bottom trawling that looks like an Iowa farm field (threat 2), and is also carrying a high load of synthetic toxins is in a very, very bad place. Any one of these threats is a severe risk, together the odds of full extinction build. On top of this, natural disturbances and variation in the environment, e.g. El Nino, a volcano, or a disease outbreak…now become extinction threats. All natural populations oscillate in size- get small enough and they will inevitably bounce across the “zero” line and go extinct. Stress, on top of stress, on top of stress applied to small populations is a recipe for collapse.

Where we stand

Urchins in Canary Islands

Understanding the loss of biodiversity on land is tough enough. In the ocean our understanding of populations and even the number of species is weak. The less we know, the easier it is to delay action or make poor choices. Jeremy Jackson (see link below) has done important work putting together a rough picture of where we stand. The results are not good. Here a few indications:

  1. Large whales -95%
  2. Sirenia (manatees, Stellar Sea cows, dugongs) – 90%
  3. Sea birds -57%
  4. Sea Turtles -87%
  5. Oysters -91%
  6. Atlantic Cod -96%
  7. Oceanic White Tip shark -99%
  8. Live coral cover (Caribbean) 80-93%

We have also lost entire species, many of them large charismatic animals. Just a few (last year reported)

  1. Caribbean Monk seal (1952- picture below)
  2. Chinese River Dolphin (2006)
  3. North Atlantic Gray Whale (18th century)
  4. Stellar Sea Cow (18th century)
  5. Great Auk (19th century)

Our own limited visibility or historical perspective to these losses strongly limits the extent to which people feel compelled to act. In some cases, its simply hard to miss something you either never knew existed, or have virtually no reference marks to. This problem of “shifting baselines” makes it hard for us to understand what we have lost. My perception of the Florida Keys is really only valid to the 1980’s. I may therefore see some loss of large branching corals, fish and turtles. I cannot, however fully appreciate the complete disappearance of sawfish, giant mantas, crocodiles…or the fun of diving with lots of really big sharks  :) This typically makes talking to old maritime people really depressing.

Most marine conservationists are becoming increasingly concerned that we are headed for a major collapse of ocean biodiversity. This will will not only diminish our practical ocean resource, but greatly risk life on earth. We cannot imagine a collapse of life on 71% of the Earth’s surface not affecting all life on land- including us.

Here are just a few good overall articles and links that get to the core of the issue

The guiding principles in collecting data for an atlas of marine life

Interested in contributing to a database of at-sea sightings of seabirds? It’s easy to do and can take as little or as much time as you wish! Help support the research of Bird Life and get involved:

Numbers of species are of little use, unless there is a context to those numbers. To be useful, we need to know the effort that went into the counting. Effort is the time spent counting, and the area of the sea around the boat that was included in the count. It’s as important to record these accurately as it is to do the actual counts properly.

A second important point is to count everything – all species are equal, even if personal preferences do not inspire you to count gulls, or you really only want to count rare petrels. Related to this is counting when there is nothing visible – knowing that a certain patch of ocean had no birds in it is potentially very useful!

A third guideline is somewhat more technical. Counting birds that are flying is very different to counting birds that are settled on the water – moving birds cover big areas –termed ‘flux’ – and are thus more likely to enter the count area than birds that are sitting still. Treating them the same will introduce a bias towards birds that are flying. These counts should be kept completely separate. You can do simultaneous counts of flying and settled birds, in the same area/transect if you wish, but they must be recorded separately.

Last, and as important as any of the preceding principles, is DO NOT COUNT SHIP FOLLOWERS. This includes birds that come in from outside the count area during the count, specifically to investigate the boat. Many birds will also circle or do zigzags around a boat, making it very difficult to know what to do. If in doubt, leave it out.

There are circumstances in which a stern count of ship-followers is useful (it’s silly to pretend that those birds don’t exist…). The field sheet has capacity for you to specify that you’ve counted ship-followers (or birds that were following a nearby vessel), and that you counted from the stern. Once a day would be plenty for this sort of count.

In order to participate, you must be able to:

  • Identify reliably and with relative ease the large majority of the species present or likely to be encountered
  • Record your position and the time of your observations with a GPS
  • Submit your data online once you have completed the counts/cruise

Some general principles for counting seabirds at sea

  • Do not count ship-followers
  • Count from the bow (front) of the vessel or an elevated point towards the bow, and looking forwards
  • Aside from ship-followers, it is crucial to count every individual from each species – do not focus only rare birds or disregard really common species
  • Extreme rarities are not of particular interest for the purposes of this project

Counting seabirds

Although disregarding ship-followers is important, exactly what constitutes a ship-follower is not always clear. As a guideline, if the same individuals were there at the start and the end of the count, or longer, ignore them. If birds come more-or-less straight to the boat from a long distance away, ignore them. However, if birds arrive during the count, and you can reasonably assume that they would have intersected the count area even if the boat wasn’t attractive to them, you should include them.

Effort-based 10-minute and snapshot counts

There are three things to decide on before starting the count:

  1. Decide on the arc (90˚ or 180˚) from the bow that will be counted (this can vary between counts, as long as you record what you are doing for each count). Why would this change? If a low sun or strong reflections makes counting to one side difficult, or there is a sail or bulkhead or some other obstruction, or you are on your own count only to one side (90˚). With two observers you can reliably count 180°.
  2. Define the distance from the boat that you are counting – typically 50-300 m (this too can vary between counts, but again, record what you are doing for each count). Much further than 300 m and small species cannot be reliably identified and are very likely to go unnoticed, which would bias counts against smaller, less visible species, so don’t count beyond this distance.
  3. Decide on the time you will be counting – 10-minute transects is standard. You can do continuous transect counts of longer than 10 minutes, but bin your observations into 10-minute intervals. For example, if you make continuous observations of seabirds for a hour, it would be best to record GPS positions every 10 minutes and record the birds seen in this period, so that you can submit 6 x 10-minute cards. This data can easily be aggregated into a single hour-long transect, but the reverse, disaggregating an hour of counting, is not true.

The principle at stake is that you record effort (i.e. how much time was spent counting, and over what area were counts done). From that, regardless of the unit used (snapshot or 10-minute counts, over 50 m or 300 m) we can calculate distribution patterns and an index of abundance. It’s important for you to gauge the conditions that you are in and use the units that will provide the most data without risking data quality.

Walk through a bird count

  1. Note the date/time/position/weather conditions as outlined in the excel spreadsheet – but probably easiest to do this with a notebook.
  2. Record the start time and GPS position (either your own or from the ship’s system). You can do this in the bridge and then go to the count stations – the loss of accuracy is not a problem if you don’t start counting the second you note these details.
  3. Decide on the count area (arc around boat, side of boat, distance from boat) and record this
  4. Start counting the numbers of each species. You can use shorthands or keys for spp, e.g. BBA for Black-browed Albatross)
  5. Try to keep track of birds that come in to investigate the boat or are following
  6. After 10 minutes, end the count, note the time (if it’s a bit more or less than 10 minutes that’s OK, just record the actual time) and record the end GSP position
  7. Repeat from step 1
  8. Tally up the species’ numbers and enter the data electronically onto the excel spreadsheet each evening. If you delay capturing data, it can become overwhelming – too big a job and people end up not doing it…and so their effort is wasted.
  9. When you have internet access, logon to seabirds.saeon.ac.za, register and upload


  1. Do a ‘snapshot count’
  2. Note the basic date/time/weather conditions as outlined in the excel spreadsheet
  3. Record the time and GPS position
  4. Decide on the count area and record this
  5. Count each species, in turn, within the count area in a single moment in time. Don’t wait for lots of birds before doing the count, just go through the species as fast as you can, one- or a couple of species at a time.
  6. The start and end times and GSP points will be the same for a snapshot count, even though you will have moved a bit

Below is an example of how to capture information efficiently in your notebook:



Completing AS@S record cards

First up, it’s really important to check that you’ve got the latest version of the fieldsheet. Pls go to http://seabirds.saeon.ac.za/ and download the most recent version

Some golden rules:

  1. Do not add or remove columns or rows or change fields or resize things
  2. If you have more than 12 transects for a day, start a new sheet for transect 13+, and in the new sheet, specify that this is Card number 2, 3, etc. (Line 15)
  3. GPS data must be in Degrees and Decimal Minutes, and not Degrees, Minutes and Decimal Seconds. The required format to be inputted to the sheet is XX.123. Note that 3 decimal places is fine, >4 is overkill
  4. Use minus to denote southern or western hemispheres. E.g. 30˚S would be entered -30.00

Wind direction: give one value, the prevailing direction during the count

Strength: give one value, taken preferably from ship’s instruments (accounting for ship speed!), the prevailing speed during the count. This is a rough measure only, accuracy within 10 kn is fine

Cloud cover: rounded to the nearest 10%

Visibility – usually this will be +500

Swell height: give one value to the nearest 0.5 m or nearest 1 m – ask the officer on duty to give this to you unless you are experienced in estimating swell height


  1. Enter the count area (how far out from the boat you included birds
  2. Find the species that you are looking for in the ‘Species list’ field,
    find the corresponding number
    enter that in Column A, starting on Row 43.
  3. Then add the numbers of that species seen flying and on water in each transect. If none seen for a subsequent transect, leave blank


  1. …enter information under the yes/no column. This is only for presence/absence counts, which we hope you will not be doing. AS@S is designed to get count data (= abundance, the numbers of each species seen per transect).
  2. …do anything to the information in column B – this is a formula and should not be touched
  3. …change the sort order on the ‘Species list’ field. If you want to find a species, use the ‘find’ function on the page (ctrl+f)


  • Occasionally you should go to the stern of the vessel and count ship-followers. Make sure that for that transect’s meta-data, on Line 28 you record that ship followers were counted.
  • You can copy and paste fields. E.g. if the count position, arc, etc. are the same for each transect, complete once then just cut and paste for each following transect
  • If you cannot identify a bird down to species, use the group codes – e.g. an unidentified tern would be 10009