by the late John Barker (1934 - 1998)
The first question I am often asked is: what
is a marine collector?
I think this is best described by the Nobel prize winning author John Steinbeck when writing about Ed 'Doc' Ricketts of Cannery Row fame in which he wrote 'commercial fishermen harvest the sea to feed men's bodies and a marine collector harvests the sea to feed men's minds'.
In the last 36 years I have worked the seas for a living, the greatest
advance I have seen in practical marine biological education has been the
development of the new technology for maintaining marine aquaria, including
synthetic seawater, silicon sealing cement for sticking glass tanks together
and improvements in the air pumps and powerheads and filtration systems.
This has enabled marine aquaria to become established in classrooms and
Wet Thumb (Marine Aquaria)
Before this, marine researchers had to go to places like Millport Biological Station Isle of Cumbrae, and Plymouth Aquarium to observe and research on living marine specimens. Teachers and students were left with the prospect of observing a preserved lump of jelly, which once was a beautiful sea anemone.
Fortunately, this is a thing of the past, and it is now possible to enjoy the pulsating beauty of our seas and estuaries in your own home or laboratory.
I started diving in 1958 to study fish in their own environment. At
that time, the only diving equipment available was government-surplus.
My first two air bottles were 25 cubic feet each (we called them 'tadpoles')
and came from a Wellington bomber from World War II.
On the plus side, most of the sea bed, rocks and wrecks had never before been seen by human eyes. I was on call to recover lost nets, pots and anchors, and this was lucky for me as well as the local fishermen. The partnership that developed was to help a great deal in my collecting in the following years.
My very first order came from London Zoo
Aquarium. It was for live shore crabs to feed their Octopuses, Octopus
vulgaris. The octopuses came from Jersey, and because of their short
life span were renewed from the Channel Islands every year.
Brighton Aquarium placed further orders for live specimens to fill their many large tanks; beginning an association that I maintained for many years. In 1960, I was approached by a large biological supply house for a list of specimens I could supply. Their catalogue at the time consisted of marine specimens that were normally discarded by commercial fishermen as 'trash' and shovelled back into the sea. However, not all specimens could be obtained this way, and orders from specialist researchers were passed on to me. These orders were an opening to many wonderful people who drew me into their experiments and were instrumental in showing me the beautiful life that could be seen under a microscope.
All marine collection is subject to winds, temperature and tides. The
sea does not give up its secrets easily; days, weeks and even months of
searching rock pools and mud flats, and making trips on fishing boats only
makes me aware that there is still much to learn.
In the 1960's the Nuffield Foundation chose the animal subjects that were part of the studies under the school curriculum. On the list of subjects covered was cell embryology. A few of the common marine invertebrate species were ideal for the job as the eggs and sperm were large enough to be observed under a low powered microscope. The Common Starfish, Asterias rubens, was one of these. They were an abundant pest and could be obtained in large enough numbers reasonably easily. One problem was they only produced sperm and eggs in the early spring.
In the early 1970s the Parasitic Barnacle, Sacculina carcini,
was used as part of a G.C.E. 'A' Level examination course. This barnacle
was of interest because its life cycle involves sending out branching roots
throughout the crab's body, altering the sexual character: the males develop
secondary female characteristics, and presence of the parasite prevents
moulting (ecdysis). The parasite looks like a
yellow blob in the place under the abdominal flap where the eggs would
Sacculina infecting the Shore Crab, Carcinus maenas
There are numerous other rhizocephalan barnacles parasiticising other crustaceans, notably a species called Clistosaccus paguri infecting the Common Hermit Crab, Pagurus bernhardus, the genus Peltogaster infecting other hermit crabs and Drepanorchis neglecta, that infects spider crabs.
European Rhizocephalan Species List
Discussion Link 2
Discussion Link 3
Sacculina notes (from Crust-L)
The following year for the same 'A' level examination the specimen picked
was the Obelia hydroid, which is one of our most beautiful animals,
although the inexperienced layman could mistake it for a plant. Their miniature
white stolons creep over the surface of the kelp fronds and other brown
seaweeds, with stems and branches bearing the anemone-like feeding polyps
that need to be viewed under a hand lens.
About this time I started supplying live specimens for government agencies
engaged in research into marine pollution around our coasts. The principal
specimen wanted was the abundant Brown
Shrimp, Crangon crangon, which was also used by both B.P. and
Shell in their studies into the effects of gas embolism on North Sea divers.
Collecting is only part of the story. It is essential that specimens
arrive alive and in good condition. Plastic bags and supplementary
oxygen are used, but each transportation project needs to be thought out
initially. Without any bad luck, specimens will arrive safely.
So when you sit for an examination or biology lesson and look into a Petri dish full of live plankton or living worm cells, you can be sure that a marine collector made this possible.
The Log from the Sea of
Cortez by John Steinbeck
'It is usually found that only the little stuffy men object to what is called "popularization" of which they mean writing with a clarity understandable to one not familiar with the tricks and codes of the cult' (Chapter 10).
'It is difficult when watching the little beasts, not to trace human parallels. The greatest danger to a speculative biologist is an analogy. It is a pitfall to be avoided - the industry of a bee, the villainy of a snake .' (Chapter 11).
Biologist, April 1993, Vol. 14 No. 2, page 62.
Feature on Ed "Doc" Ricketts by J Humphreys.
An Introduction to the Biology of British Littoral Barnacles by
P. S. Rainbow, 1984.
Field Studies Council Offprint No. 161 Vol. 6 No. 1.
John Barker Obituary (includes links to other articles)